Diffusion

Question 1

What is diffusion?

Answer 1

The movement of molecules from an area of HIGH concentration to LOW concentration, down a concentration gradient.

Question 2

Which of these cannot diffuse and why?

Solid
Liquid
Gas

Answer 2

Solids can not diffuse because the particles are tightly packed together

Question 3

How molecules move during diffusion (different concentrations)?

Answer 3

Molecules move from a high to low concentration

They keep moving until equilibrium is reached

Question 4

Give an example of things that move by diffusion

Answer 4

Oxygen
Food
Waste products etc

Question 5

How is oxygen diffused?

Answer 5

Oxygen is diffused into the lungs and transported throughout the body

Question 6

How does carbon dioxide diffuse?

Answer 6

Diffuses from body tissues and is exhaled via the lungs

Question 7

What are alveoli?

Answer 7

Alveoli are tiny air sacs, where gas exchange occurs.

Question 8

What are the adaptations of alveoli?

Answer 8

• Very thin (one cell thick)
• Network of fine capillaries
• Moist (gas molecules can easily absorb)
• Large combined surface area

Question 9

What does diffusion do in the placenta?

Answer 9

It enable nutrients and oxygen to pass from mother to foetus.

          Waste substances  Foetus ———> Mother

Question 10

How is diffusion done in plants?

Answer 10

Photosynthesis involves diffusion
When CO2 is low, it will diffuse from the air through the leaves

This is the same with oxygen

Question 11

What happens during diffusion with nerve impulses?

Answer 11

The neurotransmitter releases molecules which move from a HIGH CONCENTRATION TO A LOW CONCENTRATION to a receptor to create a nerve impulse