Unit 1 Biology Area of Study 1 Outcome

Question 1

Diffusion

Answer 1

Diffusion is the process of molecule movement down its concentration gradient, i.e. from a region of high
concentration towards a region of low concentration.

Question 2

Osmosis

Answer 2

Osmosis is the process of diffusion of water molecules across a semi-permeable membrane from a region of high
water molecule concentration to a region of low water molecule concentration.

Question 3

Diffusion across the plasma membrane

Answer 3

Diffusion of molecules across cell membranes is determined by a number of factors including, concentration
gradient of the molecule as well as its size, charge or the specificity of carrier or channel proteins in the cell
membrane.

Question 4

Dialysis

Answer 4

Diffusion can be explored in the laboratory through the use of a semi-permeable membrane such as cellulose
tubing which allows small molecules to pass through pores in the membrane while large molecules are not able
to diffuse through the pores. This method, called dialysis, is applied in both laboratory science and medicine