the link reaction + krebs cycle

Question 1

where does the link reaction occur

Answer 1

mitochondrial matrix

Question 2

what is the first stage of the link reaction

Answer 2

pyruvate is decarboxylated, where one carbon atom is removed in the form of CO2

Question 3

what happens when CO2 is removed in the link reaction

Answer 3

NAD is reduced to NADH by collecting a hydrogen from pyruvate to turn it into acetate

Question 4

what is acetate combined with and what does it form

Answer 4

coenzyme A and forms acetyl CoA

Question 5

is any ATP produced in the link reaction

Answer 5

no

Question 6

how many times does the link reaction occur for every glucose molecule and why

Answer 6

two pyruvate molecules are made from glycolysis and only one enter the link reaction, therefore happens twice for every glucose molecule

Question 7

what are the products of the link reaction for each glucose molecule (2x link reaction)

Answer 7

2 x acetyl CoA
2x CO2 as a waste product
2x NADH

Question 8

what happens to acetyl CoA and the NADH produced in the link reaction

Answer 8

acetyl CoA - krebs cycle
NADH - oxidative phosphorylation

Question 9

where does the krebs cycle occur

Answer 9

mitochondrial matrix

Question 10

what is the first stage of the krebs cycle

Answer 10

acetyl group from acetyl CoA produced in the link reaction combines with oxaloacetate to form citric acid

Question 11

which enzymes catalyses the reaction between acetyl and oxaloacetate

Answer 11

citrate synthase

Question 12

how many carbons is acteyl CoA

Answer 12

2 carbon molecule

Question 13

how many carbons is oxaloacetate

Answer 13

4 carbon compound

Question 14

how many carbons is citrate

Answer 14

6 carbon compound

Question 15

what happens to coenzyme A, when the acetyl group is used in the krebs cycle

Answer 15

goes back to the link reaction

Question 16

what is citrate converted to

Answer 16

an intermediate 5 carbon compound

Question 17

what happens when citrate is converted to a 5C compound

Answer 17

decarboxylation in the form of CO2, dehydrogenation where a hydrogen is removed which is used to produce NADH from NAD

Question 18

what happens to the 5C intermediate

Answer 18

4C molecule is produced (oxaloacetate)

Question 19

what is involved in turning the 5C intermediate into oxaloacetate

Answer 19

decarboxylation and dehydrogenation occur producing one molecule of FADH and two molecules of NADH

Question 20

what is substrate level phosphorylation

Answer 20

when a phosphate group is directly transferred from one molecule to another

Question 21

how does substrate level phosphorylation occur in the krebs cycle

Answer 21

ATP is produced from the direct transfer of a phosphate group from an intermediate compound with ADP to form oxaloacetate

Question 22

what is oxaloacetate used for when produced

Answer 22

regenerated for use in the next krebs cycle

Question 23

how many CO2 is produced from the krebs cycle

Answer 23

2

Question 24

what is the CO2 used for

Answer 24

released as a waste product

Question 25

how many ATP does the krebs cycle produce

Answer 25

1

Question 26

what is the ATP used for

Answer 26

energy

Question 27

how many NADH are produced

Answer 27

3

Question 28

what is the NADH produced from the krebs cycle used for

Answer 28

oxidative phosphorylation

Question 29

how many FADH are produced

Answer 29

1

Question 30

what is the FADH produced from the krebs cycle used for

Answer 30

oxidative phosphorylation