Plant Cell Diagram: Labeled, Interactive 2D and 3D

What is a plant cell?

A plant cell is the basic unit of life in plants, from moss to a giant sequoia. Like animal cells, plant cells are eukaryotic: their DNA sits inside a nucleus, and their work is split among membrane-wrapped organelles. What makes them different is how plants live. Plants make their own food from sunlight and hold themselves up without a skeleton, so their cells add a few parts animal cells don't have.

Plant cells are usually larger than animal cells. OpenStax Biology gives a range of 10 to 100 micrometers for eukaryotic cells, and many plant cells sit in the upper half of that range. Some, like the onion skin cells used in school microscope labs, are big enough to see clearly at low magnification.

Parts of a plant cell and their functions

Here is every part labeled in the plant cell diagram above, with its job. The first four rows are what make it a plant cell.

The cell wall: why plants stand up

The cell wall is a tough layer outside the cell membrane. It is made mostly of cellulose, long chains of sugar bundled into fibers, set in a gel of other carbohydrates. OpenStax names cellulose as the main organic molecule in the plant cell wall. Cell walls of neighboring cells are glued together, and many cells later add a thicker second wall. In woody plants that second wall is stiffened with lignin, which is what wood is mostly made of.

The wall does three jobs. It protects the cell, it gives it a fixed shape, and it stops it from bursting when water rushes in. That last job matters because of the vacuole.

The central vacuole: a water balloon that keeps plants firm

A mature plant cell usually has one large central vacuole, wrapped in a membrane called the tonoplast. Florida State University's Molecular Expressions site describes it as taking up most of the room in many plant cells, often 80 percent or more of the volume. It stores water, salts, sugars, pigments and waste, and it does the digesting that lysosomes do in animal cells.

When the vacuole is full, it pushes the cytoplasm hard against the cell wall. That push is called turgor pressure, and it is why lettuce is crisp and why a well-watered plant stands up straight. When a plant runs short of water, its vacuoles shrink, the cells go limp, and the plant wilts. Water it, and within hours the vacuoles refill and the plant lifts back up.

Because the vacuole fills so much of the cell, it shoves the nucleus and other organelles into a thin layer of cytoplasm around the edges. That is why the nucleus sits off to the side in the diagram.

Chloroplasts: where plants make food

Chloroplasts are the green, bean-shaped organelles that carry out photosynthesis. Their green pigment, chlorophyll, absorbs light. The chloroplast uses that energy to turn carbon dioxide and water into sugar, giving off oxygen. The sugar feeds the whole plant, and, through food chains, almost every animal on Earth.

Inside, a chloroplast has stacks of flat disks called thylakoids. A stack is a granum, and the fluid around the stacks is the stroma. The light-capturing reactions happen in the thylakoid membranes; the sugar-building Calvin cycle happens in the stroma. Like mitochondria, chloroplasts have two membranes and their own DNA. Alberts' Molecular Biology of the Cell explains that they descend from photosynthetic bacteria that were taken in by an ancient cell and stayed.

Only cells in the green parts of a plant have chloroplasts. A carrot root or a potato has none. To follow photosynthesis step by step, from the whole plant down to the inside of a chloroplast, open the photosynthesis diagram.

Plasmodesmata: tunnels between cells

A cell wall could cut each plant cell off from its neighbors. Plasmodesmata (one is a plasmodesma) solve that. They are narrow channels through the walls, lined with cell membrane, so the cytoplasm of neighboring cells is connected. OpenStax compares them to the gap junctions that link animal cells. Water, sugars, salts and signaling molecules travel through them, and so, unfortunately, do many plant viruses.

The parts plant and animal cells share

Most of a plant cell works just like an animal cell. The nucleus, with its nuclear envelope and nucleolus, stores the DNA. Ribosomes, the rough endoplasmic reticulum and the Golgi apparatus build, fold and package proteins, and plant Golgi also makes the pectins and other carbohydrates for the cell wall. The smooth ER makes oils and lipids. Mitochondria release energy from sugar by cellular respiration. Peroxisomes break down fats and help with a process called photorespiration in leaves. The cytoskeleton guides where new wall is laid down and carries chloroplasts around the cell.

Plant cell vs animal cell

The comparison table under the diagram lists every difference. In short:

• Plant cells have: a cell wall, chloroplasts, one large central vacuole and plasmodesmata. They store extra food as starch.
• Animal cells have: centrioles, lysosomes and, at most, small vacuoles. They store extra food as glycogen and fat.
• Both have: a nucleus, cell membrane, cytoplasm, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, peroxisomes and a cytoskeleton.

The quickest way to tell them apart in a picture is shape and color: a boxy cell with green chloroplasts and a big clear vacuole is a plant cell. Switch the diagram to Compare to see both side by side with the unique parts highlighted, or open the animal cell diagram for the animal side in full.

See real plant cells at home

A plain kitchen onion makes one of the best first microscope labs. Peel the thin, clear skin from the inside of one onion layer, lay it flat on a slide with a drop of water, add a drop of iodine to stain it if you have some, and cover it. Under low power you will see rows of brick-shaped cells with clear walls and a dark dot for each nucleus. Onion skin has no chloroplasts, because it grows in the dark. For green chloroplasts, try a single leaf of the aquarium plant Elodea or a thin moss leaf; you may even see the chloroplasts moving as the cytoplasm streams.

How to make a plant cell model

A plant cell model needs a box, not a bag, to show the cell wall. A clear plastic container or a shoebox lined with plastic works well.

Make the vacuole big, so it fills most of the box and pushes the other parts to the edges, just like a real cell. The 3D plant cell is a handy reference while building.

Using this diagram at home or in class

• Grades 3 to 5: set the depth to Kid. Start with the cell wall, chloroplasts and vacuole, then find the parts that animal cells share. Color the plant cell coloring page while you read.
• Grades 6 to 8: use Middle school depth. Have students take the Label it quiz until they score 100 percent, then complete the plant cell worksheet.
• High school biology: switch to High school depth for cellulose microfibrils, osmosis and turgor, and chloroplast structure. The numbered label-the-plant-cell sheet makes a quick quiz.

For a complete program, our best homeschool science curriculum guide compares options by grade, and the programs below teach cells and botany in depth.