Concept 7+8+9+10 Flashcards

Question

ATP structure

Answer 1

- adenine (double ring) - ribose - 3x phosphate group (LOOK AT GDOC DIAGRAMS)

Answer 2

ENERGY RELEASED FROM REACTION IS CAPTURED INTO ITS BONDS! WHY DOES ATP STORE ENERGY? 1) Potential energy stored in the P-O bonds of ATP. 2) ATP's terminal phosphate groups REPEL one another, so it takes energy to form a bond between them - Some of this energy is stored as potential energy. WHY DOES HYDROLYSIS OF ATP RELEASE ENERGY? - think of exothermic - high to low free energy 3) P-O bond has HIGHER FREE ENERGY (reactant) than the free energy of the OH bond formed by hydrolysis (LOWER FREE ENERGY product)

Answer 3

it is lost to the environment. NOT used to power more cellular work etc. - no longer free energy able to do work!!

Answer 4

HOW IS ATP USED? - Physical = mechanical, transport work - Chemical = free energy released used to drive reactions -> phosphorylate intermediate -> make it more reactive HOW IS IT REGENERATED? - Through respiration

Answer 5

HYDROLYSIS!!! - Water is added to break the bond between the phosphate groups. PRODUCTS: ATP+H2O ⟶ ADP + Pi + Free energy - Adenosine diphosphate (ADP) - 2 phosphate groups left - Inorganic phosphate molecule - Free energy (energy used for cellular work) WHAT IS THE FREE ENERGY USED FOR?

Answer 6

- phosphate groups are negatively charged - so have high POTENTIAL ENERGY + difference in energy between P-O bond and O-H bond

Answer 7

BEGINNING: - Hydrolysis of ATP: - Gives ADP, inorganic phosphate, free energy - Free energy!! OTHER THAN FREE ENERGY - INORGANIC PHOSPHATE!! - ATP can phosphorylate an intermediate of a reaction - this will make the molecule less stable -> more free energy -> more reactive -> easier to bind with other reactant to form product OVERALL: - When coupled with ATP conversion, the overall reaction releases energy: - Both hydrolysis + phosphorylation of intermediate will push the energy to occur - will change endergonic to exergonic reactions

Answer 8

1) TRANSPORT WORK - ATP phosphorylates transport proteins in the membrane - causes them to change shape - therefore allows transport of molecules through the membrane 2) MECHANICAL WORK - ATP binds non covalently to motor proteins, then hydrolysed - this causes a change in shape of motor protein - therefore allows the motor protein to move forward!!

Answer 9

CHEMICAL - 2 WAYS 1. hydrolysis of ATP - release of free energy 2. phosphorylation of intermediate - less stable, more reactive PHYSICAL - 2 WAYS 1. transport - change in shape of transport protein (phosphorylation) 2. mechanical - change in shape of motor protein (hydrolysis of ATP)

Answer 10

UNDERSTAND THE WHOLE REACTION Glutamic acid + NH3 + ATP -> Glutamine + ADP + Pi - Free energy - reffering to deltaG, gibbs free energy - Combining the steps gives the free energy change for the whole reaction - We focus on the conversion of each INDIVIDUAL SUBSTANCE STEP 1: Glutamic acid to glutamine. Needs ATP, endergonic so DeltaG>0 STEP 2: ATP hydrolysis to ADP, releases energy, exergonic, DeltaG<0 SO...OVERALL REACTION - exergonic, net deltaG<0, spontaneous eg. if you see deltaG glu = +3.4, this is energy released PER MOLE of glutamine DeltaG glu + deltaG ATP = net delta G = -3.9, exergonic

Answer 11

EXERGONIC - Energy released is captured into ATP - Done by the FORMATION of ATP from ADP and Pi (inorganic phosphate) ENDERGONIC - ATP is hydrolysed to release FREE ENERGY, which drives energonic reactions - AND they PHOSPHORYLATE another molecule

Answer 12

in biological systems is equivalent to total energy. SO...negative enthalpy - overall system decreases in energy - therefore must have LOST ENERGY

Answer 13

- when they ask in this wording, we know the answer is based on whether the reaction is SPONTANEOUS or not - enthalpy decreases - means total energy of the STSTEM decreases - reaction must be exergonic - this increases entropy as disorder increases - process is spontaneous - every spontaneous process must decrease the SYSTEM (not environment) free energy

Answer 14

- Coupling exergonic reactions with endergonic reactions. - Energy released from ATP hydrolysis (exergonic) - GOES into endergonic reactions which need energy NET/TOTAL? - Overall negative deltaG needed to complete the reaction

Answer 15

* Measure of disorder in a system

Answer 16

- G = FREE ENERGY of a SUBSTANCE itself - Delta G = helps us determine if a REACTION is SPONTANEOUS or not

Answer 17

1) Change in bond energy from reactants -> products 2) Change in Entropy of system (hence why certain reactions are endothermic, may seem non-spontaneous, but because of change in entropy, it is spontaneous)

Answer 18

ΔG = G(products) - G(reactants) PRODUCTS - REACTANTS DEFINITION = free energy change of a reaction—products minus reactants.

Answer 19

1) Car at the top of a hill 2) Molecule will be less stable 3) BUT greater potential to do work

Answer 20

1) Car at the bottom of a hill 2) Molecule will be more stable 3) BUT less potential to do work

Answer 21

FORMULA ΔG = G(products) - G(reactants) UNDERSTANDING: - Product = low G - Reactant = high G - Car starts at the top hill - car rolling downhill WHAT DOES THIS MEAN? 1) The reaction is spontaneous - doesn’t require energy input 2) SO…it is a EXOTHERMIC reaction: releases energy to the surroundings 3) Since spontaneous, means INCREASES entropy in the universe

Answer 22

FORMULA ΔG = G(products) - G(reactants) UNDERSTANDING: - Product = high G - Reactant = low G - Car starts at the bottom of the hill - has to be pushed uphill WHAT DOES THIS MEAN? 1) The reaction is NOT spontaneous - requires energy input 2) SO…it is a ENDOTHERMIC reaction: energy taken in 3) Since not spontaneous, means DECREASES entropy in the universe

Answer 23

- Energy is released - So...reactant = high energy // product = low energy - So...product - reactant = low - high = ΔG<0 - spontaneous

Answer 24

- Energy is taken in - So...reactant = low energy // product = high energy - So...product - reactant = high - low = ΔG>0 - non-spontaneous

Answer 25

reduced, and energy is released - Reactant = electronegative atom - product = EA with electrons - it has become more stable, which means lower free energy - so goes from high to low = exothermic!!

Answer 26

- reactants high energy, products low energy - dotted line for reactants (to the end of the x axis) - dotted line for products below (to the end of the x axis) - connect using a graph (MAKE SURE YOU START DRAWING FROM THE REACTANT) - hump above the reactant line - connect the 2 dotted lines by having an arrow going DOWNWARDS (energy released) , delaG<0 // endergonic is arrow going UPWARDS (energy required)

Answer 27

FORMULA ΔG = G(products) - G(reactants) UNDERSTANDING: - Product + Reactant have the same G (ie. free energy) - Car is on a flat surface WHAT DOES THIS MEAN? - The reaction is at equilibrium - Forward + reverse reactions occur at the same rate

Answer 28

COMPLEX SUGAR MOLECULE - has more HIGH ENERGY BONDS - contain more free energy - higher G SIMPLE SUGAR MOLECULE - has less HIGH ENERGY BONDS - contain less free energy - lower G

Answer 29

REACTANT - complex - can do more work - higher G PRODUCT - less complex - can do less work - lower G So... - Product - reactant = low - high = delta G<0 SO... - Exothermic - Spontaneous TIP - Because a bond is broken DOES NOT mean the reaction is automatically endothermic! - Consult the DELTA G here to truly see

Answer 30

NO - only occurs if there is sufficient activation energy - vs non spontaneous which needs LARGE amounts of energy to start this reaction

Answer 31

- when the first reaction is UNFAVOURABLE (ie. not spontaneous) - NEEDS energy to be done - so...gets its energy from the energetically favourable reaction 2!

Answer 32

Glucose + o2 --> co2 + h2o - can't tell from reactants and products alone (because 2 reactants, 2 products, otherwise ADP + Pi --> ATP stuff like this easy to tell) - do it also in REVERSE ORDER!!! - keep playing around with the order mentioned above ! - Respiration releases energy - Spontaneous - so coupling NOT needed

Answer 33

NO - yes, its originally not spontaneous - but because of H+ gradient, this has a protomotive force, provides energy for ATP synthesis

Answer 34

NO - it needs energy , therefore unfavourable - BUT it's ok because it gets its energy from light energy

Answer 35

* RMB STABILITY DOESN’T EQUAL TO DISORDER!!!!! * UNIVERSE LIKES STABILITY + DISORDER!!!

Answer 36

- Small molecules = low energy - Large molecules = high energy - Means car pushed uphill, requires energy, therefore DECREASES ENTROPY - BUT this doesn’t go against the key principles (ie. systems becoming ordered even tho universe favours disorder) * Local decrease in entropy (in organisms) is offset by a larger increase in entropy of the surroundings

Answer 37

- If reaction needs energy = so reaction is OBVIOUSLY not spontaneous = because decreases entropy of the universe - If reaction doesn’t need energy = reaction is spontaneous = because the universe favours/only wants an increase in the entropy of the universe

Answer 38

ANABOLISM (small-> big) - Joining smaller molecules to make bigger molecules - TYPICALLY endothermic - involves forming new bonds (exothermic steps) but requires more energy to synthesize complex molecules than is released during bond formation. CATABOLISM (big->small) - Breaking down bigger molecules to make smaller ones - TYPICALLY exothermic

Answer 39

OIL RIG: * (Oxidizing Agent): Gains electrons and becomes reduced. In combustion, oxygen acts as the oxidizing agent. * (Reducing Agent): Loses electrons and becomes oxidized. In combustion, propane is the reducing agent. * Oxidation Is Loss of electrons * Reduction Is Gain of electrons

Answer 40

- only when it increases entropy of the universe! - AND when it brings the system closer to HIGHER stability - EQM is the state of MAXIMUM stability

Answer 41

NO - We are open systems - Experience a constant flow of materials - only CLOSED SYSTEMS will reach eqm and do no work

Answer 42

DEFINITION - the energy required to start a reaction. EXPLANATION - eg. spontaneous reaction doesn't require energy input, but life is not so simple, A BIT of energy may needed to actually start the reaction IE. GET THE BALL ROLLING! ANALOGY - think the hill has a small bump, which the ball currently sits in -You have to push it a little to get it to roll down the other side. - That initial push is like the activation energy. - It gets the reaction going!!

Answer 43

NO - they REDUCE ae - they provide the energy needed to start a reaction - specifically the energy needed to BREAK BONDS

Answer 44

- YES - but they are not as effective

Answer 45

- SPEED UP chemical reactions - without being changed/altered themselves BIOLOGICAL CATALYST = ENZYME *enzyme is a TYPE of catalyst!!

Answer 46

- ACTIVE SITE on the enzyme is specific to the SUBSTRATE (lock+key model, fit perfectly)

Answer 47

R groups of amino acids in the active site allow for specific interactions EG. hydrogen bonds, electrostatic attractions, covalent bonds SUMMARY - R groups provide chemical functionality, - active site 3D shape ensures spatial complementarity.

Answer 48

1) A SUBSTRATE enters the ACTIVE SITE of an enzyme. 2) Forms an ENZYME SUBSTRATE COMPLEX 3) Products formed will leave the complex 4) Enzyme remains unchanged

Answer 49

- provide an alt pathway with a LOWER ACTIVATION ENERGY - but ΔG will is UNCHANGED HOW IS THIS DONE? - create an unstable environment - reactants less stable - SO...less (free) energy needed to break bonds (ONE OF MANY WAYS) SO... *ΔG DOESN'T CHANGE AS ENZYME CHANGES STABILITY, NOT THE FREE ENERGY OF THE REACTANT/PRODUCTS THEMSELVES!!

Answer 50

IT MAKES REA 1) ORIENTATION - Orient/organise the substrates in a certain way that favours bond formation 2) PHYSICAL STRAIN - Makes the substrate less stable - Means less energy needed to break bonds! 3) CHEMICAL CHARGES - Can alter/add chemical charges of the substrate

Answer 51

Let's say A ⇌ B ALL REACTIONS ARE REVERSIBLE!!! - EG. 5 moles of B formed, 5 moles of A formed - At equilibrium, for every molecule of A turning into B, one molecule of B turns back into A. - SO...the concentration of reactants and product STAY CONSTANT!!! - The amount of substrate turning into product would be the same amount of product turning into substrate

Answer 52

Substrate ⇌ Product IF REACTION ALREADY REACHED EQM - Enzymes only makes the forward and backward reaction go faster - therefore concentrations remain CONSTANT IF NOT ALREADY AT EQM - Enzymes speed up both directions, so that the system reaches its natural balance (equilibrium) even faster

Answer 53

- ALL reactions are reversible. So if AB can break down into A+B, A+B can form AB - But the paradox is why when isolated, only one reaction occurs? - Note that while all reactions are reversible, not all are at EQM!!! So one reaction may be FAVOURED over the other - This is determined by the equilibrium constant of the reaction AND the concentrations of A,B, AB - Therefore when isolated, we can say that A+B was supplied in larger amounts, and AB generated was measured (so if AB was in larger concentrations, the enzyme would catalyse AB --> A+B) EXAMPLES - Enzymes in glycolysis - dehydrogenase, depends on redox state of the sytem , can do either oxidation or reduction

Answer 54

- substrate conc - enzyme conc (usually lower than sub conc) WHEN ALL ENZYME MOLECULES BOUND TO SUBSTRATE = MAX REACTION RATE - reaction will continue, but won't proceed faster

Answer 55

WITH ENZYME 1) LOW SUBSTRATE CONC: - Presence of enzyme greatly increases reaction rate 2) HIGH SUBSTRATE CONC: - Doesn't increase as fast, reaches a plateau - All enzyme molecules occupied with substrate molecules - Maximum rate reached WITHOUT ENZYME - One straight positive line - Reaction rate increases steadily as substrate conc increases (NO PLATEAU)

Answer 56

1) Measuring how much a substrate DECREASES in a SPECIFIC PERIOD OF TIME 1) Measuring how much a reactant INCREEASES in a SPECIFIC PERIOD OF TIME

Answer 57

measurement of change in a defined time interval

Answer 58

- no more enzyme present to increase the rate of reaction. - so all enzymes in the solution are working at their maximal rate.

Answer 59

E + S -> ES -> E + P

Answer 60

V = rate of reaction - It represents how fast the enzyme is converting the substrate into the product.

Answer 61

Km = the SUBSTRATE CONCENTRATION needed to fill HALF of the available active sites/enzymes

Answer 62

Vmax = the maximum rate of reaction - at Vmax, ALL active sites are occupied by substrates (SATURATED) - Plateau on a graph

Answer 63

a measure of how much enzyme likes substrate

Answer 64

- LOW km value = HIGH enzyme affinity WHY? - let's say Enzyme A has an affinity 5 times higher than enzyme B - Imagine having a beaker of each enzyme, each with only 100 enzymes in it - so to find km, we want to know how many substrates we need to fill 50 active sites --> Enzyme A is has a very high affinity, so all 50 substrate molecules enter active sites and react --> Enzyme B has a low affinity so only 10 out of the 50 substrate molecules properly enter active sites. SO....we need to add 250 substrate molecules in total in order to fill half of the active sites

Answer 65

1) Temp - Most human enzymes have an optimal temperature of 37°C. 2) pH - Most human enzymes have an optimal pH of around 7.4. 3) Cofactors

Answer 66

1) As temp increases, activity increases - at low temps, molecules move slowly - low rate of reaction -> less collisions between enzymes + substrate 2) maximum at optimum temp 3) decreases as temp goes above/below the optimum - denaturation - enzymes energy GREATER THAN AE

Answer 67

NONPROTEIN, help enzymes

Answer 68

1) Activators 2) Coenzymes 3) Prosthetic groups

Answer 69

WHAT IS IT? - metal ions = magnesium, calcium ions FUNCTION? - Promote the formation of the active site - OR stabilize the enzyme-substrate complex.

Answer 70

WHAT IS IT? - non-protein ORGANIC molecules FUNCTION? 1. transfer chemical groups from one enzyme's active site to another enzyme's active site 2. Has a shape that allows it to bind to an enzyme’s active site WHILE having a shape that allows another substrate to bind to it (ie. Originally the substrate wouldn’t have fit in)

Answer 71

WHAT IS IT? - non-protein ORGANIC molecules FUNCTION? - SAME as a coenzyme, except it is PERMANENTLY bound to enzyme - AND transfer chemical groups from one enzyme's active site to another substance (typically in the same complex

Answer 72

1) Competitive inhibitors 2) Non competitive inhibitors 3)Irreversible Inhibitors

Answer 73

- similar structure to the substrate - it will fit into the active site of the enzyme BECAUSE OF THIS... - substrate cannot bind to the active site (it is blocked by the inhibitor) -> no product formed -> rate of reaction decreases

Answer 74

- molecule will bind on the enzyme instead of the active site (known as the ALLOSTERIC SITE) - This will change the 3d shape of the active site - substrate can no longer bind to the enzyme’s active site NOTE: - Sometimes the change in shape is not too drastic, so instead will only make the enzyme LESS EFFECTIVE

Answer 75

- perform an enzyme activity assay - vary the concentration of substrate BUT keep inhibitor concentration constant - measure rate of reaction - if increasing substrate eventually reaches vmax + overcomes inhibition, it is a competitive inhibitor WHY? -> inhibitor binds to the active site of the enzyme and can be displaced by a high enough substrate concentration

Answer 76

- Binds to active site BUT form covalent bonds with the enzyme’s amino acid side chain - The effect is permanent, enzyme will lose all activity EXAMPLE: - often toxins or poisons.

Answer 77

REVERSIBILITY: - Reversed by increasing substrate concentration KM INCREASES: - Need higher substrate conc to outweigh inhibitors, therefore higher conc to bind to half of the active sites! VMax not affected - When substrate conc is high enough, it will outnumber inhibitors, won’t be able to bind to active site, max reactivity will occur

Answer 78

- Lower than original - But will reach the same plateau

Answer 79

REVERSIBILITY - Not reversed by adding more substrate - Needs a chemical change to remove the inhibitor VMAX AFFECTED - No increase in substrate can prevent the inhibitor from binding to the active site KM NOT AFFECTED - No need to know why

Answer 80

- Lower than original - Plateau will be lower than the original plateau

Answer 81

- Most have multiple subunits (quatenary), with multiple active sites and regulatory sites - They have 4 POSSIBLE forms: ACTIVE, INACTIVE, STABILISED ACTIVE, STABILISED INACTIVE -> ACTIVE = substrate can bind to active site -> INACTIVE = substrate cannot bind to active site

Answer 82

- ACTIVATORS will bind to REGULATORY sites - This will STABILISE the active form - Substrates can bind to active sites

Answer 83

- INHIBITORS will bind to REGULATORY sites - This will STABILISE the inactive form - Substrates can’t bind to active sites

Answer 84

- These are basically ALLOSTERIC SITES - Inhibitors and activates bind specifically to other polypeptides called REGULATORY SUBUNITS AT regulatory sites!!

Answer 85

- Inactive from can OSCILLATE to the STABILISED active form - This is done by a substrate binding to ONE active site in one subunit - This will LOCK all other subunits in active conformation

Answer 86

WHEN TOO MUCH PRODUCT... 1) POSITIVE FEEDBACK - ACTIVATOR binds to the allosteric site - encourages breakdown of product 2) NEGATIVE FEEDBACK INHIBITION - INHIBITOR binds to the allosteric site - stops pathways that result in generation of product INHIBITOR TENDS TO BE THE PRODUCT, NOT THE CASE FOR THE ACTIVATOR

Answer 87

SIMILARITIES - Inhibitor/activators binds to the ALLOSTERIC SITE of the enzyme DIFFERENCES - Allosteric regulation = both "on" and "off" - ACTIVATOR + INHIBITOR - Non-competitive inhibition - INHIBITOR

Answer 88

ALLOSTERIC REGULATION = refers to any process where a molecule binds to a site other than the enzyme’s active site 1. NEGATIVE FEEDBACK INHIBITION - When we have an excess of a product in a reaction pathway… - PRODUCTS act as INHIBITORS to control the pathway + limit production - When all of the product is used up by the organism, less inhibition, more production! 2. Activators can activate ENZYMES in other pathways when too much product - Speed up that reaction, divert raw materials away from synthesis of the first product

Answer 89

- Can’t have all pathways active simultaneously - reactions will negate each other - Not energy efficient!!

Answer 90

GLYCOLYSIS + CITRIC ACID + OXIDATIVE PHOSPHORYLATION POSITIVE FEEDBACK SYSTEM: - Glucose converted to pyruvate by enzyme phosphofructokinase NEGATIVE FEEDBACK SYSTEM: - Activated by AMP - phosphofructokinase is in its active state - Inhibited by ATP (produced by the citric acid cycle and oxidative phosphorylation) and citrate: - Prevents phosphofructokinase from working, stopping the glycolysis pathway.

Answer 91

WHAT DOES IT ACHIEVE? 1) Complex transformations occur WHAT IS THE PROCESS? 2) It is a series of separate reactions. 3) Each reaction is catalyzed by a specific enzyme. PROCESS THE SAME AS OTHER ORGANISMS 4) Many metabolic pathways are similar across all organisms. 5) In eukaryotes, metabolic pathways are compartmentalized within specific organelles. ENZYMES? 6) Key enzymes can be inhibited or activated to alter the pathway's rate.

Answer 92

C6H12O6 + 6O2 --> 6H2O + 6CO2 + around 36ATP

Answer 93

1) Catabolic - Glucose is broken down into smaller molecules (co2 + h2o) 2) Redox

Answer 94

GLUCOSE UNDERGOES OXIDATION - Throughout respiration FADH2 + NADH is produced. They gained e-, which means glucose must have been oxidised (ALL STEPS EXCEPT OP WHICH USES FADH2/NADH) - OVERALL: Glucose (C,H,O) broken down into co2, loses hydrogen, hence oxidation OXYGEN UNDEGOES REDUCTION - Oxygen acts as the final electron acceptor in the ETC

Answer 95

NOT JUST AS AN ENERGY SOURCE!! - ATP provides phosphate - Hence these are used by KINASES - Hence think of steps which use KINASES! Steps 1-3 - not 7,10, that goes from ADP to ATP

Answer 96

DEHYDROGENASE - these catalyse REDOX REACTIONS - so...NAD+ --> NADH KINASE - where ATP is involved - involved in phosphorylation

Answer 97

WHAT IS AN ENZYME CONTROL? - Allosteric enzymes will always have allosteric regulation - it becomes FEEDBACK INHIBITION when the FINAL PRODUCT acts as the inhibitor SO WHY NOT STEPS 6+7? - Each step is controlled by an enzyme but... - Not all steps have allosteric enzymes! - AND we may have an enzyme for the forward reaction, but not necessarily the backward reaction

Answer 98

Thinking of steps like NAD+ --> NADH - here a hydrogen atom is lost from glucose GLYCOLYSIS - NADH used for oxidative phosphorylation for ATP synthesis ANAEROBIC RESPIRATION - NADH is used to REGENERATE NAD+ so that so ATP is continuously reproduced

Answer 99

1) Photosynthesis came BEFORE respiration - aerobic respiration relies on photosynthesis to occur 2) Suggests evolution of these processes took a long time - for oxygen to accumulate, GOE took a LONG time 3) Suggests these 2 processes evolved to be INTERDEPENDENT on each other

Answer 100

THE MORE PROTEIN COMPLEXES ELECTRONS PASS, THE MORE PROTONS PUMPED INTO THE INTERMEMBRANE SPACE - NADH enters at complex 1, so electrons will pass through complexes 2+3+4 - FADH2 enters at complex 2, so electrons will only pass through complexes 3+4

Answer 101

1) Present in almost all living organisms 2) Doesn't require oxygen 3) Does not involve complex organelles (occurs in the cytosol) HENCE PRESENT IN EARLY LIFE, WHERE THERE WAS NO OXYGEN AND CELLULAR STRUCTURES WERE SIMPLER

Answer 102

explains how the proton gradient across a membrane drives ATP synthesis: 1) electrons lost by nadh and fadh2 2) proton motive force 3) atp synthesis by movement of h+ through atp synthase ATP Synthesis: ATP synthase allows H⁺ to flow back into the matrix, using the PMF’s energy to phosphorylate ADP → ATP42. Oxygen’s Role: Acts as the final electron acceptor, combining with electrons and H⁺ to form H₂O, maintaining the PMF42.

Answer 103

1) CRISTAE - High SA:Vol ratio - Efficient movement of protons + ATP out of the mitochondria - Can pack ETC into the small membrane 2) Can make its own enzymes + proteins for krebs cycle 3) SMALL/THIN INTERMEMBRANE SPACE - H+ less spread out, higher conc - helps w/ active transport of H+ 4) MATRIX, COMPARTMENTALISATION - mitochondria has its own internal environment - enzyme can do its own function, REGULATION

Answer 104

1) transporting pyruvate outside of the mitochondria 2) heat loss, energy released as heat (ENTROPY) 3) ATP used to transport ATP into the cytosol - as it follows the 2nd law of thermodynamics, if perfect number of ATP produced, this must be WRONG

Answer 105

- each pair of electrons donated by NADH --> produce 2.5 ATP - each pair of electrons donated by FADH2 --> produce 1.5 ATP

Answer 106

NO OXYGEN, HIGH LEVELS OF INORGANIC ELECTRON ACCEPTORS All below have both: 1. Waterlogged Soils and Wetlands 2. Seafloor sediments, lake bottoms

Answer 107

immediate Recycling - converted back to pyruvate once oxygen becomes available

Answer 108

ORIGINAL - think lactate is acidic ACTUAL ANS - excess lactate is shuttled to other tissues - here it is oxidised to produce glucose (or its storage molecule glycogen) - muscle soreness tends to be due to inflammation + trauma to cells

Answer 109

1) Less energy released than cellular respiration - Glycolysis + cellular respiration = 32 ATP Glycolysis + - fermentation = 2 ATP WHY?? - Glucose only partially oxidised in fermentation - SO...More energy remains in the products than in CO2

Answer 110

- YES - Function = move around the membrane to carry electrons from one protein carrier to other other (unlike protein complexes which are fixed into the membrane)

Answer 111

1) the breakdown of some food 2) to release energy

Answer 112

respiration - breakdown of sugar to release energy - BUT many other sources we can get our energy from!

Answer 113

1) Glucose metabolism 2) Protein metabolism 3) Lipid metabolism

Answer 114

PROTEINS, LIPIDS, CARBS RULE 1 = REVERSINLE - reactions most likely can go in both directions (anabolic/catabolic) RULE 2 = all INTERCONNECTED - lipids can break down to form intermediates needed to create other of the 3 big macromolecules RULE 3 = Function - Catabolism = release energy - Anabolism = formation of macromolecules

Answer 115

1) Acetyl-CoA: - needed for many reactions eg. 2) NAD⁺ - helps with REDOX reactions YES, IMPORTANT

Answer 116

GLYCOLYSIS - series of chemical reactions that break down glucose GLUCONEOGENESIS - production of glucose within a cell

Answer 117

SOME STEPS IN GLYCOLYSIS ARE NOT REVERSIBLE - step 3 etc.

Answer 118

- Making lipids = lipogenesis - Breaking down lipids = lipolysis

Answer 119

NO!!!! SO... 1) When more protein is consumed than needed, protein is turned into carbohydrates or fats 2) Nitrogen from the amine group will be eliminated through the UREA CYCLE - BASICALLY PROTEIN METABOLSIM!!!

Answer 120

- 11 amino acids CANNOT be made by the body - called ESSENTIAL AMINO ACIDS - AND this cannot be stored - So we must be consuming amino acids all the time!

Answer 121

1) Transamination = CATABOLIC + ANABOLIC 2) Oxidative Deamination = CATABOLIC (removing nh2 group) 3) Urea cycle

Answer 122

WHEN WE NEED AN ENERGY SOURCE... - Fatty acids linked to coenzyme A (coA) - Transported into the mitochondria. Undergo BETA-OXIDATION -> Yields acetyl CoA and NADH, FADH2 - Hence ETC can occur

Answer 123

FATS HAVE MORE ENERGY PER GRAM 1) More CH2 units / covalent bonds 2) Electrons are equally shared - so will have higher energy level So ....release lots of energy once bonds are broken - Carbos only somewhat oxidised - Carbo electrons are UNEQUALLY SHARED - lower energy level

Answer 124

- Fat stores more energy so... - Fat will be stored as FAT DROPLETS in ADIPOSE TISSUE - This will release energy which can be used later on

Answer 125

- when glucose is not present for energy... - FIRST = fatty acids linked to coenzyme A. - Transported into the mitochondria BETA OXIDATION = Breaks down fatty acids into acetyl-CoA = THEN...acetyl CoA used in Krebs to make co2

Answer 126

PARTIALLY - LATER STEPS WILL EVENTUALLY FAIL BETA OXIDATION - Can occur without o2 as its oxidation - turn Fatty acids -> acetyl CoA KREBS, OXIDATIVE PHOSPHORYLATION - Acetyl CoA -> co2 -> krebs produces NADH, FADH2 - but in O.P, o2 is needed as a final electron acceptor - so fats can't be fully oxidised (like glucose into co2!!)

Answer 127

- energy released depends on the fatty acid length - BUT each oxidation cycle yields: 1) COENZYMES, GENERAL = 4ATP 2) KREBS CYCLE = 10ATP from the acetyl CoA which enters the Krebs cycle SO...lipids release much more energy than glucose! BUT...more complex reactions

Answer 128

ANS = GLUCOSE - whole process 1 glucose results in 2 acetyl coA - therefore glucose will produce more ATP before the krebs cycle, which is where acetyl coA enters

Answer 129

MALTOSE - made up of 2 glucose molecules BUT note that it requires energy to break it down into glucose thoughh

Answer 130

STEAR ACID - has 16 carbons - so can produce more acetyl coA during beta oxidation - hence the citric acid cycle will occur/be repeated more times

Answer 131

THE ACID! 2 THINGS TO THINK ABOUT 1) No. of carbons -> more carbons means more acetyl CoA 2) Make sure the molecule can go through beta oxidation etc. that breaks it into smaller units SO... - acid has 8 carbons - beta oxidation will split it into 2 carbon units - therefore 4 acetyl coA (2C) - hence can go through the krebs cycle more times

Answer 132

The initial steps of glycolysis are endergonic, requiring the input of energy that involves the hydrolysis of ATP and phosphorylation of two carbon atoms to form fructose 1,6-bisphosphate. More free energy is stored in fructose 1,6-bisphosphate than in glucose. This free energy is released in the later steps, which are exergonic oxidation–reduction reactions. This released energy is captured (1) as ADP is phosphorylated to ATP and (2) electrons are transferred from the carbon chain to NAD+ to form NADH.

Answer 133

A yeast population suddenly moved from an aerobic to an anaerobic environment would shift from cellular respiration to termentation as its energy-harvesting pathway. Since fermentation does not extract as much usable energy from glucose as cellular respiration, the cells’ doubling time, and therefore the yeast population’s growth rate, would be slowed. In terms of gene expression, the cells would shift from expressing proteins involved in cellular respiration to expressing proteins involved in fermentation.

Answer 134

The figure should be corrected as follows: instead of 1 CO2 produced, it should show 2; instead of 3 NAD+ produced it should show 3 NADH; and instead of 1 FAD+ produced it should show 1 FADH2. (Also, students could have shown 1 CoA being released at the beginning of the cycle—this allows CoA to be recycled.) REMEMBER THAT THE TABLE IN NOTES IS FOR 2 CYCLES/ROUNDS, IE. 2 OF THE INPUT ACETYL COA

Answer 135

The graph shows that an electron begins with a high level of stored free energy in NADH or FADH2, progressively loses free energy at each transfer in the respiratory chain, and reaches its lowest free energy level when it is transferred to oxygen at the last step.

Answer 136

The H+ gradient has potential energy. When H+ diffuses through the channel in the ATP synthase, this potential energy is converted into kinetic energy, causing the central subunit to rotate. This rotation causes the lower subunit to change its shape, exposing the active site for ATP synthesis, which allows ATP synthesis to proceed.

Answer 137

1) Electrons can't flow backwards 2) If complex II is blocked, even though there is a protein that transports electrons, it needs to go straight to complex III

Answer 138

If ATP is limited, acetyl CoA enters the citric acid cycle and cellular respiration uses it to produce ATP. If ATP is abundant, acetyl CoA is shuttled to fatty acid synthesis, thus storing the energy in chemical bonds

Answer 139

No, because certain organisms use anoxygenic photosynthesis, which does not produce oxygen because water is not the electron donor. For example, purple sulfur bacteria use hydrogen sulfide (H2S) as the electron donor, producing sulfur instead of oxygen. (Other examples: green sulfur bacteria use sulfide ions, hydrogen, or ferrous iron as electron donors; another group of bacteria uses compounds derived from arsenic.)

Answer 140

Reduction occurs in the stroma of the chloroplast, and the reducing agent is NADPH.

Answer 141

The three steps are (1) the fixation of CO2, (2) the reduction of 3PG to form glyceraldehyde 3-phosphate (G3P), and (3) the regeneration of the CO2 acceptor RuBP. Altogether, 18 ATP molecules are used for each cycle: 12 for phosphorylation during the reduction step and 6 in the conversion of RuMP compound into RuBP during regeneration

Answer 142

The starch grains must form due to an accumulation of glyceraldehyde 3-phosphate (G3P), which is a product of the Calvin cycle. This indicates that the Calvin cycle takes place in the bundle sheath cells.

Answer 143

Rising levels of carbon dioxide in the atmosphere would most benefit C3 plants: C3 plants can suffer from photorespiration when carbon dioxide levels are low and oxygen is able to compete with it as a substrate for rubisco, but when carbon dioxide levels are high, oxygen competing with carbon dioxide as a substrate becomes much less of a problem, so C3 plants grow very well. **C4 plants and CAM plants do not have the problem of photorespiration, but because they separate carbon fixation from Calvin cycle reactions, they must use more energy in supporting these systems. Therefore, C3 plants will be more energy efficient than C4 or CAM plants at high carbon dioxide levels.

Answer 144

The protein kinase cascade provides a means for amplifying the signal so that a single signal molecule can cause many thousands of molecules to be activated at the end of the pathway **as part of the cellular response.

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