The Krebs Cycle

Question 1

Where does the Krebs cycle take place?

Answer 1

The mitochondrial matrix

Question 2

Name the products of one turn of the Krebs cycle

Answer 2

Three NADH
One FADH2
One GTP
Two CO2

Question 3

Name the products of the Krebs cycle from one glucose

Answer 3

Six NADH
Two FADH2
Two GTP
Four CO2

Question 4

How many carbons are there in Oxaloacetate?

Answer 4

Four

Question 5

Describe the production of citrate from oxaloacetate

Answer 5

Citrate synthase converts oxaloacetate to citrate using one molecule of Acetyl-CoA

Question 6

Name the enzyme used in the isomerisation of citrate

Answer 6

Aconitase

Question 7

What type of reaction is the conversion of isocitrate to alpha-ketoglutarate

Answer 7

Dehydrogenation

Oxidation

Question 8

How many cartons has alpha-ketoglutarate

Answer 8

Five

Question 9

What other byproducts of the enzyme isocitrate dehydrogenase?

Answer 9

NADH
CO2
H+

Question 10

Name of the enzyme that converts isocitrate into alpha-ketoglutarate

Answer 10

Isocitrate dehydrogenase

Question 11

Name the complex responsible for the conversion of alpha-ketoglutarate to succinyl-CoA

Answer 11

Alpha-ketoglutarate dehydrogenase complex

Question 12

What are the byproducts of the conversion of alpha-ketoglutarate to succinyl-CoA?

Answer 12

NADH
CO2
H+

Question 13

How many carbons are there in succinyl-CoA

Answer 13

Four

Question 14

What is added to alpha-ketoglutarate by the alpha-ketoglutarate dehydrogenase complex?

Answer 14

CoA

Question 15

What is the enzyme responsible for the conversion of succinyl-CoA to succinate

Answer 15

Succinyl-CoA synthetase

Question 16

How is the CoA removed from succinate and which byproduct does this result in?

Answer 16

CoA Is displaced by phosphate molecule.

The phosphate molecule is transferred to GDP forming GTP

Question 17

Name the byproducts of the reaction catalysed by Succinyl-CoA synthetase

Answer 17

CoA

GTP

Question 18

Where might you find an isoform of succinyl-CoA synthetase that produces ATP instead of GTP?

Answer 18

Skeletal and cardial muscle

Question 19

What is fumarate produced from and which type of reaction is this?

Answer 19

Succinate

Dehydrogenation (Oxidation)

Question 20

Which enzyme catalyses the production of fumarate and what are its byproducts?

Answer 20

Succinate dehydrogenase

FADH2

Question 21

Name the four carbon sugars involved in the TCA cycle

Answer 21

Succinate
Fumarate
Malate
Oxaloacetate

Question 22

Name the six carbon sugars involved in the TCA cycle

Answer 22

Citrate and isocitrate

Question 23

Which enzymes act on fumarate and what does it produce?

Answer 23

Fumarase

Malate

Question 24

What type of reaction does Fumerase catalyse?

Answer 24

Hydrolysis

In Addition of water breaking a double bond

Question 25

Which enzyme produces oxaloacetate from Malate?

Answer 25

Malate dehydrogenase

Question 26

Name all of the dehydrogenase enzymes involved in the TCA cycle

Answer 26

Isocitrate dehydrogenase Alpha ketoglutarate dehydrogenase complex Succinate dehydrogenase Malate dehydrogenase

Question 27

Name the three enzymes to produce NADH in thes TCA cycle

Answer 27

Isocitrate dehydrogenase Alpha ketoglutarate dehydrogenase complex Malate dehydrogenase

Question 28

Which is the only enzyme is not in the mitochondrial matrix and where is it located?

Answer 28

Succinate dehydrogenase; Integral to the inner mitochondrial membrane