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

What is an animal cell?

An animal cell is the basic unit of life in every animal, from a sponge to a blue whale to you. Your body is made of trillions of them. Each one is a tiny, self-running factory: it takes in food and oxygen, makes the proteins it needs, releases energy, gets rid of waste and, for most cells, divides to make new cells.

Animal cells are eukaryotic, which means their DNA is kept inside a nucleus and their work is divided among membrane-wrapped compartments called organelles ("little organs"). Bacteria are prokaryotic: they have no nucleus and far fewer compartments. Plant cells are eukaryotic too, and they share most of the same organelles, which you can see by switching the diagram above to the plant cell.

OpenStax Biology puts eukaryotic cells at 10 to 100 micrometers across, and many animal cells sit toward the small end of that range. Even a large one is narrower than a human hair, far too small to see without a microscope. Prokaryotic cells such as bacteria are smaller still, 0.1 to 5 micrometers.

Parts of an animal cell and their functions

Here is every part labeled in the animal cell diagram, with the job each one does. Use the depth toggle above the diagram to read more about any of them.

The control center: nucleus, nuclear envelope and nucleolus

The nucleus is usually the largest structure in an animal cell and the easiest to spot in a labeled diagram. It holds the cell's DNA, the instructions for building every protein the cell will ever make. When the cell isn't dividing, the DNA is spread out as a tangle called chromatin. Before it divides, the DNA coils tightly into chromosomes.

The nucleus is wrapped in the nuclear envelope, which is two membranes, not one. Thousands of nuclear pores let messenger RNA (copies of genes) travel out to the ribosomes and let the proteins the nucleus needs travel in. The outer membrane connects directly to the rough endoplasmic reticulum, which you can see in the diagram as the blue folds hugging the nucleus.

The dark spot inside the nucleus is the nucleolus. It has no membrane. It makes ribosomal RNA and assembles the two halves of each ribosome, which then leave through the pores.

How an animal cell makes and ships proteins

Proteins do most of the work in a cell: they build structures, speed up chemical reactions as enzymes, carry signals and move things around. Making them is a team effort, and you can follow it across the diagram:

1. Nucleus. A gene is copied into messenger RNA, which leaves through a nuclear pore.
2. Ribosomes. A ribosome reads the RNA and strings amino acids together in the right order. Free ribosomes in the cytoplasm make proteins the cell uses itself.
3. Rough endoplasmic reticulum. Ribosomes on the rough ER make proteins headed for membranes, lysosomes or outside the cell. The proteins are threaded inside the ER, folded into shape and often tagged with sugar chains. The ribosomes on its surface are what make it look rough.
4. Vesicles. Finished proteins bud off in small membrane bubbles.
5. Golgi apparatus. Vesicles deliver the proteins to the Golgi's stack of flattened sacs. The Golgi finishes them, adds address tags and sorts them into new vesicles.
6. Cell membrane. Some vesicles merge with the membrane and release their cargo outside the cell, a process called exocytosis. That is how your cells release hormones, digestive enzymes and antibodies.

OpenStax Biology calls this network the endomembrane system. The smooth endoplasmic reticulum is part of it too, but it has no ribosomes. It makes lipids, including the phospholipids for new membranes and steroid hormones, breaks down some drugs and poisons (liver cells are full of it), and stores calcium.

Mitochondria: where animal cells get their energy

Mitochondria release the energy stored in food. In a process called cellular respiration, they use oxygen to break down sugar and capture its energy in ATP, the molecule cells spend like cash. Carbon dioxide and water are left over, which is why you breathe in oxygen and breathe out carbon dioxide.

In the diagram, each mitochondrion has a smooth outer membrane and a folded inner membrane. The folds, called cristae, pack in more surface area for the proteins that make ATP. Mitochondria also have their own small loop of DNA and their own ribosomes. The NIH's National Human Genome Research Institute notes that mitochondrial DNA is passed down from the mother. Scientists think mitochondria were once free-living bacteria that were swallowed by an ancestral cell and stayed, an idea called endosymbiosis.

Cells that use a lot of energy, like muscle and heart cells, have many more mitochondria than cells that don't.

The clean-up crew: lysosomes and peroxisomes

Lysosomes are small sacs filled with dozens of digestive enzymes. They break down food particles, bacteria the cell has swallowed and worn-out organelles, so the cell can reuse the pieces. Cooper's The Cell explains that the inside of a lysosome is acidic, around pH 5, and that its enzymes work best in that acid, which protects the rest of the cell if a lysosome ever leaks. When a lysosomal enzyme is missing, waste builds up; that is what happens in genetic disorders such as Tay-Sachs disease.

Peroxisomes look similar in a diagram, but they do a different job. They break down fatty acids and some toxins, including alcohol in liver cells. Those reactions make hydrogen peroxide, so peroxisomes carry an enzyme, catalase, that splits it into water and oxygen right away.

Shape and division: cytoskeleton and centrioles

An animal cell has no stiff wall, so it relies on the cytoskeleton, a network of protein fibers, to hold its shape. The cytoskeleton has three kinds of fibers: thin microfilaments, medium intermediate filaments and hollow microtubules. They also act like train tracks: motor proteins walk along microtubules carrying vesicles and organelles.

The centrioles are a pair of short cylinders, set at right angles, made of microtubules arranged in nine groups of three. They sit in the centrosome near the nucleus, which organizes the cell's microtubules. When an animal cell divides, the centrosome copies itself and the two copies organize the spindle fibers that pull the chromosomes apart. Most plant cells don't have centrioles, so they are one of the easiest ways to tell an animal cell diagram from a plant cell diagram.

Animal cell vs plant cell

Animal and plant cells share most of their parts: a nucleus, cell membrane, cytoplasm, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, peroxisomes and a cytoskeleton. The differences come from how they live. Plants make their own food and stand up without bones, so their cells add a cell wall, chloroplasts and a big central vacuole. Animals eat their food and move, so their cells stay flexible.

The comparison table under the diagram lists every difference. The quickest way to tell them apart in a picture:

• Shape. Animal cells are usually rounded or irregular. Plant cells are boxy, with a thick wall.
• Green parts. Chloroplasts mean plant.
• A huge clear sac in the middle. That is a plant cell's central vacuole.
• Centrioles and lysosomes. Those point to an animal cell.

A common mix-up: plant cells have mitochondria too. They make sugar in their chloroplasts, then burn it in their mitochondria just as animal cells do. For the full plant side, see the plant cell diagram, and to see how chloroplasts make that sugar, try the photosynthesis diagram.

Animal cells are not all the same

The diagram shows a "typical" animal cell, a model that combines parts every textbook expects to see. Real cells are specialized for their jobs:

How to make an animal cell model

Building a model is one of the best ways to remember the parts, and it is a classic school project. A gelatin cell is the most popular version: the clear gelatin is the cytoplasm, the bag or bowl is the cell membrane, and candy or fruit stands in for each organelle.

Label each part with a toothpick flag or make a key on a card. For a model that lasts, swap gelatin for clay or a foam ball cut in half. The 3D animal cell makes a good reference while you build, because you can turn it to see where each part sits.

Using this diagram at home or in class

• Grades 3 to 5: set the depth to Kid. Explore the big three (membrane, cytoplasm, nucleus) first, then mitochondria, then let your child find the rest. Print the animal cell coloring page to color while reading.
• Grades 6 to 8: use Middle school depth, which matches typical life science standards. Have students take the Label it quiz until they score 100 percent, then complete the animal cell worksheet with its word bank.
• High school biology: switch to High school depth for transcription, the endomembrane system, oxidative phosphorylation and lysosomal enzymes. The numbered label-the-animal-cell sheet works as a quick quiz with no word bank.

If you are choosing a full science program, our best homeschool science curriculum guide compares options by grade, and the programs below teach cells in depth.