Get to know the parts of a cell.
Click any organelle in the diagram to open its page: how many membranes it has, how big it is, what it does, one story of it in action, and the misconception to leave behind. Switch to the plant cell to see the wall, the central vacuole, and the chloroplasts appear.
- 1NucleusOrganelle · double membrane
- 2MitochondrionOrganelle · double membrane
- 3RibosomeMolecular machine · no membrane
- 4Endoplasmic reticulumOrganelle · single membrane network
- 5Golgi apparatusOrganelle · single membrane stacks
- 6LysosomeOrganelle · single membrane
- 7Cell membraneBoundary · phospholipid bilayer
- 8CentriolesMicrotubule pair · organizes the spindle
- 1NucleusOrganelle · double membrane
- 2MitochondrionOrganelle · double membrane
- 3ChloroplastPlastid · double membrane
- 4RibosomeMolecular machine · no membrane
- 5Endoplasmic reticulumOrganelle · single membrane network
- 6Golgi apparatusOrganelle · single membrane stacks
- 7Cell membraneBoundary · phospholipid bilayer
- 8Cell wallCellulose layer · outside the membrane
- 9Central vacuoleWater-filled sac · up to 90% of the volume
Animal cell: what you are looking at
A flexible, roughly rounded cell 10–30 µm across, bounded only by its membrane. It has a pair of centrioles near the nucleus and many lysosomes, but no wall, no chloroplasts, and no large central vacuole.
Centrioles. A pair of short microtubule cylinders at right angles; they organize the spindle during cell division.
Plant cell: what you are looking at
A boxy cell 10–100 µm across held rigid by a cellulose wall outside the membrane. A large central vacuole fills most of the interior, chloroplasts line the cytoplasm, and there are no centrioles or true lysosomes.
Cell wall. A rigid layer of cellulose fibers outside the membrane, typically 0.1–10 µm thick, that gives the cell its shape and resists turgor pressure.
Central vacuole. A water-filled sac bounded by the tonoplast that can occupy 80–90% of the cell’s volume; it stores water, ions, and pigments and keeps the cell turgid.
Hover or tab through the key to light up each structure. Every numbered organelle opens a page with its membranes, size, functions, a worked example, and a common misconception.
Print a cell to label ↗One page for every part.
Membranes, size, count per cell, and the job each structure does, with numbers you can quote.
Nucleus
Stores the genome
Explore the nucleus ↗Organelle · double membraneMitochondrion
Makes ATP by aerobic respiration
Explore the mitochondrion ↗Plastid · double membraneChloroplast
Runs the light reactions
Explore the chloroplast ↗Molecular machine · no membraneRibosome
Translates mRNA into protein
Explore the ribosome ↗Organelle · single membrane networkEndoplasmic reticulum
Folds and modifies proteins
Explore the endoplasmic reticulum ↗Organelle · single membrane stacksGolgi apparatus
Modifies proteins and lipids
Explore the golgi apparatus ↗Organelle · single membraneLysosome
Digests what the cell takes in
Explore the lysosome ↗Boundary · phospholipid bilayerCell membrane
Controls what gets in and out
Explore the cell membrane ↗Compare the organelles
Membranes are the quickest way to sort the parts of a cell. Two membranes point to an organelle that began as a captured bacterium (mitochondria and chloroplasts), or to the envelope around the genome. One membrane marks the endomembrane system, the connected set of compartments that the ER, Golgi, lysosomes, and cell membrane trade vesicles between. Ribosomes have none, which is why bacteria have them too.
| Organelle | Found in | Membranes | Main job |
|---|---|---|---|
| Nucleus | Animal cells, Plant cells, Fungi, Protists | Double: the nuclear envelope, pierced by pores | Stores the genome |
| Mitochondrion | Animal cells, Plant cells, Fungi, Protists | Double: smooth outer, inner folded into cristae | Makes ATP by aerobic respiration |
| Chloroplast | Plant cells, Algae and some protists | Double envelope plus thylakoid membranes inside | Runs the light reactions |
| Ribosome | Animal cells, Plant cells, Fungi, Protists, Bacteria and archaea | None: RNA and protein only | Translates mRNA into protein |
| Endoplasmic reticulum | Animal cells, Plant cells, Fungi, Protists | Single, continuous with the nuclear envelope | Folds and modifies proteins |
| Golgi apparatus | Animal cells, Plant cells, Fungi, Protists | Single, as 4–8 stacked cisternae | Modifies proteins and lipids |
| Lysosome | Animal cells, Protists, Fungi and plants (as lytic vacuoles) | Single, with an enzyme-resistant inner face | Digests what the cell takes in |
| Cell membrane | Animal cells, Plant cells, Fungi, Protists, Bacteria and archaea | Is one: a 7–8 nm phospholipid bilayer | Controls what gets in and out |
Bacteria and archaea (prokaryotes) have a cell membrane and ribosomes but none of the membrane-bound organelles in this table. Their DNA sits in the cytoplasm as a nucleoid, and their smaller 70S ribosomes are the reason many antibiotics can hit them without harming ours.
Animal cell vs plant cell
A flexible, roughly rounded cell 10–30 µm across, bounded only by its membrane. It has a pair of centrioles near the nucleus and many lysosomes, but no wall, no chloroplasts, and no large central vacuole. A boxy cell 10–100 µm across held rigid by a cellulose wall outside the membrane. A large central vacuole fills most of the interior, chloroplasts line the cytoplasm, and there are no centrioles or true lysosomes. Both share the nucleus, mitochondria, ribosomes, ER, Golgi apparatus, and cell membrane; the five differences below are what an exam usually asks for.
- Cell wall. Plant cells build a rigid cellulose wall outside the membrane, typically 0.1–10 µm thick. Animal cells have only their flexible membrane, so they can crawl, engulf food, and change shape.
- Chloroplasts. Green plant tissues carry 30–100 chloroplasts per cell to run photosynthesis. Animal cells have none and must eat sugar that plants made.
- Central vacuole. A mature plant cell keeps one water-filled vacuole that can fill 80–90% of its volume; its pressure against the wall (turgor) is what holds a plant upright. Animal cells have only small, short-lived vacuoles and vesicles.
- Centrioles. Animal cells organize the spindle for cell division from a pair of centrioles beside the nucleus. Flowering plants and conifers have no centrioles and build their spindle without them.
- Shape. The wall gives plant cells a fixed, boxy outline that fits neighbors like bricks. Animal cells are rounded or irregular, and their shape follows the cytoskeleton and whatever they are attached to.
- Bonus: lysosomes and storage. Animal cells digest with many lysosomes and store glucose as glycogen; plant cells digest mostly inside the vacuole and store glucose as starch grains.