Eukaryotic cells and their organelles
Inside a eukaryotic cell
- Plant and animal cells are eukaryotic — their DNA sits inside a nucleus.
- Inside are tiny working parts called organelles, each with a job, in the jelly-like cytoplasm.
- Learn each organelle's structure and function.
The main organelles
| Organelle | Function |
|---|---|
| nucleus | holds the DNA; controls the cell (nucleolus makes ribosomes) |
| rough ER | makes and transports proteins (ribosomes on its surface) |
| smooth ER | makes lipids |
| Golgi body | modifies and packs proteins/lipids into vesicles for secretion |
| mitochondria | site of respiration — releases energy as ATP |
| ribosomes | join amino acids to make proteins |
| lysosomes | sacs of enzymes that break down waste |
Practice
What is the main function of mitochondria?
Mitochondria are the site of aerobic respiration, producing ATP.
Practice
Ribosomes are responsible for:
Ribosomes carry out protein synthesis (the nucleolus makes them).
Practice
Which is true of the endoplasmic reticulum?
Rough ER (with ribosomes) makes proteins; smooth ER makes lipids.
Practice
The Golgi body:
The Golgi processes and packages molecules into vesicles to be secreted.
Practice
Match each organelle to its function.
Mitochondria = respiration; chloroplast = photosynthesis; lysosome = digestion of waste.
Plant-cell extras
- Chloroplasts — site of photosynthesis (green, stacked membranes).
- Cell wall — strong cellulose layer; supports the cell and stops it bursting.
- A large permanent vacuole (with a tonoplast membrane) — stores water and keeps the cell firm.
- Plasmodesmata — channels linking neighbouring cells' cytoplasm.
Practice
Which is found in plant cells but NOT animal cells?
Cell wall, chloroplasts and a large permanent vacuole are plant-only; the others are in both.
Plant vs animal cells
- Plant only: cell wall, chloroplasts, large permanent vacuole.
- Animal usually has: centrioles (absent in most plant cells).
- Both have: cell surface membrane, cytoplasm, nucleus, mitochondria, ribosomes, ER, Golgi.
You've got it
Key idea
- mitochondria = respiration (ATP); ribosomes = protein synthesis
- rough ER makes proteins, smooth ER makes lipids; Golgi packs them into vesicles
- plant-only: cell wall (cellulose), chloroplasts, large vacuole
- both plant and animal cells have membrane, cytoplasm, nucleus, mitochondria, ribosomes, ER, Golgi