TCA Cycle

Question 1

what are all fuels broken down into that is the source of the TCA cycle?

Answer 1

acetyl CoA

Question 2

what provides the link between glycolysis and the TCA cycle?

Answer 2

the pyruvate dehydrogenase complex (PDH)

Question 3

where is the PDH complex located in the cell?

Answer 3

the mitochondrial matrix

Question 4

what is the main goal of the PDH complex?

Answer 4

to conver pyruvate to acetyl-CoA

Question 5

what is the red subunit, E1, of PDH

Answer 5

pyruvate dehydrogenase

Question 6

what is the yellow subunit, E2, of PDH?

Answer 6

transacetylase core

Question 7

what is the green subunit, E3, of PDH?

Answer 7

dihydrolipoyl-dehydrogenase

Question 8

what is the end product of the PDH complex?

Answer 8

1 mol of NADH/H+ per one mol of pyruvate

Question 9

what is the overall reaction of the PDH complex (what kind of reaction)?

Answer 9

oxidation

Question 10

what are the two other names for the TCA cycle?

Answer 10

Krebs Cycle and Citric Acid cycle

Question 11

what does TCA stand for?

Answer 11

tricarboxylic acid cycle

Question 12

how many reaction take place in the TCA cycle?

Answer 12

8

Question 13

of all the reactions that take place in the TCA cycle how many are energy-providing?

Answer 13

5

Question 14

does the TCA cycle require O2 directly?

Answer 14

no, but it is still considered aerobic because it takes place in the mitochondria

Question 15

how many ATP “equivalents” of energy does the TCA cycle provide?

Answer 15

12

Question 16

what are the “ATP equivalents” that the TCA cycle provides?

Answer 16

3NADH/H+, 1FAD, and 1GTP

Question 17

where does the TCA get the oxygen needed for the oxidation of the CH3CO- portion?

Answer 17

from water

Question 18

how many CO2 molecules are produced by the oxydation of the CH3CO- group?

Answer 18

2 CO2

Question 19

what are defined as enzymes that remove 2H+ along with 2e- and transfer them to a cofactor?

Answer 19

dehydrogenases

Question 20

another word to describe dehydrogenation in this instance is….?

Answer 20

oxidation

Question 21

how many ATP can be taken from each NADH/H+

Answer 21

3 ATP

Question 22

how many ATP can be taken from FADH2?

Answer 22

2 ATP

Question 23

how many ATP can be made from 1 GTP?

Answer 23

1 ATP

Question 24

what is the first enzyme of the TCA cycle?

Answer 24

citrate synthase

Question 25

what does citrate synthase do?

Answer 25

combines Acetyl CoA and oxaloacetate to be citrate, gives of CoASH

Question 26

what is the second enzyme of the TCA cycle?

Answer 26

aconitase

Question 27

what does aconitase do?

Answer 27

it converts citrate to isocitrate by an isomerization reaction by dehydration the rehydration with the same H2O molecule

Question 28

what is the first enzyme that provides energy in the TCA cycle? what is made?

Answer 28

isocitrate dehydrogenase, 1 mol of NADH/H+

Question 29

what is the 3rd enzyme of the TCA cycle?

Answer 29

isocitrate dehydrogenase

Question 30

isocitrate dehydrogenase couples what two reactions?

Answer 30

oxidation and decarboxylation

Question 31

what is the 4th enzyme in the TCA cycle?

Answer 31

alpha-ketoglutarate dehydrogenase complex

Question 32

what does the alpha-ketoglutarate dehydrogenase complex do?

Answer 32

converts alpha-ketoglutarate to succinyl CoA

Question 33

what complex resembles the PDH complex?

Answer 33

alpha-ketoglutarate dehydrogenase complex

Question 34

how many enzymes are involved in the alpha-ketoglutarate dehydrogenase complex?

Answer 34

5

Question 35

what is generated by the alpha-ketoglutarate dehydrogenase complex?

Answer 35

1 mol of NADH/H+

Question 36

what is the second enzyme the provides energy in the TCA cycle?

Answer 36

the alpha-ketoglutarate dehydrogenase complex

Question 37

what two reactions are coupled by alpha-ketoglutarate dehydrogenase complex?

Answer 37

decarboxylation and acyl transfer to coenzyme A

Question 38

what is TPP?

Answer 38

thiamine pyrophosphate

Question 39

what does TPP do?

Answer 39

binds the aldehye generated from decarboxylation of alpha-keotglutarate

Question 40

in terms of the TCA cycle what is TPP?

Answer 40

a coenzyme of the alpha-ketoglutarate dehydrogenase complex

Question 41

in terms of the TCA cycle what is lipoic acid?

Answer 41

a coenzyme of the alpha-ketoglutarate dehydrogenase complex

Question 42

what does lipoic acid do?

Answer 42

acts as transferring ‘crane arm’ between TPP and coenyzme A by transferring a succinyl-residue

Question 43

what allows lipoic acid to act as a crane arm?

Answer 43

it's reactive disulfide bond

Question 44

which coenzyme of the alpha-ketoglutarate dehydrogenase complex generates energy, and in what form?

Answer 44

lipoic acid, 1NADH/H+

Question 45

what does FAD stand for?

Answer 45

flavin-adenine-dinucleotide

Question 46

what does FAD do?

Answer 46

regenerates lipoic acid

Question 47

how many reactions does CoA participate in the celll?

Answer 47

about 100

Question 48

what does coenzyme A do?

Answer 48

forms the final energy-rich thioester bond with the product of the reaction, to become succinyl-CoA

Question 49

can lipoic acid be made by our cells?

Answer 49

yes, but it is also available as a supplement