Lecture 8: Mitochondrial Bioenergetics Flashcards Preview

Molecular And Cellular Mechanisms (MCM) > Lecture 8: Mitochondrial Bioenergetics > Flashcards

Flashcards in Lecture 8: Mitochondrial Bioenergetics Deck (25):
1

Overview of TCA cycle:

what are the 3 potential starting materials?

1. Fats
2. Polysaccharides
3. Proteins

2

Overview of TCA cycle:

What are examples of starting materials
1. Fats
2. Polysaccharides
3. Proteins

1. Fatty acids and glycerol
2. Glucose and other sugars
3. Amino acids

3

Overview of TCA cycle:

What are the starting materials converted into?

Acetyl CoA

4

Overview of TCA cycle:

What are the two steps following making of Acetyl CoA?

Enters citric acid cycle, then undergoes Oxidative phosphorylation

5

What is Acetyl CoA?

Activated form of acetate

6

Which of the following statements best explains the FUNCTION of TCA?

a. It participates in the synthesis of glucose from pyruvic acid
b. Some of TCA cycle enzymes are located in the cytoplasm
c. It is an endergonic series of reaction
d. Two NADH are produced per turn
E. It requires thiamine pyrophosphate (TPP) lipoic acid, FAD, NAD+ and CoA


a. It participates in the synthesis of glucose from pyruvic acid

7

How many NADH are produced per turn of TCA?

3 NADH

8

Starting with one mole of succinic acid and ending with one mole of oxaloacetic acid, how many maximum moles of ATP could the TCA cycle produce when coupled to electron transport system and ATP synthase?

4

9

1 mol NADH = _____ mol ATP

2.5 mol ATP

10

1 mol FADH2= _____ mol ATP

1.5 mol ATP

11

1 mol GTP = ______ mol ATP

1 mol ATP

12

What are the regulated steps of TCA cycle?

1, 3, and 4

13

All of the following statements are true about the TCA cycle except which one?

A. It begins with the condensation of acetyl CoA and oxaloacetic acid
B. If the cycle begins with one mole of oxaloacetic acid and one mole of acetyl-CoA, one mole of oxaloacetic acid will be regenerated
C. The cycle requires molecular oxygen (O2) in one of its enzymatic reactions
D. The cleavage of two thioester linkages helps drive the cyle to make it exergonic
E. GTP is produced by a substrate-level phosphorylation in the cycle

C

14

All of the following statements are true about the TCA cycle except which one?

A. It begins with the condensation of acetyl CoA and oxaloacetic acid
B. If the cycle begins with one mole of oxaloacetic acid and one mole of acetyl-CoA, one mole of oxaloacetic acid will be regenerated
C. The cycle requires molecular oxygen (O2) in one of its enzymatic reactions
D. The cleavage of two thioester linkages helps drive the cyle to make it exergonic
E. GTP is produced by a substrate-level phosphorylation in the cycle

C. The cycle requires molecular oxygen (O2) in one of its enzymatic reactions

15

A metabolic process is pictured in the image below. Which intermediate in this process inhibits the rate-limiting enzyme of glycolysis and activates the rate-limiting enzyme of fatty acid synthesis?

A.
B
C
D
E

B, See figure 12.4, p 171

Citrate, from OA and acetyl CoA by the enzyme citrate synthase, inhibits pfk and allosterically activates acetyle CoA carboxylate.

16

Which of the following factors is involved in the activation of pyruvate dehydrogenase complex in low energy state?
A. High Ca2+ favors the active dehydrogenase by activating pyruvate dehydrogenase phoshatase

Refer to figure 10.2 in p 129

17

Energy demand is high during physical exercise, therefore, TCA cycle should work hard to meet the energy requirement. Which of the following principally stimulates the TCA cycle?

Stimulation of the flux through a number of enzymes by a decreased NADH/NAD+ ratio

18

Which of the following does not contribute to the chemiosmotic force (a.ka pmf) required for ATP synthesis?

PHOSPHATE HAS NOTHING TO DO

19

Malonate inhibits

Complex II

20

Amytal, Rotenone, Myxothazol, Piericidin A inhibit

COMPLEX I

21

Antimycin inhibits

COMPLEX III

22

Oligomycin inhibits

complex V

23

H2S inhibits

complex IV

24

What is the P:O ratio

Measure of efficiency of OxPhos, which couples ATP synthesis to cell respiration and is defined as molecules of ATP generated from ADP and Pi per atom

25

A patient has been exposed to a toxic compound that increases the permeability of mitochondrial inner membranes for protons. Which of the following events in liver cels would you expect to occur?

Increased rate of TCA cycle