Reaspiration.

Question 1

Site of glycolysis

Answer 1

Cytosol

Question 2

NAD

Answer 2

Nicotinamide adenine dinucleotide

Question 3

Main steps in glycolysis

Answer 3

Phosphorylation lysis phosphorylation dehydrogenation formation of ATP

Question 4

What happens in the first step of glycolysis (Phosphorylation)?

Answer 4

2 ATP molecules are hydrolysed to release two phosphates, both attached to a glucose molecule, forms hexose bisphosphate

Question 5

What happens in the second step of glycolysis (Lysis)?

Answer 5

Phosphorylation destabilises the molecule, splits into two triose phosphate molecules

Question 6

What happens in the third step of glycolysis (Phosphorylation)?

Answer 6

Inorganic phosphate group is added to a triose phosphate molecule to form two triose diphosphate molecules

Question 7

What happens in the fourth step of glycolysis (Dehydrogenation and formation of ATP)?

Answer 7

Two triose bisphosphate molecules are oxidised by the removal of hydrogen atoms, forms two pyruvate molecules, NAD coenzymes accept the removed hydrogens and are reduced to form two reduced NAD molecules, 4 ATP molecules are produced using phosphates from the triose bisphosphate molecules

Question 8

What is the kind of phosphorylation done in glycolysis?

Answer 8

Substrate level phosphorylation

Question 9

What happens in the link reaction?

Answer 9

Pyruvate enters the mitochondrial matrix by active transport by carrier proteins, pyruvate is dehydrogenated and decarboxylated, hydrogen atoms given to NAD to form NADH, resulting two carbon acetyl group is bound to coenzyme A to form acetylcoenzyme A

Question 10

Technical name for the removal of carbon dioxide and hydrogen from the pyruvate

Answer 10

Oxidative decarboxylation

Question 11

Substrate level phosphorylation

Answer 11

When a phosphate group is transferred from one substrate to another

Question 12

First step of the Krebs Cycle

Answer 12

Acetyl group combines with oxaloacetate to mak citrate

Question 13

Second step of the Krebs Cycle

Answer 13

Citrate is decarboxylated and dehydrogenated, one molecule of reduced NAD and a 5 carbon compound is made

Question 14

Equation for the formation of reduced NAD

Answer 14

NAD^+ + 2H^+ + 2e^- -> NADH + H^+

Question 15

Third step of the Krebs Cycle

Answer 15

Alpha ketoglutarate is decarboxylated and dehydrogenated, one molecule of reduced NAD and a 4 carbon compound is made

Question 16

Fourth step of the Krebs Cycle

Answer 16

4 carbon compound isomerised, one molecule of ATP made by substrate-level phosphorylation

Question 17

Fifth step of the Krebs Cycle

Answer 17

4 carbon compound dehydrogenated, one molecule of FADH2 is made

Question 18

Sixth step of the Krebs Cycle

Answer 18

4 carbon compound dehydrogenated, one molecule of NADH made, oxaloacetate regenerated

Question 19

Products of the Krebs Cycle (Both cycles)

Answer 19

6 NADH, 2 FADH2, 2 ATP, 4CO2

Question 20

Role of electron carriers in oxidative phosphorylation

Answer 20

To dissociate hydrogen into a proton and an electron, to pass electrons along the chain so energy is released

Question 21

Role of oxygen in oxidative phosphorylation

Answer 21

Final electron acceptor, forms water

Question 22

Equation for the formation of water in oxidative phosphorylation

Answer 22

O2 + 4H+ + 4e- -> 2H2O

Question 23

Where does oxidative phosphorylation happen?

Answer 23

Inner mitochondrial membrane

Question 24

Process of oxidative phosphorylation

Answer 24

NADH is oxidised and donates hydrogen to NADH dehydrogenase, hydrogen dissociates into a proton and an electron, electrons are passed along the electron carriers, releases energy, energy used to pump protons through the inner mitochondrial membrane, proton gradient forms, potential energy builds up, protons flow down gradient, allows ATP to form by ATP synthase

Question 25

Oxidative phosphorylation

Answer 25

The production of ATP in the presence of oxygen

Question 26

What is ATP made from in oxidative phosphorylation?

Answer 26

ADP and Pi

Question 27

Chemiosmosis

Answer 27

The diffusion of protons down a concentration gradient through a partially permeable membrane

Question 28

Role of the electron transport chain in chemiosmosis

Answer 28

The protons are actively pumped into the intermembrane space using energy released from the transport of electrons down the chain

Question 29

Role of proton gradients in chemiosmosis

Answer 29

Protons diffuse down the proton gradients through ATP synthase in the inner mitochondrial membrane

Question 30

Role of ATP synthase in chemiosmosis

Answer 30

Protons diffuse down the proton gradient through ATP synthase which releases the energy required to synthesise ATP

Question 31

Similarity between oxidative phosphorylation and photophosphorylation

Answer 31

Both use ATP synthase and chemiosmosis

Question 32

Fermentation

Answer 32

Breakdown of complex organic compounds into simpler inorganic compounds without the use of oxygen or the involvement of an electron transport chain

Question 33

Type of fermentation that occurs in mammals

Answer 33

Lactate fermentation

Question 34

Process of lactate fermentation

Answer 34

Pyruvate acts as an hydrogen acceptor which oxidises the NADH, catalysed by lactate dehydrogenase, pyruvate converted to lactate, NAD regenerated, used to keep glycolysis going so small amount of ATP made

Question 35

What is the reason for the oxygen debt that follow exercise?

Answer 35

Conversion of lactic acid to glucose requires oxygen

Question 36

Why can't lactate fermentation continue indefinitely?

Answer 36

Reduced quantity of ATP wouldn't be enough to maintain vital processes, accumulation of lactic acid would decrease pH which would denature proteins

Question 37

Type of fermentation that yeast does

Answer 37

Alcoholic fermentation

Question 38

Process of alcoholic fermentation

Answer 38

Pyruvate converted into ethanal, catalysed by pyruvate decarboxylase, ethanal can oxidise NADH, ethanal becomes ethanol, NAD can be used to continue glycolysis

Question 39

Benefits of being able to respire anaerobically

Answer 39

Anaerobic respiration is fast, failsafe for emergency situations, allows some organisms to survive in low-oxygen environments

Question 40

Why does anaerobic respiration produce a much lower yield of ATP than aerobic respiration?

Answer 40

Organic compounds aren't completely broken down, small quantity of ATP is synthesised by substrate-level phosphorylation alone

Question 41

How to investigate respiration rates in yeast

Answer 41

Yeast suspension and glucose solution sealed in a flask to ensure anaerobic conditions, carbon dioxide released, pushes coloured liquid along capillary tube, distance moved and diameter of tube can find volume of gas produced

Question 42

How to use data logging to investigate respiration rates in yeast

Answer 42

Yeast suspension and glucose solution in a flask, covered with layer of liquid paraffin, carbon dioxide sensor in flask, links to software

Question 43

Explanation for RQ value of proteins

Answer 43

Have to be hydrolysed and amino acids have to be deaminated which requires ATP

Question 44

Explanation for RQ value of lipids

Answer 44

Lipids have a lot of carbon-hydrogen bonds, require a lot of oxygen to break all the bonds, relatively little carbon dioxide is released

Question 45

Equation for respiratory quotient

Answer 45

RQ = CO2 produced/ O2 consumed

Question 46

Explanation for RQ value of carbohydrates

Answer 46

6 molecules of O2 are used to produce 6 molecules of CO2

Question 47

How to do investigations into the effect of factors on the rate of respiration

Answer 47

Use a respirometer

Question 48

How a respirometer is set up and used

Answer 48

Equal masses of controls and respiring things used, potassium hydroxide used as a carbon dioxide scrubber, volume of oxygen absorbed can be measured using the distance that the coloured fluid moves down the graduated tube

Question 49

Role of the outer mitochondrial membrane

Answer 49

To separate the contents of the mitochondrion from the rest of the cell in compartmentalisation

Question 50

Role of the inner mitochondrial membrane

Answer 50

To be the site of oxidative phosphorylation with electron transport chains and ATP synthase

Question 51

Role of the cristae

Answer 51

Projections of inner membrane which increase surface area available for oxidative phosphorylation

Question 52

Where does the Krebs Cycle occur?

Answer 52

Mitochondrial matrix

Question 53

Number of ATP molecules produced by aerobic respiration

Answer 53

38

Question 54

Obligate anaerobes

Answer 54

Can't survive in the presence of oxygen

Question 55

Facultative anaerobes

Answer 55

Can switch between aerobic and anaerobic respiration

Question 56

Obligate aerobes

Answer 56

Can only survive in the presence of oxygen

Question 57

What happens to lactic acid?

Answer 57

Transported by the liver

Question 58

How is glycerol used as a respiratory substrate?

Answer 58

Converted to pyruvate, produce acetyl group, enters link reaction

Question 59

Coenzymes involved in cellular respiration

Answer 59

NAD, FAD, coenzyme A, ATP

Question 60

Why may ATP be considered a coenzyme?

Answer 60

Links reactions, energy released as a result of actions of one enzyme is used by another enzyme

Question 61

Differences between use of NADH and FADH2 in oxidative phosphorylation

Answer 61

FAD electrons released further along the chain, lead to the production of less ATP

Question 62

Why is the net yield of ATP less than the theoretical maximum?

Answer 62

Some ATP used to transport pyruvate into the mitochondrial matrix, some energy released in ETC lost as heat