Cells.

Question 1

Difference between embryonic and adult stem cells (4 marks).

Answer 1

Embryonic:
- embryo ONLY.
- divide into ALMOST any cell.

Adult:
- found in ANY location.
- differentiate into LIMITED types of cells, only RELATED to location.

Question 2

How is active transport different from osmosis and diffusion (6 marks).

Answer 2

Active transport:
- DISSOLVED molecules.
- low to high concentration.
- requires energy = “active”.

Diffusion and Osmosis.
- WATER and SUGAR molecules.
- high to low concentration.
- NO ENERGY = passive.

Question 3

Definition: Diffusion.

Answer 3

NET MOVEMENT of molecules from an area of high to low concentration.
Passive = require no energy.

Question 4

Factors affecting rate of diffusion (3 marks).

Answer 4

• Concentration gradient.
• Temperature.
• Surface area.