metabolic reactions (citric acid cycle)

Question 1

What is the fifth complex present in the electron transport chain?

Answer 1

ATP synthase

Question 2

What is the chemiosmotic model?

Answer 2

chemical + electrical potential = proton motive force causing electrons to flow passively back causing ATP synthesis

Question 3

What is the free energy of the hydrolysis of ATP?

Answer 3

-52 kj/mol

Question 4

What does ATP synthase cycle through?

Answer 4

• ADP + Pi bound
• ATP bound
• empty

Question 5

How are the subunits of ATP synthase rotated?

Answer 5

through the flow of protons

Question 6

What does full rotation depend on?

Answer 6

the number of protons

Question 7

How many protons produce 1 ATP molecule?

Answer 7

4

Question 8

How much ATP do 1 NADH and FADH2 make?

Answer 8

1 NADH = 2.5 atp

1 FADH2 = 1.5 atp

Question 9

Define oxidative phosphorylation?

Answer 9

the process by which ATP is synthesised as a result of transfer of electrons from NADH or FADH2 to O2

Question 10

How can oxidative phosphorylation be uncoupled?

Answer 10

• through disruption of mitochondria or inhibiton of ATP synthase

Question 11

What do venturicidin and oligomycin do to ATP production?

Answer 11

inhibit ATP synthase

Question 12

What do uncoupling reactions do?

Answer 12

carry protons back to the matrix, dissipating the gradient

Question 13

How are ATP levels regulated?

Answer 13

• by a cell’s energy demands

the mass ratio is usually high and a decrease results in rapid increase in respiration and oxidative phosphorylation

Question 14

What is the starting material for the citric acid cycle?

Answer 14

Acetyl-coA

Question 15

How does the number of carbon atoms change around the cycle?

Answer 15

from 2-6-6-5-4-4-4-4-4

Question 16

What do oxidative decarboxylation and dehydrogenation reactions lead to?

Answer 16

the reduction of NADH and FADH2

Question 17

What happens in the 1st step of the CAC?

Answer 17

oxaloacetate becomes citrate through a condensation reactions

Question 18

What happens in the 2nd step of the CAC?

Answer 18

citrate becomes isocitrate

Question 19

What happens in the 3rd step of the CAC?

Answer 19

isocitrate becomes a ketoglutarate through oxidative decarboxylation

Question 20

What happens in the 4th step of the CAC?

Answer 20

a ketoglutarate becomes Succinyl-coA through oxidative decarboxylation

Question 21

What happens in the 5th step of the CAC?

Answer 21

Succinyl - CoA becomes succinate

Question 22

What happens in the 6th step of the CAC?

Answer 22

Succinate is oxidised to fumarate

- FAD is also reduced to FADH2

Question 23

What happens in the 7th step of the CAC?

Answer 23

Fumarate is converted to fumarase through hydration

Question 24

What happens in the 8th step of the CAC?

Answer 24

malate is oxidised to oxaloacetate, with the reduction of NAD+ to NADH

Question 25

What does the sentence “can i ask some super fantastic memes on krebs cycle” stand for?

Answer 25

• citrate
• isocitrate
• a-ketoglutase
• succinyl coA
• succinate
• fumarate
• malate
• oxaloacetate

Question 26

Is the citric cycle anabolic or catabolic?

Answer 26

neither. It is overall amphibolic, meaning that it includes both forms of reactions

Question 27

What are anaplerotic reactions? what roles do they play in the CAC?

Answer 27

reactions that replenish the CAC intermediates

- they allow concentrations of the intermediates to remain constant

Question 28

How is the CAC regulated?

Answer 28

allosteric regulation through inhibitors occurs.

Substrates and intermediates govern the rate of the cycle