The Aerobic System

Question 1

Why is the aerobic system good?

Answer 1

• It is the preferred energy system.
• Most efficient at ATP resynthesis- produces 18x more energy than any of the anaerobic systems.

Question 2

What is the mitochondria?

Answer 2

• Powerhouse of the cell.
• Site of ATP production during aerobic conditions.
• Lots of mitochondria available in the body.

Question 3

When is the aerobic system used?

Answer 3

• Used during rest and moderate intensity exercise where O2 is readily available.

Question 4

Where are the mitochondria found?

Answer 4

• Slow twitch muscle fibres.

Question 5

What do the mitochondria do?

Answer 5

• Facilitate the breakdown of glycogen and fats in order to produce energy for ATP resynthesis.

Question 6

What are the fuel sources for the aerobic system?

Answer 6

• Glycogen
• Triglycerides/fats.
• Proteins

Question 7

What takes place in the mitochondria?

Answer 7

The Krebs cycle and the Electron transport chain.

Question 8

The process (3 stages)

Answer 8

Stage 1: Aerobic glycolysis.
Stage 2: The Krebs cycle.
Stage 3: The Electron transport chain.

Question 9

Stage 1: Aerobic glycolysis

Answer 9

Takes place in the sarcoplasm.
1. Glycogen is broken down by the enzyme phosphofructokinase (PFK) into Glucose-6-phosphate.
2. This releases energy as 2 moles of ATP used for muscular contraction.
3. Pyruvate acid forms.
4. Sufficient O2 is available.
5. Pyruvate combines with Coenzyme A to form Acetyl- Coenzyme A.
- Now the energy site changes from the sarcoplasm to the mitochondria.

Question 10

Stage 2: The Krebs cycle.

Answer 10

Takes place in the Mitochondria.
1. Acetyl-coenzyme A leaves the sarcoplasm and enters the mitochondria.
2. Acetyl-coenzyme A combines with Oxaloacetic acid to form Citric acid.
3. Citric acid is then oxidised to form Hydrogen, CO2, and 2 moles of ATP.
4. Hydrogen is sent to the ETC.
5. CO2 is sent to the lungs (to be exhaled).
6. 2 moles of ATP are used for muscular contractions.

Question 11

Stage 3: The Electron transport chain.

Answer 11

Takes place in the mitochondria.
1. Hydrogen atoms are split into ions and electrons.
2. They are charged with energy.
3. Hydrogen atoms combine with O2 to produce water.
4. Hydrogen electrons provide energy to resynthesise ATP (34 moles of ATP).