Enzymes and Anaerobic Respiration

Question 1

When might your body perform anaerobic respiration as opposed to aerobic respiration?

Answer 1

When you do vigorous exercise and your body can’t supply enough oxygen to your muscles, they start doing anaerobic respiration (they make do without it).

Question 2

Define anaerobic respiration.

Answer 2

The incomplete breakdown of glucose, which produces lactic acid.

Question 3

What is the GCSE level word equation for anaerobic respiration?

Answer 3

Glucose -> energy + lactic acid

Question 4

For what 3 reasons is anaerobic respiration NOT the best way to convert glucose into energy?

Answer 4

1. Lactic acid builds up in the muscles which gets painful.
2. Causes muscle fatigue- they get tired and stop contracting efficiently.
3. Anaerobic respiration does not produce nearly as much energy as aerobic respiration.

Question 5

What is the advantage of anaerobic respiration?

Answer 5

You can keep on using your muscles for a little while with no oxygen- handy in an emergency.

Question 6

What will happen when you stop exercising after resorting to anaerobic respiration?

Answer 6

You will have an ‘oxygen debt’.

Question 7

What happens when you have an oxygen debt?

Answer 7

You have to ‘repay’ the ‘oxygen debt’ by breathing hard for a while after you stop to get more oxygen into your blood. This blood flows through your muscles to remove the lactic acid by oxidising it into CO2 and water.

Question 8

How does your body know to try to oxidise your blood?

Answer 8

While high levels of CO2 and lactic acid are detected in the blood by the brain, the pulse and breathing rate stay high to try and rectify the situation.