Biology FRO 2
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YOU DO NOT COPY DNA IN MITOSIS REPLICATION HAPPENS IN SPHASE Biology 1020 Final Replacement Opportunity FRO 2 Study Guide Chapters 110 12 13 focus on material after 6 Chapters 16 Exam 1 study guide gt5 questions total Chapter 7 Membranes 813 questions total Group 1 23 questions Roles of Biological Membranes know them separation selective passage surface for chemical events Border keeping in in and out out membranes separate aqueous environments so that differences can be maintained the plasma membrane surrounds the cell and separates the internal and external membranebound organelles have their interior separated from the rest of the cell Border Guarding controlling what gets in and out maintains environment in the cell as the outside changes Surface for chemistry many enzymes are embedded in membranes helps make reactions easier to control can help in getting reactants together getting catalysts and reaction chains together avoid equilibrium More surface chemistry raising ags sending or receiving messages proteins and glycoproteins are used for chemical recognition and signaling Lipid Bilayer and Fluid Mosaic Model reasons for spontaneous bilayer amphipathic roughly cylindrical phospholipids model as 2dimensional uid with embedded proteins that move along the membrane including tested predictions of the model and reasons for rejecting sandwich model what effects and can stabilize membrane uidity general types and roles of membrane proteins Page 1 of 21 Physical properties of cell membranes the lipid bilayer and the fluid mosaic model biological membranes are lipid bilayers w associated proteins glycoproteins phospholipid molecules spontaneously form bilayers in aqueous eviornments due to their amphipathic nature distinct hydrophobic and hydrophilic regions and overall cylindrical structure hydrophilic head comes om a polar organic molecule linked via a phosphate group to the glycerol backbone hydrophobic tails come om 2 chains of fatty acids linked to glycerol cylindrical shape that favors the formation of lipid bilayers detergents come to a point at their single hydrophobic tail and favors lipid spheres over lipid bilayers can solubilize lipids to varying degrees high enough concentrates of detergents will disrupt cell membranes Fluid mosaic model describes the structure and properties of cell membranes uniformly 8 nm thick with a globular nature some proteins imbedded in lipid bilayers that act as twodimensional uids materials can be moved along the membrane due to uid properties digestion of certain transmembrane proteins applied to one side will produce protein agments that di er om the other side biological membranes act as twodimensional uids or liquid crystals ee to rotate or move laterally but rarely ip the uidity of a membrane is a function of both temperature and molecules in an unsaturated fat a C C double bond produces a bend that causes phospholipids to be spaced out gt ee motion colder temperatures unsaturated fats more uid higher temperatures gt saturated fats less uid other lipids ex cholesterol can stabilize membrane uidity organisms control membrane uidity by several means regulating temperature changing fatty acid pro le of their membranes adding uidity modi ers or stabilizers biological membranes resist having open ends a lipid bilayer will spontaneously selfseal resulting in spherical vesicles shape can be modi ed with structural proteins with an internal aqueous lumen fusion of membrane surfaces can occur when they are in close proximity common between vesicles and various organelles contents of separate lumens mix delivers the material in the vesicle lumen to the outside of the cell MembraneAssociated Proteins membrane proteins are classi ed as either integral of peripheral integral proteins are amphipathic proteins rmly bound to the membrane and can Page 2 of 21 only be released by detergents transmembrane proteins 1P extend completely across the membrane hydrophobic ahelices are common spanning domains some wind backandforth across the membrane peripheral proteins are not embedded in the membrane bound by ionic or hydrogen bonds to a hydrophilic protein of an integral protein the protein pro le of one membrane side typically di ers from the other side more proteins are on cytoplasmic side of the plasma membrane revealed by freezefracturing plasma membranes types of processing differs on the target side Group 2 35 questions Transport Across Membranes What is diffusion and that it is net movement What diffuses easily and What doesn t osmosis and associated terms hypotonic etc which way water flows between hypotonic and hypertonic solutions consequences of placing cells in hypotonic or hypertonic solutions diffusion no energy requirement active transport energy required movement against concentration gradient roles of proteins in facilitated diffusion and active transport harvesting energy from diffusion Transport and transfer across cell membranes cell membranes are selectively permeablevary depending on the membrane most permeable to small molecules and lipidsoluble substances CAN H20 CO2 02 CANNOT amino acids sugars ions some passage across the membrane is assisted with special channels diffusion across membranes is based on random motion of particles no energy a difference in concentrations establishes a concentration gradient which provides energy for diffusion often equilibrium is not reached due to continual removalproduction rate of di usion is dependent on temp size shape and charge nature osmosis is diffusion of a solvent usually water across a membrane solutes affect movement by affecting the concentration of water osmotic pressure is determined by the amount of dissolved substances in a solution it is the tendency of water to move into a solution two solutions with same osmotic pressure gt isotonic different solutions gt hypertonic higher pressure water will ow into it and hypotonic lower pressure water will ow out of it turgor pressure is hydrostatic pressure in cells with a cell wall a cell wall enables cells to take in more water without bursting cells and in water and push against cell wall which pushes back used as part of maintaining structure if lost they wilt Page 3 of 21 carriermediated transport special integral membrane proteins assist in transport across membranes facilitated diffusion is when net transport follows a concentration gradient but proteins are needed to assist in transport the carrier protein often provides a regulated channel or pore through the membrane typically used to transport ions and large molecules like glucose added energy is not required in some cases harvested during transport carriermediated active transport requires energy to work against a concentration gradient energy is often supplied by ATP powering a protein pump that moves a substance against a gradient linked transport can also provide the energy for active transport Na K H is transported down its gradient providing energy often produced by active transport via a pump that uses ATP another substance is transported at the same time against the gradient using the energy Group 3 35 questions Endocytosis and Exocytosis functions of both for getting large particles into or out of the cell forms of endocytosis Large particles are transported across the membrane via exocvtosis and endocvtosis Transport and transfer across cell membranes exocvtosis fusion of vesicles or vacuoles with the plasma membrane that results in secretion outside the cell or discarding waste outside the cell endocvtosis vesicles or vacuoles bud into the cell from the plasma membrane bringing materials into the cell several types Endocytosis phagocvtosis large solid particles are ingested including whole cells in some cases pinocvtosis smaller regions of dissolved materials are ingested receptormediated endocytosis receptor proteins in the plasma membrane bind to speci c molecules causing protein conformational shape changes that lead to the formation of a coated vesicle Signal Transduction process of information transfer across plasma membrane protein receptors involved in receiving signal shape change and information transfer cAMP as common signal carrier inside cell Page 4 of 21 Signal transduction is the transfer of information across the cell membrane two aspects signal reception and signal transmission Signal Transduction signal reception special protein receptors in the cell membrane bind to signaling molecules Outside the cell signal transmission the receptor now activated changes shape in some way then it transfers information to the interior of the cell often done using a series of protein activations and eventual formation of a second messenger such as cAMP on the cytosolic side of the cell membrane signals often wind up greatly ampli ed Roccptoc gm 0 W W 39W W W LTIquot 39 o n a up 1 0 WHO 2am I won 39 EsAim M Ml wm 4 Mule m n V39 a o o o o 5 Tc 3 ooo39olnoecaw Y on39noponm a 39 a d5 c Ampumoon W Oquot Q C IOOOIWINWO 7 Amwkwon O O I 039 O Q m ooooooooom c you 2275 Cell Contacts types and roles of cell contacts similarity in function of gap junctions and plasmodesmata Specialized Contacts junctions Between Cells Cell Contacts functions typically connect cells and allow special transport between connected cells anchoringjunctions hold cells tightly together common type in animals is desmosome which form strong bonds like merging of cytoskeletons making it hard to separate materials can still pass space between cells not involved in transport of materials tight z39unctions between some animal cells are used to seal of body cavities cell plasma membranes are adjacent with tight seal materials cannot pass not involved in transport gap iunctions between animal cells act as selective pores proteins grouped in cylinders of 6 subunits that can open to form a pore which small molecules can pass connect cells plasmodesmata acts as selective pores between plant cells with relatively wide channels between adjacent cells connect plasma membranes of two cells allows some exchange plant cell walls preform functions of tight junctions and desmosomes Page 5 of 21 Chapter 8 Energy and Enzymes 813 questions total Group 1 46 questions Energy Thermodynamics and Metabolism know how thermodynamics governs chemical reactions know the terms for chemical reactions and how they relate to each other anabolismcatabolism exergonicendergonic etc know about coupled reactions ATP is the main energy in currency in cells Enzymes regulate reactions Energy and Thermodynamics energy for work change in state of motion of matter I kcal 4 I 64 kJ energy conversion energy for change potentialkinetic potential energy capacity to do work ex chemical bonds kinetic energy energy of motion actively performing work Law of Thermodynamics describe the constraints on energy usage you can t win and you can t break even First law the total amount of energy matter in a closed system remains constant also called conservation of energy you cant win the universe is a closed system living things are open systems Second law in every energy conversion some energy is converted to heat energy heat energy is lost to its surroundings and heat cannot be used for work every energy conversion increases the entropy of the universe no energy conversion is I 00 eficient you can t break even just to maintain their current state organisms must get a constant in ux of energy because of energy lost in conversions Metabolism anabolism catabolism metabolism divided into anabolism anabolic reactions processes that build complex molecules from simpler ones and catabolism catabolic reactions processes that break down complex molecules into simpler ones Chemical Reactions and Free Energy chemical reactions change in chemical bonds substance concentrates and free energy free energy energy available to do work in a chemical reaction depend on bond energies and concentrations of reactants and products bond energy energy required to break a bond value depends on bond reactions will reach dynamic equilibrium earn the relative concentrations of reactants and products is correct gt Ycells manipulate concentrations so equilibrium is rare exergonic reactions the products have less free energy than reactants the difference in energy is released and available to do work Page 6 of 21 thermodynamically favored spontaneous but not necessarily fast catabolic reactions are usually exergonic ATP H2O gt ADP P is highly exergonic endergonic reactions the products have more free energy than the reactants the difference in free energy must be supplied stored in chemical bonds not thermodynamically favored not spontaneous together the coupled reactions must have a net exergonic nature mm l f MM 0 my Amount 039 M quotW 50 c 0D WM 10 gt0 Fm quotw m l t 39v WWWM W mumw a quotmom mam mom robmd lb Fmrgomc mtth may toquf i energy currency and energy transfer molecules ATPADP NADHNAD NADPHNADP know the role of ATP as energy currency in cells and how that works coupled reaction typically with phosphorylated intermediates know the general equations for reactions involving these compounds know which are the energy storage forms include FADHZFAD here for all but ATPADP know which form is reduced and which is oxidized include FADHZFAD here ATP is the main energy in cells nucleotide with adenine base ribose sugar and a chain of 3 phosphates last two phosphates unstable bonds gt easy to break and release energy hydrolysis of AT P to ADP and inorganic phosphate Pi releases energy ATP H2O gt ADP Pi Intermediates when ATP hydrolysis is couples to a reaction to provide energy often phosphorylated compounds the inorganic phosphate is transferred onto another compound rather than being immediately released energy transfer in cellular reactions is often accomplished through transfer of a phosphate group from ATP Page 7 of 21 making AT P involves an endergonic condensation reaction typically created in catabolic reactions and used in anabolic reactions linking those aspects of metabolism cells maintain high levels of AT P relative to ADP 101 maximizes energy overall concentration of AT P is only enough for a few seconds cells use and produce 10 million molecules per second Redox reactions are also used for energy transfer used to harvest energy from some chemicals the acceptors of that energy typically cannot used directly as energy currency electrons can also be used for energy transfer redox reactions recall reduction gain electrons and energy electrons and energy simultaneously in cells catabolism typically involves removal of H atoms from nutrients carbs and transfer of p and e to intermediate electron acceptors intermediate acceptor example nicotinamide adenine dinucleotide NADH the reduced for is NADH other commonly used acceptors are NADP FAD and cytochromes NADPNADPH important in photosynthesis FADFADH2 flavin adenine dinucleotide cytochromes small ironcontaining proteins iron is electron acceptor oxidation lose 2 439 o 2 H39 2 l 9 P4 39 NAD quot NADH H sari Am a aware M I JTC NH 2m Roduction oi may I c NH g x quotmm 3900quot Oxidation o NADH u l mco mw Nicotimmido oxidized Ion39n Mom loan Group 2 47 questions Enzymes know what a catalyst is speeds up reaction by lowering activation energy not consumed in the reaction know how enzymes work in general know terms active site enzymesubstrate complex apoenzyme coenzyme Page 8 of 21 know how to in uence enzymecatalyzed reaction rates What to add to speed up the rate when substrate gt enzyme What to add to speed up the rate When substrate lt enzyme allosteric activationinhibition inhibition irreversiblereversiblecompetitivenoncompetitive Enzymes manipulation of reaction is essential and largely de ning of life organisms use enzymes to manipulate reaction speed enzymes regulate chemical reactions in living organisms an organic molecule typically protein that acts as a catalyst increases the rate of a chemical reaction without being consumed in the reaction enzymes only alter reaction rate thermo governs whether reaction occurs work by lowering activation energy of a reaction catalysts greatly reduce the activation energy requirement Course of reaction without enzyme 39tho t w39 quot EA with enzyme is lower Reactants Course 0 reaction with enzyme Free energy gt 46 is unaffected by enzyme Products Progress of the reaction gt Enzymes lower activation energy by forming a complex with the substrates forming enzymesubstrate complex is dependent on the shape the site where the substrates bind to the enzyme is called the active site when the enzymesubstrate complex forms there are typically shape changes in the enzyme and substrates called induced le ES complex typically very unstable short lived breaks down into released products and a free enzyme that is ready to be reused overall enzyme substrates gt ES complex gt enzyme products Reduction in activation energy is due to four things I enzyme holds reactants substrates close together in the right orientation for reaction 2 enzyme may put a strain on existing bonds gt easier to break 3 enzyme provides a microenvironment for the reaction 4 active site is directly involved during transition states Page 9 of 21 o Subcan m oc w on mm W oh to it occur an Granule quotI on Wood M quot39 f 9 mm mm in mm on by m OWM Om 0 Wagon bond and tune hon 0 Active 0 and R group 01 Its 0000 actd can m E and W up Poacher by Enzymeosubstrale o quottoquot g mm Iov complex mm a oat on 0 Choosing the 00081300 and 330011 quotI mutton mu pcovodtng Onocooh micromnom We may as tho catstyne Man Substrates Enzyme Mach 0 i 0 Susan at no can Into 39 mooucu Products Enzyme names usually end in w or M Many enzymes require additional chemical components coZactors to function apoenzyme cofactor gt active enzyme bound together cofactors can be organic or inorganic organic examples coenz mes ex ADP NAD NADP FAD charged inorganic examples metal ions like Ca2 Mg2 not charged by reaction have optima temperature and pH Cells can regulate enzyme activity to control reactions increase substrate amt gt increase reaction rate up to saturation of avail enzyme increase enzyme amt gt increase reaction rate if substrate amt gt enzyme amt activators allowenhance catalytic activity inhibitors reduceeliminate catalytic activity sometimes uses an allosteric site a receptor site on an enzyme where and inhibitor or activator can bind a common ex of allosteric control isfeedback inhibition the last product in a metabolic pathway binds to enzyme is allosteric site in an early step inhibits activity of the enzyme irreversible inhibition enzyme is permanently inactivated or destroyed drugstoxins reversible inhibition if inhibitor is removed the enzyme activity can be recovered competitive inhibition inhibitor is similarly structured to substrate and competes for binding to the active site noncompetitive inhibition binds to allosteric site alters enzyme shape to make active site unavailable Page 10 of 21 Chapter 9 How Do Cells Harvest Energy 812 questions total Group 1 79 questions Aerobic Respiration know the overall reaction be able to use information from the chart described below examples know where each stage occurs in eukaryotic cells be able to follow the carbons and carbon compound in and out for each stage glucose pyruvate acetyl CoA etc know which and how much of the energy storing molecules ATP etc are made in each stage know where notable items such as the pyruvate dehydrogenase complex electron transport chain ATP synthase oxaloacetate 4 carbons and citrate 6 carbons fit in regulation of aerobic respiration ATPADP balance phosphofructokinase NOTE be able to make and fill out from memory the chart table from the lecture notes we lled out this table in class General Pathways for making ATP aerobic cellular respiration a generally e cient process that require 02 anaerobic respiration processes similar aerobic respiration but no 02 fermentation generally ine cient processes used mainly when other pathways cannot be used when ATP is needed quickly no 02 Aerobic respiration a redox process C6HI206 602 6H2O gt 6CO2 I2H2O energy in 3638 ATP molecules glucose is oxidized to carbon dioxide and oxygen is reduced to water substratelevel phosphorylation coupled reactions directly phosphorylate ADP or GDP dehydrogenation reactions redox reactions that transfer hydrogens to NAD or FAD decarboxylation reactions carboxyl groups are removed and releases as CO2 preparation reactions molecules are rearranged to prepare for other reactions substratelevel and dehydrogenation provide energy for cells Aerobic respiration is conventionally divided into four stages glycolysis occurs in the cystol glucose is converted to 2 pyruvate molecules a 3carbon molecule released energy is stored in a net yield of 2 ATP and 2 NADH molecules erSl phase requires energy investment phosphorylation using two AT P charges the sugar with two phosphates two molecules of Q are formed second phase energy payof yields pyruvate amp every captured in ATP amp NADH C6Hl206 2ADP 2Pi 2NAD gt 2C3H303 2ATP 2NADH 4H 2H20 KNOW THE CHART T HAT S FILLED IN ON CANVAS l l Page 11 of 21 AT PADP balance regulates much of oxidative phosphorylation ATP synthesis continues until ADP stores are largely depleted rapid use of AT P leads to excess ADP and thus speeds up aerobic respiration phosphofructokinase enzyme for one of the earliest steps in glycolysis regulated in mammals Group 2 13 questions Nonglucose energy sources in aerobic respiration Where they t in relative energy yield per unit weight compared to glucose Anaerobic Respiration and Fermentation Where or When used Why used Page 12 of 21 such as NAD regeneration What is produced such as lactic acid ethanol relative energy efficiency compared to aerobic respiration N onglucose energy sources other substances can be oxidized to produce ATP in living systems along w carbs proteins lipids are major energy sources in foods nucleic acids not common so proteins are broken into amino acids which can be broken down further amino group is removed deamination amino group may be converted to urea remaining carbon chain enters aerobic respiration same amount of energy per unit weight as glucose lipids are more reduced than glucose gt more energetic over twice as much energy per weight Anaerobic respiration done by bacteria that live in environments where 02 is not abundant still uses an electron transport chain other compound such as N 03 SO4A2 or CO2 serves as the ultimate electron acceptor not as efficient as aerobic respiration Fermentation involves no electron transport chain inefficient net is 2 ATP per glucose molecule if glycolysis only then NAD must be regenerated thus fermentation where NADH reduces an organic molecule alcohol fermentation produces ethanol C 02 and NAD pyruvate is converted to ethanol and C 02 to regenerate NAD ethanol is a potentially toxic waste product and is removed from cells yeast in low 02 environments used in making alcoholic beverages baking lactic acidfermentation pyruvate is reduced to lactate to regenerate NAD Chapter 10 Photosynthesis 713 questions total Group 1 24 questions Terms for organisms based on how they obtain energy and how they obtain carbon know these terms chemotrophs can only get energy directly from chemical compounds phototrophs can get energy directly from light can also use chemical compounds autotrophs can fix carbon dioxide and use it as a carbon source heterotrophs cannot fix C 02 use others organic molecules as a carbon source photoautotrophs carry out photosynthesis light energy to fix C 02 energy in chemical bond photoheterotrophs use light energy but cannot fix C 02 chemoautotrophs obtain energy from reduced inorganic molecules and use some of it to fix C 02 chemoheterotrophs use organic molecules as both carbon and energy sources dependent Page 13 of 21 The electromagnetic spectrum and visible light know terms relative energies UV vs infrared blue vs red light etc Electromagnetic Spectrum visible light is a form of electromagnetic radiation which consists of particles or packets of energy photons that travel as waves amount of energy is inverse to wavelength visible light ranges from high energy violet at 380 nm to low energy red at 760 nm molecules can absorb photons and become energized high energy electron can be freed from the atom it was bound to ionization moderate energy electron moves to a higherenergy orbital can return to lower level emitting a photon uorescence low energy change in motion of substance or minor changes in energy states Chloroplasts be able to match names with labels on a diagram know where the structures and substances used in photosynthesis are located photosystems including chlorophyll and accessory pigments in thylakoids membrane etc note that this material overlaps with some of the rest of the material on photosynthesis in photosynthetic eukaryotes photosynthesis occurs in the chloroplasts innerouter membrane stroma fluidfilled region inside the inner membrane thylakoids dislike membranous sacs found in stroma interconnected selves amp inner membrane thylakoid lumen fluidfilled region inside thylakoid granum sack of thylakoids chlorophyll the main light harvesting molecule is found in the thylakoid membrane pigments are compounds that absorb light all pigments have absorption spectrum Page 14 of 21 chl a a green pigment absorbs violet and red light accessory pigments are also found in the thylakoid membrane m is the main accessory pigment carotenoids are important yellow and orange accessory pigments action spectrum the relative rate of photosynthesis for given radiation wavelength range Group 2 47 questions Photosynthesis know the overall reaction and photosynthesis converts energy from light into stored energy inc chemical bonds C 02 is xes and used in synthesizing carbohydrates 6CO2 I2H2O gt C6H1206 602 6H2O light reactions occur in the thylakoids capture light energy consume water produce oxygen energy is placed in ATP and NADPH in the stroma C3 cycle occurs in the stroma consumes C 02 and energy produces carbohydrates for the lightdependent reactions follow electron flow for both cyclic and noncyclic electron transport know positions and roles of water Photosystem IIP680 Photosystem IP700 2 different electron transport chains ferredoxin NADPNADPH follow proton gradient establishment and use to make ATP know Where things are Photosystem components electron transport chains and ATP synthase in the thylakoid membrane water splitting and excess protons in the thylakoids lumen ATP and NADPH made in the stroma 12H20 IZNADP I8ADP I8Pi light energy gt 602 IZNADPH 12H I8ATP 18H20 takes into account amt of NADPH and AT P needed to create one molecule of glucose Photosystem 1 P680 gt plastoquinone Pa gt plastocyanin Pc gt Photosystem 1 P700 gt ferredoxin ATP synthase is located in the inner mitochondrial membrane and the thylakoid membrane cyclic electron transport is possible for P700 all it can accomplish is to enhance the protein gradient that can be used to make ATP for carbon xation C3 cycle know Where it occurs stroma know the parts C02 xation carbon reduction RuBP regeneration including the positions in the cycle and number of carbons for RuBP C02 3PGA G3P how many of each of those are involved in getting one 6carbon sugar 6 6 12 and 12 Page 15 of 21 IZNADPH 12H 18ATP 18H20 6C02 gt C6H1206 IZNADP 18ADP 18Pi 6H20 the position of RUBISCO use and of shunting off 2x G3P to make a 6earbon sugar the positions and numbers of ATPs and NADPHs used one of each per 3PGA to G3P one ATP per RuBP regenerated carbon fixations C 02 combines w the 5carbon compound RuBP RuBP CO2 gt 23PGA ATP consumed for each RuBP formed You might want to be able to make the table below from memory PROCESS in carbon carbon ATP NADPH Other notable items C3 cycle compounds compounds used used in out 390 uptake 6 RuBP 6 l2 3PiA 0 0 RUBISH enzyme CO carbon 12 3PGA l2 3P 1 2 reduction making 2 HP l Minor 0 0 Uses some ol39enymes glucose side glucose also used in glycolysis pathway RuBP ll i3 6 RuBP 6 0 Regeneration ot all 6 regeneration RuBP makes this a cycle TOTAL 6 03 l 7olla 0 IX 12 Group 3 12 questions Supplemental earbon xation pathways C4 and CAM pathways know the reactions know why this is done and why it works and the cost done to increase C02 concentration to avoid photorespiration in the C3 eyele works because PEP earboxylase allows C02 uptake even at very low C02 and high 02 costs extra 12 ATP per glueose made in C3 eyele know differences between C4 and CAM C4 has initial earbon xation in a different location from C3 eyele CAM has initial earbon fixation at a different time done when exposed to intense light or arid conditions 12 more AT P per glucose or fructose than C3 alone C4 works by altering the location of the initial CO2 xation CAM works by altering the time of initial C 02 xation Page 16 of 21 Photorespiration know what it is and when it is most likely to occur low C02 and high 02 relationship to C4 and CAM rubisco can add 02 to RuBP rather than C 02 called photorespiration because it occurs in the light and consumes O2 produce C 02 and H20 Chapter 12 The Cell Cycle How do cells divide 47 questions total Cell division in prokaryotes know terms I Cu will nqn 0t vrpluolmn Plasma membnme E C quot L quot N Phl C39H 00 0me o kLh39rvnouro Two Lopca v rcphCIHC ROMS n mqm quotmon quotcrooner ow opy 0 mo om u may aqch HMquot D We ol vev end 0 the c39 a Nophcnhon c anh39ums quot One pr u the ongn u now at oath and d quot c CI 0 Rophralwn 1m shes 7M plum mcmnuoo q ows mama we now on w z a door 106 D Q o no GSJKJH Jquot rolls gtan A prokaryotic cell divides by binary ssion splitting into two nearly equal halves The main circular DNA molecule of the cell is replicated The new plasma membrane and cell wall materials are laid down between the two DNA circles eventually separating the cells prokaryotic cells can have a generation time as short as 20 minutes Eukaryotic DNA molecules are organized in chromosomes know terms and their relationships recognize a karyotype display Eukaryotic DNA in chromosomes chromatin long DNA molecule with associated proteins chromosomes densely packaged chromatin during cell division protects DNA Page 17 of 21 Each chromosome contains hundreds of thousands of m functional units of heredity typically instructions for protein or RNA genome organisms complete DNA sequence humans have 25k genes in genome Chromosomes each species has a characteristic number of chromosomes humans 46 chromosomes for an individual is the karvo pe function chromosomes carry the genetic information of the cell The eukaryotic cell know what is going on during the phases G1 S G2 mitosis cytokinesis G0 terms associated with cell cycle regulation cyclins etc Eukaryotic Cell Cycle when cells reach a certain size growth wither stops or the cells must divide highly regulated the generation time is between 820 hours interphase G1 gt S DNA synthesis gt G2 gt mitotic M phase Mitosis can be divided into 4 stages prophase metaphase anaphase and telophase PMAT know what is going on in each of the PMAT phase especially with chromosomes remember sister chromatids have kinetochores on opposite sides in PampM Mitosis prophase chromatin condenses to form chromosomes each chromosome forms a pair of sister chromatids joined at the centromere and contain kinetochore mitotic spindle organize between the two poles nuclear membrane disappeared nucleoli disintegrated sister chromatids are attached by their kinetochores to the microtubules from opposite poles Mitosis metaphase chromosomes line up along the mid plane of the cell high condensed mitosis checkpoint kinetochores are all attached to microtubules Mitosis anaphase sister chromatids separate and are moved toward opposite poled the protein tethers at the centromere between the chromatids are broken each former sister chromatid can now be called a chromosome motor proteins move chromosomes towards the poles along the kinetochores microtubules assures that each daughter cells receives on of the duplicate sets of genetic material Mitosis telophase prophase is essentially reversed the mitotic spindle is disintegrated chromosomes decondense nuclear membranes reform around genetic material to form two nuclei nucleoli reappear Page 18 of 21 Cytokinesis know what it does divides the cell into two daughter cells splitting the cytoplasm and cell contents know the differences in plant and animal cell cytokinesis Cytokinesis divides the cell into two daughter cells cytokinesis usually begins in telophase and ends shortly thereafter in animals a cleavagefurrow develops usually close to where the metaphase plate was eventually closes enough for separation of the plasma membrane resulting in two separate cells in plants a cell plant develops usually close to where the metaphase plate was vesicles fuse and grow outward until reaching the plasma membrane and separating the cell vesicles contain materials for making the primary cell wall and a middle lamella cytoplasm and with it most organelles is usually distributed randomly but roughly equally sometimes cell division is a regulated polar division that purposefully distributes unequally Chapter 13 Meiosis and Sexual Life Cycles 36 questions total different modes of reproduction require different types of cell division meiosis reason for it halving chromosome number for sexual reproduction and proper use of terms diploid haploid etc asexual requires mitosis and creates cells that are genetically identical to their parent cells sexual specialized sex cells gametes to form a single sex cell zygote the o spring are different from parent cells it requires meiosis or else each generation would have double the amount of chromosomes Meiosis I creates diploids and Meiosis II creates haploids Meiosis I and meiosis II are each divided into prophase metaphase anaphase and telophase PMAT with accompanying cytokinesis know what is going on in each phase of meiosis I and meiosis II and in interkinesis especially follow the processes involving homologous chromosomes know sister chromatid kinetochores are sidebyside in meiosis I opposite sides in II and understand how this relates to when sister chromatids separate Meiosis I and II both consist of phase Prophase Metaphase Anaphase and Telophase along with cytokinesis Prophase I chromatin condenses to create chromosomes and homologous chromosomes pair The resulting structure with 4 total chromatids two sister from each pair called a tetrad T etrads held together by a synaptonemal complex Enzymes cause breaks in chromatids which Page 19 of 21 result in crossingover By end of prophase the spindle form nuclear vesicularized nucleoli disintegrated and homologous chromosomes are held together by chiasmata Metaphase I tetras line up along the middle of the cell Anaphase I chromosomes separate and move toward opposite poles Each pole gets one pair T elophase I spindle fibers disintegrate chromosomes partially decondense nuclear membranes may form around genetic material and cytokinesis occurs Interkinesis period between meiosis I and II Prophase II same as prophase I except the chromatin didn39t decondense Metaphase II chromosomes line up in middle and sister chromatids are connected by kinetochores to spindle fibers from opposite poles Anaphase II sister chromatids segregate towards opposite poles T elophase II spindle disintegrated chromosomes decondense and nuclear membranes reform around genetic material Summary know the key differences between mitosis and meiosis mitosis one DNA replication and one division homologous chromosomes dont pair or cross over and it results in two identical daughter cells meiosis one DNA replication but has two divisions resulting in 4 unique daughter cells homologous chromosomes pair crossover and aren t segregated The products of meiosis can vary between sexes and between species know the position of meiosis in the life cycle for different eukaryotes know the differences in animal spermatogenesis and oogenesis In eukaryotes the zygote undergoes meiosis and most of the life cycle is spent as haploid cells in animals the somatic cells are typically diploid and special germ line cells undergo meiosis to form haploid gametes spermatogenesis typically produces 4 haploid sperm for each germ cell that undergoes meiosis oogenesis typically produces I haploid egg cell ovum for each germ cell that undergoes meiosis the rest of the genetic material goes to polar bodies cells that get little of the original cytoplasm and eventually die Page 20 of 21 Why sex be able to distinguish between descriptions of Miller s Ratchet the DNA repair hypothesis and the Red Queen hypothesis Miller is Ratchet asexual populations tend to accumulate harmful mutations by chance over time with no good way to get rid of them like turning a ratchet you can t go back recombination can overcome this DNA Repair many species reproduce sexually only during times of stress some types of DNA repair such as fixing doublestrand breaks can only take place with a diploid cell and that type of repair is most likely needed in times of stress also this allows these species to overcome Miller is Ratchet by simple recombination Red Queen sex allows for populations to store genetic diversity so that it is available for each generation this only provides an advantage if the environment provides everchanging physical andor biological constraints an evolutionary arms race between parasites and their hosts may be a key factor in producing such treadmill evolution Page 21 of 21
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