38. CITRIC ACID CYCLE (KREBS CYCLE)

Question 1

1. Where does the Citric Acid Cycle (Kreb’s Cycle) happen?

Answer 1

• in the mitochondrial matrix

Question 2

2. Where does Oxidative Phosphorylation happen?

Answer 2

• in the inner mitochondrial membrane

Question 3

3. Where is the Electron Transport Chain (ETC) located?

Answer 3

• it is located on the Inner Mitochondrial Membrane

Question 4

4. What is Chemiosmosis?

Answer 4

• this is where the H⁺ gradient drives ATP Synthesis
• it does this through the use of ATP Synthase
• this process takes place in the Mitochondrial Matrix

ATP SYNTHASE:
- an enzyme located on the Inner Mitochondrial membrane

Question 5

5. What are three key aspects that are found in the Inner Mitochondrial Membrane?

Answer 5

1. Krebs Cycle Enzymes
2. Electron Transport Chain enzymes and complexes
3. ATP Synthase Complexes
   (F₀ F₁ ATPase = a transmembrane enzyme)

Question 6

6. Where does the Citric Acid Cycle take place?

Answer 6

• in the Mitochondrial Matrix

Question 7

7. What does the Citric Acid cycle complete?

Answer 7

• the oxidation of organic molecules

THIS RESULTS IN THE PRODUCTION OF:
- CO2
- Energy

Question 8

8. What is converted during the Citric Acid Cycle?

Answer 8

• Pyruvate is converted
• this is a product of Glycolysis
• it is converted into Acetyl-CoA
• Acetyl-CoA enters the Krebs Cycle
• this happens before the Citric Acid Cycle begins

Question 9

9. What produces the Acetyl-Coenzyme: A Acetyl-CoA?

Answer 9

• Glycolysis
• Beta Oxidation of Fatty Acids

Question 10

10. What is responsible for breaking down Fatty Acid chains?

Answer 10

• Peroxisomes

Question 11

11. What produces Citric Acid?

Answer 11

PYRUVATE IS BROKEN DOWN:
- CO2 is released

ACETYL-COA:
- binds to Oxaloacetate (OAA)

THIS PRODUCES:
- Citric Acid

Question 12

12. What coenzymes are produced during the Citric Acid Cycle?

Answer 12

• NAHD
• FADH₂
• they are then transferred to the Electron Transport
  chain

Question 13

13. What are the net products that are produced through the Krebs Cycle?

Answer 13

EACH ACETYL-COA THAT ENTERS THE CYCLE IS CONVERTED TO:
- 2 CO2
- 3 NADH
- 1 FADH₂
- 1 ATP

Question 14

14. Which aspects contribute to the Krebs Cycle Energy Gain?

Answer 14

• 1 ATP
• 3 NADH
• 1 FADH₂

1 NADH = 3 ATP molecules (∴ 9 ATP molecules)
1 FADH₂ = 2 ATP molecules (∴ 2 ATP molecules)

Question 15

15. What is the Net Energy Profit of the Kreb’s Cycle?

Answer 15

• 12 molecules of ATP from one Krebs Cycle

Question 16

16. Upon Glycolysis, how many Pyruvates are produced by one Glucose Molecule?

Answer 16

• 2
• this is then converted into 2 Acetyl-CoA molecules

Question 17

17. What is generated from one Glucose Molecule?

Answer 17

• 2 Citric Acid Cycles

Question 18

18. What are the overall products from the 2 Citric Acid Cycles?

Answer 18

• 4 CO2
• 2 ATP
• 6 NADH
• 2 FADH₂

NB:
- these are double the amount of products from one
Citric Acid Cycle