10.2 Respiration and gas exchange

The average person can only hold their breath for about 18 seconds.

• True

• False

Only .............................. of the air is oxygen the rest is mainly nitrogen.

• 12%

• 21%

• 79%

A lung full of pure air supplies more oxygen than a lung full of pure oxygen.

• True

• False

Breathed-out air has ................................................................. breathed-in air.

• equal amounts of oxygen and carbon dioxide as

• less carbon dioxide and more oxygen than

• less oxygen and more carbon dioxide than

Breathing renews the air in the lungs.

• True

• False

Breathing renews the air in the lungs. It keeps the ..................................... concentration in the alveoli as high as possible to make diffusion into the blood as fast as possible.

• nitrogen

• carbon dioxide

• oxygen

A chemical reaction in which cells all over your body use oxygen to release energy from food molecules such as glucose.

• Anaerobic respiration

• Aerobic respiration

Cells use the energy from respiration to....

• To keep themselves alive.

• Stay warm.

• Grow.

• Reproduce.

• Move.

Muscle cells use .......................... the energy from respiration for movement.

• a lot of

• fewer amounts of

When you sit, you need ................. oxygen than when you run.

• less

• more