aerobic respiration

Question 1

the link reaction; enzyme involved; co-factors involved

Answer 1

pyruvate + coA + NAD -> acetyl CoA + CO2 + NADH produced (PYRUVATE DEHYDROGENASE)
Cofactors: FAD/ lipoic acid/thiamine pyrophosphate

Question 2

what does CoA do?

Answer 2

makes thioester bonds with carboxylic acids (pyruvate has a carboxylic group)

Question 3

how many steps in tca

Answer 3

8

Question 4

step 1 in TCA

Answer 4

oxaloacetate + acetylCoA -> citrate

CITRATE SYNTHETASE

Question 5

Step 2 in TCA

Answer 5

citrate isocitrate

ACONITASE

Question 6

step 3 in TCA

Answer 6

Isocitrate -> alpha-ketogluterate (c5)
ISOCITRATE DEHYDROGENASE
NADH produced
CO2 produced

Question 7

step 4 in TCA

Answer 7

alpha-ketogluterate + coA -> succinyl coA (C4)
KETOGLUTERATE DEHYDROGENASE
NADH produced
CO2 produced

Question 8

step 5 in TCA

Answer 8

succinyl coA -> succinate
SUCCINATE THIOKINASE
CoA produced
GTP produced

Question 9

step 6 in TCA

Answer 9

succinate -> fumarate
SUCCINATE DEHYDROGENASE
FADH2 produced

Question 10

step 7 in TCA

Answer 10

fumarate -> malate
FUMARASE
H2O used

Question 11

step 8 in TCA

Answer 11

malate-> oxaloacetate
MALATE DEHYDROGENASE
NADH produced

Question 12

how many NADH , FADH and GTP produced in TCA

Answer 12

3 NADH
1 FADH
1 GTP

Question 13

how much ATP is yielded by TCA

Answer 13

1 NADH yields 2.5 ATP
1 FADH yields 1.5 ATP
total= 3x2.5 + 1.5 + 1 (from GTP)= 10

Question 14

3 irreversible and key stages of TCA

Answer 14

oxaloacetate + acetyl-coA-> citrate (citrate synthetase)
isocitrate ->alpha-ketogluterate (isocitrate dehydrogenase)
alpha-ketogluterate + coA -> succinyl coA (ketogluterate dehydrogenase)

Question 15

how is isocitrate dehydrogenase inhibited or activated

Answer 15

activated by ADP

inhibited by NADH

Question 16

how is ketogluterate dehydrogenase inhibited

Answer 16

NADH

and succinyl coA

Question 17

how is citrate synthetase inhibited

Answer 17

NADH

succinyl coA

Question 18

where else can oxaloacetate be derived from

Answer 18

pyruvate by

PYRUVATE CARBOXYLASE

Question 19

what else can happen to oxaloacetate

Answer 19

transamination into ASPARTATE-> other aa/purines/pyrimidines
conversion to PEP-> glucose by PEP CARBOXYLASE

Question 20

what else can happen to malate

Answer 20

-> pyruvate by malic enzyme

Question 21

what else can happen to citrate

Answer 21

FA/sterols

Question 22

what else can happen to alpha-ketoglutarate

Answer 22

transamination into GLUTAMATE -> aa/purines