TCA Cycle

Question 1

What happens to pyruvate in aerobic conditions?

Answer 1

converts to acetyl coenzyme A

Question 2

what does Acetyl CoA do?

Answer 2

Links glycolysis from cytoplasm to krebs in matrix of mitochondria

Question 3

What cells lack mitochondria?

Answer 3

RBC - only perform glycolysis

Question 4

What is each pyruvic acid converted to?

Answer 4

2 carbon acetyl group

Question 5

How is acetyl coA made?

Answer 5

remove 1 molecule of co2 as waste so NAD+ to NADH

Question 6

What is the net gain from glycolysis and link reaction?

Answer 6

2 ATP - 4 NADH - 2 Acetyl coA

Question 7

What is pyruvate dehydrogenase deficiency?

Answer 7

sex linked disease
build up of lactic acid in body (lactic acidosis)
nausea vomiting - neuro problems

Question 8

What occurs in krebs cycle?

Answer 8

Redox and decarboxylation reactions

Question 9

What do redox reactions do?

Answer 9

Transfer energy to NAD and FAD

Question 10

How many ATP molecules in krebs?

Answer 10

12 ATP - 24 per glucose

Question 11

What does acetyl group in krebs cycle do?

Answer 11

Generates 6 carbon molecule citrate - coA recycled

Question 12

What does acetyl group entry create?

Answer 12

citrate and regenerates coA

Question 13

What happens to citrate?

Answer 13

Isomerisation to isocitric acid

Question 14

Where does oxidative decarboxylation occur?

Answer 14

Remove CO2 and forms NADH and alphae ketoglutarate from isocitrate dehydrogenase

Question 15

Where does substrate level phosphorylation occur?

Answer 15

from succinyl coA displaced for phosphate transferred to GDP and donated to ATP forms succinate

Question 16

Where does dehydration occur?

Answer 16

succinate oxidised to furmarate by FADH2 formation

Question 17

Where does hydration occur?

Answer 17

Furmurate converted to malate by adding water

Question 18

What does dehydrogenation do?

Answer 18

converts to oxaloacetate and forms NADH

Question 19

Which enzyme allows substrate level phosphorylation?

Answer 19

succinyl coA synthetase

Question 20

What does regulation of TCA depend on?

Answer 20

substrate availability
inhibition by product accumulation
allosteric inhibition

Question 21

What is citrate synthase inhibited by?

Answer 21

Citrate and ATP

Question 22

What is isocitrate dehydrogenase inhibited by?

Answer 22

NADH and ATP activated by ADP

Question 23

What is Alpha ketoglutarate dehydrogenase inhibited by?

Answer 23

NADH and succinyl coA

Question 24

How is TCA regulated?

Answer 24

Pyruvate dehydrogenase inhibited by NADH and acetyl coA

Question 25

What regulates the enzyme in TCA?

Answer 25

pyruvate dehydrogenase kinase and phosphatase

Question 26

What is ATP used for in TCA?

Answer 26

phosphorylate a key SER residue to inactivate the enzyme

Question 27

What is kinase activated by?

Answer 27

ATP, NADH, acetyl coA

Question 28

What inhibits kinase in TCA?

Answer 28

Pyruvate

Question 29

What happens in Arsenic poisoning?

Answer 29

headaches, confusion, drowsiness - convulsions occur - organs affected are skin and kidney and liver - allosteric inhibition of essential metabolic enzyme PDH complex

Question 30

What is the ETC?

Answer 30

series of electron carriers - as electrons pass through chain exergonic reactions release energy used to form ATP

Question 31

What is chemiosmosis?

Answer 31

Links chemical reactions with pumping of H+ ions - final electron acceptor is oxygen to form water

Question 32

What is flavin mononucloetides?

Answer 32

Flavoprotein - vitamin B2

Question 33

What are cytochromes?

Answer 33

Proteins with iron containing group can exist in reduced Fe2 and oxidised Fe3 form

Question 34

What do iron-sulfur centres?

Answer 34

contain 2 or 4 iron atoms bound to sulfur atoms - forms electron transfer centre

Question 35

What are copper atoms bound to?

Answer 35

2 proteins in the chain participate in electron transfer

Question 36

What is coenzyme Q?

Answer 36

is a non-protein carrier in lipid bilayer

Question 37

Where do electrons pass from?

Answer 37

NADH TO NADH reductase - electrons accepted by FMN then passed to iron clusters

Question 38

Where are Electrons passed to?

Answer 38

coenzyme Q 0 ubiquinone - shuttles electrons to cytochrome reductase

Question 39

Where are Electrons next shuttled by cytochrome c?

Answer 39

to cytochrome oxidase copper converted to Cu+

Question 40

What does cytochrome c oxidase pass?

Answer 40

pass 4 electrons to molecular oxygen to form 2 molecules of water

Question 41

How many molecules of ATP generated in ETC?

Answer 41

32 or 34

Question 42

What made in glycolysis that cant enter mitochondria?

Answer 42

NADH

Question 43

What does NADH do?

Answer 43

Donate electrons to malate or glycerol phosphate shuttle

Question 44

What organs use malate shuttles and how many ATPs?

Answer 44

3 ATP molecules | Liver, kidney, heart

Question 45

What shuttle does rest of body use?

Answer 45

glycerol phosphate shuttle - 2 ATP molecules FAD as H acceptor

Question 46

What does NADH from cytosol give 2 electrons to?

Answer 46

DHAP - dihydroxyacetone phosphate to form glycerol-3-phosphate

Question 47

What does Glyc-3-phos bind to?

Answer 47

Inner membrane dehydrogenase which has FAD prosthetic group

Question 48

What does G3P transfer its electrons to?

Answer 48

FAD prosthetic group - CoQ binds to FAD to take electron to ETC to cytochrome reducate

Question 49

What is cytosolic NADH electrons equivalent to?

Answer 49

Mitochondria generated FAD electrons

Question 50

How many ATPs from glycolysis?

Answer 50

oxidation of glucose to pyruvic acid molecules = 2 ATP substrate level phosphorylation Production of 2 NADH + 2H - 4-6 ATP oxidative phosphorylation

Question 51

How many ATPs in Link reaction?

Answer 51

6 ATP from oxidative phosphorylation - 2 NADH and 2 H

Question 52

How many ATP from krebs and ETC?

Answer 52

Oxidation of succinyl coA to succinic acid = 2 GTPs to atp Production of 6NADH % h = 18 Oxidative ATP Production of 2 FADH - 4 Oxidative ATPS

Question 53

Total ATP per glucose molecule?

Answer 53

36-38