krebs cycle

Question 1

Where does the Krebs cycle take place?

Answer 1

Matrix of mitochondria

Question 2

Which enzyme catalyses conversion of citrate to isocitrate?

Answer 2

Aconitase

Question 3

What is the function of aconitase?

Answer 3

Catalyses conversion of citrate to isocitrate

Question 4

Which enzyme catalyses conversion of isocitrate to a-Ketoglutarate?

Answer 4

Isocitrate dehydrogenase

Question 5

What is the function of isocitrate dehydrogenase?

Answer 5

Catalyses conversion of isocitrate to a- ketoglutarate, forming NADH and CO2

Question 6

Which enzyme catalyses conversion of a-Ketoglutarate to succinyl-coA?

Answer 6

a-Ketoglutarate dehydrogenase complex

Question 7

What is the function of a-ketoglutarate dehydrogenase complex?

Answer 7

Catalyses conversion of a-ketoglutarate to succinyl-coA, forming NADH and CO2

Question 8

Which enzyme catalyses conversion of succinyl-coA to succinate?

Answer 8

Succinyl co-A synthetase

Question 9

What is the function of succinyl-coA synthetase?

Answer 9

Conversion of succinyl-coA to succinate, releasing GTP

Question 10

Which enzyme catalyses conversion of succinate to fumarate?

Answer 10

succinate dehydrogenase

Question 11

What does succinate dehydrogenase catalyse?

Answer 11

Conversion of succinate to fumarate, releasing 2H- to form FADH2

Question 12

Which enzyme catalyses conversion of fumarate to malate?

Answer 12

Fumarase

Question 13

What is the function of fumarase?

Answer 13

Conversion of fumarate to malate

Question 14

Which enzyme catalyses conversion of malate to oxaloacetate?

Answer 14

malate dehydrogenase

Question 15

What does malate dehydrogenase catalyse?

Answer 15

conversion of malate to oxaloactetate, forming NADH

Question 16

What is the first step of the Krebs cycle?

Answer 16

Pyruvate converted to acetyl co-A by pyruvate dehydrogenase complex, releasing NADH and CO2

Question 17

Which enzyme catalyses conversion of pyruvate to acetyl coA?

Answer 17

pyruvate dehydrogenase complex

Question 18

Give 3 sources of acetyl co-A

Answer 18

from pyruvate,

beta oxidation of fatty acids, or breakdown of amino acids

Question 19

Why does the TCA cycle only occur aerobically?

Answer 19

oxidative phosphorylation is required to convert NADH and FADH2 back to NAD+/FAD+ co-enzymes

Question 20

Where does pyruvate come from?

Answer 20

Glycolysis

Question 21

What is pyruvate converted into?

Answer 21

acetyl coA

Question 22

What is acetyl coA converted into?

Answer 22

Citrate

Question 23

What is citrate converted into?

Answer 23

Cis-aconitate

Question 24

What is cis-aconitate converted into?

Answer 24

Isocitrate

Question 25

What is isocitrate converted into?

Answer 25

a-ketoglutarate

Question 26

What is a-ketoglutarate converted into?

Answer 26

Succinyl coA

Question 27

What is succinyl coA converted into?

Answer 27

Succinate

Question 28

What is succinate converted into?

Answer 28

Fumarate

Question 29

What is fumarate converted into?

Answer 29

Malate

Question 30

What is malate converted into?

Answer 30

Oxaloacetate

Question 31

What does oxaloacetate combine with, and what does this form?

Answer 31

Acetyl coA, forming citrate