Unit 1 - Energy Systems In Muscle Cells

Question 1

Describe the process that occurs there is not enough oxygen for Aerobic respiration

Answer 1

Just like in aerobic respiration It generates 2NADH and 2ATP from each molecule of glucose as it is broken down to pyruvate

This process is followed by the conversion of pyruvate to lactic acid (lactate)​

NAD is also regenerated as the hydrogen of NADH has also been transferred to produce lactate. ​

NAD is essential here as it enables glycolysis to continue to produce more ATP.

Question 2

What is the result of built up lactic acid in muscles?

Answer 2

• Fatigue​
• An oxygen debt

Question 3

Describe Oxygen Debt

Answer 3

Oxygen debt is repaid when exercise comes to an end. Oxygen becomes available and aerobic pathways are used again. The energy generated by aerobic respiration is then used to convert lactic acid back to pyruvate.

Question 4

What are the Two types of Skeletal Muscles?

Answer 4

1. Slow Twitch
2. Fast Twitch

Question 5

State Properties of Slow Twitch Muscle Fibres

Answer 5

1. These contract slowly, but sustain contractions for longer
2. Good for endurance activities
3. Rely on aerobic respiration to generate ATP
4. Have many mitochondria
5. Have a large blood supply
6. Have a high concentration of myoglobin (myoglobin is an oxygen storing protein present in muscle cells)
7. Major storage fuel is fats

Question 6

State Properties of Fast Twitch Muscle Fibres

Answer 6

1. Muscle fibres contract quickly
2. Over short periods of time
3. Good for bursts of activity
4. Generates ATP through glycolysis
5. Only a few mitochondria
6. Lower blood supply
7. Major storage fuels are glycogen and creatine phosphate