Diffusion

Question 1

What is diffusion?

Answer 1

Particles moving from an area of higher concentration to an area of lower concentration

Question 2

In multicellular organisms, distance for diffusion to all the cells are too large so we need…

Answer 2

1. Respiratory/breathing system (for bringing oxygen to the blood)
2. Circulatory/cardiovascular system (for transport to tissues)

Question 3

What does the capillary do?

Answer 3

Brings de-oxygenated blood to the alveoli. Oxygen is breathed in to the alveoli and diffuses through the cells into the blood

Question 4

What factors can increase the rate of diffusion?

Answer 4

1. Short distance (thin cell)
2. Maintaining a steep concentration gradient
3. Large surface area
4. Moisten air so that oxygen dissolves more easily

Question 5

How can we maintain a steep concentration gradient?

Answer 5

• Good ventilation (breathing)
• Good perfusion (blood flow) which removes oxygenated blood from lungs and takes it to the body