Cell structures
Every living organism is built from cells. For 4BI1 you need to recognise eight structures and know which cells contain them.
| Structure | Found in | What it looks like |
|---|---|---|
| Nucleus | Plant + animal | Large, round, darkly stained |
| Cytoplasm | Plant + animal | Jelly-like filling |
| Cell membrane | Plant + animal | Thin layer around the cytoplasm |
| Mitochondria | Plant + animal | Small rod-shaped organelles |
| Ribosomes | Plant + animal | Tiny dots, free or on membranes |
| Cell wall | Plant only | Rigid outer layer of cellulose |
| Chloroplasts | Plant only | Green discs containing chlorophyll |
| Permanent vacuole | Plant only | Large fluid-filled sac in the centre |
The trap examiners set
The cell membrane and the cell wall are not the same thing. A plant cell has both: the membrane sits just inside the wall. An animal cell has only the membrane.
Write "cell wall" when you mean "cell membrane" and you lose the mark, even if the rest of the answer is right.
Drawing cells in the exam
- Use a sharp pencil and draw clean, continuous lines — no sketchy or hairy lines
- Do not shade or colour in
- Label lines must be straight, drawn with a ruler, and must touch the structure they name
- Labels go outside the diagram, never inside it