1. Cells and diffusion Make sure you revise:
Animal cells – functions of each part
Plant cells – functions of each part
Different types of cells
Diffusion - and examples of diffusion

2. Animal Cells Animal cells have:
A nucleus which controls the activities of the cell
Cytoplasm where most chemical reactions take place
Cell membrane controlling substances entering and leaving the cell
Mitochondria where most energy is released during aerobic respiration
Ribosomes where proteins are made

3. Plant Cells Plant cells also have
A rigid cell wall for strength and support the cell
Chloroplasts which absorb light to make energy
Vacuole filled with cell sap

4. Specialised cells

5. and close to control exchange of gases and water loss
1. Guard cell – can open
and close to control exchange of gases
and water loss
2. Sperm cell – long tail providing movement s it can swim to and fertilise egg. Nucleus contains genetic material
3. Red blood cell – concave disc shape - increases area to carry more oxygen
4. Egg cell (ovum) – large – maximum exposure for sperm, has a large food store
6. White blood cell – can change shape to digest microbes
7. Neurone – long like wires to carry messages around the body
5. Root hair cell – large surface area to absorb water and minerals. Thin cell wall so minerals can pass through easily. Positioned close to xylem tissue.

6. Bacterial cells
A bacterial cell consist of a cytoplasm and a membrane surrounded by a cell wall
the genes are not in a distinct nucleus

7. Yeast cells Yeast is a single-celled organism.
Yeast cells have a nucleus, cytoplasm and a membrane surrounded by a cell wall

8. Diffusion and concentration gradients
high
concentration
low
Diffusion is the spreading of the particles of a gas, or of any substance in solution.
This results in a net movement from a region where they are of
a higher concentration to a region of lower concentration
The greater the difference in concentration, the faster the
rate of diffusion.