B2- Energy from Respiration

Question 1

How does the body change to accommodate increased respiration during exercise?

Answer 1

During exercise, muscles need more energy so more glucose and oxygen needs to be transported to the muscles.

• Increased heart rate➡️Greater blood flow➡️O2 + glucose delivered to cells quicker.
• Increased and deeper breathing➡️More O2 in lungs + blood.
• Increased breathing rate➡️Removes CO2 made in respiration quicker.

Question 2

How is energy used?

Answer 2

Heat- maintain a constant body temperature.

Muscle contraction (movement).

Building large molecules from small molecules.

For active transport.

Question 3

Define aerobic respiration.

Answer 3

Aerobic respiration is the release of energy from food when oxygen is available.

Question 4

When is anaerobic respiration needed?

Answer 4

Anaerobic respiration is needed when there isn’t enough oxygen for aerobic respiration.

Question 5

Explain how oxygen passes from the blood to mitochondria in the cells (3 marks).

Answer 5

Diffuses (1) from a high concentration to a low concentration (1) through the cell membrane/cytoplasm (1).

Question 6

What is the equation for anaerobic respiration?

Answer 6

Glucose ➡️ Lactic Acid [+ energy].

Question 7

What is oxygen debt?

Answer 7

To oxidise the lactic acid, lots of oxygen is needed. The extra oxygen needed is known as oxygen debt.

Question 8

What is the equation for aerobic respiration?

Answer 8

Glucose + oxygen ➡️ carbon dioxide + water [+ energy].

Question 9

What is the issue with anaerobic respiration?

Answer 9

• Anaerobic respiration didn’t produce as much energy as aerobic respiration.
• Anaerobic respiration produces lactic acid which causes muscle fatigue and pain.