Cell BiologyExplorer14 minLesson 3 of 7
Organelles
Your cells are not simple bags of fluid — they are highly organised cities, with specialised structures handling energy, manufacturing, waste disposal, and more. Click any organelle in the diagram to explore what it does.
Click to explore a structure
Click any structure to zoom in; press Esc or the back button to zoom out
← Click to explore a structure
Organelle at a glance
| Organelle | Key role |
|---|---|
| Nucleus | Stores DNA; controls gene expression |
| Mitochondria | ATP synthesis via cellular respiration |
| Rough ER | Protein synthesis and initial processing |
| Smooth ER | Lipid synthesis; detoxification |
| Golgi Apparatus | Protein modification and trafficking |
| Lysosome | Intracellular digestion and recycling |
| Centrosome | Microtubule organisation; spindle assembly |
| Peroxisome | Fatty-acid oxidation; H₂O₂ neutralisation |
Animal cell vs. plant cell
Animal cell vs. Plant cell
Hover each cell to highlight what makes it unique
Animal cell only
- Centrosome (centrioles for cell division)
- Lysosomes common; small vacuoles only
Plant cell only
- Cell wall (cellulose — rigid support)
- Chloroplasts (photosynthesis)
- Large central vacuole (≥90% of cell volume when mature)
Found in both cell types
Key concepts
Division of labour
Each organelle is a specialist. The nucleus issues instructions, the ER and Golgi manufacture and ship proteins, and mitochondria supply the energy to run it all.
Membrane-bound
Most organelles are enclosed by a lipid bilayer that lets them maintain a distinct internal chemistry — different pH, enzyme concentration, or ion balance from the cytoplasm.
Endomembrane system
The nuclear envelope, rough ER, smooth ER, Golgi, lysosomes, and secretory vesicles are all physically or functionally connected — one integrated protein-trafficking network.
When organelles malfunction
Organelle failure underpins many diseases. Lysosomal storage disorders (e.g. Tay-Sachs) arise when hydrolytic enzymes are missing. Mitochondrial myopathies impair ATP production in muscle and nerve cells. Peroxisome biogenesis disorders (Zellweger syndrome) prevent very-long-chain fatty-acid breakdown. Understanding organelle biology is therefore directly relevant to medicine.