BIOL FOR SCI MAJ I
BIOL FOR SCI MAJ I BIOL 1201
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LECTURE PRESENTATIONS For CAMPBELL BIOLOGY NINTH EDITION Jane B Reece Lisa A UIry Michael L Cain Steven A Wassel39man PeterV Minorsky Robert E Jackson Chapter 7 Lectures by Erin Barley Kat een Fitzpatrick FNfembrane Models Scientific 7 339 Inquiry 39 Cellular membranes are fluid mosaics of lipids and proteins Hydrophilic head Hydrophobic ta 91912 Fig 7 1 Fig 7 3 gt Lu a 393 9396 3 39v 7399 gzzzgsagto39 a 0V gt wow 39 Phospholipid bilayer l bl suing as Pearson Ben Hydrophilic regions of preteih Hydrophebiie regions of refein Fig 7 4 ii EQlHl39ii iiiliQilgilE Extracellula Proteins Inside of extracellular layer Plasma membrane Cytoplasmic layer s Conyllgh 2005 Pearson Education inc publishing as Pearson Bamamin cummian 91912 Inside of cytoplasmic layer Fig 7 5 bdmnbnum FluidiQy 1 le yaw it rr Lil liiiiiiliil twigsti i ijJJn Liais c 39nr p39m m PWJ b39 39 39 39 iHH HHVlHHE s s A A v P 1 o P v s 4 quot 39 0 Cholesterol wthin the animal cell membrane nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn as Pearson Baniamin Cummings Fig 76 Do membrane proteins move quotquot Mixed proteins Mouse ce afteri hour Human cell Cooyrlgm a 2005 Pearson Education inc publishing as Pearson Eenamin Cummlngs Hybrid cell Fig 750 i i ifii wx wi iquotta i i i i i ijiiff39ji i 0 Cholesterol within the animal cell membrane Cholesterol modulates membrane fluidity iii ii i l i i t r U nnlquotl 10 I I II extracellular matrix ECM l x f I 3 I quot39u 39 Sfiwiwfk Peripheral proteins Integral protein CYTOPLASMIC SIDE OF MEMBRANE Copyright 2008 Pearson Education lnc publishing as Pearson Benjamin Cummings 91912 Six major functions of membrane proteins Transport quot Enzymatic activity Signal transduction Cell cell recognition Intercellularjoining Attachment to the cytoskelewwtu ssss WWW matrix ECM Copyright 2008 Pearson Education Inc publishing as Pearson Benjam n Cummings Fig 7 9 Signal transduction c Signal transduction d Cellcell recognition e Intercellularjoining f Attachment to the cytoskeleton and extracellular matrix ECM Copyright 2008 Pearson Education inc publishing as Pearson Benjamin Cummings Figure 711 Receptor but no CCR5 Plasma membrane Ioreceptor CCR5 HIV can infect a cell that has CCR5 on its surface as in most people 2011 Pearson Education Inc HIV cannot infect a cell lacking CCR5 on its surface as in resistant individuals oanyngmeeme Pearson Enueauum in publishing as Pearson Benjamin Cummmgs 91912 Plasma membrane is selectively permeable Hydrophobic dissolve in the lipid bilayer Polar molecules eg sugars do not cross the membrane easily Transport proteins allow passage of hydrophilic substances channe proteins hydrophilic channel that select molecules or ions can use as a tunnel aquaporins facilitate the passage ofwater quotcarrier proteins bind to molecules and shuttle them across the Fi 711 9 MOIECUIeS 0f dye Membrane cross section Net diffusion Net diffusion b Diffusion of two solutes Copyrigh 2006 Pnnrson Education met publishing an Penman Eemnmln Cumming Fig 712 Lower nghel39 Same concentration concentration concentration of sugar of solute sugar of sugar Selectively permeable membrane Effects of Osmosis on Water Balance Copyligh 2m6 Pearson Education Inc punirshlng es Pearson Bengamln Cummings Hgnm Hypotonic solution lsotonic solution Hypertonic solution H20 a Animal cell Lysed b Plant cell Turgid normal 91912 Hg M 50pm Filling vacuole a A contractile vacuole fills with fluid that enters from a system of canals radiating throughout the cytoplasm Contracting vacuole b When full the vacuole and canals contract expelling fluid from thlgngcg llo Copyright C 2008 Pearson Education Inc p n Bewamm Cummings Water Balance of Cells with Walls 0 Cell walls help maintain water balance 0 Plant cell in hypotonic solution swells until the wall opposes uptake the cell is now turgid firm 0 If a plant cell and its surroundings are isotonic there is no net movement of water into the cell the cell becomes flaccid limp and the plant may wilt In a hypertonic environment plant cells lose water eventually the membrane pulls away from the wall a usually lethal effect called plasmolysis Copyr ght 2008 Pearson Education Inc publ shing as Pearson Benjamin Cummings 91912 Fig 715 Active transport uses energy to move solutes against their gradients Active transport moves substances against their concentration gradient requires energy usually ATP Active transport is performed by specific proteins embedded in the membranes allows cells to maintain concentration gradients that differ from their surroundings Carrier protein QQ o Solute b A carrier protein Copyright 2008 Pearson Education Inc publishing as Pearson Benjamin Cummings 9 i The Need for Energy in Active Transport Active transport moves substances against their concentration gradients Active transport requires energy usually in the form of ATP 0 Active transport is performed by speci c proteins embedded in the membranes Na1 1 low K 1 high Animation Active Transport 91912 Fig 7 17 Passive mm We tramp Ion Pumps Maintain Membrane Potential Membrane potential voltage difference across a membrane distribution of positive and negative ions electrochemical gradient ion s concentration gradient membrane potential Diffusion Facilitated diffusion l 0 Desktoppumpcyclemediummov Gouylighl m Pearsan Edunailoni inc nuniismng as Pearson Esmeum Cummings Copyright 2008 Pearson Education Inc publishing as Pearson Benjamin Cummings Concept 75 Bulk transport across the plasma membrane occurs by exocytosis and endocytosis Small molecules and water enter or leave the cell through the lipid bilayer or via transport proteins Large molecules such as polysaccharides and proteins cross the membrane in bulk via vesicles Bulk transport requires energy 91912 Exocytosis Endocytosis In endocytosis the cell takes in macromolecules by forming vesicles from the plasma membrane 0 Endocytosis is a reversal of exocytosis involving different proteins 0 There are three types of endocytosis Phagocytosis cellular eatingquot Pinocytosis cellular drinkingquot Receptormediated endocytosis In exocytosis transport vesicles migrate to the membrane fuse with it and release their contents 0 Many secretory cells use exocytosis to export their products Animation Exocytosis and Endocytosis Introduction Anima ion Exocytosis o In phagocytosis a cell engulfs a particle in a In pinocytosis molecules are taken up when vacuole extracellular fluid is gulped into tiny vesicles 0 The vacuole fuses with a lysosome to digest the particle Anima ion Phagocytosis Animation Pinocytosis In receptormediated endocytosis binding of ligands to receptors triggers vesicle formation A ligand is any molecule that binds specifically to a receptor site of another molecule Animation ReceptorMediated Endocytosis Fig 7200 RECEPTORMEDIATED ENDOCYTOSIS Fort Will x a e 1 mvwrumwb ji I s Acoated pit and a coated vesicle formed during receptor mediated endocytosis TEMs Plasma membra gE quotis itquot Eamum in publishing as Penman Bcnlumln Cummmg 91912 Figure 722 Phagocytosis Receptor Mediated Endocytosis EX RACELLULAR FLU D 2011 Pearson Educanan Inc Fig mm Passive transport Facilitated diffusion Channel Carrier protein protein CanyrlgthZDml Pearson Education inc publishing as Pearson Benjamin Cummings 91912 Fig 7UN2 Active transport 0 00 You should now be able to 1 Define the following terms amphipathic molecules aquaporins diffusion 2 Explain how membrane fluidity is influenced by temperature and membrane composition 3 Distinguish between the following pairs or sets of terms peripheral and integral membrane proteins channel and carrier proteins osmosis facilitated diffusion and active transport hypertonic hypotonic and Copy gltsotnnldsplutinLissacm 4 5 Explain how transport proteins facilitate diffusion Explain how an electrogenic pump creates voltage across a membrane and name two electrogenic pumps Explain how large molecules are transported across a cell membrane Copyr ghi 2008 Pearson Education Inc publ shing as PearsonBenjamin Cummings 10 82312 LECTURE PRE SENTATIONS For CAMPBELL BIOLOGY NINTHEDITION Jane B Reece LisaA Urryg Michael L Cain StevenA Wassetmanl Peter V Mjnorsky RobeIt B Jackson Chapter 3 Water an Life Lectures by I x K l Erin Barley Kathleen Fitzpatrick l Polar covalent bonds in water molecules result in hydrogen bonding The water molecule is a polar molecule 0 water molecules form 5 I H 1 hydrogen bonds H 6 bgngfgequot bonds H Polar covalent 6 bonds 539 Animation Water Structure 0 l C pl M it Four emergent properties of water contribute to Earth s suitability for life Four of water s properties that facilitate an environment for life are Cohesive behavior Ability to moderate temperature Expansion upon freezing Versatility as a solvent 1 Cohesion of Water Molecules Collectively hydrogen bonds hold water molecules together a phenomenon called cohesion Cohesion helps the transport of water against gravity in plants Adhesion is an attraction between different substances for example between water and plant cell walls Animation Water Transport 82312 Figure 3 3 Adhesion Two types of waterconducting cells Cohesion Direction L of water movement i 20H Pearson Educaimn Inc 2 Surface tension 82312 3 Moderation of Temperature by Water A heat sinkWater absorbs heat from warmer air and releases stored heat to cooler air Water can absorb or release a large amount of heat with only a slight change in its own temperature why Some de nition Heat and Temperature Kinetic energy is the energy of motion Heat is a measure ofthe total amount of kinetic energy due to molecular motion Temperature measures the intensity of heat due to the average kinetic energy of molecules calorie cal is the heat required to raise the temperature of1 g of water by 1 C joule J 1 J 0239 cal or 1 cal 4184 J specific heat amount of heat that must be absorbed or lost for 1 g ofthat substance to change its temperature by 1 C 82312 Figure 3 5 Water s High Specific Heat 920quot P eeee an Education inc The specific heat of water is 1 calg C Water resists changing its temperature because of its high specific heat Figure 3 6 Hydrogen bond Liquid water i Hydrogen bonds break and reform Hyd rogen bonds are stable 2011 Pearson Education Inc 82312 Water The Solvent of Life more de nitions A solution is a liquid that is a homogeneous mixture of substances A solvent is the dissolving agent of a solution The solute is the substance that is dissolved An aqueous solution is one in which water is the solvent When an ionic compound is dissolved in water each ion is surrounded by a sphere of water molecules called a hydration shell Figure 37 82312 Figure 3 8 man Pearson Educahon Inc Hydrophilic and Hydrophobic Substances Hydrophilic Hydrophobic colloid 82312 82312 Molecular mass is the sum of all masses of all atoms in a molecule Numbers of molecules are usually measured in moles where 1 mole mol 602 x 1023 molecules Avogadro s number and the unit dalton were defined such that 602 x 1023 daltons 1 g Molarity M is the number of moles of solute per liter of solution Figure 3UN02 H 2 quot392o Hydronium Hydroxide ion H3O ion OH39 Acids and Bases An acid is any substance that increases the H concentration of a solution A base is any substance that reduces the H concentration of a solution s ga e Hydronium Hydroxide ion H3O ion OH39 The pH Scale In any aqueous solution at 25 C the product of H and OH is constant and can be written as HOH 1014 The pH of a solution is defined by the negative logarithm of Hconcentration written as pH log H 82312 Figure 310 H H H OH H OH H H H H Acidic solution H H 0H OH OH H H H Neutral solution OH OH OH H OH DHHDHDH Basic solution increasingly Basic 4 H lt OH39 pH Scale 0 1 Os Battery acid 2 Gastricjuice lemonjuice 3 Vinegar wine cola 4 Tomatojuice eer Black coffee 5 Rainwater 6 Urine Saliva 7 7 Pure water Human blood tears 8 Seawater Inside of small intestine 9 10 Milk of magnesia Household ammonia I V 12 Household 1 3 bleach Oven cleaner 14 Buffers The internal pH of most living cells must remain close to pH 7 Buffers are substances that minimize changes in concentrations of H and OH in a solution Most buffers consist of an acidbase pair that reversibly combines with H 82312 Acidification A Threat to Water Quality H2C03 gt H HCO3 Human activities such as burning fossil fuels threaten water quality 1 002 is the main product of fossil c0324 Ca2 gt caco3 r 532 fuel combustion About 25 of humangenerated 002 is absorbed by the 82312 oceans 002 dissolved in sea water forms carbonic acid this process is called ocean acidification Figure 3UN03 11 Figure 3UN04 Liquid water transient hydrogen bonds Ice stable hydrogen bonds s20quot Pearson Education lnc Figure 3UN05 Acids donate H in aqueous solutions Neutral H 0H1 7 Bases donate OH39 or accept H in aqueous solutions 14 82312 82312 Chapter The Stru tul e andhfunc gm of Large Bi logical ul quot Overview The Molecules of Life Carbohydrates prwds Protems Nudewc aods Macromolecules are arge mo ecu ea composed of thousands of cova enuy connected atoms Mo ecu ar structure and mncuon are nseparab e 82312 Macromolecules are polymers built from monomers A polymer is a long molecule consisting of many similar building blocks These small buildingblock molecules are called monomers Three of the four classes of life s organic molecules are polymers Carbohydrates Proteins Nucleic acids What have we left out Figure 5 2a a Dehydration reaction synthesizing a polymer WJH Short polymer Unlinked monomer HO Dehydration removes a water molecule forming a new bond Longer polymer Figure 5 2b b Hydrolysis breaking down a polymer Ho G Q Hydrolysis adds a water molecule breaking a bond The Synthesis and Breakdown of Biological Polymers Dehydration Hydrolysis Animation Polymers 82312 82312 Carbohydrates serve as fuel and building nlaterial Carbohydrates include sugars and the polymers of sugars The simplest carbohydrates are monosaccharides or single sugars Carbohydrate macromolecules are polysaccharides polymers composed of many sugar building blocks Sugars Monosaccharides have molecular formulas that are usually multiples of CH20 Glucose C6H1206 is the most common monosaccharide Monosaccharides are classified by The location of the carbonyl group as aldose or ketose The number of carbons in the carbon skeleton Figure 5 3a Aldose Aldehyde Sugar Ketose Ketone Sugar Trioses 3carbon sugars C3H603 H T H C OH H f OH H C OH H C OH H H Glyceraldehyde Dihydroxyacetone Figure 5 3b Aldose Aldehyde Sugar Ketose Ketone Sugar Pentoses 5carbon sugars C5H1005 H 397 H C OH H C OH H C OH H C OH H C OH H lz OH H C OH H C OH J H Ribose Ribulose 82312 Figure 5 30 Aldose Aldehyde Sugar Ketose Ketone Sugar Hexoses 6carbon sugars CGH1206 H o T l H Clt OH H Cli OH H c 0H mg HO H HO Cl H HO C H H f OH HO H H C OH H CIS OH H ID OH H li OH H 0H H CII OH H C OH H H l Glucose Galactose Fructose Fioure54 1quot 60H20H H zf oa H at H HO 3C H L H 4C 1 H 4C OH OH H o OH 239 H 5 0H 3 0 H 6 OH 0 H b Abbreviated Though often drawn as linear skeletons in aqueous solutions many sugars form rings Monosaccharides serve as a major fuel for cells and as raw material for building molecules ring structure 82312 82312 A disaccharide is formed when a dehydration reaction joins two monosaccharides This covalent bond is called a glycosidic anage Animation Disaccharide Figure 5 5 Glucose Glucose Maltose a Dehydration reaction in the synthesis of maltose Glucose Fructose Sucrose b Dehydration reaction in the synthesis of sucrose a son Pearson Education Inc Polysaccharides Polysaccharides the polymers of sugars have storage and structural roles The structure and function of a polysaccharide are determined by its sugar monomers and the positions of glycosidic linkages Figure 5 6 Chloroplast Starch granules a S arch 7 1 pm a plant polysaccharide Mitochond yam ria G lycogen gr 4 v anules gt a 2 b Glycogen 05pm an anlmal polysaccharlde 2011 82312 Figure 57 a a and glucose ring structures b Starch 1 4 linkage of a glucose monomers c Cellulose 1 4 linkage of p glucose monomers azon Pearsnn Educsuon Inc Figure 5 8 Cellulose microfibrils in a plant cell wall Cell wall Microfibril 5 Glucose Q0 monomer 2011 Pearson Educalrun Inc 82312 Figure 5 9 CHZOH 4 The structure 2 of the chitin monomer 4 Chitin forms the exoskeleton of arthropods quot5 L A Chitin is used to make a strong and flexible surgical thread that decomposes after the wound or incision heals Concept 53 Lipids are a diverse group of hydrophobic molecules Lipids are the one class of large biological molecules that do not form polymers The unifying feature of lipids is having little or no affinity for water Lipids are hydrophobic because they consist mostly of hydrocarbons which form nonpolar covalent bonds The most biologically important lipids are fats phospholipids and steroids 82312 Figure 510 T H T H C Fatty acid HcOH in this case palmitic acid J Glycerol a One of three dehydration reactions in the synthesis of a fat Ester linkage b Fat molecule triacylglycerol Figure 511 a Saturated fat b Unsaturated fat Structural formula of a saturated fat mOIeCUIe I Structural H formula of an unsaturated fat molecule Spacefilling 39 39 39 quot quot model of stearic 39 39O 9 r V acid a saturated 7 05 fatty acid Spacefilling model of oleic acid an unsaturated fatty acid 39 l Cis double bond 39 causes bending 2011 Pearson Education Inc 82312 11 82312 Trans fats Essential fatty acids Energy storage Figure 512 CH2 NCH33 Phospholipids CH CH c n g 2 I 2 GlycerOI I Hydrophilic head 2 395 U 395 Fatty aCldS 437 2 3 Hydrophilic g head I Hydrophobic tails a Structural formula b Spacefilling model c Phospholipid symbol Mon Em n Figure 513 2011 Pearson Education inc Steroids Steroids are lipids characterized by a carbon skeleton consisting of four fused rings Cholesterol is a steroid H30 82312 13 82312 Concept 54 Proteins include a diversity of structures resulting in a Wide range of functions Proteins account for more than 50 of the dry mass of most cells Protein functions include structural support storage transport cellular communications movement and defense against foreign substances Figure 515a Enzymatic proteins Function Selective acceleration of chemical reactions Example Digestive enzymes catalyze the hydrolysis of bonds in food molecules Figure 515b Storage proteins Function Storage of amino acids Examples Casein the protein of milk is the major source of amino acids for baby mammals Plants have storage proteins in their seeds Ovalbumin is the protein of egg white used as an amino acid source for the developing embryo Ovalbumin Amino acids for embryo Figure 5150 Hormonal proteins Function Coordination of an organism s activities Example Insulin a hormone secreted by the pancreas causes other tissues to take up glucose thus regulating blood sugar concentration 39 7 rNrmal blood sugar 82312 Figure 515d Contractile and motor proteins Function Movement Examples Motor proteins are responsible for the undulations of cilia and flagella Actin and myosin proteins are responsible for the contraction of muscles Actin Myosin IW Q a Muscle tissue i1 100 um 2011 Pearson Education inc Figure 515e Defensive proteins Function Protection against disease Example Antibodies inactivate and help destroy viruses and bacteria Antibodies Bacterium 82312 Figure 515f Transport proteins Function Transport of substances Examples Hemoglobin the ironcontaining protein of vertebrate blood transports oxygen from the lungs to other parts of the body Other proteins transport molecules across cell membranes Transport protein Cell membrane 2qu Pearson Education Inc Figure 5159 Receptor proteins Function Response of cell to chemical stimuli Example Receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells 39 1 Receptor Lgprotein h Dzou Pearson Education inc 82312 Figure 515h Structural proteins Function Support Examples Keratin is the protein of hair horns feathers and other skin appendages Insects and spiders use silk fibers to make their cocoons and webs respectively Collagen and elastin proteins provide a fibrous framework in animal connective tissues 391EJA 1 I 39 Connective tissue 60 Mm w 201 I Pearson Education in Enzymes are a type of protein that acts as a catalyst to speed up chemical reactions Enzymes can perform their functions repeatedly functioning as workhorses that carry out the processes of life Animation Enzymes 82312 18 Figure 5UN01 Si Amino group group de chain R group a carbon I or quot39 i N39 c H H a 0H eon Pearson Education Inc Carboxyl Figure 516 Nonpolar side chains hydrophobic cHS CHa CH Side chain 7 H R gruup KHzcm 2 H CH3 cH H2 stcH H3N7 Li io39 sti f io HaN i Zil io H3N 7rf7c i io Harrioi io H o H o H o H o Glycine Alanine Valine Leucine lsoleucine Gly or G Ala or A Val orV Leu or L lie or 1 CH EHg gt g Hz Hz sz llsz 5quot HJN 7 K JO39 HJN 7C I T 7039 Hsu ic p io ng i go H o H o H o H o Methionine Phenylalanine Tryptophan Proline Met or NI Phe or F Tm or W Pro or P Polarside chains hydrophilic DH NH2 0 quotquotW0 C OH OH HS SH 0 pH r c H lH2 141 H2 Hawicicio H3N 764C70 Hawicicior 2 i l iii iii ii Ho 0 i Hangcioitr szit H foio HSN ilfi io i i Threonine cysteine 1yrosine Asparagine Glutamine Ser or S or T Cys or C 1yr or Y Asn or N Gln or Q i any a Basic osi 39 el charged A 39 I1 quot2 c nega ver charged EH Em A H NH 0 o 0c0 CH nz NH y H a iii on c H2 sz H2 csz Hawifil fio Hanwoi io HN397t 7 io HN397t 7 io HJN39ilfit iio H o H o H o H o H o Aspariic acid Glutamic acid Lysine Arginine Hi dine Asp or D Glu or E Lys or K Arg or R His or H 2011 Pearson Edubalion Inc 82312 82312 Figure 517 New peptide bond forming Side chains SH 23 H2 Back 1 l 739 7 bone H N C N l39 N 3 I39I3 OH H 0 H 0 H o A 39 A Amino end Peptide Carboxyl end Nterminus bond Cterminus mm mm nc Protein Structure and Function A functional protein consists of one or more polypeptides precisely twisted folded and coiled into a unique shape aA ribbon model m f Lxrgl c 20 Figure 519 Antibody protein 2011 Fearsun Education Inc Protein from flu virus Figure 5 20a acids my 5 a Amino a a a e 0 Primary structure 9 H 9 3 tn 0 u a a x H w o R I 4 1o H3N Aminoend in 30 25 20 15 1a Wg savvyww 79 g R W 35 50 g a a mag ma Primary structure of transthyretin a 5 vi 70 65 G 5 14 En r9 m aa v g9 w Va 43575 30 a 90 in A mamp A5 95 HS 1 D 105 I00 am A gang ama m Egg 45quot 9 5 WV r 0 125 o r r u 175 quot 39 mw Cw Carboxyl end 2011 Fearsnn Education Inc 82312 21 Secondary Structure regular repeating main chain structures stabilized by H bonds Copyright 2008 Pearson Education Inc publishing as Pearson Benjamin Cummings Tertiary structure is determined by interactions between R groups rather than interactions between backbone constituents These interactions between R groups include hydrogen bonds ionic bonds hydrophobic interactions and van der Waals interactions Strong covalent bonds called disulfide bridges may reinforce the protein s structure Animation Tertiary Protein Structure 82312 22 Figure 5 20f EH2 quot5 Hydrogen NH2 bond CH2 I39l2 Disulfide b dge CH2 Polypeptide backbone Hydrophobic interactions and van der Waals interactions Ionic bond Fig 521e Tertia Structure 82312 23 82312 0 Quaternary structure results when two or more polypeptide chains form one macromolecule Collagen is a fibrous protein consisting of three polypeptides coiled like a rope Hemoglobin is a globular protein consisting of four polypeptides two alpha and two beta chains Animation Quaternary Protein Structure Figure 5 20b Secondary Tertiary Quaternary structure structu re structure on helix Hydrogen bond1 3 pleated sheet xquot x r r l I we I 4 9 r L 19 9 i39y g 9 a 2167 a 9 w H 1 B Strand 4 9 edit 9 a Transthyretin 7 6quot 391 viii Hydrogen Transthyretin protem I 1 4quot 7 bond polypeptide 24 Figure 5 20i 0 subunit Hemoglobin Figure 5 21 Secondary Primary Quaternary Red Blood Structure and Ternary Structure Functlon Cell Shape Structures 1 7 Normal Molecules do not 7 j39 7 hemoglobin associate with one 395 2 f w another each carries 2 3 X 1 oxygen 87 4 r E 7 i 7 Q o 5 lt f 6 5 subunit a a if 10 um 16 E 7 39 7 Q 1 Exposed Sicklecell Molecules crystallize 5 hydrophobic hemoglobin into a fiber capacity 8 2 region to carry oxygen is E 3 reduced 0 E 4 8 5 B 6 3 7 5 subunit E 2 w 2011 Pearson Educaucn Incl 82312 25 What Determines Protein Structure In addition to primary structure physical and chemical conditions can affect structure Alterations in pH salt concentration temperature or other environmental factors can cause a protein to unravel This loss of a protein s native structure is called denaturation A denatured protein is biologically inactive Figure 5 22 t oena ratio7 r r A I y f r t y T Xi J K Normal protein enatura oo Denatured protein 82312 26 Protein Folding in the Cell It is hard to predict a protein s structure from its primary structure Most proteins probably go through several stages on their way to a stable structure Chaperonins are protein molecules that assist the proper folding of other proteins Diseases such as Alzheimer s Parkinson s and mad cow disease are associated with misfolded proteins Figure 5 23 Correctly f folded protein M Polypeptide Cap Hollow l cylinder Chaperonln Steps 0f Chaperonm 9 The cap attaches causing 9 The cap comes fully assembled ACtlon the cylinder to change off and the 0 An unfolded poly shape in such a way that properly folded peptide enters the it creates a hydrophilic protein is cylinder from environment for the released one end folding of the polypeptide 82312 27 Scientists use Xray crystallography to determine a protein s structure Another method is nuclear magnetic resonance NMR spectroscopy which does not require protein crystallization Bioinformatics uses computer programs to predict protein structure from amino acid sequences Figure 5 24 EXPERIMENT Diffracted Xrays Xray source X39ray a r beam 7 Crystal Digital detector Xray diffraction pattern RES U LTS RNA D NA RNA polymerase II 82312 28 82312 Concept 55 Nucleic acids store transmit and help express hereditary information o The amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene 0 Genes are made of DNA a nucleic acid made of monomers called nucleotides The Roles of Nucleic Acids There are two types of nucleic acids Deoxyribonucleic acid DNA Ribonucleic acid RNA 0 DNA provides directions for its own replication 0 DNA directs synthesis of messenger RNA mRNA and through mRNA controls protein synthesis 0 Protein synthesis occurs on ribosomes 29 Figure 5 251 02011 Pearson Educaxian Inc Figure5 252 a 2611 FearsarkEduea anrlnc 823 1 2 30 Figure 5 253 N g gg k l7 ezon Pearson Educshon Inc Figure 5 26ab 5 end The Components of Nucleic Acids Nucleoside Nitrogenous base 6 5c 4 l lt6 CH2 170 Phosphate 3IC group Sugar pentose b Nucleotide 3 end OH a Polynucleotide or nucleic acid 92011 Fearsan Educahan Inc 8231 2 31 82312 Figure5260 Nitrogenoius bases Pyrimidines NH O O I 2 u n HI 10 3 H 0 0 H 0 H H H Cytosine Thymine Uracil C T in DNA U in RNA Sugars Pur39quotes HOCH 0H HOCH2 0H H H H H H OH H OH OH NH2 Deoxyribose Ribose Adenine A Guanine G in DNA in RNA c Nucleoside components ozou Pearson Euucauun Inc Figure 5 27 Sugarphosphate backbones Hydrogen bonds Base pairjoined by hydrogen bonding Base pairjoined by hydrogen bonding a DNA b Transfer RNA 2011 P ssss an Educamn Inc 32 82312 The Theme of Emergent Properties in the Chemistry of Life A Review 0 Higher levels of organization result in the emergence of new properties 0 Organization is the key to the chemistry of life 33 Overview A Chemical Connection to Biology B o ogy S a mumdwacwphnary Scwence meg orgamSmS are an jeciio baswc aws of physwca and chemwstry Ezmz 82012 Figure 2 3 Sodium Chlorine Sodium chloride An element substance that cannot be broken down to other substances by chemical reactions A compound substance consisting of two or more elements in a fixed ratio A compound has characteristics different from those of its elements Table 21 Table 21 Elements in the Human Body Percentage of Body Mass Element Symbol including water Oxygen O 650 Carbon C 185 963 Hydrogen H 95 Nitrogen N 33 Calcium Ca 15 Phosphorus P 10 Potassium K 04 Sulfur S 03 37 Sodium Na 02 Chlorine CI 02 Magnesium Mg 01 Trace elements less than 001 of mass Boron B chromium Cr cobalt Co copper Cu fluorine F iodine I iron Fe manganese Mn molybdenum Mo selenium Se silicon Si tin Sn vanadium V zinc Zn 82012 Figur 2 5 n element s properties depend on the structure of its atoms Cloud of negative Electrons charge 2 electrons Nucleus a b ozou Pearson Educatron Inc Atomic Number and Atomic Mass Atoms of the various elements differ in number of subatomic particles An element s atomic number is the number of protons in its nucleus An element s mass number is the sum of protons plus neutrons in the nucleus Atomic mass the atom s total mass can be approximated by the mass number Periodic Table L1 334 Of the Elements 82012 Isotopes Atoms of an element have the same number of protons but may differ in number of neutrons Isotopes are two atoms of an element that differ in number of neutrons Radioactive isotopes decay spontaneously giving off particles and energy Nucleus Protons charge determine element Electrons charge form negative cloud and determine NeUtrons no Charge chemical behavior determine isotope Atom o Figure 2 6a TECHNIQUE Compounds including ncubators radioactive tracer right blue Human cells 0 Human cells are incubated r e g A l with compounds used to make A 45 50quot DNA One compound is labeled with 3H Incubator are 7 placed in tubes i 7 their DNA is isolated and I unused labeled 39 w w w W w compounds are removed ozon Fear DNA old and new Figure 2 60 RESULTS Optimum 3Q temperature for DNA synthesis x 1000 Counts per minute 10 20 30 40 50 Temperature C Figure 27 Cancerous throat ssue 82012 The Energy Levels of Electrons Energy is the capacity to cause change Potential energy is the energy that matter has because of its location or structure The electrons of an atom differ in their amounts of potential energy An electron s state of potential energy is called its energy level or electron shell Figure 2 8 aA ball bouncing down a flight of stairs provides an analogy for energy levels of electrons Third shell highest energy level in this model Energy Second shell higher absorbed energy level First shell lowest energy I eve Energy lost Atomic nucleus 9201 Pearson Eaucauon Inc 82012 82012 Electron Distribution and Chemical Properties The chemical behavior of an atom is determined by the distribution of electrons in electron shells The periodic table of the elements shows the electron distribution for each element Figure 2 9 Atomic number titliiftt ul39nr mass number H Element symbol Electron distribution diagram Fi ure 210 g x39 First shell Neon with two filled q v39 15 Shells 1o electrons 7 Second shell a Electron distribution diagram First shell Second shell 0 E 15 orbital 2s orbital Three 2p orbitals b Separate electron orbitals 1s 2s and 2p orbitals c Superimposed electron orbitals m Education Concept 23 The formation and function of molecules depend on chemical bonding between atoms Atoms with incomplete valence shells can share or transfer valence electrons with certain other atoms These interactions usually result in atoms staying close together held by attractions called chemical bonds 82012 Figure 2113 Hydrogen atoms 2 H Share 1 e H H l molecular formula H2 Hydrogen molecule H2 Figure 212a Name and Electron Lewis Dot Space Molecular Distribution Structure and Filling Formula Diagram Structural Model Formula H H a Hydrogen H2 V l H H ozou Pearson Education Inc 82012 Figure 212b Name and Electron Lewis Dot Space Molecular Distribution Structure and Filling Formula Diagram Structural Model Formula 9 b Oxygen 02 00 Figure 2120 Name and Electron Lewis Dot Space Molecular Distribution Structure and Filling Formula Diagram Structural Model Formula H H c Water H20 ID H H 2011 Pearson Edunalion Inc 82012 Figure 212d Name and Electron Lewis Dot Space Molecular Distribution Structure and Filling Formula Diagram Structural Model Formula H H g H H d Methane CH4 H H li H H 2011 Pearson Education Inc Figure 213 82012 11 Figure 2141 Ionic Bonds Na C Sodium atom Chlorine atom 9999 an Figure 2142 Na Cl Na Cl Sodium atom Chlorine atom Sodium ion Chloride ion a cation an anion Sodium chloride NaCl 2qu Pearson Educaiiun no 82012 Figure 215 Weak Chemical Bonds Most of the strongest bonds in organisms are covalent bonds that form a cell s molecules Weak chemical bonds such as ionic bonds and hydrogen bonds are also important Weak chemical bonds reinforce shapes of large molecules and help molecules adhere to each other 82012 82012 Hydrogen Bonds A hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom Hydrogen bond 339 i l 5 6 9 r3 E ii n n h39 n r H 39 G W Figure 216 Water H20 Hydrogen bond Ammonia NH3 Van der Waals Interactions If electrons are distributed asymmetrically in molecules or atoms they can result in hot spots of positive or negative charge Van der Waals interactions are attractions between molecules that are close together as a result of these charges 82012 Molecular Shape and Function A molecule s shape is usually very important to its function A molecule s shape is determined by the positions of its atoms valence orbitals In a covalent bond the s and p orbitals may hybridize creating specific molecular shapes Figure 217 Four hybrid orbitals z s orbital Three p orbitals r 4 i gt Tetrahedron a Hybridization of orbitals SpaceFilling BallandStick HybridOrbital Model Model Model with ballandstick model I 39 Unbonded I Electron quot h 9 r a H i Water H20 9 Methane CH4 Vk t we Elt4tii K ill b Molecularshape models 207 Educahon m 82012 F39 218 39gure Carbon Nitrogen Hydrogen Sulfur Natural endorphin Oxygen Morphine Nht urar 7 en etphin i I Endorphin Brain Cequot receptors b Binding to endorphin receptors 920 Emma me Chemical reactions make and break chemical bonds Chemical reactions are the making and breaking of chemical bonds The starting molecules of a chemical reaction are called reactants The final molecules of a chemical reaction are called products 82012 Figure 2UN02 Reactants Reaction Products Photosynthesis is an important chemical reac on Sunlight powers the conversion of carbon dioxide and water to glucose and oxygen 6 602 6 H20 gt C6H1ZO6 6 02 82012 18 chemical reactions are reversible Chemical equilibrium N is reached when the I forward and reverse reaction rates are equal v quot If I 82012 19 82012 BIOLOGY FOR SCIENCE MAJORS Bl0l12033 Moodle Grades are based on exams amp quizzes 3 Exams 50 multiple choice each 600 points Final exam 75 multiple choice questions 250 Unannounced quizzes 50 asten39ng BiologyAssignments 100 Parti 39p 39 10 TOTAL 1010 points Course grading A 9001010 800899 C 700799 D 580699 Examinations Exam l Exam 2 Exam 3 Exam 4 lncldss and multiple choice Student ID and 2 pencils required Scantrons are provided Sep l9 Wed Oct l7 Wed NOV l4 Wed DecA Tue Missed Exams 48 hr rule Textboolc Campbell and Reece 9m ed masteringbiologycomi hilglvmmm asleringbiologxxom l Lecture slides will be posted on Moodle 82012 Pearson Technology Help Tuesday August 215 11 am till 3 pm LSU Union Bookstore Upstairs Heip With registering fur Mastering andDr MyLabs 7 bring yuur CuurseiD s NEWCDMER1201 Participation Make sure your clicker is registered 9 MEI12 Of ce Hours M 4 ms an pm W4 ms an pm urby appmntment 5u5 Chuppm HaH The guuelmes forAcadermc Imeng described at w as m asIsueduacademm mnegnmare stnc y enforced m nus class mmmsmmus m swan um mummm 1 Chapter 1 J Introtluc on 1e esin 1e Study of ife Ezmz Figure 14 K g The biosphere I Ecosystems Organs and organ systems Communities 7 a 2 xv V Organisms Atoms Populations Molecules What you should get out of this course 0 What do I want you to get from the course 82012 Fig 13 Respons to the environment Evolutionary adaptation Energy processing quot 1 development I 39 A Reproduction Growth and Theme New Properties Emerge at Each Level in the Biological Hierarchy Life can be studied at different levels from molecules to the entire living planet The study of life can be divided into different levels of biological organization Emergent properties result from the arrangement and interaction of parts within a system Emergent properties characterize nonbiological entities as wellbicycle 82012 82012 The Power and Limitations 0fReducti0nism Reductionism is the reduction of complex systems to simpler components that are more manageable to study studying the molecular structure of DNA helps us to understand the chemical basis of inheritance An understanding of biology balances reductionism with the study of emergent properties new understanding comes from studying the interactions of DNA with other molecules Systems Biology 0 A system is a combination of components that function together 0 Systems biology constructs models for the dynamic behavior of whole biological systems 0 The systems approach poses questions such as How does a drug for blood pressure affect other organs How does increasing CO2 alter the biosphere 82012 Theme Life Requires Energy Transfer and Transformation A fundamental characteristic of living organisms is their use of energy to carry out life s activities Work including moving growing and reproducing requires a source of energy Living organisms transform energy from one form to another For example light energy is converted to chemical energy then kinetic energy 0 Energy flows through an ecosystem usually entering as light and exiting as heat Theme Structure and Function Are Correlated at All Levels of Biological Organization 0 Structure and function of living organisms are closelv rlated Theme The Cell Is an Organism s Basic Unit of Structure and Function The cell is the lowest level of organization that can perform all activities required for life All cells Are enclosed by a membrane Use DNA as their genetic information Figure l 8 Prokaryotlc cell Eukaryotic cell DNA no nucleus Membrane Membrane Cytoplasm Nucleus membrane enclosed Membrane DNA throughout enclosed organelles nucleUS 1 um 82012 Theme The Continuity of Life Is Based on Heritable Information in the Form of DNA Chromosomes contain most of a cell s genetic material in the form of DNA Cell division is the basis of all reproduction growth and repair of multicellular organisms t glisllll fl a in dllciztali mm Linn Figure 111 Nucleus a DNA double helix b Single strand of DNA 82012 10 Theme Feedback Mechanisms Regulate Biological Systems Feedback mechanisms allow biological processes to selfregulate Negative feedback means that as more of a product accumulates the process that creates it slows and less of the product is produced Positive feedback means that as more of a product accumulates the process that creates it speeds up and more of the product is produced Figure 113a Nega ve feedback lllllllllllllL gt EEnzyme1 u 7Illlllllllllllc Enzyme 2 Excess D blocks a step Enzyme 3 a Negative feedback 82012 11 82012 Figure 113b Enzyme 4 Positive feedback IIIIIIHII 5 Enzyme 5 5 Excess Z z stimulates a V 39mmmlmnV t 5 ep Z Enzyme6 H b Positive feedback V The process In studying nature scientists make observations and then form and test hypotheses The word science is derived from Latin and means to know Inquiry is the search for information and explanation The scientific process includes making observations forming logical hypotheses and testing them 82012 Making Observations Biologists describe natural structures and processes o This approach is based on observation and the analysis of data Inductive Reasoning Inductive reasoning draws conclusions through the logical process of induction Repeating specific observations can lead to important generalizations For example the sun always rises in the east 13 Forming and Testing Hypotheses Observations and inductive reasoning can lead us to ask questions and propose hypothetical explanations called hypotheses A hypothesis is a tentative answer to a well framed question A scientific hypothesis leads to predictions that can be tested by observation or experimentation Figure l 24 82012 82012 Deductive Reasoning and Hypothesis Testing Deductive reasoning uses general premises to make specific predictions Hypothesisbased science often makes use of two or more alternative hypotheses Failure to falsify a hypothesis does not prove that hypothesis Theories in Science 0 In the context of science a theory is Broader in scope than a hypothesis General and can lead to new testable hypotheses Supported by a large body of evidence in comparison to a hypothesis 82012 Science Technology and Society The goal of science is to understand natural phenomena The goal of technology is to apply scientific knowledge for some specific purpose Science and technology are interdependent Biology is marked by discoveries while technology is marked by inventions The combination of science and technology has dramatic effects on society For example the discovery of DNA by James Watson and Francis Crick allowed for advances in DNA technology such as testing for hereditary diseases 0 Ethical issues can arise from new technology but have as much to do with politics economics and cultural values as with science and technology What you should get out of this course What do I want you to get from the course 82012 17 LECTURE PRESENTATIONS For CAMPBELL BIOLOGY NINTH EDITION Jane B Reece Lisa A Urry Michael L Cain Steven A Wassennan Peter Vquot Minorsky Robeit B Jackson A Tour 0 the i i 39 Lectures by Erin Barley Kat leen Fitzpatrick 2011 Pearson Education Inc Figure 61 Overview The Fundamental Units of Life Microscopy Magni cation the ratio of an object s image size to its real size Resolution the measure of the clarity of the image or the minimum distance of two distinguishable points Contrast visible differences in parts of the sample Figure 62 10 m height 1 m nerve and 01 m Chicken egg 1 cm Frog egg 1 mm 100 pm Most plant and animal cells 10 pm Most bacteria 1 m 100 nm Ribosomem 10 nm Proteins Lipids 1 nm 01 nm 2011 Petersen Educsiiun m Figure 63 Light Microscopy LM Bri ht eld Confocal 9 unstained specimen Bright eld stained specimen Phasecontrast IE 3 2 Differential interference contrast Nomarski Fluorescence 2011 Pearson Education Inc Deconvolution Superresolution Electron Microscopy EM Lon tudinal section Cross section um ofc um l l 2pm Transmission electron Scannlng electron microscopy TEM microscopy SEM Figure 64 TECHNIQUE 9 Cell Fractionation ls Homogenization Tissue I cel gt Homogenate Centrifuged at 1000 times the Centrifugation force of gravity 1 m39quot Supematant poured into nex be Differential 20000 g centrIfugatIon 20 in Pellet rich in nuclei and cellular debris 150000 g 3 hr Pellet rich in mitochondria and chloro plasts if cells are from a plant Pellet rich in microsumes pieces of plasma and cells intemal membranes Pellet nch In nbosome 2011 Pearson Educailuu m Figure 65 7 Fimbriae Nucleoid Ribosomes Plasma membrane Bacterial chromosome Cell wall Capsule i i 05 um a A typical Flagella b A thin section rodshaped through the bacterlum bacterium Bacillus coagulans TEM 2011 Pearson Educalion Inc Figure 68a ENDOPLASMIC RETICULUM ER Rough Smooth ER Flagellum ER Nucleolus NUCLEUS Chromatin Centrosome 39 Plasma membrane CYTOSKELETON Microfilaments Intermediate filaments Microtubules Ribosomes Golgi apparatus Lysosome Mitochondrion 2011 Peavsun Educauun Inc Figure 66 a TEM of a plasma OutSIde of cell membrane Hyd rophilic region Hydrophobic region qumphi39m Ph os39ph olipid Proteins region b Structure of the plasma membrane 2011 Pearson Education Inc Figure 67 Total surface area sum of the surface areas height x width of all box sides x number of boxes Total volume height x width x length x number of boxes Surfacetovolume StoV ratio surface area volume 2on Pearson Education lnc Surface area increases while total volume remains constant o ovo r Oi 6 150 750 1 125 125 6 12 6 A Panoramic View of the Eukaryotic Cell A eukaryotic cell has internal membranes that partition the cell into organelles Plant and animal cells have most of the same organelles BioFIix Tour of a Plant Cell BioFIix Tour of an Animal Cell Figure 68a ENDOPLASMIC RETICULUM ER Rough Smooth ER Flagellum ER Nucleolus NUCLEUS Chromatin Centrosome 39 Plasma membrane CYTOSKELETON Microfilaments Intermediate filaments Microtubules Ribosomes Golgi apparatus Lysosome Mitochondrion 2011 Peavsun Educauun Inc Figure 68a Rough endoplasmic reticulum Smooth endoplasmic reticulum Ribosomes Central vacuole Golgi apparatus Microfilaments Intermediate filaments Microtubules CYTOSKE LETON Mitochondrion Peroxisome Plasma membrane Chloroplast Cell wall Plasmodesmata Wall of adjacent cell ozon Pearson Education Inc Figure 69a Nucleolus Chromatin Nuclear envelope Inner membrane Outer membrane Nuclear pore Pore complex Ribosome lt Closeup of nuclear envelope A Chromatin 2011 Pearson Educaulm Inc Figure 69 The eukaryotic cell s genetic instructions are housed in the nucleus and m carried out by the ribosomes Nucleus Nucleolus Nuclear envelope Rough ER Pore complex ASun ace envelop 4 Closeup of nuclear envelope APore complexes TEM 4 Nuclear lamina TEM Q20quot Pearson Enucallon Inc Figure 610 Ribosomes Protein Factories 025 me I I aw v I r Ribosomes bound to ER Large subun Small subun TEM showing ER and ribosomes Diagram of a ribosome 2011 Pearson Educanen Inc Figure 611 The endomembrane system regulates protein traf c and performs metabolic functions in the cell 39 4 520 Pearson Educallon Inc Nuclear envelope ER lumen Cisternae Rlbosomes Transport vesicle 39 Smooth ER at 1 and w c 1 R w quotA pvx 391 quot a r 7 3399 5 quotg Figure 61 1a Smooth ER smooth ER Synthesis of lipids carbohydrate metabolismdrugpoison detoxi cationcalcium storage rough ERbound NUClear ribosomes ycoproteins secretion envelope Distribution of transport vesicles proteins surrounded by membranes membrane gt tory for the cell Rough ER ER lumen Cisternae Transitional ER Ribosomes Transport vesicle 02cm Pearson Education Inc Figure 612 The Golgi Apparatus Shipping and cis face Receiving Center receiving side of 01 Hm Golgi apparatus Cisternae trans face shippin9 Side Of TEM of Golgi apparatus Golgi apparatus Figure 613 Lysosomes Digestive Compartments 1 m Vesicle containing ILI two damaged 1 I m organelles Nucleus Mitochond rion fragment Peroxisome fragment Digestive enzymes 7 Lysosome Lysosome 7 39 7 V 7 P Q Plasma mem brane a v erOXIsonie Lysosome Dig estio n b Autophagy a Phagocytosis 82ml Peersan Eaucauan Inc Some types of cell can engulf another cell by phagocytosis this forms a food vacuole httpwwwyoutubecomwatchvfoquAU5fFQ A lysosome fuses with the food vacuole and digests the molecules Lysosomes also use enzymes to recycle the cell s own organelles and macromolecules a process called autophagy Animation Lysosome Formation Figure 614 A plant cell or fungal cell may have one or several vacuoles derived from endoplasmic reticulum and Central vacuole Cytosol Mon Pearson Educallun inc Figure 617 I Chemical Energy ConverSIon Mitochondria are the sites of cellular respiration a metabolic process that uses oxygen to generate ATP lntermembrane space Outer membrane Inner Mitoc on rial Free membrane ribosomes DNA in the Cristae v mitochondrial Nuclear DNA matrix a Diagram and TEM of mitochondrion m b Network of mitochondria in a protist cell LM ozou Pearson Education in Figure 618 Chloroplasts Capture of Light Energy Ribosom es Inner and outer n34 membranes equot DNA Thylakoid Intennembrane space a Diagram and TEM of chloroplast b chloroplasts in an algal cell man Pearson Educanon Inc Figure 619 1am Chloroplast Pabxbome t ochond on 2011 Pearson Educalmn Inc Cytoskeleton a network of bers that organizes structures and activities in the cell 10 um 2011 Pearson Education Inc Figure 621 I 739 Receptor for motor protein Motor protein Microtubule ATP powered of cytoskeleton a Microtubule Vesicles 025 pm 2011 Pearson Emmerich Inc Table 61 Yahle 61 The Structure and Function of the Cytoskeleton Main funclicns ub lin dimer consisting oi dtuoulln and BLubulin ainlenance oi el M shape compression resisting 39 girdersquot Cell motility as in cilia or flagella Chromosome movements in cell division Organelle movements Maintenance ol cell shape tension bearing elements Changes in cell shape Muscle contraction Cytoplasmic streaming Cell motility as in pseudopouia Cell division cleavage furrow formation 10m l quotl Micmtubules Micro iaments Intermediate Property Tubulin Polymers Actin Fllamenls Filaments Structure Hollow Lubes wall consists of 39 39 aclln each W n into thitker l3 columns of lubulin molecules a polymer of ac n subunits cables Diameter ZS nm with 15mm lumen 7 nm Br l 2 nm Protein subunits Aclin ne of several diiierent prote s such as o in keratins depending on cell type Maintenance of cell shape tension bearing elements Anchorage or nucleus and certain other rganelles Formation ol nuclear lamina 17m Keratln proteins Fibrous subunit keratins ether oileiVog 3 I 201I Pearson Edueetion tne 1 l39bona ltll lfecul39ll Diversity of List quot Overview Carbon The Backbone of Life meg organrsms consrsr mosuy or carbonrbased compounds Carbon rs unparaeed rn rrs aprmy to rorm arge comp ex a dwersemo ecu es Protems DNA carbohydratesr and other morecures that drstrngursn ng matter are 5 composed or carbon com ounds Organic chemistryrs the study or compounds that contam carbon 82312 Vitaism the idea that organic compounds arise only in organisms was disproved when chemists synthesized these compounds Mechanism is the view that all natural phenomena are governed by physical and chemical laws Carbon atoms can form diverse molecules by bonding to four other atoms Oxygen Nitrogen Carbon valence 2 valence 3 valence 4 Hydrogen valence 1 82312 Figure43 Name and Molecular Structural Balland SpaceFilling Comment Formula Formula Stick Model Model a Methane CH4 b Ethane C2H6 c Ethene ethylene C2H4 Figure 44 Carbon Hydrogen Oxygen N39trogen valence 4 valence 2 Valence 3 valence 1 Carbon atoms can partner with atoms other than hydrogen for example Carbon dioxide 002 OCO 82312 82312 Figure 4UN01 H 5 c O I N H Urea CONH22 Urea Figure 45 a Length c Double bond position H H H H H H Ethane Propane 1Butene 2Butene b Branching d Presence of rings Butane 2Methylpropane cycohexane Benzene isobutane oeon Peavson Educanun Inc Hydrocarbons Hydrocarbons are organic molecules consisting of only carbon and hydrogen Figure 46 Nucleus Fat droplets 10 um a Part ofa human adipose cell b A fat molecule 82312 Figure45 a Length c Double bond position H H H H H H H H H new HHH H H H H H H H H Ethane Propane 1Butene 2Butene d Presence of rings b Branching H H Butane 2Methylpropane isobutane Cyclohexane Benzene 2011 Pearson Educahon inc F39 u 47 lg re a Structural Isomers X X H X C C C C H H X H cis isomer The two Xs trans isomer The two Xs are on the same side are on opposite sides c Enantiomers L isomer D isomer man Pearson Education Inc 82312 Isomers Isomers are compounds with the same molecular formula but different structures and properties Structural isomers have different covalent arrangements of their atoms Cistrans isomers have the same covalent bonds but differ in spatial arrangements Enantiomers are isomers that are mirror images of each other Animation Isomers Figure 48 Effective Ineffective Drug cond39tlon Enantiomer Enantiomer Pain lbUprOfen inflammation w Slbuprofen Rlbuprofen Albuterol Asthma RAlbuterol SAlbuterol 82312 82312 The tragedy of thalidomide o o o 0 NH NH N rrrrrr v o N o o o Concept 43 A few chemical groups are key to the functioning of biological molecules Distinctive properties of organic molecules depend on the carbon skeleton and on the molecular components attached to it o A number of characteristic groups can replace the hydrogens attached to skeletons of organic molecules 82312 The Chemical Groups Most Important in the Processes of Life Functional groups are the components of organic molecules that are most commonly involved in chemical reactions The number and arrangement of functional groups give each molecule its unique properties Figure 4UN02 O Estradlol CH3 iiiiiiiiiiiiiiiiiiiii nc o The seven functional groups that are most important in the chemistry of life Hydroxyl group Carbonyl group Carboxyl group Amino group Sulfhydryl group Phosphate group Methyl group Figure 49a CHEMICAL 7 I GROUP Hydroxyl Carbonyl Carboxyl O o o STRUCTURE J 70quot c c l O J quot may be written Ho 39 Alconols Theirspeci c narnes Ketones irtne carbonyl group is Carboxylic acids or organic acids COMPOUND usually end in oI within a carbon skeleton Aldenydes irtne carbonyl grou is at the end ortne carbon skeleton EXAMPLE 0 l quot o l T ltl lt H 2 c quot4rin u i x H OH H H H Etnanol Acetone Acetic acid H H a l Hcc c7 l H H H Propanal FUNCTIONAL ls polar as a result of the A 39 PROPERTIES 39 39 39 H b near 39 erfip 39 atorn acetone and propanai is so polar water 39 39 39 nillirm ri e 0 0 organic compounds such as to two major groups of sugars 7C 3 c Hs sugars ketoses containing ketone groups and aldoses containing 0quot 0 aldehyde groups Nonionized Ionized Found in cells in the ionizedform with a c arge of and called a carboxylate ion 2ml Pearson Education Inc 82312 Figure 49b Amlha Sullhyd39ryl Phosphate Methyl 1 H 9 All T a N 4 SH 7 o T o 6i GH v i 2 H l may be 0 J H written lls Amines Thiols Organic phosphates Methylated compounds i 2 0 OH x o H H 1 OH OH I H N c 2 i I i C CAN Hi 69H2SH H c c c o P o i i i l l i H l H N 0 ill u H H H Glycine Cysteine Glycerol phosphate 5 Methyl cytidine Acts as a base can Two sulfhydryl groups can Contributes negative charge to Addition of a methyl group pick up an H from the react ronning a covalent the molecule ofwhich it is apart to DNA or o molecules surrounding solution bond This cross linking 2 when at the end of a molecule bound to DNA affects the water in living helps stabilize protein 1 when located expression of genes organisms stmcture internally in a chain of Arrangemth of methyl Ph SPha 5 groups in male and female H Cross linking of cysteines 39 39 39 w 4 en 2 7N7H in hairprotelns maintains groups have the potential to react shape and function l the curliness or straightness with water releasing energy of hair straight hair can be Nonionized Ionized permanently curled by shaping it around curlers and then breaking an 39 F quotd 39quot quot5 39quot quot 9 re forming the cross linking ionized form with a charge of1 ozou Pearson Education Inc Figure 49a Hydroxyl STRUCTURE 7g OH Alcohols NAME OF I Their specific COMPOU N D l names usually may be written end in oI H s polar as a result FUNCTIONAL IIquot IIquot of the electrons PROPERTIES spending more H OH time near the H H electronegative oxygen atom Can form hydrogen bonds with water molecules helping dissolve organic compounds such as sugars EXAMPLE Ethanol mow Paarson Education Inc 82312 11 Figure 49b STRUCTURE EXAMPLE 2011 Pearson Edutalion lnc Carbonyl Acetone H H o l l H C C C H H H Propanal O 0 Ketones if the carbonyl group is within a carbon skeleton A ketone and an NAME OF COMPOUND Aldehydes if the carbonyl group is at the end of the carbon skeleton FUNCTIONAL aldehyde may be PROPERTIES structural isomers with different properties as is the case for acetone and propanal Ketone and aldehyde groups are also found in sugars giving rise to two major groups of sugars ketoses containing ketone groups and aldoses containing aldehyde groups Figure 490 STRUCTURE EXAMPLE 2011 Pearson Educniion inc Carboxyl Acetic acid Carboxylic acids or organic acids COMPOUND Acts as an acid can Nonionized NAME OF FUNCTIONAL donate an H because the PROPERTIES covalent bond between oxygen and hydrogen is so polar O O C i C H OH 0 Ionized Found in cells in the ionized form with a charge of 1 and called a carboxylate ion 82312 Figure 49d Amino STRUCTURE Amines NAME OF 51 H COMPOUND quot N A H EXAMPLE Acts as a base can FUNCTIONAL pick up an H from the PROPERTIES 0 T H surrounding solution CCN water In IIVIng I organisms HO H H H T H N N H Glycine l H H Nonionized Ionized Found in cells in the ionized form with a charge of 1 Figure 49e Sulfhydryl STRUCTURE Thiols NAME OF COMPOUND t SH I may be written HS EXAMPLE Two sulfhydryl groups can FUNCTIONAL 0 OH react forming a covalent PROPERTIES C bond This crosslinking I helps stabilize protein H CH2 SH structure N Crosslinking of cysteines H in hair proteins maintains the curliness or straightness Cysteine 2on Pearson Euucanun Inc of hair Straight hair can be permanently curled by shaping it around curlers and then breaking and reforming the crosslinking bonds 82312 13 Figure 49f Phosphate STRUCTURE Organic phosphates NAME OF 3 COMPOUND p o 0 EXAMPLE Contributes negative FUNCT39ONAL charge to the molecule PROPERTIES 0H OH H o of which it is a part 2 when at the end of Hcccopo a molecule as at left I l 1 when located H H H 0 internally in a chain of phosphates GlyceFOI Phosphate Molecules containing phosphate groups have the potential to react with water releasing energy Figure 49g Methyl STRUCTURE Methylated compounds NAME OF COMPOUND 3 H 93 igt H 49 H EXAMPLE NH2 Addition of a methyl group FUNCTIONAL to DNA or to molecules PROPERTIES c ca bound to DNA affects the c expression of genes N I il 0 c Arrangement of methyl 0 N H groups in male and female I sex hormones affects their shape and function 5Methyl cytidine 2011 F eeee on Education Inc 82312 82312 ATP An Important Source of Energy for Cellular Processes One phosphate molecule adenosine triphosphate ATP is the primary energy transferring molecule in the cell 0 ATP consists of an organic molecule called adenosine attached to a string of three phosphate groups The Chemical Elements of Life 0 The versatility of carbon makes possible the great diversity of organic molecules 0 Variation at the molecular level lies at the foundation of all biological diversity LECTURE PRESENTATIONS For CAMPBELL BIOLOGY NINTH EDITION Jane Bl Reece Lisa A UrryE Michael L Cain Steven A Wasserman Peter V Minorsky RobeIt E Jackson Lectures by 1 Erin Barley Katltleell Fitzpatrick Definitions Metabolism the totality of an organism s chemical reactions 0 Catabolic release energy by breaking down complex molecules into simpler compounds 0 Anabolic consume energy to build complex molecules from simpler ones Enzyme 1 7 Enzyme 2 Enzyme Reaction 1 Reaction 2 Reaction 3 Starting Product molecule Copyrlghi Inc 91912 LIFE IS WORK Worllt requires energy The immediate source of energy is ATP How do we produce the required amount of ATP oxidation of glucose to CO2 n conditions that support life enzymes as catalysts Reactions are part of a complex network of chemical reactions metabolism These reactions must obey the laws of thermodynamics energy cannot be created or destroyed entropy disorder is only increasing Kinetic energy is energy associated with motion Heat thermal energy is kinetic energy associated with random movement of atoms or molecules Potential energy is energy that matter possesses because of its location or structure Chemical energy is potential energy available for release in a chemical reaction Energy can be converted from one form to another Animation Energy Concepts 91912 The Laws of Energy Transformation Thermodynamics sTudy of energy TransformaTions closed sysTemliquid in a Thermos is isolaTed from iTs surroundings open system energy and maTTer can be Transferred beTween The sysTem and iTs surroundings The First and Second Law of Thermodynamics rst law otihermodynamics The energy or The unlverse ls slanl 7 Energy can be Transferred and Transformed buTchonnoTbe Troyed pnnerple ofconservallon or energy 7 Durlng every energy Transfer or Transformallon some energy ls unusable andlsoflen oleE heal second law otihemiodynamics 7 Every energy Transfer or rrgnsrorrngn39on lncreoses The entropy dlsorderl or The unlverse Energy flows lnTo an ecosysTem ln The form of llghT and exlTs ln The form of heaT FreeEnergy Change AG 0 The change in free energy AG during a process is relaTed To The change in enThalpy or change in ToTaI energy AH change in enTropy AS and TemperaTure in Kelvin T AG AH 7 TAS 0 Only processes with a negative AG are spontaneous S must increase 5 1 rr r e Remember membrane transport Free Energy Stability and Equilibrium 0 Free energy is a measure of a sysTem s insTa biIiTy iTs Tendency To change To a more sTabIe sTaTe 0 During a we 4 ci e and The sTabiliTy of a sysTem increases Equilibrium is a sTaTe of maximum sTabiIiTy A process is sponTaneous and can perform work only when iT is moving Toward equilibrium 91912 The relationship of free energy to stability work capacity and spontaneous change 0 More free energy higher G 0 Less stable 0 Greater work capacity easedi se energyquotcan 39 nessedtbduwork Less free energy lower G o More stable 0 Less work capacity a Gravitational motion b Diffusion c Chemical reaction Cavytlghl o 2005 Pearson Edunalion inn pubiishmg as Pearson Benmmln Cummmgs Equilibrium and Metabolism Reactions in a closed system eventually reach eguilibrium and then do no work 0 Cells are not in equilibrium they are open systems experiencing a constant flow of materials 0 A defining feature of life is that metabolism is never at equilibrium 0 A catabolic pathway in a cell releases free energy in a series of reactions Copyright 2008 Peaison Education Inc publishing as Pearson Benjamin Cummings LE 8621 An exergonic reaction proceeds with a net release of free energy and is spontaneous Reactants Amount of energy released Free energy gt 0 Products Progress of the reaction gt a Exergonic reaction energy released Inr H H39i Copyright a a v An endergonic reaction absorbs free energy from its surroundings and is nonspontaneous Amount of energy required AG gt 0 Products Reactants Free energy gt Progress of the reaction b Endergonic reaction energy required comraging lnr Ublishillgu i 91912 LE 8 7a LE 8 7b Closed and open hydroelectric systems can serve as analogies a A closed hydroelectric system Copyright b An open hydroelectric system Copyright LE 8 7c ATP powers cellular work by coupling exergonic reactions to endergonic reactions A cell does three main kinds of work Mechanical Transport Chemical To do work cells manage energy resources by energy coupling the use of an exergonic process to drive an endergonic one c A multistep open hydroelectric system Copyrigmo 39 LE 8 8 The Structure and Hydrolysis cit ATP Adenine NH2 Ribose Copyright 91912 Figure 89 a Glutamic acid conversion to glutamine bConversion reaction coupled with ATP hydrolysis c Free energy change for coupled reaction 2011 Pearson Educallan Inc W gt Glutamic Ammonia acid AGGlu 34 kcallmol Glutamine W LADP ADP Glutamic acid Phosphorylated Glutamine intermediate r AGGlu 34 kcallmol W are AGGIH 34 kcallmol AGA P 73 kcallmol Net AG 39 kcallmol LAGA P 73 kcallmol j ATP drives endergonic reactions by phosphorylation transferring a phosphate group to some other molecule such as a reactant LE 8 9 1 Adenosine triphosphate ATP i Inorganic phosphate Adenosine diphosphate ADP Copyrighl I lnr 395 LE 8 11 Copyright c 91912 LE 8 12 The Regeneration of ATP Energy for cellular work endergonic energy consuming processes Energy from catabolism energonic energy yielding processes ADP i Copyrighl 39 Ines my Enzymes speed up metabolic reactions by lowering energy barriers A catalyst is 1 chemical agent that speeds up 1 reaction without being consumed by the reaction An enzyme is o cotolytic protein Hydrolysis of sucrose by the enzyme sucrose is on example of on enzyme catalyzed reaction Sucrase 39 Sucrose Glucose Fructose C 2H220 C H 20 C H 20 Copyright 39 m H q 39 39 39 HTl lZe M M Transition state Reactants Free energy gt Products Progress of the reaction gt cam Pearson Education In Figure 813 Course of reaction E A without without enzyme enzyme EA with enzyme T is lower gt E Reactants cu C 0 Course of AG is u ffected 8 reaction by enz e L u wuth enzyme quotquotquotquotquotquotquotquotquotquotquotquotquotquotquot quotProducts quotu Progress of the reaction gt 91912 Figure 814 Su bstrate 0 Active site Enzyme Enzymesu bstrate complex a b o 2cm Pearson Educalicn Inc Figure 8151 O Substrates enter actlve srte d f Su bst rates 9 Substrates are held in active site by weak interactions Enzymesubstrate complex Enzyme man Pearson Educmion Inc LE 8 18 Optimal temperature for Optimal temperature for typical human enzyme enzyme of thermophilic heat tolerant E bacteria 0 N 24 1 5 N a 1 1 I Ii 1 I 039 29 4390 60 80 1100 Temperature gt aso ptimgalgfempera refor two e nzym es Optimal pH for pep sin optimal pH T stomach enzyme fortrypsin c intestinal g enzyme g 2 9 E E m I l l I I l I I I l I 0 2 3 4 539 6 7 8 9 10 pHI gt bO pt39ir nial pH tar Moenzwh es Copyrighl 39 w H Figure 8152 O Substrates enter actlve Slte 9 Substrates are held in active site by weak interactions Substrates Enzymesubstrate complex 6Active site can a lower EA and speed up a reaction Active site Enzyme 0 Substrates are converted to products eeon Pearson Eduanlinn Inc Figure 8153 O Substrates enter actIve sIte Iquot d f Su bst rates 9 Substrates are held in active site by weak interactions Enzymesubstrate complex QActive site can lower EA and speed up a reaction available for two new substrate molecules Enme 9 Products are released Products 0 Substrates are converted to products 91912 Why doesn t cholesterol help you build muscle ADB39KBXO I V Ctlololctml l in 14 0 CHC Hac CH Cquot gt H0 0 Pregnanaiona Progesterone cu cu CM CO C OH co CHI on on 3quot won cu CH CH HO O O nahyavoxy 200 dlhydro Enzyme regulation Feedback inhibition transcriptional control Allosteric Transport Regulation of Enzymes metabolic pathways are tightly regulated switch on or off the genes that encode specific enzymes transcriptional control allosferic regulation profein s function at one site is affected by binding of a regulatory molecule at another site compartmentalizafion l l progestech 0 O CH o CH CH HO 0 H0 Dehydroeplandromm Androstenediooe Ealrone on 1 l on CH cuquot cu HO 0 H0 Androslenudlot Yentotlm Eltrndlol l7 p LE 8 19 li 39 r i I 1 2 39 quot J i whiffquot i 5 quot l A competitive inhibitor mimics the substrate competing for the active site quot 9 aNorma binding A substrate can Substrate bind normally to the active site of an Active site enzyme 1 iiPf J J W J J 4 394 J 1 a Enzyme 9 Competitive inhibitor b Competitive inhibition Q A noncompetitive inhibitor binds to the enzyme away from the active site altering the conformation of the enzyme so that its active site no longer functions Noncompetitive inhibitor c Noncompetitive inhibition W y Copyright L i l C 2 5773 f Iquot a quotJ m Hmm I NEH l Active site available Isoleucine US ce Active site of enzyme 1 is no longer able to catalyze the conversion of threonine to intermediate A pathway is switched off 2011 Pearson Education Inc ed up by II Feedback inhibition 432 AL Isoleucine binds to allosteric site L quot Initial substrate threonine Threonine in active site Enzyme 1 threonine deaminase Intermediate A V Enzyme 2 Intermediate B V Enzyme 3 Intermediate C quot Enzyme 4 Intermediate D Enzyme 5 w I End product 4 isoleucine Figure 822 2011 Pearson Education Inc Enzymes for another stage of cellular respiration are embedded in the inner membrane Mitochondria The matrix contains enzymes in solution that are involved in one stage of cellular respiration 91912 Speci c Localization of Enzymes Within the Cell 0 Structures within the cell help bring order to metabolic pathways Some enzymes act as structural components of membranes In eukaryotic cells some enzymes reside in specific organelles for example enzymes for cellular respiration are located in mitochondria Cofactors Mitochondrial if x T Matrix r W 39 39 H p vlt 39 I Succinateg gFumar t 5 KSDFIA Cofactors are nonprotein enzyme helpers 7 s Cofactors may be inorganic such 2 g quot l a I as a metal in ionic form or V W organic 4 An organic cofactor is called a coenzyme Coenzymes include vitamins 1O
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