Midterm 1 Study Guide!
Midterm 1 Study Guide! Life Sciences 2
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This 11 page Study Guide was uploaded by Jenna Kovsky on Saturday October 17, 2015. The Study Guide belongs to Life Sciences 2 at University of California - Los Angeles taught by Dr. Cooper/Dr. Esdin in Fall 2015. Since its upload, it has received 370 views. For similar materials see Cells, Tissues, and Organs in Biology at University of California - Los Angeles.
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Date Created: 10/17/15
LS 2 Study Guide for Midterm 1 1021 gt Covalent Bonds the sharing of electrons between atoms often not equally O O strongest type of bond Types I Nonpolar Covalent Bond When electrons are equally shared I Polar Covalent Bond When electrons are NOT equally shared related to the difference in the electronegativities of the atoms involved gt Noncovalent Bonds weaker than covalent bonds 0 Types I Ionic Bonds One atom eg sodium donates an electron to another atom eg chlorine the one donating becomes positively charged and the one receiving becomes negatively charged I Hydrogen Bonds weak since the bond between oxygen and hydrogen in water is polar it causes a slight difference in charges between the oxygen and the hydrogen the hydrogen atom in water can form a hydrogen bond with the oxygen of an adjacent water molecule I Hydrophobic Interactions oil sits on top of H20 does not dissolve because it s nonpolar it s forced to the surface so it s not in the way of the water molecules forming hydrogen bonds I Van Der Waal s Forces electrons are continuously oscillating between different parts of the molecule This movement creates dipole charges and leads to transienttemporary very weak interactions between opposite dipoles only occur when atoms are in very close proximity gt Lipids biological macromolecules with carbon hydrogen and oxygen insoluble in water 0 fats triglycerides glycerol 3 carbons with 3 carboxyl groups and fatty acids stored in specialized adipose cells adipocytes storage form of fat in the body can be broken down to release ATP energy provide thermal insulation I fatssoid at room temperature oisiquid at room temperature phospholipids glycerol backbone with 2 fatty acids and a polar headgroup phosphate group polar hydrophilic head can interact with water nonpolar hydrophobic tails cannot I amphipathic Describes a molecule with a polar end and a nonpolar end cholesterol steroid ring structure antipathic intercalates into the lipid bilayer because it s so thin when it interacts with fatty acid tails of phospholipids it can slow down movement of phospholipids w Van Der Waal s interactions stabilizes the plasma membrane I LDL Lowdensity lipoproteins carry cholesterol from liver to the tissues for use by cells but tend to leave some behind in arteries causing issues bad cholesterol I HDL highdensity lipoproteins remove cholesterol from cells transport to the liver for excretion as bile good cholesterol I Lower ration plasma LDLHDL is associated with a decreased risk of atherosclerotic heart disease Blood cholesterol levels of 200 mgdL or less is desirable Less than 130mgdL of LDL is desirable 130159 mgdL of LDL is borderline high risk 160 mgdL or over of LDL is high risk gt Carbohydrates provide energy important in cell recognition ratio of Hydrogen to Oxygen is about 21 0 monosaccharides the simplest sugars glucose is the major one found in blood most have 5 pentose or 6 hexose carbon atoms linked together to form larger sugars disaccharides made of 2 monosaccharides eg gucosefructosesucrose a dehydration reaction results in formation of a glycosidic bond galactose glucose lactose gucosegucosematose I Lactose Intolerant lack the enzyme lactase that breaks the glycosidic bond of lactose oligosaccharides about 320 residues sugars important on surface of cells polysaccharides greater than 20 residues sugars I starch polymer of glucose present in plants I glycogen storage form of carbohydrate in animals branched polymer of glucose O I cellulose long chains part of plant cell wall chains lie parallel and form hydrogen bonds between them gt Proteins humans have about 30000 different proteins made up of amino acids Amino Acid amino group with a carboxyl group and a side chain which varies between each of the 20 amino acids Polar Sidechain NonPolar Sidechain Arginine Alanine Asparagine Cysteine Aspartic Acid Leucine Glutamine Isoleucine Lysine Glycine Serine Phenylalanine Tyrosine Valine Threonine Methionine Histine Proline Glutamic Acid Tryptophan o Peptide Bond does not have free rotation double bond characteristics give rigidity 0 Structural organization of Proteins primary structure linear sequence of the amino acids usually an amino group at one end of the sequence and a carboxylic acid group on the other secondary structure localized polar acids tend to face outward to interact with water while nonpolar face inward 0 Alpha helix hydrogen bonds link alpha helix together like a corkscrew hydrogen bonds form H linked to Nitrogen and the Oxygen in another peptide bond 0 Beta pleated sheet like a folded fan or accordion type thing held together by hydrogen bonds formed between peptide bonds tertiary structure the way the protein folds in 3 dimensions influenced by hydrogen bonds ionic bonds disulfide bonds which are covalent van der waal s forces quaternary structure not all proteins have it caused by association of more than one polypeptide chain the arrangement of individual chains that are called subunits Protein Function biological catalysts transporters structure and support defense Denaturation when a protein gets unfolded can be caused by changes in pH temperature salinity etc of environment sometimes proteins can be renatured o Sickle Cell Disease Sickle Cell Anemia hereditary change in primary structure of one single amino acid worse under low oxygen levels chains of hemoglobin occur distorting the shape of the RBC becomes shaped like a sickle this awkward shape makes it hard for the RBC to flow through blood vessels more fragile than normal RBCs gt Nucleic acid long polymers made of nucleotides 5 carbon sugar with Hydrogen group in DNA and Hydroxyl group OH in RNA Condensation reaction between nucleic acids eliminates water and forms a phosphoester bond between the phosphate group of one nucleic acid and the sugar of another 0 Sugar Deoxyribose in DNA Ribose in RNA The carbon atoms making up each sugar are numbered followed by a prime mark 1 2 3 4 and 5 o Phosphate Group o Nitrogencontaining base I Purines 2 rings Adenine and Guanine I Pyrimidines 1 ring Cytosine Thymine DNA only and Uracil RNA only 0 DNA hereditary material hydrogen bonds form between complementary bases Adenine with Thymine Guanine with Cytosine I Replication strands separate the hydrogen bonds connecting them are easily broken Semiconservative replication 0 RNA usually single stranded but can be double eg tRNA I mRNA messenger RNA I rRNA ribosomal RNA I tRNA transfer RNA I Ribozyme catalytic RNA gt Protein Synthesis Emmwmm o Transcription DNA gets transcribed into RNA litiflft 39di lemlmlhmmmi If a 0 Translation RNA gets translated into proteins quot V quot a i j39 quot I I small and large ribosomal subunits separately bind to either side of the mRNA strand I tRNA has an anticodon made of 3 bases and is covalently bonded to an amino acid I tRNA matches up its anticodon with the corresponding 3 bases called a codon on the mRNA strand at the ribosome I as the tRNA molecules line up so do their H 7 V I I attached amino acids which make peptide 39 7 39 memm thEMMESSW bonds between em to form 9 ary istranslatedintoaspeci c protein structure of the protein gt Microscopy 0 Light Microscopy uses normal visible wavelengths of light and a glass lens Resolution02 pm I Brightfield microscopy light passes directly through cells can t distinguish details or contrasts I Phase contrast microscopy shows contrast by emphasizing different refractive indices can see light and dark regions of a cell I Differential Contrast uses 2 beams of polarized light on the sample can see where cell casts a shadow on one side I Stained Bright field microscopy stain enhances the contrast eosin stain makes positive structuresmolecules red or pink eg proteins hemotoxin stain makes negative structuresmolecules blue or purple eg DNA I fluorescence microscopy fluorescent dye that binds to specific structures eg Green Fluorescent Protein aka GFP I confocal microscopy uses fluorescent dye eliminates light that is out of focus to get a clear 2D image 0 Electron Microscopy electron magnets focus a beam of electrons onto the sample to make an image Resolution2nm I transmission electron microscopy if electrons are absorbed the structure looks darker if they pass through it looks lighter detected on a fluorescent screen I scanning electron microscope directs electrons to the surface of the sample and causes other electrons in the sample to be emitted The emitted e can be visualized on a screen to reconstruct a 3D image I freezefracture microscopy freeze the cells and crack them open with a knife bumps are protein aggregates 0 Cell fractionationlcentrifugation isolatepurify specific intercellular structures steps I homogenizegrind up tissue sample I spin in tube in centrifuge I particles sediment out into pellets at the bottom of the tube I heavier particles sediment out first eg nuclei sediment out before mitochondria gt Miller and Urey experiment hypothesized that inorganic compounds under the right conditions can give rise to organic compounds even when oxygen is not present 0 heated solution of simple chemicals to make atmosphere of methane ammonia hydrogen gas water 0 applied electrical current to simulate lightning which they believed provided the energy needed for the synthesis of organic molecules that are the building blocks of life condenser cooled atmospheric gases into a rain that organizes compounds collectedanalyzed condensed liquids 0 found organic compounds amino acids and simple sugars gt The RNA World Hypothesis before DNA and proteinbased life RNA carried genetic information and catalyzed certain reactions DNA evolved from this RNA 0 riboses bases and phosphates together formed RNA 0 some RNA molecules gained the ability to replicate 0 RNA molecules began to make catalytic proteins 0 catalytic proteins increased the efficiency of replication which led to protein synthesis and then eventually evolved into doublestranded DNA which became primary genetic info storage gt Left Hierarchical Organization gt Types of Tlssues o Epithelial tissue forms boundaries I V r Cirgan U H T 3 packed tightly together in sheets held together by rgamsm I swim I yam 39EEMEE proteins that form tightjunctions provide Alums Muleeules Drganelles CELLS permeability layer 0 connective tissue cells interspersed in matrix can be hard and calcified matrix like bone or a plasma matrix like blood also adipocytes where triglycerides are located nervous tissue neurons conduct and generate electrical signals action potentials muscle tissue skeletal muscle bicep cardiac muscle heart smooth muscle digestive tract blood vessels gt Characteristics of Living systems 0 Cellular oroanization all organisms consist of one or more cells 0 Sensitivity organisms respond to various stimuli in different ways 0 Growth interconvert chemical molecules metabolism and energy released is used to grow I anabolism making a complex molecule from a simpler one eg forming glycogen from glucose to store energy I catabolism breaking a complex molecule down into a simpler one eg breaking down glycogen to get glucose 0 reproduction reproduce passing on traits to new generations homeostasis maintain relatively constant internal conditions eg pH temperature etc different from their environment homeo quotsamequot stasis stay stay the same I interstitial fluid fluid between cells acidosis blood becoming more acidic bad thing gt Viruses not considered alive made up of nucleic acid core wrapped in protein no membrane nucleus or organelles cannot reproduce without host no metabolism gt The Cell Theory 1 all organisms are composed of cells 2 the cell is the basic building block of life 3 all cells arise by division of a preexisting cell gt Size of cells most cannot be seen by the naked eye they must maintain a large surface areatovolume ratio to efficiently transfer materials in and out of the cell as an object gets larger its volume increases more PI IkEl yF t ii GI I5 Euker ent it calls latent min ute in size Fairly iarue in Elie tl39ilulcleer retingn nunleni j net Slurru ride I lltiyr La Inueler Ef ihh rue Nuclear material eurrnumzie I a milder HIE m brill ne Elitale Ehremeeeme tirese ni Mere thn thrumse me IllE39SEI39It en E Hutcleeluae ah sentit Nuclenlue prese It Membrane henna feel eruene esv are eheent Membrane belied e uraenelles llt39 preent Eel dieisinn In fissimn nr hitli lding the m itasis Eel di rris ien meisis hr mitnsi 5 er chloroplasts originated from symbiosis between separate prokaryotes prokaryote ingested some aerobic bacteria and protected it and gave it energy over a long time the aerobic bacteria became mitochondria aerobe no longer able to survive alone 0 O O O gt Orga O rapidly than its surface area advantageous for cells to be small gt cyanobacteria bacteria prokaryotes cthat can perform photosynthesis our current aerobic atmosphere is thought to have arisen from these gt endosymbiosis theory eukaryotes arose from prokaryotic cells when larger prokaryotes absorbed smaller ones several key organelles mitochondria evidence these organelles have two membranes are about the size of some bacteria and have their Nucleus largest organelle has most of the cell s DNA enclosed by a nuclear envelope which has I chromatin DNA combined with protein condenses and tightly coils to form chromosomes I mature erythrocytes Red Blood CellsRBC do not have a nucleus they are full of hemoglobin and have a lifespan of 120 days so they don t really need a nucleus and it takes up too much Ribosomes all cells synthesize proteins on ribosomes in eukaryotes free in cytoplasm attached to surface of Rough Endoplasmic Reticulum in energyproducing organelles mitochondrial matrix I consist of a type of RNA together with protein comprising a large and small subunit which in a similar manner absorbed cyanobacteria became chloroplasts own set of DNA nelles nuclear pores in it when the cell is about to divide space they do have them when they are developing chloroplast stroma associate during protein synthesis I an enzyme ribozyme actually makes the peptide bonds during protein synthesis Endomembrane system a series of interrelated membranes and compartments in eukaryotes I Endoplasmic Reticulum cells which synthesize proteins for export contain large amounts of ER 0 smooth ER lacks ribosomes site for hydrolysis of glycogen and synthesis of steroids 0 Rough ER contains attached ribosomes manufacture proteins for export from cell incorporation into membranes or moved into organelles to the endomembrane system I Golgi apparatus looks like a stack of pancakes modifies packages and sorts proteins series of flattened sacs cis region lies closest to nucleus trans region closer to cell surface synthesizes some polysaccharides for the cell wall I signal sequences direct proteins to various organelles hydrophobic beginning polypeptide polypeptidegtERgtGolgigtsecretory vesicles I secretory vesicles stored in pancreatic beta cells until they are needed to carry insulin their release is triggered by increased blood glucose hyperglycemia I lnsulinbinds to certain cell types to promote the intake of glucose into those cells effectively lowering blood glucose 0 mitochondria converts energy from food into ATP adenosine triphosphate the energy currency of the cell inner and outer membrane inner membrane highly folded forming cristae mitochondrial matrix contains ribosomes and DNA respiratory chain for converting O2 and glucose into ATP spans the inner mitochondrial membrane cristae increase the surface area of this membrane leaving more room for ATP synthesis 0 plastids present in plants and some protist food manufacture or storage eg chloroplasts carry out photosynthesis 2 membranes both unfolded I inner membrane forms a stack of flattened disklike things thylakoids are inside and contain chlorophyll which harvests light energy I granum stacks of thylakoids stroma fluid surrounding granums o Organelles for Breakdown and Storage I lysosomes suicide bags pinch off from the membrane of the Golgi apparatus break down almost any organic substance interior is very acidic pH 55 which is optimal for the following enzymes none in plants autophagy breaking down worn out old organelles o proteases break down proteins 0 lipases break down lipids o nucleases break down nucleic acids 0 carbohydratedigesting enzymes I Tay Sachs Disease unable to break down ganglioside lipid build up esp in neurons peroxisomes in plants and animals one membrane RH202gtR H202 hydrogen peroxide involved in breaking down lipids I glyoxysomes in plants specialized peroxisomes break down lipids particularly during cell germination I vacuoles in plant cells store waste and provide turgor water gives pressure to keep rigid similar role to lysosomes which plants do not have 0 Organelles for Support and Movement I cytoskeleton maintains cell shape facilitates cell movement some fibers act as tracks for motor proteins components 0 microfilaments strands of actin39 involved in movement during cell division to divide nucleus and the cytoplasm during cytokinesis and muscle contraction smallest diameter of the cytoskeleton components also used for support 0 intermediate filaments tough fibrous protein molecules twisted into ropelike structures stabilize cell structure keratin in hair and nails 0 microtubules hollow cylinders made of tubulinstructure and function of cilia and flagella centrioles and movement of organelles larger diameter form mitotic spindle during cell division I cilia made of 9 microtubules wavelike motion back and forth caused by movement of dynein along microtubules I motor proteins eg dynein and kinesin ATP energy to change shape amp move things microtubules to move things around the cell have feet to walk around microtubule tend to go towards negative end kinesin can move vesicles or organelles around the cell gt fluidity of a bilayer depends on its composition and temperature 0 as temperature falls lipid bilayer changes from a fluid state to a rigid ge state undergoes phase transition at a characteristic temperature o temp at which this occurs is lower ie membrane more difficult to freeze if hydrocarbon chains are short or have double bonds gt cholesterol intercalates slip in between phospholipid bilayer and provides stability Ill gt Lipids in Membrane structure basic membrane foundation lF l lEiEtIh iipid is a lipid bilayer made of phospholipids that form bilayer Mayer sheet with hydrophobic tails pointing inward gt Fluid Mosaic Model explains how proteins are gt t A r t j incorporated into the bilayer carbohydrates are attached I 39ira ellular Hydmph bic tail to either proteins or lipids facing outwards from the cell gt Membrane proteins 0 categories I integral penetrate into the bilayer most are transmembrane contain an alpha helix of nonpolar amino acids spanning the hydrophobic interior of the membrane I peripheral located outside of the bilayer attached by noncovalent bonds to the polar headgroups of the phospholipids or to integral proteins 0 mobility of proteins in membranes some move freely within the bilayer while others are held in place many cells eg RBC have a cytoskeletal protein network I RBCs are good to work with in membrane research bc of the ease of obtaining them and if you lyse break open and centrifuge them only plasma membrane is present I beneath the cytoplasmic surface of the RBC spectrin forms a mesh I spectrin is attached to membrane junctional complexes by actin and to ankyrin peripheral protein which in turn is attached to an anion channel integral protein 0 role of membrane proteins I transport proteins I receptors for molecular messengers from other cells responds to signal transmitted via some kind of ligand eg a hormone I form junctions between cells gt Membrane carbohydrates project from exterior surface of the membrane when attached to proteins of phospholipids within the membrane serve as recognition sites on the cell surface 0 glycoproteins carbs bound to membrane proteins bound carbs are oligosaccharide chains enable cells to recognize foreign substances 0 glycolipids form cell identity markers gt Cell adhesion in an organism or tissue cells recognize and bind to each other via surface membrane proteins in animal cells specific cell junctions allow cells to adhere to each other 0 tightjunctions epithelial cells form sheets that are held together by tightjunction proteins prevent molecules from slipping between cells protective mechanism 0 desmosomes cytoplasmic plaque on inside of each cell with adhesion proteins running between each cell s plaque could be attached to cytoskeletal proteins for extra support 0 gap junctions particular protein that has 6 subunits creates a small pore in each cell connexons line up between the two cells aqueous pore between two adjacent cells I very important in the heart allow ions to move between cells and facilitate the spread of action potentials from cell to cell causing the heart muscles to contract 0 plasmodesmata aqueous pore in plants gt extracellular matrix outside cells has collagen most prevalent protein in the human body contains 0 fibronectin protein that connects to integrin in a noncovalent bond 0 integrin anchors the extracellular matrix to the cell s internal cytoskeleton is connected to actin which is within the cell membrane Hydrophilic head O and polysaccharide complex protein proteoglycan gt Movement of Molecules across cell membranes 4 main methods 0 O O diffusion simplest method passive for molecules that are lipidsoluble or a gas random molecular motion produces net migration of molecules toward regions of lower concentration I when molecules are uniformly distributed they are in equilibrium I higher lipid solubilitygtdiffuse faster I O2 and 002 can readily diffuse across biological membranes osmosis diffusion of water molecules usu through aquaporins ion channel passive uses channel proteinaqueous pore in membrane through which something can move carriermediated mechanismtransporter passive allows polar molecule to shovel through then releases it on the other side Facilitated Diffusion allows polar and large molecules to be transported into cells certain molecules eg glucose bind to carrier proteins in the membrane and are transported across I passive net movement is toward the lowest concentration going down the concentration gradient to uniformly distribute molecules to reach equilibrium I specific a particular carrier transports only certain molecules I the cell may become saturated if all the protein carriers are in use Active Transport transport across a membrane by a carriermediated process against the concentration gradient this requires expenditure of chemical energy ATP I movement against concentration gradient means that the molecule or ion is moving from a region of low concentration to one of higher concentration uphill I primary active transportrequires direct participation of ATP secondary active transport doesn t use ATP directly but rather the energy in an ion gradient established by primary active transport more Na sodium on the outside of the cell more K potassium inside I The sodiumpotassium NaK pump moves 3 Na ions out of the cell for every 2 K ion it moves in I uniport protein that moves one molecule in one direction symport moves multiple moleculestypes of molecules in the same direction I antiport moves multiple types of molecules in opposite directions eg NaK pump Endocytosis transports macromolecules large particles and small cells plasma membrane envelops materials and forms a vesicle inside the cell 3 types I phagocytosis celleating large particles or cells are engulfed eg in the immune system when phagocytes a type of white blood cell engulf foreign substances I pinocytosis celldrinking small dissolved solutes or fluids enter I receptormediated endocytosis a speci c membrane receptor binds to a particular macromolecule at sites called coated pits that contain clathrin Exocytosis materials in vesicles are secreted from the cell when vesicles fuse with the plasma membrane Exocytosis I g i a 39 I a a Ir o 6 39 I w I t39ilsi f quot 2quot b 39 l I I quot Endocytosrs f I30 9 I g 39 391 I i 399 Itquot 1 390 I AMIquota tine i t a39u i f Secretory vesicle Vesicle Ienclosome Cell membrane gt Energy the capacity to do work 0 kinetic energy workassociated water molecules moving in a river have kinetic energy if they flow through a dam into a lake with an electrical turbine that kinetic energy is interconverted into another form via the turbine potential energy stored energy VV energy flows into the biological world from the sun stored as potential energy in the chemical bonds of sugar molecules formed by photosynthesis first law of thermodynamics energy cannot be created or destroyed it can only undergo conversion from one form to another second law of thermodynamics during any energy interconversion some energy is released as heat which adds to the entropy increasing disorder of the system life converts energy from the sun to other forms of energy to sustain life the energy is never lost but as it s used more and more becomes heat you generate heat when you exercise because the work put in for muscle movement by ATP is not 100 efficient some of the work escapes in the form of heat metabolism the sum of all chemical processes occurring within a cell or organism o metabolic pathway reactions often occur in series product of one reaction becomes a reactant in the next reaction chemical reactions establish equilibrium and the equilibrium constant Keq is the ratio of the concentration of products and reactants at equilibrium 0 a high KeOI indicates that the reaction favors the productsgoes far towards completion 0 a low KeOI indicates that the reaction favors the reactants Gibbs free energy energy that is free for use by cells changed when chemical bonds are broken in the course of chemical reactions 0 Usable EnergyUnusable EnergyTotal Energy 0 AHAGTAS or AGAHTAS o GGibbs free energy Ttemperature Achange in Henthalpy basically heat Sentropy disorganization glycogen carbohydrate store in human body triglycerides lipid store in human body Adenosine Triphosphate ATP the energy currency of cells 0 ATP H20 gt ADP Pi energy 0 called hydrolyzing which releases the energy associated with breaking the bond of one of the phosphate groups Takes a lot of energy to make ATP so then breaking the bonds releases a lot of energy standard conditions 1 M 25 degrees Celsius AG7 kcalmol in cell AG much higher 12 kcalmol cells can make ATP in 2 ways 0 substratelevel phosphorylation simplest way direct transfer of phosphate group to ADP from another molecule need a very energetic molecule I written as xp ADP gt ATP x denotes a high energy covalent bond I enzyme used to speed up this reaction I last step in glycolysis converting 1 glucose to 2 pyruvate using pyruvate kinase 0 chemiosmosis majority made this way in inner mitochondrial membrane requires oxygen EnergyCoupling Cycle of ATP 0 exergonic reactions create energy cell respiration catabolism o endergonic reactions release energy active transport cell movement anabolism o bioluminescence uses molecule called luciferin luciferin 02 ATP gt light Activation Energy the energy required to destabilize existing chem bonds and start a chem rxn 0 before a rxn reaction can proceed an energy barrier must be overcome energy must be supplied to break existing chemical bonds 0 a catalyst lowers the energy barrierlowers the activation energy required to start the reaction they increase the rates of reactions but do not affect the final equilibrium Enzymes 0 proteins that carry out most catalysis in cells some catalysis is by RNA ribozyme VV VV usually relatively specific in their choice of reactant moleculessubstrate substrate molecules bind at the active site some require coenzymes nonprotein organic molecules to function Role of enzymes in Metabolism may couple exergonic and endergonic allosteric enzymes multiplesubunit proteins allodifferent stericshape OOOOOO enzymes have an optimum pH and temperature at which they function most effectively I when plotting reaction rate against concentration of substrate you get a View sigmoidal Sshaped curve I allows you to modulate the activity of an enzyme in a metabolic pathway through a small change in substrate I eg Hemoglobin not an enzyme but is an allosteric protein mm W o 4 subunits 2 alpha 2 beta 0 each subunit has heme group with Iron so oxygen can bind 0 when the 1st oxygen binds it changes the shape which makes it easier for its adjacent subunit to bind oxygen 2nd easier to bind 3rd even easier 4th not Elma th quiteaseasw o cooperatIVIty In bIndIng onygen is I molecules to the subunits 17 f eennet bind gt1 competitive inhibitor directly competes with the substrate u u to bind to the enzyme binds at active site noncompetitive inhibitor binds to protein not at active site this binding changes the shape of the protein so the substrate cannot bind at the active site irreversible inhibition most inhibition is reversible but some are not a E rnpe live inhibitien sources of energy 0 autotrophs use light energy to synthesize food molecules 0 heterotrophs and autotrophs extract energy from food EmmaMn Nieneernpetititre inhibitor eherngee Shape ef enzyme ee it eennet bind to euleetrete b3 Nemeem peritiue inhibitien o extraction of energy from food occurs in states enzymes break large molecules into smaller ones digestion Glycolysis conversion of glucose to pyruvate followed by cellular respiration Cellular Respiration conversion of pyruvate to carbon dioxide and water in the presence of oxygen 0 pyruvate converted to Acetyl Coenzyme A Acetyl 00A in the mitochondrial matrix CESHQO6 602 gt 6002 energy 2 ATP Redox Reaction Transfer of electrons is an oxidationreduction redox reaction 0 reduction gain of one or more electrons by an atom ion or molecule 0 oxidation loss of one or more electrons 0 Reduced A Oxidized B gt Oxidized A Reduced B Coenzyme NAD is an electron carrier in many redox reactions 0 NAD Nicotinamide Adenine Dinucleotide important for the breakdown of glucose 0 nicotinamide ring covalently linked to sugar and phosphate with a nucleotide O electrons in NADH are very energetic gt Generation of ATP by Oxidative Phosphorylation 0 ATP formation in mitochondria results from flow of electrons through the respiratory chain NADH molecules transfer electrons to a series of membrane protein complexes the respiratory chain In conjunction with e transport down the respiratory chain protons are pumped across the membrane from the matrix energy of this proton gradient across the inner mitochondrial membrane is used to drive ATP synthesis chemiosmosis Return of protons to the matrix is coupled to synthesis of ATP via an ATP synthase allows protons to flow back into matrix via a protein channel the final electron acceptor is molecular oxygen gt Electron Transport Chain Electron travels in the following chain 0 gt Chemiosmosis not confined to mitochondria done in chloroplasts and bacteria as well same thing as oxidative phosphorylation but only in mitochondria O O NADHQ Reductase complex gt Ubiquinone gt Cytochrome c Reductase Complex gt Cytochrome c gt Cytochrome c Oxidase Complex gt H20 Image to the right energy of electrons as they go through the ETC NADHQ 39 Reductase 39 Non polar Ubiquinone Coenzyme Q Cyt c Reductase 39 V ENERGY OF ELECTRON Cyt c Oxidase experiment 1 I I put mitochondria in pH 8 I then changed the outside medium to pH 4 I outer membrane is fairly leaky but inner membrane is less permeable experiment 2 I used totally artificial system I Flnding ATP synthase is needed for ATP synthesis I Halobacteria contain bacteriorhodopsin retinal linked to a protein 0 when oxygen levels are low bacteriorhodopsin uses the protein lightdriven proton pump to harvest light 0 photons strike amp the energy of the photon is absorbed creating a proton gradient gt Glycolysis oxidizes glucose to pyruvic acid anaerobicallywithout oxygen occurs in 10 separate enzymatic reactions in the cytoplasm net gain of 2 ATP form 2 NADH gt Krebs Cycle also called citric acid or tricarboxylic acid cycle 0 O pyruvate enters mitochondria and is oxidized forming acetyl coenzyme A high energy compound Acetyl 00A 20 unit combines w oxaloacetate 4C unitto form citric acid tricarboxylic acid and 00A results in complete oxidation of acetyl units to 002 Oxidation of NADH theoretically yields 3 ATP in practice 25 ATP per NADH FADH2 yields 15 ATP cellular respiration yields much more energy than glycolysis net yield approx 32 ATP moleculesglucose
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