Exchange and Transport

What is an exchange surface?

A specialised area that is adapted to make it easier for exchanges to occur.

What is urea and what organ is it removed from the body by?

Urea is a poison produced by breaking down amino acids, and it’s removed by the kidneys.

What is carbon dioxide and what organ is it removed from the body by?

Carbon dioxide is a waste gas in aerobic respiration, and it’s removed by the lungs.

What two things are needed for aerobic respiration?

Oxygen and glucose.

What are dissolved food molecules needed for?

To produce new substances for the body.

What is diffusion?

The movement of particles from a high to low concentration gradient.

What are the surfaces where diffusion happens like?

They’re thin so the distance of diffusion is short, and they have a large surface area so there is more room for diffusion to occur.

What happens if a cell’s volume is too big?

It can’t fill up via diffusion fast enough.

What are alveoli?

Pocket-shaped structures that excrete carbon dioxide.

Why do alveoli have walls that are one cell thick?

So the rate of diffusion can be increased.

What are the smallest blood vessels in the body?

Capillaries.

What are arteries?

The blood vessels that carry blood away from the heart.

What is an erythrocyte?

A red blood cell, therefore it carries oxygen.

What is the formula for aerobic respiration?

oxygen + glucose —> carbon dioxide + water

What is in the blood that enters the capillaries?

It has low oxygen and high carbon dioxide levels.

What is in the blood that exits the capillaries and why has it changed?

It has high oxygen and low carbon dioxide levels, because carbon dioxide has diffused out and oxygen has diffused in.