MCAT ExamKrackers Science Study Guides
MCAT ExamKrackers Science Study Guides
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Date Created: 01/30/14
EXAMKRACKERS AUDIO OSMOSIS ORGANIC CHEMISTRY Lewis Dot Structures 0 Count total number of valence e for all 0 Two electronsbond 0 Arrange remaining around atoms to satisfy around octet rule Breaking octet rule 0 Atoms with more than octet of electrons must come from third period on periodic table since vacant d orbitals are required 0 Sulfur phosphorus o Boron beryllium may contain less than an octet Valence number of bonds an atom normally makes 0 Carbon tetravalent o Nitrogentrivalent 0 Oxygen divalent o Halogens monovalent Formal charge number of electrons on neutral atom minus how many electrons that atom has in the Lewis structure Fischer projection vertical lines are directed into plane of the page Dashed lines go into page Solid wedges come out of the page Newman projection staring down length of bond typically between 2 carbons Amides carbonyl compound 0 Bonded to a nitrogen Amine nitrogen bonded to carbons andor nitrogens Gemdihalide a ccompound with 2 halogens attached to the same carbon Single halogens attached to adjacent carbons vicdihalide Alcohol that has donated a proton alkoxide ion Carbon triple bonded to nitrogen nitrile Carboncarbon double bond attached to something else vinyl NO nitroso NO2 nitro Meth eth prop but pent hex hept oct non dec Npropyl and nbutyl are just NORMAL straight chains with 34 carbons Secbutyl and tertbutyl and both refer to first carbon on chain 0 Sec stands for secondary as in the first carbon on the chain is secondary o Tert stands for tertiary meaning attached to 3 other carbons Isobutyl shaped like a T with first carbona s primary Isopropyl shaped like a T with first carbon as secondary To name look for longest carbon chain with most substituents Carbon with double or triple bonds should get lowest number possible Order substituents alphabetically ignoring number prefixes Electrons are at their lowest energy level when they are closest to the nuclei Bond is formed when a pair of electrons can lower their energy by positioning themselves between the two nuclei Sigma bond electrons spend the msot time between the nuclei Pi bond electrons must occupy space above and beyond sigma bond because there is no room between the nuclei Sulfurgt phosphorusgt and silicon are highly unlikely to form double and triple bonds in this order Electrons in pi bond must have higher energy than sigma electrons Pi bond is more reactive than sigma bon Overall bond length of a double bond is shorter than a single bond and bond strentth is greater Bond strength and length are inversely related Orbital in s subshell has lower energy than orbital in p subshell Neutral carbon has 4 valance electrons 2 in s subshell and l in p subshell 0 Higher energy p orbitals combine with lower energy s orbitals combine to form a molecular orbital between the two Hybridized orbitals on oxygen in water sp3 Hydrogens in water s because hydrogen has only 1 valence electron 0 Carbon in 2 single bonds and 1 double bond sp2 Sp2 120 degrees Sp3 1095 degrees Lone pairs and ring structures can deform angles slightly Water bonds 1045 degree angles instead of 1095 expected angle Sp linear Sp2 trigonal planar Sp3 tetrahedralpyramidal or bent o Sp3 of ammonia pyramidal o Sp3 of methane tetrahedral Resonance occurs with delocalized electrons Molecule does not resonate back and foth o Weighted average of resonance structures 0 Actual benzene has no double bonds but they are partial double bonded in character as in the single bonds are shorter and stronger in character but still considered single bonds 0 Resonance stabilizes a molecule Actual molecule is most stable than any of the resonance structures 4 rules for resonance 0 Atoms must not be moved only electrons 0 Number of unpaired ele ctrons must remain constant 0 Resonance atoms must lie ins ame geometric plane This is why benzene is a at molecule 0 Only proper lewis structures can be resonance structures Ring structures must satisfy Huckel s rule ONLY RING STRUCTURES Even though most molecules are neutral they can have separation of charge 0 Center of charge of negatively charged electrons may not COINCIDE with center of charge of positively charged nuclei 0 A dipole moment is created when this happens Dipole moment is pointing fromn center of positive to center of negative charge 0 Mu d between centers of chargetotal charge q of either center NOT CHARGE OF BOTH CENTERS Strongest kind of dipoledipole force is hydrogen bond 0 Hydrogen bonds are still far WEAKER bonds 0 Dipole moment is a vector 0 Dipole moments of bond may add up to 0 and thus cancel Thus a molecule with polar bonds dipole moments may not be polar overall Momentary dipoles only forces that cause nonpolar molecules to be attracted to one another 0 London Dispersion forces 0 Van der Waals forces I This may also refer to ALL types of dipole forces I Must look at context in which it is used 0 O Iso same Isomers have same molecular formula but are not same compound Newman projection with anti gauche eclipsed 0 Anti has two largest groups as far as possible as possible 0 Gauche groups exactly opposite are NOT the biggest groups Different compounds with same molecular formula are isomers If isomers have different bondbond connections they are structural isomers 0 Two dichlorobutanes but one has both halogens attached to first carbon whereas the other has one attached to each carbon 0 Obviously same molecular formula but different connections 0 Have different molecular and physical properties Chirality almost always have 4 different substituents attached Absolute configurations 0 Number substituents from highest to lowest priority based upon atomic weight o Counterclockwise S o Clockwise R o If one carbon is double bonded to an oxygen it is considered to be bonded to two oxygens for the purpose of priority assignment Relative configuration requires comparison of 2 chiral molecules 0 If they have same relative configuration it means similar substituents are in same place in terms of their chiral centers 0 Relevant in terms of snl and sn2 reactions in which half of the configurations are retained and completely inverted respectively Chiral compounds rotate plane polarized light 0 When photon strikes a molecule it refracts rotating the electric field When same photon strikes mirror image it rotates back exactly the same distance Mirror image cancels out the rotation Achiral molecules are their own mirror image and thus mirror images cannot be separated from compound so these never have opportunity to rotate planepolarized light Enantiomers rotate in same degree but in same directions Clockwise d Counterclockwise both of tehse l are called observed rotation 0 Specific rotation observed rotation with parameters such as concentration etc Light is an electromagnetic wave where each photon creates an electric field and a magnetic field perpendicular to each other and to direction of photon movement Enantiomers and diastereomers are the two types of stereoisomers Enantiomers have SAME physical amp chemical properties except way they rotate plane polarized light and the way they react to other chiral compounds Racemic mixture mixture of enantiomers Resolution separating a racemic mixtures Cistrans isomers are diastereomers Occurs when two atoms are connected by a bond that cannot rotate about its axis and 2 carbons have an identical substituent Cis isomers have dipole moments HIGHER BOILING POINTS HIGHER HEATS OF COMBUSTION Trans isomers more symmetrical AND TEND TO HAVE HIGH MELTING POINTS E HIGHEST PRIORITY ATOMS ARE ON DIFFERENT SIDES Z HIGHEST PRIORITY ATOMS ARE ON SAME SIDE In labeling EZ divide the double bond vertically and label and then compare the highest priority groups of each one horizontally Meso compounds more than one chiral carbon and an internal plane of symmetry 0 Cannot have enantiomers Methyl carbon is attached to 3 hydrogens Physical properties of alkanes o The more carbons the higher the meltingboiling point 0 True waxes are ether 0 Branching increases the melting point but decrease the boiling point I This is because breanching chains are more compact which weakens van der Waals forces and lowers the boiling point while same compound structure allows same alkane to pack easily and form a solid 0 Alkanes are less dense than water Specific gravity 07 insoluble in water Think of oil spill 0 When alkane is attached to polar group the polarity and solubility go down Ring strain is 0 for cyclohexane OOO OOO Effects of ring strain can be seen using a bomb calorimeter With ring strain will exhibit a high heat of combustion per CH2 group when placed here Ring strain gives molecule higher energyCH2 group Cyclohexane o Exists as several conformers same molecular formula and connectivityb ut different orientation 0 Conformers are chair half chair twist and boat 0 Important ones to know are chair and boat 0 Twist is lower in energy than boat 0 Boat is in higher energy than chair conformation o For hydrogen neither axialequatorial is favored from an energy position Alkanes are not very reactive 0 Do not react with strong acidsbases o If add enough energy they will react violently with oxygen Combustion a reaction with oxygen Energy of activation of combustion with alkanes is very high but once the reaction begins the reaction is exothermic enough to be selfperpetuating 0 Products are water and carbon dioxide 0 Radical reaction 0 Exothermic high activation energy 12 does not typically react with alkanes to form alkyl halides Halogenation requires heat or light to initiate reaction 0 Chain reaction I Halogen molecule alone will not react with alkane Halogen ishomolytically cleaved this creates 2 radicals I The unpaired radical is neutral but is highly reactive and is very unstable I Never exists in high concentration I Radical reaction initiation propagation termination 0 Net reaction is sum of initiation and propagation I l halogen l alkane 1 alkyl halide 1 hydrogen halide 0 Termination steps are important when there are few reactants available 0 Usually results in mixed products like multi halogenated alkyol halides and alkyl halides halogenated at different carbons o Exothermic 0 Reactivity of alkyl radicals is same as reactivity of carbocations Methyl are most reactive o Iodine is least reactive halogen and most selective o Bromine prefers to add tertiary while uorine reacts with any primary or secondary or tertiary Alkenes 0 Pi bond occupies space above and below sigma bond 0 Inductively electronwithdrawing 0 Greater molecular weight higher the boiling point and density Slightly more soluble in water than alknes not very soluble in water 0 Typically oat on water as they are less dense o Easily dissolve in solvents with low polarity Synthesizing alkenes 0 Via elimination reaction 0 E1 or E2 mechanism 0 El occurs in two steps and E2 occurs in one step E2 reaction 0 E2 dehydrohalogenation 0 Strong bulky base is added to alkyl halide I Base is too bulky to act as nucleophile I As a base it must accept a proton Dehydration of alcohol 0 El reaction IMPORTANT Add a hot concentrated acid to an alcohol Has a carbocation intermediate Leaves an alkene Acid is actually a catalyst here 0 Maj or product is most substituted alkene Catalytic hydrogenation 0 Two hydrogens are added one to each carbon in double bond 0 SYN addition hydrogens add to same side of alkene o Erythro similar functional groups are on same side in a fischer projection OOOOO Threo func gropus on different sides on Fischer project Catalyst is heterogeneous Exothermic reaction CATALYST DOES NOT CHANGE THERMODYNAMICS OFA REACTIONENDOEXO o Hydrogenation of an alkyne makes an alkene Oxidation of an alkene 0 Adding ozone O3 which is high energy 0 Cleaves through double bond leaving 2 separate molecules with carbonyl groups 0 Permanganate with HEAT also splits alkene in two I If aldehydes is formed it is oxidized to carboxylic acid I Without heat permanganate followed by a base makes a glycol in hydroxylation o Glycol diol o OsO4 also produces a glycol when added to alkene Electrophilic addition 0 Electrophile will usually have a positive or partial positive charge 0 Add to alknees by attacking pi bond electron cloud 0 Add via Markovnikov s rule I Electrophiles hydrogen ions add to elast substituted carbon of alkene this is because it forms the most stable carbocation 0 Whenever a carbocation is formed a skeleton rearrangement may occur Peroxides HBr will add antimarkovnikov where hydrogen adds to most substituted carbon 0 Radical reaction where bromine radical adds before the hydrogen 0 Occurs with HBr not HCl not HI not HF Adding water to an alkene o Reversing dehydration of an alcohol 0 Cold dilute acid cause addition of water to an alkene I Electrophilic addition 0 Carbocation is formed hydroxyl group is added and alcohol is formed 0 MARKOVNIKOV ADDITION I Rearrangement must be possible Oxymercuration o Prevents carbonskeletal rearrangement during hydration o Organiometallic compound bonds to both doublebonded carbons 0 Water attacks from opposite side in an anti addition 0 Forms an alcohol 0 Alcohol may also be used as the solvent in this reaction Hydrating alkene with anti Markovnikov addition 0 Hydroboration BH3 and then peroxides o REMEMBER PEROXIDES CAUSE ANTIMARKOVNIKOV Halogenation of an alkene o Electrophilic 0 As they are more reactive alkenes do not need to create a readical in order to make them react with halogen 0 Anti addition 0 One halogen adds to each but on opposite sides Benzene is a at sixcarbon ring 0 Bonds have only partial doublebond character as pi electrons are delocalized around the ring 0 Undergoes electrophilic substitution not addition I Addition would destroy its resonance leading to a more unstable molecule and such reactions are unlikely to occur Ortho on either side directly Meta two carbons away Para directly across the ring from the substituent If substituent is electronwithdrawing it deactivates and directs next substituent to add at meta position I Oxygens withdraw electrons via double bonds I Nitrogens with 4 bonds they withdraw electrons I Halogens are actually electron withdrawing but NOT meta directed OOOO OOOO I Carbonyls nitriles Cyanide o If it is electrondonating it activates ring and directs to add ortho or para I Halogens are the exception here I Oxygens donate electrons via single bonds I Nitrogens with only 3 bonds donate electrons I Alkyl groups are electron donating I Benzene SNl Occurs in 2 steps First step is the slow step Usually alkyl halide is tertiary for no backside attack Halogen acts as the leaving group and a small nucleophile bonds to the carbocation Rate depends solely on the concentration of the substrate alkyl halide Carbocation attens out and nucleophile can add to either side If it were chiral product would be a racemic mixture Works best in polar solvents which would STABILIZE THE CARBOCATION Does not occur often with secondary I Carbocations are too unstable Skeletal carbocation rearrangement is possible Snl and El usually occur together to form mixed products 0 OOOOOOOOO O Sn2 Occurs in 1 step Alkyl group is NOT bulky Nucleophile is a nonbulky strong base Halogen is dislodged after the nucleophile comes in Inversion of relative configuration occurs Rate depends upon nucleophile and the substrate Requires primary secondary carbon as substrate 0 If base is too strong and substratebase is sterically hindred an e2 reaction will occur Nucleophilicity 0 Base bonds to a proton and a nucleophile bonds to a carbon 0 Good base is often a good nucleophile I Base is always a better nucleophile than its conjugate acid Less bulkiness in the base nucleophile Negative chargeamppolarizability nucleophile Electronegativitiy reduces nucleophilicity o Nucleophilicity increases going down and to the left on the periodic table Nucleophile and 5 S s o Sn2 requires strong nucleophile whereas it is unimportant in snl o Substrate tertiary snl and rest sn2 o Solvent polar solvent increase rate of snl by stabilizing carbocation but inhibit sn2 by stabilizing nucleophile o Speed sn2 depends on nucleophile and substrate whereas snl depends only on substrate 0 Stereochemistry snl racemic and sn2 inversion o Skeleton in sn2 no carbocation rearrangement as there is no carbocation Alcohol organic compounds containing a hydroxyl group CO bond is longer than OH bond Bond angle is closer to 1095 degree angle due to bulk of alkyl group Lower molecular weight alcohols are miscible with water because alcohol can hydrogen bond and are also less dense than water Boiling points decrease with branching Alcohols are very weak acids weaker than water in most cases Primary alcohols are most acidic followed by secondary then tertiary Alkyl group in alcohol is electron donating Phenol is benzene with a hydroxyl group Conjugate base of alcohol alkoxide ion We can synthesize alcohol by adding Grignard reagent to a carbonyl group Grignard is organometallic compound Metal has a partial positive charge because metals like to lose electrons leaving alkyl group with negatively charged OOO OOOOOOO carbon Negative charge thus makes a nice nucleophile Grignard is nucleophile attacking carbonyl carbon Oxygen is protonated in an acid bath afterwards Reduce ketonealdehydes to make alcohol via NaBH4 and LiAlH4 These two are salts that make ions when placed in water Both are eager to donate a hydride ion H Acid bath protonates oxygen afterwards o NaBH4 only reduces to primary and secondary alcohols o LiAlH4 will reduce esters and acetates to alcohol as well Thus stronger reducing reagent Alcohol can be oxidized to make ketone aldehydes or carboxylic acid Primary oxidizes to aldehydes or carboxylic acid Secondary oxidizes to ketone Hydroxyl group by itself is a terrible leaving group If we add acid halide to alcohol it protonates hydroxyl group and halide acts as nucleophile 0 Use SOCl2 as halide Ether polar aprotic solvent with low reactivity and dissolves a wide range of solvents without reacting When adding hydrogen halide ether is split Epoxide reactive ether in a ring similar to a triangle Reactive because it has much angle strain Order of acidity weakest to strongest alkane alkene H2 NH3 alkyne aldehydes alcohol water carboxylic acid Carbonyls pi electrons are pulled towards oxygen Oxygen might even accept one pair of the electrons and take on a negative charge Carbonyl carbon has a partial positive charge Carbonyl carbon makes 3 sigma bonds and is sp2 hybridized Compound is at at carbonyl carbon Aldehydes similar chemistry to ketones Simplest one is formaldehyde methanol Simplest ketone is acetone or 2 propanone Higher boiling points than similar weight ethers but lower boiling points than alcohols Good solvents for alcohols and means short chain aldehydesketones are soluble in water Aldehydes and ketones are susceptible to Nucleophilic attack Like to undergo Nucleophilic addition because they don t have good leaving groups May also behave as a BronstedLowry acid They donate the alpha hydrogen When conjugate base is stabilized acid gets stronger Oxygen in carbonyl is willing to take on an electron from the carbonyl bond Stabilized by resonance Aldehydes and ketones are weaker acids than alcohol Tautomers structural isomers where a proton has shifted Exist in equilibrium These are NOT resonance structures Tautomerizatoin is reaction with equilibrium favoring aldehydesketone Aldehydesketone in alcohol intermediate compound is hemiacetal or hemiketal Catalyzed by acid or base Can take it one step further by adding another equivalent of alcohol to form an acetal or ketal Can only be catalyzed by acid not base because acid creates water as the leaving group We can reverse this reaction just by adding acid Germinal diol carbonyl carbon has oxygen replaced by two hydroxyl groups Aldol condensation aldehydesketone reacts with itself and behaves both as acid and as Nucleophilic addition substrate Can be catalyzed by acidbase Alpha hydrogen is removed forming negatively charged alpha carbon on enolate ion and this attacks carbonyl on other aldehydesketone Aldol is then formed in the end This much is called aldol addition The condensation part a second alpha hydrogen is removed with hydroxyl group Conjugation double bonds separated by just one single bond More stable than isolated double bond systems A double bond between alpha and beta carbon of carbonyl is conjugated Here electrophile may add to carbonyl oxygen Following with nucleophile that adds to beta carbon Carboxylic acids common names formic acetic and benzoic acid 0 Strong organic acids but weak compared to strong inorganic acids Weaker than hydronium ion for instance 0 Spreading negative charge over a larger area always stabilizes Follow same meltingboiling point trends as hydrocarbons with much higher melting and boiling points due to hydrogen bonding Chains with 8 or more carbons are generally solid Carboxylic acids like to undergo Nucleophilic substitution True for derivates of these as well Add PCl3 PCl5 or SOCl2 to carboxylic acid get Nucleophilic substitution Acid chloride is left behind Called an acyl chloride and donates an alpha hydrogen Acid chloride is more acidic than an aldehyde 0 Chloride ion is a good leaving group 0 Alcohol acid chloride ester 0 Carboxylate acid chloride anhydride Amines ammonia derivatives with one or more alkyl or aryl groups bound to hydrogen Ammonia primary and secondary amines form hydrogen bonds Hydrogen bonds formed by amines are not as strong as those formed by alcohols Act as nucleophile or as lewis base Electron donating groups strengthen basicity of amines Nitrogen is willing to make a fourth bond by taking on a positive charge 0 Like to be nucleophiles 0 Add to carbonyl carbon in presence of an acid 0 Amine attacks carbonyl carbon but nal result is complete replacement of carbonyl oxygen with nitrogen Product is called an imine o Amine can react with any of carboxylic acid derivatives to create an amide which is an amine attached to a carbonyl 0 Acid chlorides are most reactive then followed by anhydride then ester then amide Amide is most stable of them all Alkyl halide will react with ammonia to make primary amine Nitriles carbon is partially positive Can be hydrolyzed in acid to give a carboxylic acid Can be reduced to give amines Fatty acids long chained carboxylic acids Be able to draw structure of an amino acid Alpha amino acids are used to make proteins Nearly all organisms use same 20 alpha amino acids 0 10 of common amino acids are essential to humans Two amino acids attached by one peptide bond dipeptide Isoelectric point of amino acid when amino acid starts with negatively charged carboxylic acid and positive amine zwitterions Four characteristics dipolar creates high melting point water solubility large dipole moments and makes amino acid less acidic than most carboxylic aids but less basic than most amines Isoelectric point is pH at which this amino acid exists as a zwitterion Carbohydrates are a one to one ratio of carbon to hydrogen Glucose is a hexose Makes glycogen starch cellulose and chitin Plants store glucose as starch Plant cell walls are made of cellulose Beta linkages in cellulose and chitin Alpha linkages in others Humans absorb only D glucose NMR protonNMR usually on the MCAT Uses constant frequency photon source and changes magnetic field til resonance is detected If no electrons around nucleus all protons would exhibit resonance at same field strength Protons shielded from external mag Field by electrons require a stronger external magnetic field to exhibit resonance 0 Electron withdrawing groups deshield protons allowing them to resonate at lower field strength Numbers increase to the left Larger numbers indicate a weaker magnetic field strength To left is called downfield Carbonyl proton has peak at around 95 ppm IMPORTANT o Spinspin splitting occurs when neighboring hydrogens that are stereochemically different from each other I such hydrogens are enantiotropic to each other Each peak splits in same number of peaks as non enantiotropic neighbors plus 1 Group of peaks with more hydrogens has greater total area under the peak Horizontal line called integral trace can be drawn at spectrum and will rise and stay at new height each time it reaches top of new peak and extent it rises is proportional to this amount of hydrogen A rise of 2 represents twice as many hydrogens as a rise of 1 IR spectroscopy infrared Perpendicularly oriented constantly changing magnetic field 0 Elastic component tends to increase frequency 0 Carbonyls register strongly Deep sharp dip at 1700 cm l which is unit called wavenumber Number of waves in each centimeter Alcohols are at 32003600 with very broad peaks Fingerprint region each compound has unique IR spectrum which is between 6001400 No polar bonds make weaker signals Chromatography resolution of a mixture by passing it over a surface that adsorbs compound in mixture at different rates Moving phase and stationary phase Stationary phase is the surface and moving is some type of solution As moving phase moves over stationary compounds with greater affinity for stationary move more slowly More polar have greater affinity for stationary phase In column chromatography solution with mixture is dripped down a column of glass beads Paper chromatography know it Thin layer chromatography Gas chromatography mixture dissolved in heated carrier gas Results recorded as peaks Distillation separation based upon boiling points Unless azeotrope boiling point of mixture is same as boiling point of compound in mixture with lowest boiling point Poured into condensing ask Should be done slowly Crystallization crystals tend to form from pure substances Mixture to be purified is melted and crystallized many times Extraction based upon solubilities Nonpolar layer and aqueous layer Nonpolar layer usually contains mixture Acid is added and apparatus with both layers is shaken vigorously Acid protonates mixture in nonpolar mixture Protonated bases settle out in aqueous which is drawn off Next weak base is added and shaken Weak base Deprotonates strong acids which settle in aqueous and are drawn off Strong base is added and apparatus is shaken Deprotonates weak acids which then also settle out in aqueous solution EaXAMKRACKERS PHYSICS NOTES When multiplying two vectors 0 Vproduct VlV2sintheta o In multiplying two vectors the resultant vector will be perpendicular to both vector 1 and vector 2 O Hsintheta AHcostheta Average velocity is independent of the path chosen In a displacement vs time graph the area undemeath the graph has NO MEANING Linear motion equations could only be used on the straight portions of displacementvstime graphs since these are the only points wherein acceleration is constant In terms of a velocityvstime graph the slope represents the acceleration of the object If one takes the area of the portion between the curve and zero on a velocityvstime graph the area is equal to the distance If one takes the area of the portion below the zero velocity as negative the total area represents displacement To calculate the displacement on a velocityvstime graph one must take the area undemeath the xaxis and subtract it from the area above the xaxis A projectile continues its motion by virtue of its own inertia In projectile motion since there is no acceleration in the horizontal direction this means there is NO CHANGE in horizontal velocity throughout the ight Peak height of a projectile o VsinthetaSquare root2gh I G l0m2quot2 That s POSITIVE 10 I This same equation with replacing v nal for vinitial may be used to nd the nal velocity of a projectile dropped from a certain height h 3e4 With a projectile wherein air resistance is ignored or negligible the path the projectile takes is independent of the mass of the projectile In projectile motion height is dictated only by the vertical velocity 0 Horizontal range is dictated by both horizontal and vertical velocities In projectile motion if two projectiles leave the earth with the same vertical velocity they will land at the same time regardless of their horizontal velocities o A bullet shot horizontally from a gun and a rock dropped from the same height will land at the same time Factors that alter air resistance 0 Speed 0 Surface area 0 Shape Mass changes the effect of air resistance but does not change air resistance Maximum velocity is reached when all gravitational potential energy is 0 and is being converted to kinetic energy generally this is before an object dropped hits the ground Always remember that displacement is a vector For example if two balls are dropped down ramps of l m each but one ramp is vertical while the other is inclined at 30 degrees then their displacements are NOT equal Even though both may travel lm they are travelling at different directions Therefore their displacements are different Objects streamlined with smooth surfaces experience less air resistance than irregularly shaped objects At terminal velocity acceleration is 0 Larger masses experience less deceleration due to air resistance because they are less affected by the same force of air resistance AIR RESISTANCE HAS LESS EFFECT ON THE MORE MASSIVE OBJECT Use bowling ball and bowling pins air molecules example When an graph is multiplied by a negative constant it is re ected over the xaxis If a system is not uniformly dense then the center of mass lies in the more dense area from its geometric center With the universal law of gravitation the movement of the force vector is from the center of one mass towards the center of the other mass In an ideal inclined plane the normal force is always equal to mgcostheta o This works regardless of the angle of the plane 0 The net force due to JUST gravity and normal force is always mgsintheta Normal force along a curved surface 0 Mgcosthetamvquot2r An object on a frictionless incline with an angle between 0 and 90 will accelerate at some fraction of g Most centripetal force problems on the MCAT may be solved via equating the centripetal force to the force responsible for it A satellite is constantly falling towards earth via its centripetal force due to gravity of the earth but due to its massive velocity it always misses the ground by the same distance Thus to someone in circular orbit falling with the satellite it appears to be oating when in fact it is not El sine cosine ij on X1 2 U 1 3O 1 7 0 0 E 45 3 T 1 X3 60 2 TlI 4 90 T2 Kinetic friction coef cientnormal force Static friction is less than or equal to coef cientnormal force To determine whether or not a system is sliding down its contiguous surface nd the calculated net force without friction If it is less than coef cient of static frictionnormal force then the system is probably not moving The negative sign in Hooke s law can usually be ignored of the MCAT but just in case don t forget that it s there The point where an object violates Hooke s law is called the yield point The point where it breaks is called the fracture point For any system IN EQUILIBRIUM the upward force downward force and the leftward force rightward force THIS METHOD ALLOWS YOU TO USE ALL POSITIVE NUMBERS EVEN FOR GRAVITY o The net force acting on a system in equilibrium is 0 which makes sense because if there is constant velocity this means there is no acceleration which by Newton s second law means that there is no net force By MCAT de nition torque is a twisting force Lever arm is a position vector extending from the point of rotation to the vector of force which would cause the angle between these two vectors to be 90 degrees In torque problems if one would like the board to be in static equilibrium then one chooses the board as the system 1 Joule lkgmquot2squot2 o Joules are used for macroscopic objects whereas electronvolts are used for microscopic objects The universe is considered an isolated system Conservative forces do not alter temperature or intemal energy Nonconservative forces include kinetic energy and the pushingpulling applied by humans or animals For conservative forces 0 0change in potential energy change in kinetic energy 0 Conservative forces do not do work For nonconservative forces 0 Work change in kinetic energy change in potential energy Forces that are 90 degrees to the displacement such as normal force or gravity with an item moving horizontally do not do work Greater work manifests itself by greater acceleration greater velocity and less time required to achieve the displacement POWER is a scalar quantity Momentum of an isolated system is always conserved The momentum of the center of mass of an isolated system is constant in magnitude and in direction In elastic collisions Hooke s law is followed perfectly whereas in inelastic collisions it is not with an inelastic collision momentum is conserved BUT kinetic energy is dissipated into intemal energy In a multidimensional system there are two equations for conservation of momentum one for momentum in the Xdirection and one for momentum in the ydirection Airbags do not decrease momentum but they do increase the time over which the collision occurs so that less force is exerted upon the driver In a forcevstime graph the area under the graph represents change in momentum IMPULSE All that machines do is reduce the force necessary to do work THEY DO NOT REDUCE THE WORKLOAD Nonideal machines actually increase the workload because they increase intemal energy through friction Levers are the machines with fulcrums with a pulley F T and 2T mg We multiply the tension here by 2 because pulleys have 2 stringsropes not just one In order to overcome the force pushing an object down an inclined plane one must overcome Fdsintheta which is the force which is pushing the mass down In modi ed levers which look like pulleys the tension is not the same throughout as it would be with a regular pulley Pulleys ramps and levers act under the same principle they increase the distance over which work is to be done effectively reducing the force In dealing with pulley problems choose the pulley as the system DO NOT USE THE MASS AS THE SYSTEM With pulleys and levers the goal is to accomplish dynamic equilibrium with the objects moving upward at a constant velocity meaning there is no net force or acceleration acting upon them On a ramp W mgh ALL machines decrease the force necessary to accomplish a task These machines could be ideal or nonideal with nonideal machines making the work increase Radioactive decay concems atoms which spontaneously break apart 0 All atoms other than hydrogen are subject to such decay Radioactivity may be predicted by protonzneutron ratio and no atoms with greater than 83 protons are considered stable All radioactivity questions only concem 4 variables 0 Amount of half lives 0 Length of half lives 0 Initial amount of substance 0 Final amount of substance 5 types of radioactive decay 0 Alpha decay 0 Beta decay o Positron emission 0 Electron capture 0 Gamma ray emission In alpha decay an alpha particle is lost Beta decay is creation of an electron and a proton from a neutron and the expulsion of the newly created electron INCREASE ATOMIC NUMBERBY l A neutrino is a virtually massless particle also emitted during beta decay In positron emission a proton is transformed into a neutron and a positron is emitted The atomic number goes down by l DECREASE THE ATOMIC NUMBER AND KEEP THE ATOMIC WEIGHT THE SAME 0 Positive electron is written AFTER the arrow Electron capture is the capture of an electron along with the merging of that electron with a proton to create a neutron Thus a proton is destroyed and a neutron is created o DO THE SAME MATHEMATICALLY AS WITH THE POSITRON EMISSION SINCE BOTH ARE BETA DECAY AND KEEP ATOMIC WEIGHT THE SAME WHILST DECREASING THE ATOMIC NUMBER BY 1 0 Negative electron is written BEFORE the arrow and a gamma particle is also released A gamma ray is a high frequency photon It has no charge and does not change the identity of the atom om which it is emitted Gamma decay accompanies other types of decay o For example when electrons and positrons collide which is called ANNIHILATION and deals with matterantimatter Emcquot2 gives the rest mass energy of an object o Latent energy of an object 0 Will only be tested if energy is created or destroyed o mthe mass which is created or destroyed Also referred to as the mass defect nucleon proton neutron ssion and ision both release large amounts of energy and this energy is released due to the mass defect the most stable nuclei have the strongest binding energies Both ssion and ision produce nuclei which are more stable a uid is a liquid or a gas in a uid any existing molecular bonds are constantly breaking and reforming due to the high kinetic energy of the molecules the only permanent force which a uid can exert is one normal to its surface gravity has an insigni cant effect on gas molecules due to their high average velocities two intensive properties in dealing with uids are density analogous to mass and pressure analogous to energy often in dealing with uid mechanics an assumption is made which states that this uid is incompressible This is because when a uid is compressed its volume changes without changing its mass thus changing the density which is generally a dif culty in solving problems speci c gravity density of substancedensity of water DENSITY OF WATER l000kgmquot3 amp lgcmquot3 Fluid pressure results om the impulse of molecular collisions o PFA Fluid pressure is a measure of kinetic energy due to random velocities within a uid distributed over the uid volume Atmospheric pressure 101000 Pascals Gauge pressure measure of pressure compared to the pressure of the local atmosphere Absolute pressure gauge pressure atmospheric pressure Pressure applied anywhere in an enclosed incompressible uid is distributed evenly undiminished throughout the uid Hydraulic lift is a machine that works by Pascal s principle while reducing force necessary for a certain workload to be completed Buoyant force is the upward force acting on a submerged object and is equal to the weight of the uid displaced by the object Does not change with depth Pressure difference densitygravitydifference in height A illy submerged object displaces its volume in uid A oating object displaces its weight in uid If an object is not uniformly dense the center of mass and center of buoyancy will not coincide The object would experience a torque and spin Buoyant force densityvolume displacedgravity A oating object displaces an amount of uid equal to its own weight 0 Fraction submerged density of oating objectdensity of medium in which object is oating Pressure depends only on depth and density not the shape of the container Viscosity is the measure of a uid s temporal resistance to forces not perpendicular to its surface When one says a uid is incompressible this means it has uniform density Mass ow rate I densityVolume ow rate densityareavelocity Uniform translational KE in a uid is achieved by borrowing some energy from the random translational kinetic energy thus causing pressure to decrease For a uid lled container with a spigot opening one can use velocity square root of 2gh to nd velocity Velocity and pressure are inversely proportional A streamline is a path followed by a hypothetical particle o The velocity of a particle along any point of a streamline is tangent to the curve made by the streamline o The magnitude of velocity is inversely related to the distance between the streamlines 0 That is the closer the streamlines the greater the velocity with a real uid the velocity is greater in the innermost part of the tube which is irthest away from the edges This is because the innermost uid particles experience much less drag than the ones on the outside This is why dust remains on fans even though the fan is moving at high speed there is a lot of drag on the edges of the fan surface area 2pird volume dpirquot2 the driving force behind the ow of a uid is the uid s tendency to nd its greatest entropy if for example a needle is oating on the surface of water it is not supported by buoyant force but rather by surface tension of the water a sphere has the lowest surface area volume ratio of any shape surface tension depends on the temperature of the uid in a test tube if the cohesive forces of the uid is stronger than the adhesive forces between the uid and the tube then the uid forms a convex shaped meniscus and is pulled down the tube if adhesive forces are stronger than the cohesive forces the uid forms a concave meniscus and is pulled upward via capillary action For ideal ow volume ow rate is constant at all points Stress ForceArea but the units are Nmquot2 Strain change in dimensionoriginal dimension and has no units since it is a ratio Modulus of elasticity stressstrain An object s maximum elasticity is called the yield point wherein the object will regain its shape once stress is removed Beyond the yield point the object will remain intact but not in its original shape Young s modulus works for tensile compression amp tensile stretching forces Young s modulus E Shear stress modulus G Bulk stress modulus B Modulus stressstrain for elasticity Young s modulus o EFAchange in heightoriginal height Shear stress modulus o G FAchange in x directionoriginal height Bulk stress modulus o B change in pressurechange in volumeoriginal volume 6cmquot2 6 10 4 mquot2 Mechanical waves require some medium through which to travel Nondispersive medium one through which a wave maintains its shape and does not disperse as it travels Waves on a string are transverse waves Sound waves are longitudinal waves For a transverse wave the sine function represents the vertical displacement of the medium with respect to the time or displacement of the wave For longitudinal waves the sine inction represents either change in pressure or horizontal displacement of the medium with respect to time or displacement of the wave The product of wavelength and frequency is the velocity of the wave The period is the number of seconds required for one wavelength to pass a certain point Amplitude A is maximum displacement FROM 0 and is always positive The velocity of a wave is dictated by the medium through which it travels A change in frequency or wavelength does not change the velocity of the wave in a nondispersive medium Two aspects of a medium which in uence velocity of a wave 0 Elastic component tendency of the medium to resist a change in shape I Stores potential energy 0 Inertial component tendency of the medium to resist a change in motion I Stores kinetic energy In a sound wave 0 Velocity square root Bdensity where B is the bulk stress modulus Within a gas the greater the temperature the greater the random velocity the greater the sound wave velocity Because solids are less compressible than gases this means solids have a higher bulk modulus In surface waves gravity acts as the elastic component and they are neither completely transverse nor completely longitudinal Intensity increases with the square of the amplitude and the square of the frequency for all waves B l0logII0 where B is the decibels With decibels if one adds 2 zeros to the intensity one adds 20 decibels If one adds 3 zeros to the intensity one adds 30 decibels Adding 20 decibels is multiplying the intensity by l0quot2 Adding 30 decibels is multiplying the intensity by l0quot3 Adding 10 decibels is multiplying intensity by 10 The phase of a wave relates to wavelength frequency and placetime of origin Each wavelength represents 360 degrees Phase constant the angle by which 2 waves differ If 2 waves of the same wavelength reach the same point but travel different distances to get there then they are out of phase with each other Interference superposition of waves which may be constructive or destructive After passing through each other waves that interfere will revert to their original shape unaffected by the interference Beats occur when 2 waves of slightly different frequencies are superimposed Beat frequency ABSOLUTE VALUE OF FlF2 Pitch correlates to frequency Any refracting wave will continue with the same orientation and same frequency but with a smaller amplitude and a different wavelength from the original medium If the original medium is less dense than the second medium the wave is inverted If original medium is denser than the second medium the wave s orientation remains upright When a wave is transferred from one medium to another the wavelength changes but the frequency stays the same Standing wave when string moves violently up and down at antinodes where maximum constructive interference occurs and does not move at all at nodes where the two waves collide Harmonic series a list of the wavelengths from largest to smallest of the possible standing waves for a given situation The longest wavelength creates the rst harmonic which has the smallest number of nodes 2 Each successive node added creates the subsequent harmonic For a harmonic series where each end is tied down as a node or where each end is an antinode the equation is o Lnlambda2 where L is the distance between the 2 ends of the string For a harmonic series where a string or pipe is only tied down or open at one end that is it has one node and one antinode the equation changes to o L nlambda4 and the n can only be an odd number V f lambda for any harmonic If an outside driving force is applied to a structure at natural frequency the structure will experience maximum vibration velocities and maximum displacement amplitudes The condition where the natural frequency and the driving frequency are equal is called resonance Any motion that repeats itself is called periodic or harmonic motion Simple harmonic motion is a sinusoidal inction in time In simple harmonic motion acceleration is directly proportional to displacement but opposite in sign Acceleration and displacement are related by the square of the frequency If a spring follows Hooke s law a mass bouncing off of a massless spring exhibits simple harmonic motion In simple harmonic motion there is an oscillation between kinetic and potential energy with no energy being lost to the surroundings Period for motion of a mass on a spring 0 T 2pi square root mk Period is inversely proportional to velocity A pendulum has total gravitational energy at the top of its swing and total kinetic energy at the bottom 0 T 2pi square root Lg Unexpected examples of simple harmonic motion 0 Orbit of a planet viewed from the side 0 Tether ball game viewed from the side 0 Electrons oscillating back and forth in AC current The Doppler effect results because waves are unaffected by the speed of the source which produces them 0 This causes an observer not to hear sound with the pitch with which it was emitted and also causes an observer not to see light with the color with which it was emitted Approximation of Doppler effect 0 Change in frequencysource frequency vc 0 Change in wavelengthsource wavelength v c When relative velocity brings source and observer closer the observed frequency goes up and observed wavelength goes down The relative velocity is the net speed at which the source and observer are approaching each other For light when the source and observer are approaching each other the wavelength shortens creating a blue shift When they separate the wavelengths lengthen creating a red shift For objects moving in same direction at same speed there is no Doppler effect The relative velocity is zero and therefore the frequency is zero Current runs in the opposite direction of electrons The net charge in the universe and net charge is created by separating electrons from protons Charge on proton and electron l6xl0quotl6C Coulomb s law 0 F kqqrquot2 0 K 899xl0quot9 A major difference between gravitational and electric forces is that gravitational forces are always attractive and electric forces may be attractive or repulsive The center of charge exists at the center of a hollow sphere even though there is no actual charge at this center Lines of electric force point from positive to negative Electric eld E kqr 2 Force on a charge in an electric eld o F Eq Potential energy of a charge in an electric eld o U Eqd Electric potential is zero for particles separated by an in nite distance Voltage Ed which is the potential for work by an electric eld in moving any charge from one point to another Voltage due to a point charge kqr Within an electric eld movement perpendicular to the eld does not result in change in potential P qd which is an electric dipole which is created by two charges with the same magnitude but moving in opposite directionsTHIS DIPOLE POINTS FROM NEGATIVE TO POSITIVE WHICH IS OPPOSITE IN CHEMISTRY At large distances the electric eld of a dipole varies by lrquot3 A dipole placed in an electric eld will tend to align itself in orientation opposite that of the eld A dipole not perfectly aligned will have potential energy of U pEcostheta Voltage workcharge Poor conductors are represented by network solids such as diamonds and glass The electric eld inside a uniformly charged conductor is 0 Current moving charge which is measured in amps or Coulombssecond The direction which the positive charge moves Just like uids electrons move in all random directions but at a slower speed they move in a single direction called drift speed Rho stands for resistivity here just as it has stood for density previously Resistance resistivitylengtharea o If a length of wire is doubled or crosssectional area cut in half the resistance is doubled Voltage currentresistance A node is any intersection of wires Kirchhoff s first rule the amount of electricity owing through a node is the same that goes into the wire Kirchhoff s second rule the voltage around a circuit must sum to 0think of this as the displacement vector if you end up back where you started then the displacement is zero Battery adds energy to a circuit by increasing voltage between one point and the other Assume batteries have no internal resistance unless otherwise indicated Capacitor used to temporarily store energy in a circuit In a parallel plate capacitor two plates are placed parallel from one another One is positively charged and one is negatively charged They both hold the same exact amount of charge and there is a uniform electric eld throughout the capacitor K l4piepsilon Electric eld lKQAepsilon 0 K dielectric constant 0 Q charge on either plate 0 A area Something with high capacitance can store more charge at a lower voltage C QV Charge sits on the surface of a charged conductor not within it o For this reason an increase in the thickness of the plates of a capacitator do not increase how much charge is held by them The farther the plates are separated the greater the voltage the lower the capacitance C K Aepsilond 0 K dielectric Area under a chargevsvoltage graph is the energy U 12QV o This equation represents the potential energy sustained by a capacitor The dielectric constant refers to the substance between the plates of the capacitor which must be an insulatorotherwise it would conduct charge and not allow buildup of charge 0 Dielectric acts to build up electric eld and thus allow greater capacitance 0 Also acts to limit the amount of voltage across the plates 0 Work is done on the dielectric to induce its dipoles to point towards the electric eld and then this energy is stored Dielectric of Air is close to one and in a vacuum is 0 unity ALL OTHERS INCREASE FROM THERE Lines connecting components of a circuit are completely nonresistive wires When resistors are in series their total effective resistance is the sum of all of their individual resistances When resistors are in parallel their total effective resistance RECIPROCAL is the sum of all of their individual reciprocals WITH CAPACITORS THE OPPOSITE RELATIONSHIP IS TRUE Power IV 0 Iquot2RVquot2R BUT THESE 2 EQUATIONS ARE ONLY APPLICABLE TO energy dissipated as heat BY A RESISTOR The current going through a resistor generates heat The rate at which heat is generated is power dissipated The electric eld is constant throughout a capacitor and the dipoles on either end point in opposite directions Thus the net force 0 Adding a resistor in parallel decreases overall resistance The voltage of the battery is not affected by changes within the circuit Direct current is when the electrons move in a single direction around the circuit Alternating current is generated by movement of electrons in simple harmonic motion 0 Voltage or current in alternating current is described by a sine inction Maximum voltage square root2Vrms 0 V voltage 0 You may use the same equation but replacing the Voltages with Currents 0 Note the Vrms is NOT under the square root Magnetic eld and radius are related by the BioSavart Law 0 B mui2pir Rms voltage in US is typically 120 V with maximum voltage being l70V Magnetic eld is measured in units of T or Tesla Magnetic poles have never been found to exist separately one pole always accompanies the other Magnetic lines point from the north pole to the south pole A changing electric eld becomes a magnetic eld A stationary eld does not create a magnetic eld Magnetic elds follow the inverse square law when it comes to distance Direction of magnetic eld due to a currentcarrying wire 0 Use right hand rule 0 Grab wire with nger pointing in direction of the current 0 The direction in which ngers point is the direction of the magnetic current F qvBsintheta o Theta is the angle between the magnetic eld and the velocity of charge Force is directed perpendicularly to magnetic eld amp velocity Second right hand rule is used to nd direction of force 0 Thumb remains pointing in direction of current of a positive charge 0 Fingers point in direction of magnetic eld o The palm of one s hand points in the direction of the force 0 if the charge is negative the palm rule is reversed and the back of the hand is what points in direction of force Since electric force is always perpendicular to velocity it does no work Force changes direction but never the magnitude of velocity Force always acts as centripetal force and can be set equal to mvquot2r in order to nd radius of curvature of the particle F iLBsintheta A changing magnetic eld creates an electric eld which is NOT conservative and is instead dissipated as heat in the charged particle Forces due to an induced electric eld are not conserved F qvB X s mean magnetic eld is directed INTO the page Circles mean the magnetic eld is directed out of the page A charged particle moving parallel to a magnetic eld experiences no force A current will ow in a loop of wire to oppose changes in magnetic eld inside the loop A changing electric eld creates a magnetic eld and the converse is also true An electromagnetic eld is a transverse oscillation where the two elds electric and magnetic are perpendicular to each other and the direction of propagation is similarly perpendicular to both 0 All are created by acceleration of electric charge Speed of propagation of electromagnetic eld EB Rate at which an electromagnetic wave is transferring energy per unit area 0 EBsintheta poynting vector Visible light spectrum 390 10 9 to 700 10 9 o Shorter wavelengths correspond to violet light and longer wavelengths correspond to red light o Wavelengths towards the violet part of the spectrum have more energy remember this by knowing that they have so much energy that ultraviolet light which is just beyond visible violet light has so much energy that it gives you sunbum Index of refraction speed of light propagating through a medium 0 Ncv I C speed of light through a vacuum The greater the index of refraction the slower the light moves through that medium Ray will tum towards normal as it enters the glass and away from normal as it exits the glass Re ection is indicative of either wave or particle theory diffraction occurs when waves bends around comers Water n 13 Glass n 15 Each photon in light represents an electromagnetic wave Isotropic light light emanating from a point source Planepolarized light light with electric elds all pointing in one orientation When isotropic light is polarized it loses one half its density as it loses light in one direction and keeps all light perpendicular to that direction Angles of re ection and refraction are measured from a line normal to the medium Angle of re ection angle of incidence Collision of photon against a medium is completely elastic and they lose no kinetic energy Snell s law 0 Nlsinthetal n2sintheta2 The path that light travels is the one which would take the shortest time When light crosses into a new medium the frequency stays the same but the wavelength changes Energy of light hf 0 Thus higher frequencies lower wavelengths have higher energies o This equation gives energyphoton o If we double the frequency we double the photons and we increase intensity by a factor of 4 When light is coming from a medium with a higher incidence of refraction the angle of incidence could be so great so as to cause total intemal re ection Critical angle theta inverse sinn2nl Longer wavelengths move faster through a medium than shorter wavelengths and therefore bend less dramatically Chromatic dispersion the spreading of light by a prism spreads white light into all colors of the visible spectrum All types of waves refract and diffract Diffraction 0 When a wave moves through an aperture it bends around the comer of the opening 0 Only signi cant when aperture size is on the order of the wavelength or smaller 0 The smaller the aperture and the longer the wavelength the greater the diffraction 0 When waves diffract constructive light bands interference and destructive dark bands interference occur 0 May also result in dispersion or creation of colors Mirrors re ect light lenses refract light Re ection in a at mirror is a virtual image Diverging lenses are concave Converging lenses are convex Thicker center in a lens converges light Smaller radius of curvature indicates a sharper tum Light is re ected by concave mirrors and refracted by converging lenses through a focal point Light is re ected by convex mirrors and refracted by diverging lenses away from a focal point Focal length of a mirror M2 Factors affecting focal point of a lens 0 Radius of curvature 0 Index of refraction of lens and of medium When nln2 a lens will not refract light Focal point of a lens varies with frequency resulting in chromatic aberration Power of lens inverse of focal length lf Lenses are considered in nitely thin so refraction occurs at the center of the lens Lateral magni cation 0 Height I height o dido If this quantity comes out to be negative the image is inverted Thin lens equation 0 lf ldo 1di I eye is positive that real is inverted System for determining lensmirror problems 0 First draw an eye on one side of the paper This is the observer On the side with the eye write real positive inverted Images and focal points on the opposite side will be virtual negative and upright In dealing with a mirror the eye is in front of it just as you stand in front of a mirror In dealing with a lens the eye is behind it just as you stand behind a camera lens to take a picture Objects are always positive when they are in front of a lens or a mirror and they are always negative when they are behind a lens or a mirror If object is in front convex mirrors and diverging lenses make negative virtual and upright images F IS ALWAYS NEGATIVE o Concave mirrors and converging lenses make positive real and inverted images except when the object is WITHIN the focal distance THEN the image is negative virtual and upright F IS ALWAYS POSITIVE o BOTH THE ABOVE RULES ONLY APPLY WHEN THE OBJECT IS IN FRONT IF OBJECT IS BEHIND REVERSE THEM IN TWOLENS SYSTEMS BE CAREFUL AS THE OBJECT OF THE SECOND LENS WHICH IS THE IMAGE OF THE FIRST LENS MAY BE BEHIND THE SECOND LENS M l1dof Ml di f In a singlelens system the object cannot be behind the mirrorlens nor can it have a negative distance Two lens system 0 Lateral magni cation of system mlm2 0 Power of system plp2 Positive magni cation gives a virtual upright image and negative magni cation gives a real inverted image Diverging lens and convex mirror only produce images smaller than the object Converging lenses and concave mirrors produce images smaller than object when object is more than 2 focal lengths away from mirror 0 Image is larger when object is within 2 focal lengths o O OOOOO EXAMKRACKERS GENERAL CHEMISTRY Radius of one nucleus is 10 4 Angstroms o l angstrom 10 10 meters A nucleon protons neutrons is made up of 3 quarks l electron charge unit 16 l0quot19 coulombs A stands for mass number not atomic number It is Z which stands for number of protons and thus atomic number One atomic mass unit amu or simply u is also called a Dalton Hydrogenl protium Hydrogen2 deuterium Hydrogen3titrium 6022 l0quot23 atomic mass units 1 gram moles gramsatomic weight Each horizontal row is called a period Each vertical row is called a group or family Traits of metals 0 Lustrous o Malleable easily hammered into thin strips 0 Ductile easily stretched o Thermally conductive o Electrically conductive All metals except mercury exist as solids at room temperature Nonmetals have lower melting points than metals and tend to form negative ions Also they tend to form covalent oxides Metals tend to form positive ions and ionic oxides Elements in same family tend to have similar chemical properties but hydrogen is an exception to this rule In nature alkali metals only exist in compounds and react exothermically with water Heavier alkaline earth metals are more reactive than lighter alkaline earth metals Alkaline earth metals are tougher than alkali earth metals They tend to have higher melting points and are harder and more dense Hydrogen is de nitely a nonmetal The molarity of O2 is equal to the molarity of any other ideal gas at the same temperature and pressure 0 Density divided by molecular weight is molarity Oxygen s group is called the chalcogens Halogens are highly reactive Smaller atoms have less room to stabilize which makes them bond more strongly to water higher heats of hydration Large atoms have d orbitals allowing for more than 4 bonds Large atoms cannot easily form pi bonds Small atoms make strong pi bonds due to overlap of p orbitals When transition metals lose electrons they FIRST lose from their s subshell and THEN from their d subshell Cations are much smaller than neutral atoms and anions are larger than neutral atoms Effective Z average nuclear charge Z electrons between nucleus and electron in question Zeff or effective nuclear charge increases going left to right and top to bottom on the periodic table Atomic radius increases from top to bottom Ionization energy the energy necessary to detach an electron from a nucleus The second ionization energy is always much greater than the first Ionization energy increases from left to right and from BOTTOM TO TOP Electronegativity increases from left to right and from BOTTOM TO TOP AS WELL Electron affinity increases from left to right and from BOTTOM TO TOP AS WELL Electron affinities for noble gases are endothermic whereas electron affinities for other elements are exothermic Metallic character increases from right to left and from top to bottom Noble gases do not follow the trends for electron affinity or electronegativity Fquot139s2ifjit 39Ibb1raiia Ei n1n TE EJEV Kilo la 1 E39wi 1 1ilquotI iE eiil 115 E M E U U i In TI GTE ii39iquotIiLiITC ii IZT lquot39 Ir lU1Ele T1 10 5 I igi P il J u 39EII1j i39 Ii ID H Bond length the point where the energy level is the lowest Bond energybond dissociation energy energy necessary to achieve complete separation between atoms No energy is ever released by breaking a bond Glucose is 40 carbon by mass If a cation is made from a nonmetal it ends with ium like ammonium Cupric is copper 2 Couprous is copper 4 More oxygenated species will use the ate suffix H2S hydrogen sul de H2SO4 sulfuric acid H2SO3 sulfurous acid For binary compounds name is given with element first which is farthest to the left and lowest in the periodic table Physical change 0 Melting o Evaporation o Dissolution o Rotation of polarized light Running to completion moves to the right until at least one of the reactants is depleted o If a reaction reaches equilibrium first it will not run to completion Limiting reagent is NOT the one for which we have the least It is the one which would be used up FIRST if the reaction had run to completion 39lZ Tl l39iiI395LilllIlHEquoti l 595 E 4 C 395 rsun11pur5 vitiiIn1 If r w 1 15 Eusngle Iji5q11IL39 39nIiE 1 ll A EC 3 E JE139f alSL sTaliaa 5iJ1g e ap1accariEa ru Wrrtollaoloe D5139i39i 3Z39ILZ n1El I1I l i f N3 ifquoti39 quotIi if ffF a391lian rnlsr sI IZiI39F1 l39l39 r139 1v ar1J1quotI iE m I11i1 1t Eampi5I These reaction types are not mutually exclusive The naught symbol indicates standard state conditions Solids may be crystalline or amorphous Crystalline solids 0 Sharp melting point 0 Very definite shape with repeating units of atoms ions or molecules 0 Salts are ionic crystals 0 Metallic crystals single metal atom bonded together by delocalized electrons I Delocalized electrons allow the atom to effectively conduct heat and electricity and they also make them malleable and ductile 0 Ice is a molecular crystal 0 Network crystals are diamond and silicon oxide Amorphous solids such as glass SiO2 have a melting point range Principal quantum number n o Designates the shell level 0 The greater this number the greater the size and energy 0 For the representative elements the principal quantum number is their period in the periodic table o For transition metals the principal quantum number lags one behind the period number 0 For lantahanides and actinides the quantum number lags 2 shells behind the period Azimuthal quantum number 1 0 L n l to 0 o Designates the subshell o Ll is the p subshell o L 0 is the s subshell o Gives the shape of the subshell Magnetic quantum number m 0 From 1 to 1 0 Designates the orbital in which the electron lies Spin quantum number ms 0 May have a value of either 2 or 2 Pauli exclusion principle 0 No two atoms have the same 4 quantum numbers Number of total orbitals within a shell nquot2 Heisenberg uncertainty principle arises from the inherent uncertainty which exists in attempting to place the exact position in space of a particle due to its dual waveparticle nature Uncertainty is on the order of Planck s constant For MCAT momentum is mostly related to the position Hund s rule each subshell must contain at least 1 electron and unpaired electrons in orbitals will have parallel spins Wavelength hmv In photoelectric effect the minimum amount of energy required to eject an electron is the work function Kinetic energy hf work 0 degrees Celsius and 1 atmosphere STP Mean free path distance travelled by a gas molecule between collisions All gases are miscible with one another regardless of polarity 0 However given time and low temperatures heavier gases will logically tend to settle below lighter ones It is possible to cool a gas by increasing its volume When a gas expands kinetic energy is lost At STP any one mole of gas will occupy a volume of 224 Liters if it is behaving ideally Kinetic energy 32RT 0 Also valid for liquids o This is the average kinetic energy for a mole of gas molecules Velocitylvelocity2Square rootm2ml Effusion rate leffusion rate 2 Square rootm2ml Diffusion is the spreading of one gas into another gas or into empty space Volume decreases with increasing pressure or decreasing temperature Low temperatures cause gas molecules to settle close together Gases generally deviate above 10 atm and at temperatures near their boiling point Volume of a real gas is greater than volume of an ideal gas Real gas exerts less pressure than predicted by the ideal gas law Negative deviation from PVRT results from intermolecular forces mainly Positive deviation from PVRT 1 results from molecular volume mainly Kinetics deals with reactions as they move towards equilibrium whereas thermodynamics deals with reactions after they have established equilibrium 0 Kinetics tells how fast equilibrium is achieved whereas thermodynamics tells us what it looks like The rate of ANY reaction increases with temperature 0 This is because more collisions with sufficient relative kinetic energy occur Elementary reaction occurs in a single step Concentrations of intermediates are usually small as they are unstable and react as soon as they are formed The rate law may only be determined by experiment Steps after the ratedetermining step will make NO contribution to the rate law A catalyst creates a new reaction pathway which typically includes an intermediate A catalyst may lower the activation energy or increase the steric factor A catalyst CANNOT alter the equilibrium constant and it increases the rates of both the forward and the reverse reactions A heterogeneous catalyst is in a different phase from the reactants and products Adsorption the binding of molecules to a surface A catalyst increases the energy of collisions Reaction rates can be enhanced by increasing the surface area of the catalyst as this allows for more adsorption sites A catalyst DOES NOT prevent the original reaction from proceeding but adds another altemate better reaction 0 However typically the rate of the original reaction is negligible when compared to the rate of the catalyzed reaction Rate constant of a liquid is a function of the solvent and of the temperature Equilibrium is the point of greatest entropy Equilibrium constant K concentration of products A coefficientsconcentration of reactantsquotcoeff1cients o This equilibrium constant depends on temperature ONLY Do not use solids or pure liquids such as water in the law of mass action The reaction quotient Q describes reactions not at equilibrium whereas K describes reactions which are at equilibrium 0 Q is not a constant and can have any positive value 0 If Q K the reaction is at equilibrium 0 If Q is greater than K the reverse reaction rate will be greater than the forward reaction rate 0 If Q is less than K the forward reaction rate will be greater than the reverse reaction rate Three types of stress which obey Le Chatelier s law 0 Coolingheating of a reaction system 0 Changing the pressure 0 Addition or removal or a productreactant Haber process 0 All gas reaction Exothermic Creates heat N2 3H22NH3heat If we add N2 the system tries to compensate by reducing the parital pressure of N2 in the forward reaction 0 If we add He inert the total pressure increases in the container but there is no change in equilibrium direction There is no shifting I This is because this does not change the partial pressure of the other gases OOOO The solubility of salts generally increase with increasing temperature even if the reaction in question is exothermic Equilibrium WILL probably shift with temperature but the DIRECTION of this shift is dictated by thermodynamics The activation energy does not change during the reaction Macroscopic properties are described via 0 Extensive traits proportional to the size of the system I Volume number of moles 0 Intensive traits independent of the size of the system I Pressure temperature Path functions work heat 0 Depend on the pathway utilized to reach a certain result State functions are pathwayindependent Any energy transfer that is not heat is work Conduction transfer of thermal energy via molecular collisions and this requires direct physical contact 0 In all cases a fatter conduit contributes to ow a longer one impedes ow and rate of ow depends upon a gradient o The order in which we layer slabs or blankets does not affect the rate of conduction Convection ocean air currents 0 Thermal energy transfer via uid movements Radiation 0 Only heat transfer that occurs through a vacuum Thermal energy transfer via electromagnetic waves Rate of radiation depends upon temperature and surface area An object that radiates heat faster also absorbs heat faster An object that is a more efficient radiator comes to equilibrium more quickly 0 Dark colors radiate and absorb better than light colors which tend to re ect A system at rest may still be able to do PV work 0 Constant pressurechange in volume 0 No change in volume no PV work 0 Occurs when a gas expands against a force OOOO In a pressurevvolume graph the area undemeath the curve is WORK Change in energy E Q W o This incurs the convention that work done ON the system is positive if work done BY the system is positive the equation then becomes E qw Temperature is kinetic energymole of gas molecules Heat cannot be completely converted to work in a cyclical process Heat engine converts heat to work Qh wqc 0 Heat entering engine is equal to the workd one by the engine added to the heat leaving the engine 0 This can be reversed to create a refrigerator Work is not a state function and thus we must know the pathway in order to calculate it Thermodynamic efficiency describes what percent of input energy is converted into work 7 state functions ie independent of the pathway taken to get there 0 Internal energy I Includes vibrational rotational translational electronic rest mass energy and intermolecular potential energy I Vibrational rotational and translational energies affect temperature I Intemal energy heat heat energy thermal energy 0 Enthalpy I Enthalpy U PV I Enthalpy is measured in joules Not conserved ENTHALPY OF THE UNIVERSE IS NOT CONSTANT I Depends only on temperature I Extensive property Standard state 25 degrees Celsius Enthalpy of reaction enthalpy of products enthalpy of reactants For constant pressure closed system amp PV work only Enthalpy q heat Pathwayindependent If enthalpy is positive endothermic If enthalpy is negative exothermic On an energy diagram the increase in energy is the activation energya dn the peak of the hill is the transition state where bonds are breaking and new bonds are forming Intermediates exist between the lumps BETWEEN Catalysts do not affect enthalpy Activation energy for an endothermic reaction is greater than that for an exothermic reaction Catalysts affect rate but DO NOT affect equilibrium ENTHALPY OF A SOLID AT STP IS 0 o Entropy OOOO Nature s tendency to create the most probable situation which happens to be a state of disorder Second law of thermodynamics entropy of an isolated system will never decrease Entropy change of forward reaction is equal to negative entropy change of the reverse reaction DICTATES THE DIRECTION OF A REACTION Reactions at equilibrium have achieved maximum universal entropy Entropy must increase in a reaction in order for such reaction to proceed Entropy is an EXTENSIVE property and increase with number volume or temperature ENTROPY OF UNVIERSE WILL INCREASE IN A SPONTAENOUS REACTION ENTROPY OF SYSTEM MAY OR MAY NOT Temperature Pressure Volume Gibbs free energy Is equal to enthalpy the product of temperature and entropy change Best for constant temperature amp constant pressure reactions Equilibrium is when this change in Gibbs free energy is zero constant temperature and pressure reversible process PV work only If negative increase in entropy and spontaneous reaction I Represents the maximum NON PV work that is available to be done by a reaction I Extensive property I Nonconserved in that an isolated system may have changing Gibbs free energy I AT THE BOILING POINT OF A SUBSTANCE GIBBS IS ZERO AS SYSTEM IS IN EQUILIBRIUM Zeroth law of thermodynamics temperature exists For an ide amdjl gas the graph of volumevstemperature is exactly linear Any increase in thermal energy also increases temperature KE 32kT Energy and number of moles are extensive properties Temperature is an intensive property Virtually all physical properties change with temperature The greater the random translational kinetic energy of gas molecules per volume the greater the pressure 0 PRESSURE IS AN INTENSIVE STATE FUNCTION The most kinetically favored reaction is the one with the lowest activation energy The largest energy drop is the one with the biggest energy drop Entropy heattemperature Change in entropy for an irreversible reaction is positive always Solution homogeneous mixture of two or more single compounds of a single phase such as solid liquid or gas Brass is solid solution of zinc and copper In ideally dilute solutions the mole fraction of the solvent is nearly 1 A colloid is like a solution but with larger particles of solute 0 Too small to be separated via filtration 0 large and charged enough to be separated by a semipermeable membrane WORKS dialysis Hemoglobin for example May be any combination of phases EXCEPT GAS AND GAS Foam aerosol emulsion sol Foam is gas in liquid like whipped cream Aerosol is fog smoke or solids in gas Emulsion is a liquid in liquid or solid such as milk or butter Sol is solid particles in a liquid like paint Colloidal suspensions will scatter light in the Tyndall effect I True solutions will not do so 0 solvent equivalent for colloids is called a dispersion medium OOOOOOOO 0 May be lypophilic or lypophobic to this dispersion medium I Protein in water is lypophilic I Emulsi ed fat in water is lypophobic 0 Adding heat or an electrolyte may cause coagulation Ionic molecules are dissolved by polar substances Solvation when an ion is dissolved into its anions and cations Harrie Frmula rLEriEe l Cl39 nitrate l I39n3 smllfite E5L39539D mlfzliee 39iL 39fE l Lf 5C rI E Lla sI i l7E ClCF u 11iritze C lC Equotiuri39z1 te C rlll erua1vr1ampr E39quotlCJ3939 ZELI l3 iE L lquotE39 CGfquot i3939lIZEL139 l i39I391 LEL7E lr39llquotl F f P11Lfa plma e Weak electrolytes form few ions in solution Molarity moles of solutevolume of solution Molality moles of solutekilograms of solution Mole fraction moles of solutetotal moles of solutesolvent Mass mass of solutemass of solution 100 Ppm mass of solutetotal mass of solution l0quot6 Normality mass of acid or base that can fumish or accept one mole of protons o A 1 molar solution of HZSO4 is 2 normal as it can donate 2 protons for each HZSO4 Heat of solution heat needed to braek intermolecular bonds of solute heat needed to break intermolecular bonds of solvent heat needed to form bonds between solvents and solutes 0 First two steps are endothermic and last step is exothermic If a reaction releases energy ie is exothermic this indicates that the ending intermolecular bonds are stronger than the starting material This is because the less energy a system has the more stable it is The opposite is true for endothermic reactions When a solution forms entropy increases Vapor pressure increases with temperature as vaporization is an endothermic process Boiling when vapor pressure of the liquid equals atmospheric pressure Melting when vapor pressure of solid phase equals vapor pressure of liquid phase Nonvolatile solution solute with no vapor pressure Negative heats of solution form stronger bonds and lower vapor pressure In an ideal solution the vapor pressure of the whole solution is somewhere between the vapor pressures of either solute When the rates of dissolution and precipitation are equal the solution is said to be SATURATED In calculating the solubility product always leave out pure liquids and solids Solubility is the maximum number of the moles of solute that may be dissolved in a solvent not to be confused with the solubility product For solubility the order in which you add the solutes is irrelevant A common ion added will shift equilibrium towards precipitation but it will NOT affect the solubility product Compounds with nitrates ammonium and alkali metals are soluble usually Ionic compounds containing halogens are soluble except with silver mercury or lead compounds in which case they are insoluble sulfates compounds are soluble except for lead mercury and heavier ALKALINE metals heavier alkaline metals are soluble when paired with sulfides and hydroxides carbonates phosphates sulfides and hydroxides are generally insoluble except for the above cases when mentioned pressure and temperature are factors which affect solubility 0 pressure on a solid has little effect but pressure on a gas does significantly in uence solubility o solubility k P I P vapor partial pressure of the gas in question I K Henry s constant I C is solubility of the gas in molesliter typically I May also be written as Pressure partial vapor Kmole fraction AS TEMPERATURE INCREASES THE SOLUBILITY OF GASES DECREASES Larger gases tend to be more soluble as they experience greater van der Waals forces Common ion effect example adding a strong base to a saturated solution of calcium hydroxide causes more calcium hydroxide to precipitate and this is because it shifts the equilibrium Le Chatelier s principle If a system is heated while at rest and no PV work is done nearly all the energy goes into raising the temoperature of the system Heat capacity a measure of the energy needed to CHANGE the temperature of a system 0 C qdelta T largely used for heat capacity of entire system 0 Constant pressure heat capacity is greater than constant volume heat capacity 0 Always POSITIVE on the MCAT the heat added will always increase the temperature 0 Assume heat capacity does not change with energy unless otherwise indicated 0 Q mcdelta T largely used as speci c heat capacity of a certain staetd substance 0 Speci c heat of water l caloriegramdegree Celsius Calorimeter measures energy change 0 Coffee cup calorimeter measures energy change at constant pressure which is atmospheric pressure I Measures heat of reaction change in enthalpy I Q change in enthalpy at constant pressure I Use q mcdelta T 0 Bomb calorimeter I Measures energy changes at constant volume I Qchange in intemal energy During phase changes the temperature does not change as the energy is going into breaking the bonds that take the substance from one phase to another Enthalpy change associated with melting heat of fusion Each phase of a substance has its own speci c heat Evaporation occurs when partial pressure above a liquid is less than the liquid s vapor pressure but atmospheric pressure s greater than the vapor pressure Entropy and enthalpy are both positive during melting and vaporization Phase changes at constant pressure are govemed by temperature Triple point point wherein substance can exist in equilibrium as a liquid solid and gas Critical temperature temperature above which substance cannot be liquefied regardless of the pressure applied 0 Pressure required to produce liquefaction at this temperature is called the critical pressure 0 Critical temperature and critical pressure together comprise the critical point Supercritical uid beyond critical point and has characteristics of a uid and a gas On a heating curve you can nd the heat of fusion by measuring the length of the at line representing heat of fusion Colligative properties depend on number not kind 0 Vapor pressure 0 Boiling point 0 Osmotic pressure 0 Freezing point Boiling point elevation equation 0 Delta T kmi I M molality I I number of particles into which a single particle will dissociate when added to solution I A substance boils when its vapor pressure local atmospheric pressure I Molality does not change with temperature I MOLARITY does change with temperature Osmotic pressure 0 Tendency of water or other solvent to move into solution via osmosis o Osmotic pressure iMolarityRT The smaller the cation and the higher the charge the more acidic the substance is pH logH pOH logOH pH pOH 14 many reactions in living cells involve the transfer of a proton if there is an acid in a reaction there must also be a base the stronger the acid the weaker its conjugate base The stronger the base the weaker its conjugate acid Bases taste bitter and are slippery Amphoteric may act as either an acid or a base Sllfilllg urlia1Ei i Elrtr ngj asee I39iiquoti lI39IIiE39 I39ll39lif mir39 H1 0 239i Ll l L lIff L lquotlgquot39Iquot 2l I1 lLlf au39EJ I I1ui m 1 u39cmni39 1iil HEI T l1E II t73ir39i1quotJillititftll iii I t 1LiL f5L2 KUH l1niru 11ulira139eia39 tea39iutl HC ii 39L1quotn39iiri lrr liZf iquotiu quot39a iH mlrvr axi l HHD1 1 jW luidE ismm H l 1a39r39a1EafEac1jl EIL II39 JI i 3939Ei39iLJrquot 39n339 i139 as4iair139 IquotI aI il39J391 i l1lLurin n39icl Allifl i 5u39i i11111i 39 39IJ ilI397llIi39 Tl5al J39 iTi1Elii39 2iLsziiam oxide CEI39l39 Polyprotic acids may donate more than 1 proton 0 Second proton donated is usually so weak that it has a negligible effect on the pH Acids dissociate less in more concentrated solutions Acid dissociation decreases with acid concentration but acid strength increases with acid concentration More oxygens stronger acid Increasing bond strength and increasing polarity decreasing acidity Hydrides can be acidic basic or neutral Hydride acidity increases to the right and down Kw 10 l4 pKw l4 pHpOH pka pkb 14 o in this law of mass action pure solids and liquids are given a value of l Ka greater than 1 or pka less than 0 is indicative of a strong acid Titration curve of strong acid by a strong base For equally strong acid base titrations the equivalence point is usually at pH 7 o HWOEVER FOR STRONG ACIDS WHOSE CONJU GATE BASE IS A STRONG ACID THIS IS NOT THE CASE Titration of weak acid with a strong base is shown below J pH 1 End pomt quotEquiv1lencepoinl quot l 8 1ltmquot A quot 39 39 39 39 39 39 39 39 39 39 39V 39 39 39 39 39 39 39 39 39 39 39 39 P t N r 2 quotquot Half equivalence pomt Y am A I l7 u I pxS I The half equivalence point is when exactly one half of the acid has been neutralized by the base 0 The concentration of the acid is equal to the concentration of the conjugate bae 0 Also shows point in titration where solution is most buffered Hendersonhasselbach 0 pH pka logAHA a buffer is made from equal and copious amounts of weak acid and conjugate base concentration of conjugate base at the equivalence point number of moles of acidvolume of acidvolume of base used to titrate indicator is used to find the equivalence point usually a weak acid whose conjugate base is a different color when concentrations of a weak acid and its conjugate base are equal the pH pka so to find pH just take the log of Ka transition metals change oxidation state according to the metals to which they are bonded reducing agent gives electrons to an atom 0 atom in the reducing agent is oxidized o victim atom is reduced reducing and oxidizing agents are compounds not atoms money metals except nickel do not oxidize spontaneously meaning they have negative oxidation potential values 0 this means they do not oxidize easily 0 this includes silver copper gold platinum mercury the higher the electric potential the stronger the oxidizing agent the lower the electric potential more negative the stronger the reducing agent hydrogen has a reduction potential of 0 reducing and oxidizing are intensive properties do not multiply by coefficients etc galvanic cell tums chemical energy into electrical energy 0 also called a voltaic cell 0 creates an electrical current 0 must have an ionic conductor usually in the form of a salt bridge to prevent build up of electrons on either side of the galvanic cell 0 anode is negative and cathode is positive I electrons move towards the cathode since opposites attract 0 RED CAT AN OX I Reduction takes place at the cathode and oxidation takes place at the anode o The cell potential E is also called electromotive force between the two terminals when they are not connected I Drop in emf increases as current increases Emf decreases as current increases I Cell potential for galvanic cell is always positive There is always available energy here to do work 0 Concentrations are always 1M REQUIREMENT FOR GALVANIC CELLS l39E3939t39ll5liEI E11Ei Ii Enhlciijll ClIh39im E 39 g Ill lul3939 I J lii ll I This means that the anode contains platinum and zinc and the cathode contains copper and platinum 0 Positive cell potential indicates spontaneous reaction I Delta G nFE N moles of electrons transferred in balanced redox reaction F Faraday s constant E EMF work chargevoltage Negative delta G indicates work is being done BY the system not ON the system o IN NONSTANDARD STATE CONDITIONS I Delta G delta G standard RTlnQ 0 At equilibrium there is no energy available to do work delta G 0 at equilibrium 0 Delta G standard varies with temperature standard implying in a cell with 1M concentrations If K 1 then delta G standard 0 and equilibrium exists If K is greater than 1 then delta G is less than 0 0 Thus if equilibrium constant K is greater than 1 the this reaction will proceed spontaneously at standard state If K is less than 1 then delta G is greater than 0 Only an electrolytic cell can have negative electric potential A concentration cell always has nonstandard molarities and thus requires the Nemst equation to solve Galvanic cells are spontaneous Electrolytic cell on the MCAT has negative EMF 0 Here CATHODE IS NEGATIVE AND ANODE IS POSITIVE 0 Yet reduction still takes place at cathode and oxidation still at anode o In an electrolytic cell electrons ow to the cathode Since a concentration cell is a subtype of a galvanic cell in more limited form its reactions also always occur spontaneously Current is coulombs second And current is also known as charge second BIOLOGY Most abundant chemical in any living cell water Cytosol is in aqueous water solution All major macromolecules are broken down via hydrolysis Molecules of a liquid are held in liquid via bonds to other molecules Water has many intermolecular bonds hydrogen bonds which are the strongest type of such bonds Water is a polar molecule so it dissolves other polar molecules but not other nonpolar molecules Amphipathic molecule has polar and nonpolar regions Lipids all lipids are not fat 0 Have low solubility in water 0 Six major groups I Fatty acids I Amphipathic The longer the carbon chain the less water soluble the fatty acid I Short chains are slightly water soluble o Unsaturated have lower melting point 0 Saturated all single bonds connect the carbons int eh carbon chain I Triglycerides I 3 carbon chains dangling from a 3 carbon backbone Each carbon chain is attached by an ester group Adding water to ester breaks it into alcohol and carboxylic acid I Phospholipids I 3carbon backbone I Amphipathic I Cell membranes are made of this I Polar regions face aqueous solution inside and outside the cell I Glycolipids I Like phospholipids but with carbohydrate replacing phosphate I Steroids I Usually carried by lipoproteins LDL and HDL ie I Lipoprotein surrounds lipids by phospholipid and protein shell which does dissolve in the blood I Slightly amphipathic I Terpenes I Form of hydrocarbon including vitamin A Proteins made up of long chains of amino acids HAL basic amino acids histidine arginine lysine Nonpolar amino acids hydrophobic 20 essential amino acids those which body cannot produce on its own Primary sequence includes location of disfulfide bonds between cysteines Held together by covalent bonds Secondary structure is held together by hydrogen bonds between amine and carboxy Amino acid is called a residue when it s incorporated into a polypeptide chain Tertiary structure bending of secondary structure into bended shape or glob Many structural proteins do not have tertiary and quaternary structure DISFULFIDE BOND CREATES TERTIARY STRUCTURE AS DO HYDROGEN BONDS ELECTROSTATIC FORCES BETWEEN IONIC PORTIONS OF THE RESIDUE Van der waals forces also Also hydrophobichydrophilic effects cause tertiary structure Quaternary structure consists of 2 or more polypeptides held together by same ve forces which hold together tertiary structure 0 Each polypeptide here is referred to as a subunit Denaturation disrupts the 5 forces which exist in tertiary and quaternary as well as secondary structure Primary structure being held by covalent bonds are not destroyed Carbohydrates CxH20y Glucose is an aldehydes with 4 chiral carbons o In fischer projections the hydroxyl grups are to right left right right Anomeric carbon is the one that is to the right going clockwise after oxygen in the ring Beta anomer when OH on anomeric carbon points up Alpha anomer when OH on anomeric carbon points down Glucose is stored in long carbohydrate chains glycogen I Each glucose molecule attaches to the next via alpha linkage 0 Plant cell walls are made of cellulose beta linkages 0 Animals can break alpha but not beta linkages Water as always breaks nucleic acids in nucleotides Other important nucleic acids 0 Cyclic AMP O O O O o NADH o FAD 0 ATP Minerals inorganic elements which exist as ions inside and outside cell 0 Establish electrochemical gradients 0 Act as cofactors to enable protein function 0 Form matrix compounds in bone and elsewhere Enzymes increase reaction rate by trillions of times and there is an enzynme for nearly every reaction 0 Lowers activation energy 0 Usually a protein 0 Enzyme is usually larger than substrate I Substrate molecule the enzyme works on 0 There is lock and key theory or induced fit theory Enzyme specificity enzyme must be tailormade for a reaction 0 Saturation kinetics since a single enzyme molecule works on one set of substrates at at ime the reaction rate increases only as long as there are unoccupied enzyme molecules There is a Tmax for the number of enzymes Pepsin has optimal pH between 12 Salivary amylase has optimal pH between 67 Feedback inhibition in enzymes occurs when product of reaction near end of chain of reactions inhibits a reaction early in the chain saving the energy which would otherwise be wasted 0 Competitive inhibition I Will bind to active site I Substrates attach to and release from the active site very rapidly many times per second I Competitive inhibitor can be overcome by increasing substrate concentration 0 Noncompetitive inhibition I Bind to an allosteric site I Does not attach to the active site I Changes shape of enzyme by binding to allosteric site substrate does not fit as well I INCREASNIG SUBSTRATE CONCENTRATION DOES NOT HELP 0 Irreversible inhibition 0 I Covalently bond to the substrate Zymogen or proenzyme inactive form of enzyme Enzyme may be activated or deactivated by phosphorylation or dephosphorylation or by control proteins Enzymes are named with ase in the end Cellular respiration 0 Energy acquiring stages of metabolism which begins by breaking down macromolecules into basic nutrients This step requires energy 0 First step glycolysis Some organisms use other reactions that are similar I TAKES PLACE IN CYTOSOL AND NO OXYGEN REQUIRED I Begins with glucose and produce 2ATP 2NADH and 2 3carbon pyruvates I Fermentation ethanol is formed in yeast rather than lactic acid In aerobic respiration products of respiration are transferred to mitochondrion o In mitochondrial matrix each NADH produces 3 ATP via electron transport chain 0 Inside matrix each pyruvate is converted to acetyl coA which transfers two carbons to oxaloacetate to make citrate to begin CAC CAC 0 Makes 1 ATP 3 NADH and 1 FADH 0 Each NADH is converted to 3 ATP via ETC 0 Each FADH is converted to 2 ATP via ETC 0 One pyruvate one turn of krebs cycle 0 One glucose 36 ATP s for two runs of CAC ETC 0 Series of proteins called cytochromes embedded in inner membrane of mitochondrion 0 Use energy of electrons to pump protons into intermembrane space leaving the space with a low pH 0 ATP syntahse is an integral protein of this membrane that allows protons to ow back into the matrix I Uses energy of electrochemical gradient between intermembrane space and matrix to produce ATP Aerobic respiration o Oxidation or combustion of glucose 0 Glucose oxygen goes to carbon dioxide and water 0 Oxygen is final acceptor in ETC Triglycerides 0 Broken into glycerol and fatty acids 0 Glycerol enters glycolysis in middle 0 Fatty acids transported into matrix in mitochondrion and are converted to acetyl coA where 2 NADH are made for every 2 carbons of fatty acid 0 Amino acids enter at various portions of process depending upon AA Protein may be made of one or several polypeptides One gene one polypeptide For most proteins eukaryotes have just one copy but for genes encoding for tRna rRNA and heterochromatin cell contains multiple copies For most proteins one significant mutation causes cell to completely lose that protein Phosphate group in DNA is attached to 5th group on each pentose DNA replication is bidirectional 0 Process begins at middle of double stranded DNA and replication proceeds along both directions 0 DNA helicase unzips the helix 0 Replisome holds helicase and DNA polymerases moving in a single unit along the DNA 0 Moves from 35 direction but operates in the 53 direction 0 DNA ligase ties together okazaki fragments in lagging strand rRNA is synthesized in nucleolus half life of RNA is typically only 30 minutes much shorter than half life of DNA transcription must take place only in nucleus and in mitochondrial matrix 0 begins when initiation factors find a promoter on the DNA promoters in a given species are all similar most common promoter a consensus sequence in prokaryotes promoters may be followed by several genes called an operon in eukaryotes promoters are usually followedby only one gene RNA polymerase synthesizes from 53 Transcription is much slower than replication and has less fidelity I No proofreading and repair system 0 Primary RNA typically contains Introns Post transcriptional processing 0 May consist of nucleotide addition or modification of bases 0 Usually only occurs to rRNA and tRNA in prokaryotes Vector a virus PCR polymerase enzyme is used from Archaea and piece of desired DNA is mixed with many copies of primers 0 Mixture is heated to denature the DNA 0 When cooled primers attach to the SS DNA 0 Mixture is heated again 0 Polymerase replicates the strands 0 Each run doubles the DNA mRNA moves into cytoplasm via nuclear pores and into the ribosome ribosome is made of Large and Small subunits 0 large subunit has E P A sites A site is AA site P is polypeptide site mRNA lines up on large subunit tRNA containing anticodon sits in P site while second tRNA lines up behind it with its amino acid in A site takes place in cytosol or on rough endoplasmic reticulum o if translation occurs in cytosol protein usually works in the cytosol If occurs in RER polypeptide is thrust through RER and into lumen inside space or cavity Down Syndrome is a chromosomal aberration Silent mutation alters codon but not the amino acid Change in amino acid sequence missense mutation Nonsense mutation stop codon in middle of chain Deletions and insertions alter the codon reading frame frameshift mutation 0 Unless they occur in multiples of three Transposition a small ring of DNA is removed from chromosome and transposed to another section Forward mutation for instance if a bacterium lacks the ability to make histidine a forward mutation would be the loss of the ability to make another amino acid OOOOOO O OOOO Most DS DNA is wrapped tightly around histone proteins Humans have 46 chromosomes Cells with homologous pairs of chromosomes diploid cells Chromosome pair 23 designates gender in humans I Cell life cycle processes 0 Interphase I G1 first growth phase Cell is split and energy is devoted to growth in size I S phase where energy is devoted to replication I G2 cell prepares to divide Appropriate cellular organelles double in number 0 Mitosis I Mitosis 0 Nuclear division 0 Prophase chromosomes condense Nuclear membrane disintegrates Centrioles move to opposite cell poles Spindle apparatus is formed by microtubules o Metaphase chromosomes line up along equator of spindle forming metaphase plate 0 Anaphase sister chromatides split and move to either pole Split is called disjunction Cytokineses may begin as early as this and is accomplished through microfilaments o Telephase nuclear membrane reforms and chromosomes recondense 0 Net result two genetically identically daughter cells I Meiosis o 2 divisions and only germ cells undergo meiosis o Spermatogenesis I Meiosis of spermatogonium gonna be a sperm I Diploid cell I After S phase spermatogonium becomes a primary spermatocyte still diploid I Undergoes meiosis I In prophase I each chromosome synapses with homologue Just lining up I Resulting group is called tetrad I Crossing over occurs here I 1 form of genetic recombination I Longest stage of meiosis I Metaphase I tetrads line up at spindle equator I Chiasmata points where crossing over occurs I Anaphse I I Chiasmata are torn apart I Centromeres remain intact I Homologgues are separated I Telephase I I Does not always occur I Nuclear membrane reforms I Net result of Meiosis 1 reduction division Reduces ploidy number Creates 2 haploid cells secondary spermatocytes No homologous pairs I Meiosis 2 is just like mitosis o Oogenesis I Male spermatogenes producse 4 gametes through meisosis I Oogenesis producse only 1 gamete I At time of birth all eggs are arrested at primary oocytes stage I At puberty menarche occurs where upon one primary oocytes undergoes meiosis I At each nuclear division a small nuclear body rather than an entire cell is released I Polar body formed during reductiondivision may or may not occur meiosis 2 I Oocytes produces polar bodies in order to conserve cytoplasm Oogonium produces only 1 gamete I MCAT is mainly concerned with humans I Viruses are comparable in size to large proteins Protein coat on virus capsid Inside are nucleic acids and sometimes proteins Most animal plant and bacteriophaagse have lipid rich envelope borrowed from lipid membrane of host cell gained via reverse endocytotic process Bacteriophagse have icosahedral capside 20sided 0 Have a tail and tail fibers 0 Tail fibers attach on protein receptor on the host cell Living organisms possess both DNA and RNA and are capable of reproduction without enzymes form another cell Viruses are species specific Once viral material is inside cell a lysosome attaches to the phagosome Viral capsid never has to transport across membrane because it is released into cc cytosol Lytic cycle and lysogenic cycle 0 Lytic is immediate o Lysogenic is latent Viral nucleic acids become incorporated in host cell genome Often inactivated by stress to become lytic I Provirus or prophage Virion inactive form of a virus Metabolically inactive but ready to infect a new host cell Virus may possess single or double stranded DNA or RNA in or strand RNA Reverse transcriptase reverse transcribes RNA to DNA HIV Viroids infectious pieces of naked RNA Only infect plants Prions single protein molecule capable of reproducing without using DNARNA mad cow disease All bacteria are prokaryotes with no membranebound nucleus No complex membranebound organelles 70S ribosomes30S50S Eukaryotes are 80S ribosomes40S60S Bacteria have Double stranded DNA Membrane establishes concentration gradients between inside and outside of cell 0 Semipermeable to almost everythingpermeable to a degree Also selectively permeable Size and charge determine how easy it is for a molecule to passively diffuse across a membrane without the use of a carrierprotein channel without using energy Facilitated diffusion is passive transport and must be in direction of electrochemical gradient as opposed to active transport such as sodium potassium pump Secondary active transport electrochem gradient of one molecule is used to pump another molecule across membrane at times against its gradient Does not use ATP directly but rather indirectly Bacteria can be gram positive gram negative depending how they stain Gram positive purple Gram negative pink Gram negative can contain fimbriae or pili Bacterial agella is very different from human agella Made from protein agellin Polymerized to make a long slender helix and rotate powered by a proton pump Move via run and tumble Bacteria move by chemotaxis Bacteria reproduce by binary fission no genetic recombination in this method Bacteria can recombine genes via conjugation transduction and transformation Conjugation bacterium with F plasmid transfers its genetic material to its F partner F is needed for sex pilus Transformation bacteria pick up naked DNA from its environment Transduction transfer of genetic information through a vector such as a virus Endospore high resistance to heat and lethal agents Botulism caused by endospores In order to grow all organisms require carbon energy and electrons Carbon source may be organic or inorganic Organisms that can use CO2 as carbon source autotrophs Heterotrophs rely on organic matter for carbon Energy comes from sun or chemical reactions Gain e from inorganic matter lithotrophs Gain e from organic organotrophs Fungi divides into divisions not phyla All fungi are exodigesters spit on food lie in it and absorb its nutrients Many are considered saprophytic eat dead matter Possess septa cell walls made of chitin Hyphae tangled mass of thread like structure Entire tangled mass mycelium Most life is haploid and capable of asexual reproduction More likely to reproduce asexually in GOOD conditions More likely to reproduce sexually in BAD conditions since its offspring may have genetic variation so it is better able to survive conditions may not be bad for an offspring which is different from either parentIMPORTANT Spores haploid Yeast single celled fungi that evolved from multicell ancestors Produce asexually via fissionbudding Facultative anaerobes that produce ethanol Protists eukaryotes All eukaryotes have a nucleus that contains cell s genetic material chromosomes Surrounded by nuclear envelope double phospholipid bilayer TWO bilayers with a narrow lumen in between RNA leaves nucleus via nuclear pores Nucleolus makes subunits of ribosomes Endocytosis 3 types phatocytosis large material pinocytosis small material and receptor mediated endocytosis All mediated by membranebound proteins In vertebrates only certain white blood cells are capable of phagocytosis Many cells are capable of pinocytosis nonselective method RME specific uptake of macromolecules hormones nutrients Cholesterol is taken up by RME Endosomes represent lumen side of the cell ER separates lumen side from cytosol side of the cell Rough ER appears like at sacs with little black dots dots ribosomes Translates proteins Once in ER lumen proteins go to Golgi apparatus Lysosomes are vesicles that are full of hydrolytic enzymes and bud off of Golgi Work best in acid 0 Break down macromolecules into nutrients and waste products Peroxisomes catalyzes condensation reactions opposite of lysosomes Detox alcohol oxidize hydrogen peroxide DO NOT bud off from golgi Multiply by fission Smooth ER tubular sacs Acts in lipid synthesis especially phospholipid synthesis Detoxifies poisons in liver cells Controls calcium concentration in cytosol Cytoskeleton aids in movement of cellular materials and movement of cell itself Made of microfilaments and microtubules Microfilaments made of polymerization of actinProvide structure for cell and scaffold for movement Microtubules are made of tubulin Major MTOCcentrosome Flagella and cilia are made of microtubules Flagella wiggles to move uid directly away to propel cell as in sperm Cilia acts in whiplike fashion to move uid rapidly Both made in 92 arrangement Mitochondria two membranes Inner has many folds called cristae Space between inner and outer intermembrane space Have own circular DNA Believed to have evolved via endosymbiosis Glycocalyx on exterior surface of cell Important for recognition of other animal cells Allows microbes to recognize host cells and infect them Cancer cells have abnormal glycocalyx Gap junctions little tunnels between contiguous cells to allow passage of ionsnutrients In cardiac and smooth muscle tissue to allow action potential to spread Tight junctions create water tight barrier Serve as barrier to lateral movement of membrane proteins Desmosomes occur usually with tight junctions Matrix made from collagen or plastin to hold cell in place Tissue with extensive matrix connective Single celled organism can have sustained life on its own Multi celled organisms cannot live on their own Tissue epithelial connective muscle and nervous these 4 types in vertebrates 3 systems for communication nervous paracrine and endocrine Neurotransmitters travel short distances Paracrine hormones such as prostaglandins travel millimeters and endocrine hormones travel all over the body Nervous system fast and direct Opposite of endocrine system Neuron cannot divide as it is so specialized Depends on glucose only for energy Transfers signal from dendrites to soma to axon terminals Action potential begins in axon hillock Neuron is positive on outside and negative on inside Resting potential is negative relatively Sodiumpotassium slowly leak across cell membrane Resting is an equilibrium between pumping and leaking rates When sodium rush into cell potential goes up depolarization Minimum change of potential threshold potential Sodium channels are inactivated immediately after opening From repolarization to Hyperpolarization absolute refractory period cannot create another action potential During Hyperpolarization relative refractory period difficult to create another action potential Synapse is where neuron transfers signal to next cell Space between cells synaptic cleft Impulse causes calcium voltage gated ion channels to open Neurotransmitters are spilled into synaptic cleft via exocytosis Unidirectional process Neuroglia support cells Schwann cells and oligodendrocytes contain myelin which wrap around axon and insulate it Allow for salutatory conduction which is much faster than normal transfer of action potential Myelinated axons white matter SAME DAVE sensory is afferent motor is effort Dorsal is afferent ventral is efferent Central nervous system brain and spinal cord and contains interneurons CNS job is integration Peripheral everything else somatic and autonomic parts Somatic is voluntary and innervate skeletal muscle Autonomic are involuntary and innervate smooth cardiac muscle glands and visceral organs Both these parts are divided into sensory and motor neurons Autonomic nervous is divided into sympathetic and parasympathetic areas Sympathetic fight or ight and parasympathetic is rest and digest Muscle gland or organ is usually innervated by both Intestines are Inactivated by sympathetic and are ACTIVATED by parasympathetic unusual Ganglion group of cell bodies in peripheral nervous system Effectors target tissue glands or organs All neurons in PNS use acetylcholine as neurotransmitter except post ganglionic sympathetic neurons which use epinephrine Brain medulla oblongata controls breathing heart rate Cerebellum controls balance equilibrium and muscle coordination Prefrontal cerebral cortex elaboration of thought Hypothalamus hunger thirst sex pleasure pain blood pressure and water balance Eye lens focuses images on the retina Retina is at back of eye and made of rods and cones Rods light and dark Cones colors Iris is group of smooth muscles making opening of eye Ear outer ear contains ear ap or pinna and auditory canal Auditory malleus incus and stapes that transfer sound energy from ear drum to inner ear at oval window Cochlea in inner ear transduces sound to electrical signal Semicircular canals in inner ear monitor position orientation and acceleration of head why cats always land on their feet Exocrine glands release enzymes to external environment via ducts sweat glands ie Endocrine glands release general hormones directly into blood without ducts Each endocrine hormone requires a protein receptor Metabolic activities growth and reproduction Classes of hormones peptides tyrosine derivatives and steroids Peptide hormones may be big or small and often include carbohydrate portions Made at rough ER usually Modified twice before it becomes an active hormone Water soluble and dissolve in blood and can t pass lipid bilayer Once peptide hormone attaches to receptor a second messenger system is activated such as a G protein which may either stim or inhibit another protein called adenylate cyclase which increases cAMP which activates protein kinase which phosphorylates or dephosphorylates an enzyme Second messenger system magnifies effect exponentially Each step involves more and more molecules Steroids similar and usually derived from cholesterol Lipid soluble rings Made at smooth ER and in mitochondria Usually have protein carrier to take through blood and diffuse through lipid bilayer Act at level of transcription in nucleus Adrenal cortex gonads and placenta produce steroids Tyrosine derivatives thyroid hormones and catecholamines epinephrine and Norepinephrine Catecholamines behave like peptides and thyroids behave like steroids Know negative feedback Hypothalamus controls secretions of pituitary glands Posterior pituitary does not produce hormones but hypothalamus produces them PP only releases Pituitary only makes peptide hormones Anterior pituitary releases FSH LH ACTH TSH prolactin and GH ACTH stimulates adrenal cortex to release glucocorticoids Prolactin promotes mammary gland development and milk production GH stimulates growth by increasing transcriptionlation GH somatotropin Posterior pituitary releases vasopressin ADH and oxytocin Oxytocin causes milk letdown and uterine contraction Thyroid is just below larynx Makes Calcitonin T4 and T3 T4 and T3 are lipid soluble and their effect is to increase gene transcription T3 and T4 increase basal metabolic rate and act on nearly all cells Calcitonin lowers plasma calcium concentration and increase calcium in bone Decreases osteoclast activity Parathyroid set of 4 tiny glands attached to thyroid which secrete PTH which increase production of osteolasts and increase absorption of calcium in kidneys and intestines Also affects phosphate secretionabsorption depending on organ Pancreas behind and below stomach Endocrine and exocrine gland Endocrine islets of Langerhans Alpha cells secrete glucagon Beta secrete insulin Glucagon stimulates glycogenolysis and gluconeogenesis in liver Both make glucose Insulin small protein and causes 80 of body to become more permeable to glucose by new formation of protein channels Does not affect neurons When cells become mor permeable to glucose blood glucose goes down Glucagon raises blood glucose Adrenal cortex sit atop kidneys two glands per kidney cortex and medulla Cortex is outside medulla is middle of it Cortex makes only steroids Medulla makes Norepinephrine and epinephrine Aldosterone made in cortex and is mineralocorticoid Increases blood pressure Reabsorbs sodium and pulls in water along with sodium Does not increase concentration of sodium that much since water follows and dilutes it Cortisol glucocorticoid Stress hormone and stimulated by stress conditions Increases blood glucose by mobilizing fat and proteins to make glucose Increases glucocneugenesis and suppresses immune system currently unclear Adrenal medulla is made of chromaf n cells Spermatogenesis is in seminiferous tubules Testosterone hardens epiphyseal plates of long bones Sertoli cells nurture sperm Immature sperm matures in epididymus Prostate bulbourethral and seminiferous add uid to ejaculate uid Oogonia in ovary become primary oocytes in fetal stage Arrested at birth At puberty FSH stimulates zona pellucida to form from granulosa cells Theca cells develop around oocytes and relase androgens Follicle is this complex which bulges from ovary via positive feedback resulting from luteal surge rapid increase in Lh concentration o cause ovulation Follicle bursts upon ovulation Fimbriae sweep oocytes into fallopian tubes and cilia sweep it to uterus Fertilization usually occurs in fallopian tube Placenta secretes estrogen hCG and progesterone Egg undergoes meiosis I and II after penetration by sperm Zygote then undergoes cleavage and becomes morula which is dense body Undergoes blastulation to become blastocyst which is uid filled Invaginates to form gastrula Blastopore becomes mouthanus Deuterosomes make new hole for mouth Formation of three cell layer occurs in gastrulation Ectoderm mesoderm and endoderm Any molecule that can be broken down into nutrients undergoes hydrolysis Food goes mouth esophagus stomach SI LI anus Pancreas liver and gall bladder dispel chemicals into duodenum in SI Digestion begins in mouth via salivary amylase which digests carbohydrates chemically Chewing is physical digestion Tongue assists in making and swallowing the bolus which is partially voluntary and involuntary Epiglottis covers opening of wind pipe to allow swallowing to esophagus Most important job of stomach is store food and releaes little bits of food at a time into intestine Physically digests food by churning Low pH to denature proteins Four cell types mucus parietal G and chief cells Mucus cells protect from acid Parietal release HCl into lumen G cells release gastrin into capillaries around stomach Chief cells secrete pepsinogen inactive pepsin that is activated by HCl Optimal pH of pepsin 2 Stomach makes food into chyme which is released into small intestine bits at a time Surface of each villus is composed of many enterocytes Villi function to increase surface area of SI Microvilli appear fuzzy under microscope and this is brush border with many digestive enzymes Pancreas secretes bicarbonate ion to buffer solution in SI Trypsin amylase lipase and nucleases are also secreted by pancreas Releases at least one molecule for each type of macromolecucle in living cells Trypsinogen is activated to enterokinase and trypsin activates the other enzymes Lipase works to break down lipids especially triglycerides Fat coagulates in SI and it is emulsified by bile which is a physical process of secretion Bile is secreted by liver and gall bladder Duodenum digests J ejunum and ileum do absorption Maj or role of large intestine is to absorb water E coli has mutualistic relationship with humans in L1 by providing vitamins K B12 thiamine and ribo avin Food can only be absorbed if broken down into most basic nutrients Sucrose and lactose disaccharides Chitin is in insect exoskeletons and also in fungi mushrooms ie Animals can t digest cellulose or chitin Lactose glucose and galactose Glucose and galactose are absorbed via secondary active transport mechanism in SI Fructose is absorbed via facilitated diffusion Digestion of protein begins in stomach where HCl denatures it and pepsin attacks middle of polypeptide chains Trypsin and chymotrypsin break down polypeptides into di and tripeptides Most dietary fat triglycerides Micelles are amphipathic molecules FIGURE OUT HOW FATS TRANSPORT Maj or role of liver regulate glucose concentration in blood Has sinosoids to facilitate gas and nutrient exchange Can expand to store blood Also destroys irregular red blood cells Makes most of body s lipoproteins Filters blood Metabolizes fats carbs and proteins Detoxification also Cardiovascular system delivery of nutrients oxygen removal of wastes redistribution of heat transport of hormones Trace a drop of blood right atrium is on left side of the page Left ventricle is strongest part of heart as it must pump blood through entire systemic portion Pulmonary carries blood to lungs to be oxygenated Left ventricle blood goes into aorta Arteries take blood away from the heart Arteries carry oxygenated blood in systemic system opposite of pulmonary system Arteries are elastic and stretch as they fill From aorta goes to arteries arterioles capillaries venules veins and into vena cava Capillaries are one cell thick approx equal to diameter of red blood cell Gas and nutrient exchange occurs across capillary walls Hydrostatic pressure decreases from aorta to vena cavae Osmotic pressure remains constant along capillaries Net pressure force due to hydrostatic and osmotic pressure pushes uid out of capillaries At venule end net pressure pushes uid back into capillaries 10 net loss of uid to interstitial space as blood is passed from one end of capillary to the other Total cross sectional area is greatest at capillaries and velocity is lowest here to allow more time for gasnutrient exchange Vena cavae empty into right atrium which lls right ventricle which feeds pulmonary arteries Pressure decreases as blood moves from pulmonary arteries to pulmonary veins Heart contracts starting at atria and then to ventricles Contraction is created by action potential electrical stimulus which starts at SA node in right atrium SA node is made of myocytes that spontaneously contract at a rate faster than normal heart beat SA node is innervated by vagus nerve parasympathetic which slows heart rate Action potential then spreads via gap junctions in intercalated discs and hesitates at AV node then enters ventricles carried down bundle of His and out across Purkinje fibers Contraction of ventricles systole Signal for breathing begins in medulla oblongata of brain and runs to diaphragm When diaphragm contracts it expands volume of chest Air is pushed into lungs When diaphragm relaxes volume decreases and raises pressure Recoil of lungs drives the air out Nasal cavity lters moistens and warms hair Wind pipe lies in front of esophagus and larynx is at top of it and contains vocal cords Trachea wind pipe Trachea is ciliated to move trapped particles up towards pharynx and branches to become right and left primary bronchi which branch to form bronchioles which end in alveolar sacs Air we breathe is 21 oxygen and 79 nitrogen Nitrogen doesn t react with anything in the body since N2 is so stable CO2 mixes with water in presence of carbonic anhydrase to make carbonic acid As lungs remove Co2 concentration of carbonic acid decrease and pH of blood rises Hemoglobin is inside red blood cells and has four polypeptide chains as subunits Each polypeptide has heme group to hold one iron atom One iron binds to one oxygen atom When first hemoglobin binds affinity of other hemoglobins to bind oxygen increase cooperative binding and this is affected by many conditions such as 23BPG Also affected by partial pressure of Co2 temperature pH and H ions H Co2 BPG and increase in temperature increase hemoglobin affinity of oxygen Heat is produced by breakdown of glucose Products of respiration stimulate hemoglobin to drop off oxygen at tissues Myoglobin has only 1 subunit and does not have cooperativity Not affected by H CO2 or BPG Oxygen dissociation curve compares percent oxygen saturation of hemoglobin and Oxygen partial pressure Oxygen dissociation curve for hemoglobin is sigmoidal caused by presence of BPG Curve shifts to right in presence of H Co2 and heat Myoglobin curve is not sigmoidal but rather to the left of hemoglobins and has parabolic shape Fetal hemoglobin has curve to the left of maternal hemoglobin Chloride shift as blood enters lungs it drops off CO2 Chloride is released from cell as bicarbonate enters As a result arterial red blood cells contain fewer ions than venous red blood cells Lypmph system recycles interstitial uid Drains this and empties into blood and empties at right lympathic duct and at thoracic duct Does NOT drain CNS Thoracic duct services left arm and rest of the body It is an open system as opposed to circulatory system Uses skeletal muscle contraction body movement and arterial pulse to move uid through lymph system Also monitors blood for infection Blood plasma buffy coat and hemotocrit volume occupied by red blood cells 55 in men and 45 in women The higher hematocrit the more viscous the blood Buffy coat is volume of white blood cells Plasma is aqueous with proteins such as albumin and immunoglobulins antibodies and fibrinogen Serum is plasma without clotting factors Erythrocytes red blood cells have no organelles and live for about 120 days All leukocytes function as part of immune system 0 Granulocytes stay in blood for hours only then live in tissue for 45 days 0 Neutrophils phagocytotic cells that indiscriminately attack foreign invaders Release antibiotic proteins against bacteria fungi and viruses 60 of leukocytes in cells Basophils and mast cells release histamines Monocytes are immature and become macrophages in tissue Megakaryocytes remain in bone marrow and form platelets which are little pieces of cells B and T lymphocytes which are involved in acquired immunity Innate immunity non speci c and offers protection against substances indiscriminately Includes all white blood cells other than lymphocytes Also skin stomach acid In ammation is immune response caused by histamines prostaglandins and lymphokines Some of tehse activate macrophages Blood vessels dilate in in ammation to increase blood ow to in amed area Granulocytes and monocytes migrate to in amed area and swells to impede progress of foreign agent to other areas of body Two types of acquired immunity humoral and cell mediated and both are initiated by antigens Antigen illicit an immune response Humoral immunity involves creation fo antibodies by B lymphocytes Antibodies are formed in lymph tissue and attack matching antigens B cells develop in liver and mature in bone marrow When macrophages phagocytize a foreign invader the metabolize it and display its antigens at its surface If B cell with matching antibody protein nds this macrophage and helper T cells are present the B cell is activated T cell releases lymphokine that superaftivates B cell Upon activation B cell is differentiated into plasma cells and memory cells Plasma cells grow large and multiply and secrete antibodies Memory cells look jus tlike original B lymphocyte in case antigen comes back in the future This is all called the primary response requires 20 days to reach full effect once body acquires memory cells secondary response requires 5 days for full potential and usually makes body immune to particular disease Antibodies can activate a protein complement cascade which attracts macrophages and Neutrophils and activates them Can also rupture cell membrane of invader or cause them to agglutinate Activates basal cells and mast cells Antibodies can also cover toxic site of a toxin Cell mediated immunity T Cell immunity mature in Thymus Single T lymphocyte carries thousands of antibodylike proteins Proliferate into memory T cells and killer T cells when differentiated Memory cells are for the future Killer T cells bind to antigen carrying cell and secretes perforins to perforate cell membrane and cause lysis They kill many cells without dying themselves as they do not phagocytize but rather just puncture other cells Suppressor T cell prevents T cells from destroying healthy cells 4 major blood types A B AB 0 named for type of antigen the blood cell carries on its surface 0 blood has neither A nor B antigens A blood does not make A antibodies and so on for the rest 0 is universal donor AB is universal receptor as it does not make any antibodies A and B are codominant and expressed without blending or blood is Rh factor Rh positive can receive or blood as it doesn t make antibodies Rh does not have antigen on blood Important in pregnancy If pregnant woman is rh and fetus is Rh blood may mix in delivery causing blood to make antibodies Only a problem for future pregnancies and may cause anemia in it as antibodies can move through placental barrier Muscle functions body movement stabilization fo position moving substances through body generating heat to maintain body temperature Muscle cells can only pull Skeletal muscle cardiac and smooth are the 3 types Skeletal muscle voluntary Connect via tendons to bone Ligaments connect bone to bone Muscles function in agonistantagonist pairs Sarcomere is made of actin and myosin and is striated Actin thin filament and myosin thick lament Laid side by side to form sarcomere Many sarcomeres are stacked to form myo bril which is wrapped in sarcoplasmic reticulum which is double phospholipid bilayer Several wrapped are wrapped again by sarcolemma which is muscle cell membrane Muscle cell muscle fiber Skeletal muscle cell is multinucleated and cannot divide Sarcolemma has T tubules as tunnel like structures Action potential spreads into T tubules to rapidly deliver action potential to sarcoplasmic reticulum Parts of sarcomere that get smaller in contraction H zone and I band Tropomyosin blocks myosin heads from attaching Sarcoplasmic reticulum releases calcium when action potential comes and calcium enters cytosol and bind to troponin which is attached to tropomyosin to pull it back and reveal attachment site for myosin head Myosin head binds to actin and pulls hard ATP is needed to attach to myosin head to cause it to release the action ATP is hydrolyzed and bends back to original position In rigor mortis myosin head must stick to actin Body controls amount of muscular force using motor units Large motor units one neuron innervates many muscle fibers Motor units are red sequentially from small to large until desired force is reached Fingers have small motor units Back has large motor units Slow twitch type I slower to contract and slower to fatigue Less powerful Calf muscles have mnay of these fibers Biceps have many type II fibers Muscles grow by hypertrophy Cardiac muscle striated Uninucleated Not attached to a bone Connected via intercalated disks at their ends with gap junctions Involuntary innervated by autonomic nervous system just like smooth muscle Smooth muscle is not striated Two types of smooth multi unit and single unit Multi unit smooth muscle each fiber is capable of independent contraction Iris and piloerector muscles Usually innervated by one neuron Single unit smooth muscle hundreds of fiber contract as a single unit Syncytial arrangement just like cardiac muscle Sometimes also called visceral smooth muscle Bone is living tissue has many functions support of soft tissue protection of internal organs assistance in movement mineral storage blood cell production energy storage as adipose cells Body can resorb bone Fat is stored in bone marrow Long bones are curved for strength Short bones are Cuboidal ankle wrist Flat bones have large areas for muscle attachment sternum skulletc Compact bone surrounds all types of bones and made of osteons Forms when osteoclasts burrow through compact bone to form a tunnel Osteoblasts follow along sides of Osteon reforming bone as they go Spongy bone has red bone marrow which also contains adipose cells and macrophages Yellow bone marrow adipose tissue Blood lymph vessels and nerves are found in osteons Remodeling process of bone is continuous Cartilage is exible resilient connective tissue Made from collagen and chondroitin sulfate for elasticity to return to original shape Cells are called chondrocytes with no blood vessels or nerve except for parachondrion Joints are in any place two or more bones meet Fibrous cartilaginous and synovial are 3 types of joints Fibrous has little movement Cartilaginous has limited movement Synovial have much movement such as knees and elbows If both alleles are same for a characteristic homozygous If alleles are different heterozygous Expression of a trait phenotype Each gamete receives only 1 allele by a random process Law of segregation implies complete dominance Two traits are separate and do not blend to form the phenotype Alleles for a given characteristic are found at same locus on chromosomes and gamete receives only one of these Punnett squares are needed for MCAT Law of independent assortment alleles for different characteristic have equal likelihood of going to same or different gametes Only good for characteristics whose alleles are found on separate chromosomes Phenotype of dihybrid cross 933l Incomplete dominance blended expression Codominance both traits are exhibited AB blood type ie Complementarity two genes are mutually dependent upon each other to exhibit wild type Epistasis one gene in chain depends upon another but reverse is not true Collaboration two genes together produces a completely different phenotype Penetrance percentage of those individuals carrying a gene who also express its phenotype Expressivity how the phenotype is expressed Recessive mutations are abundant in populations Heterozygote advantage ie sickle cell anemia and malaria dynamic Inbreeding increases percent of homozygosity resulting in more homozygotic recessive diseases Males lack diploid protection for diseases at the sex chromosome Whatever a male receives from mom whether dominant or recessive he expresses that phenotype ie hemophilia or colorblindness In somatic cells in females one sex chromosome condenses into a Barr body in a random process ie calico cats If half cells express dominant allele dominant phenotype results Holandric traits found on y but not x chromosome Most common is the hairy pinna Evolution change in gene pool Not necessarily the change in phenotype King Philip Came Over from Germany Kingdom phylum class order family genus species Genus is capitalized and species is not Both written in italics Humans phylum chordate Class mammalia order primata Vertebrata is a subphylum of chordata Chordate o Bilateral symmetry Deuterostomes Coelom Notochord Pharyngeal slits Dorsal hollow nerve cord 0 Tail Niche is the way species exploits its environment No two species can occupy a niche indefinitely 0 One will always utilize the niche more effectively Species organisms which can reproduce fertile offspring in the wild Isolations prevent breeding and lead to development of new species Types of isolation geographic seasonal behavioral mechanical gametic incompatibility developmental isolation hybrid isolation Founder effect initial members that were isolated are different from remaining members Allopatric geographically isolated Sympatric share a habitat Fit surviving reproducing and ensuring that offspring reproduce K strategists o Ensures survival of offspring Few offspring Elephant Do well in stable habitats with higher competition for limited resources Better in density dependent factors 0 Growth curve is sigmoidal until carrying capacity R strategists 0 Many offspring Growth curve is sigmoidal until carrying capacity Better in density independent factors Frog For shortlived unpredictable habitats with plentiful resources Mate early Grow rapidly o Shorter life spans Divergent evolution as groups of same population develiop away from eachc other becoming more different Convergent evolution similar structures form on different species as they adapt to similar environmental issues Wings on bats and birds Structures are called homoplasties Mutualism both species benefit as in E coli and humans Commensalism one benefits and one is unaffected as in birds nesting in trees Parasitism one species benefits and the other is harmed OOOOO O O O O OOOOOO Hardy Weinberg gene pool is likely to remain constant under following conditions 0 OOOOO Mutation equilibrium Large population Immigration doesn t alter gene pool Random mate selection Reproductive success is random PA2 2pq qquot2 l Pql Q is recessive alleles and p is dominant alleles Pq is heterozygotes Universe came into being 1215 billion years ago Hot matter was thrown outwards in all directions outwards Solar system arose 10 billion years ago Earth formed 45 billion years ago Life arose 36 billion years ago in heterotrophic prokaryote Chemosynthesis then photosynthesis followed 5 million years ago ancestral line separated from chimpanzees 10k years ago first city was founded
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