TCA cycle

Question 1

the TCA cycle occurs in what part of the cell?

Answer 1

mitochondrial matrix

Question 2

Where does the Acetyl-CoA oxidation occur?

Answer 2

mitochondrial matrix

Question 3

What is Acetyl-CoA oxidation?

Answer 3

Oxidation of pyruvate by pyruvate
dehydrogenase complex (PDC) to
produce acetyl-CoA which is oxidised in TCA cycle

Question 4

Acetyl-CoA is oxidised into ??? to produce electrons (through energy release) to feed electron transport chain via NADH and
FADH2

Answer 4

CO2 molecules

Question 5

Function of CoA is to

Answer 5

to carry and accept acetyl groups

Question 6

conversion of pyruvate to Acetyl-CoA is catalysed by ???

Answer 6

pyruvate dehydrogenase complex

Question 7

conversion of pyruvate to Acetyl-CoA using pyruvate dehydrogenase complex is located in the ???

Answer 7

mitochondrial matrix

Question 8

Conversion of pyruvate to acetyl-CoA requires how many enzymes?

Answer 8

5 enzymes

Question 9

which Thiamine pyrophosphate (TPP), lipoyllysine, and FAD are
prosthetic groups covalently bound to ???

Answer 9

pyruvate dehydrogenase complex

Question 10

Lipoic acid is covalently linked a lysine residue to give ???

Answer 10

lipoyllysine

Question 11

what uses substrate channeling?

Answer 11

the pyruvate dehydrogenase complex

Question 12

why does the PDC use substrate chaneling?

Answer 12

• intermediates of reaction are tethered to surface
• maintains high substrate concentration
• prevents “theft” of activated acetyl group by other enzymes

Question 13

As a prosthetic group of the PDC, Thiamine pyrophosphate (TPP) uses which vitamin as a cofactor?

Answer 13

Vitamine B1

Question 14

elevated level of pyruvate in the blood is often an indicator of defects in ???

Answer 14

pyruvate oxidation.

Question 15

TRUE or FALSE: the TCA Generates
* 3 NADH
* 1 FADH2
* 1 GTP

Answer 15

TRUE

Question 16

succinate dehydrogenase is
located in the ??? membrane

Answer 16

inner mitochondrial

Question 17

TCA step 1: C_C bond formation to make ???

Answer 17

citrate

Question 18

Step 2: Isomerization via ???

Answer 18

cis-aconitate

Question 19

Step 3: Reaction of isocitrate to a-ketoglutarate with enzyme ???

Answer 19

isocitrate dehydrogenase

Question 20

step 4: dehydrogenation of a-ketoglutarate to succinyl-CoA involves the enzyme ???

Answer 20

a-ketoglutarate dehydrogenase

Question 21

Steps 3 and 4 are important because they produce ??? via oxidative carboxylations

Answer 21

Oxidative decarboxylations to give 2 NADH

Question 22

Which enzymes catalyse the two
oxidative decarboxylation steps (3&4) in the TCA cycle? gives 2 NADH

Answer 22

isocitrate dehydrogenase and a-ketoglutarate dehydrogenation

Question 23

Step 5: Substrate-level phosphorylation to give ???

Answer 23

GTP

Question 24

Step 6: Dehydrogenation to give reduced ???

Answer 24

FADH2

Question 25

Step 7: Hydration of fumarate to ???

Answer 25

malate

Question 26

Step 8: Dehydrogenation to give ???

Answer 26

NADH

Question 27

Aconitase is the enzyme that catalyses reaction of citrate to ???

Answer 27

isocitrate

Question 28

Aconitase contains an iron-sulfur (Fe-S) centre as its coenzyme which acts in both binding of the substrate and in the catalytic addition or removal of ???

Answer 28

H2O

Question 29

TRUE or FALSE a-ketoglutarate dehydrogenase is very different to pyruvate dehydrogenase complex

Answer 29

FALSE

Question 30

Carbon atoms of CO2 are from ???-->a-ketoglutarate-->succinyl-CoA

Answer 30

isocitrate

Question 31

anaplerotic reactions are those that ??? the TCA cycle

Answer 31

replenish the TCA cycle

Question 32

At which steps is NADH produced?

Answer 32

3, 4, 8

Question 33

at what step is GTP produced?

Answer 33

step 5

Question 34

At what step is FADH2 produced?

Answer 34

step 6

Question 35

TRUE or FALSE: Malate Dehydrogenase is found found in both the mitochondrion and the cytoplasm

Answer 35

TRUE

Question 36

Malate dehydrogenase helps shuttle NADH into mitochondrion by the cytoplasmic version using up NADH to convert ??? to malate which is transported to mitochondrion where mitochondrial version oxidises malate --> ??? to recreate NADH

Answer 36

oxaloacetate