Human and Social Biology Form 3

Form 3 HUMAN AND SOCIAL BIOLOGY Trinity

Week 3 Topic: Diffusion, Osmosis and Active Transport – Answer ALL the following questions:

1.     Suggest why diffusion through cell surface membranes is said to be passive process.

2.     Blood consists of blood cells and a liquid portion known as plasma. Both components of the blood may be concentrated or dilute with various substances at any given point in time.

a.      Define the term concentrated.

b.     Define the term dilute

c.      Which would be more harmful – our blood plasma becoming more dilute or more concentrated than our red blood cells?

3.     Make a table to compare the processes of diffusion and osmosis.

4.     Explain why energy is needed for active transport.