Chapter 14: the citric acid cycle

Question 1

The substrates and products of the pyruvate dehydrogenase complex (PDC) reaction

Question 2

What type of reaction the PDC reaction is

Question 3

Where in the cell the PDC reaction occurs?

Question 4

What metabolic pathways are linked by the PDC reaction?

Question 5

The names of the five cofactors required by PDC

Question 6

Which coenzymes are catalytic and why they are called like that

Question 7

Which coenzymes are co-substrates and why they are called like that

Question 8

What is going on in the 5 steps of the PDC reaction

Question 9

Role of FAD in the PDC reaction

Question 10

Role of NAD+ in the PDC reaction

Question 11

What are the effects of acetyl-CoA and NADH in the activity of PDC?

Question 12

Other names of the citric acid cycle

Question 13

Compound that feeds the cycle, where it does come from and what happens to it in the cycle

Question 14

The energy products of the cycle

Question 15

Type of reaction for each step of the cycle and understand what’s going on in each step

Answer 15

Reaction 1:
Reaction 2:
Reaction 3: CO2 is lost. This reaction is a oxidative decarboxylation. The secondary alcohol is being converted to a ketone. The substrate is oxidized and NAD+ is reducied to NADH.
Reaction 4: Another example of oxidative decarboxylation. It is thel loss of 2nd CO2. The oxidation is taking place in the carbon and it is becoming a sulfur. This is the second reaction that froms NADH.
Reaction 5: “substrate level” phosphorylation of GDP. Known as this when ATP is not used. Forming energy in thr form of GDP.
Reaction 6: oxidation of substrate generates QH2 (uniquinol)
Reactoin 7: Hydration of substrate. The additon of water across the double bond.
Reaction 8: Oxidation of malate regenerating oxalocetate.

Question 16

The regulatory steps of the cycle and their characteristics

Answer 16

All regulatory steps are large and negative **Double check
**Regulation of cycle occurs at the 3 irreversible steps

Question 17

What is major inhibitor and activator of the cycle?

Answer 17

Major inhibitor NADH. It will act on the three enzymes

Question 18

Citric acid intermediates that can be used as precursors of other compounds

Question 19

Examples of compounds that can be synthesized from intermediates of the cycle

Question 20

How can citrate be taken out of the mitochondria and what is it taken out for?

Question 21

What is meant by anaplerotic reactions of the citric acid cycle?