Animal-cell organelles
An animal cell is the smallest structural and functional unit of the body. The plasma membrane controls exchange with the surroundings. The nucleus contains genetic material and coordinates cell activities. Mitochondria release energy during respiration, ribosomes build proteins, and the endoplasmic reticulum transports and processes materials.
| Organelle | Function |
|---|---|
| Nucleus | Stores DNA and coordinates cell activities. |
| Plasma membrane | Controls movement of substances into and out of the cell. |
| Mitochondrion | Site of aerobic respiration and energy release. |
| Ribosome | Site of protein synthesis. |
| Golgi apparatus | Modifies, sorts, and packages cell products. |
| Lysosome | Contains enzymes that digest worn-out material and particles. |
| Endoplasmic reticulum | Network for synthesis and transport of cell products. |
Plant and animal cells
| Feature | Plant cell | Animal cell |
|---|---|---|
| Cell wall | Present | Absent |
| Chloroplasts | Present in green parts | Absent |
| Vacuole | Usually large and permanent | Small or temporary |
| Shape | More fixed because of the wall | Often flexible |
| Food storage | Usually starch | Usually glycogen |
Revision questions
- State the function of the nucleus, mitochondrion, and ribosome.
- Give three differences between plant and animal cells.
- Explain why plant cells can photosynthesise but animal cells cannot.
