Revision sections 2 and 6

Identify the substances which leave the cell by diffusion.

• oxygen

• carbon dioxide

• starch

• urea

Active transport reuiqres additional energy for molecules to move against the concentration gradient.

• True

• False

Describe the structure of the cell membrane.

When oxygen is absent, pyruvate is turned into ........ in animal cells.

• carbon dioxide

• yeast

• lactate

All substances exist at the same concentration between cells and their environment.

• True

• False

Describe what happens to a plant cell with a lower water concentration inside the cell.

Name a cellular activity which requires energy.

Why is diffusion important?

• helps provides cells with raw materials

• helps remove waste materials

• provides the cell with oxygen

• removes CO2 and urea from cells

Identify the correct term for a difference in the concentration of a substance.

A cell which has a high energy requirement will have more...........present.