Plant Cells & Animal Cells
Compare plant and animal cells: which organelles they share, the three parts only plants have, and how to use those parts as evidence to identify an unknown cell.
What you'll do in this lesson
A voice-first session with the Crimsora tutor on Plant Cells & Animal Cells, then targeted practice and FRQs — with the tutor adapting to where you get stuck.
What this lesson covers
Slide a piece of onion skin under a microscope, then a swab from the inside of your cheek. Both are made of cells, and both cells are running the same basic business: storing instructions, building proteins, releasing energy, controlling what comes in and goes out. But the onion cells look like a brick wall — straight edges, boxy corners — while the cheek cells look like flat, floppy blobs.
That difference is not an accident of how the slide was made. It comes from a small set of structures that plant cells have and animal cells do not. In this lesson you will sort cell parts into two groups: the shared parts, which tell you almost nothing about what kind of cell you are looking at, and the plant-only parts, which are the real evidence. By the end, you should be able to read a description of an unknown cell and defend your identification by naming the specific structure that settles it.
That difference is not an accident of how the slide was made. It comes from a small set of structures that plant cells have and animal cells do not. In this lesson you will sort cell parts into two groups: the shared parts, which tell you almost nothing about what kind of cell you are looking at, and the plant-only parts, which are the real evidence. By the end, you should be able to read a description of an unknown cell and defend your identification by naming the specific structure that settles it.
The Parts Almost Every Cell Has
Plant cells and animal cells are both eukaryotic, which means their genetic material is packed inside a nucleus. Because they share that basic design, they share most of their equipment.
Every plant cell and every animal cell has a cell membrane, the thin flexible layer that surrounds the cell and controls what enters and leaves. Inside is cytoplasm, the jelly-like fluid where organelles sit and chemical reactions happen. Floating in that cytoplasm is the nucleus, the control center holding DNA. Mitochondria release usable energy from sugar. Ribosomes build proteins. The endoplasmic reticulum and Golgi body package and ship those proteins. Both cell types also have vacuoles — storage sacs — though their size is very different, which matters later.
Here is the part students most often miss: because these structures are shared, they can never be used as evidence for one type over the other. If a description says "this cell has a nucleus and many mitochondria," you still know nothing about whether it is a plant or an animal. That sentence is true of both. A surprising number of wrong answers come from students grabbing the first organelle they recognize and treating it as a clue.
Think of it like identifying a vehicle. Wheels, seats, and a steering wheel appear on cars and trucks alike, so spotting a steering wheel does not tell you which one you are looking at. You need a feature that only one of them has. In cells, that means you need to look for the plant-only parts.
One more shared idea: mitochondria are in plant cells too. Plants make sugar, and then they still have to break that sugar down for energy, just like you do.
Every plant cell and every animal cell has a cell membrane, the thin flexible layer that surrounds the cell and controls what enters and leaves. Inside is cytoplasm, the jelly-like fluid where organelles sit and chemical reactions happen. Floating in that cytoplasm is the nucleus, the control center holding DNA. Mitochondria release usable energy from sugar. Ribosomes build proteins. The endoplasmic reticulum and Golgi body package and ship those proteins. Both cell types also have vacuoles — storage sacs — though their size is very different, which matters later.
Here is the part students most often miss: because these structures are shared, they can never be used as evidence for one type over the other. If a description says "this cell has a nucleus and many mitochondria," you still know nothing about whether it is a plant or an animal. That sentence is true of both. A surprising number of wrong answers come from students grabbing the first organelle they recognize and treating it as a clue.
Think of it like identifying a vehicle. Wheels, seats, and a steering wheel appear on cars and trucks alike, so spotting a steering wheel does not tell you which one you are looking at. You need a feature that only one of them has. In cells, that means you need to look for the plant-only parts.
One more shared idea: mitochondria are in plant cells too. Plants make sugar, and then they still have to break that sugar down for energy, just like you do.
The Three Parts Only Plants Have
Three structures separate plant cells from animal cells, and all three are worth knowing by name and by job.
The cell wall is a rigid layer made mostly of cellulose that sits outside the cell membrane. It does not replace the membrane — a plant cell has both. The wall gives the cell a fixed, boxy shape and supports the plant against gravity. This is why a stem can stand up without a skeleton, and why plant cells under a microscope look like a stack of rectangles with visible straight borders between them.
Chloroplasts are green organelles containing chlorophyll, the pigment that captures light energy. Inside chloroplasts, photosynthesis converts light energy, carbon dioxide, and water into sugar. Animals cannot do this, which is why animals must eat. Chloroplasts are why leaf cells are green.
The large central vacuole is a single huge fluid-filled sac that can take up most of the space inside a mature plant cell, pushing the other organelles toward the edges. It stores water and dissolved substances, and the pressure of the water inside pushes outward on the cell wall to keep the cell firm. When a plant does not get enough water, those vacuoles shrink, pressure drops, and the plant wilts. Animal cells have vacuoles too, but they are small and scattered, not one dominant compartment.
The cell wall is a rigid layer made mostly of cellulose that sits outside the cell membrane. It does not replace the membrane — a plant cell has both. The wall gives the cell a fixed, boxy shape and supports the plant against gravity. This is why a stem can stand up without a skeleton, and why plant cells under a microscope look like a stack of rectangles with visible straight borders between them.
Chloroplasts are green organelles containing chlorophyll, the pigment that captures light energy. Inside chloroplasts, photosynthesis converts light energy, carbon dioxide, and water into sugar. Animals cannot do this, which is why animals must eat. Chloroplasts are why leaf cells are green.
The large central vacuole is a single huge fluid-filled sac that can take up most of the space inside a mature plant cell, pushing the other organelles toward the edges. It stores water and dissolved substances, and the pressure of the water inside pushes outward on the cell wall to keep the cell firm. When a plant does not get enough water, those vacuoles shrink, pressure drops, and the plant wilts. Animal cells have vacuoles too, but they are small and scattered, not one dominant compartment.
| Structure | Plant cell | Animal cell |
|---|---|---|
| Cell membrane | Yes | Yes |
| Nucleus | Yes | Yes |
| Mitochondria | Yes | Yes |
| Ribosomes | Yes | Yes |
| Cell wall | Yes | No |
| Chloroplasts | Yes | No |
| Large central vacuole | Yes | Small vacuoles only |
| Usual shape | Boxy, fixed | Round or irregular |
Using Plant-Only Parts as Evidence
The skill this lesson is really building is reasoning from evidence, not memorizing a list. When you are handed a description, a drawing, or a microscope image, work through it in a fixed order.
First, scan for the three plant-only structures: cell wall, chloroplasts, large central vacuole. If even one is clearly present, the cell is a plant cell, and that structure is your evidence. Second, if none of the three appears, check whether the description is complete enough to rule them out. A round cell with no wall and no chloroplasts, sitting in a description that lists many organelles, is an animal cell. Third, state your evidence in a full sentence: "This is a plant cell because it has chloroplasts, and only plant cells carry out photosynthesis."
A weak answer says "plant, because it looks like one." A complete answer names the structure and says what that structure does. Your teacher is looking for the link between the part and its job.
Be careful with shape alone. Shape is a hint, not proof, because a cell can be squashed on a slide or drawn sloppily. The straight edges of plant cells come from the cell wall, so if you use shape as your reason, connect it back to the wall: "the straight, rigid edges suggest a cell wall."
Also watch the absence trap. Saying "it has no chloroplasts, so it is an animal cell" works only when you can actually see the whole cell. Root cells and cells deep inside a potato are plant cells with very few or no chloroplasts, because they never get light. Those cells still have a cell wall and a central vacuole, so the wall is usually the safest single piece of evidence.
First, scan for the three plant-only structures: cell wall, chloroplasts, large central vacuole. If even one is clearly present, the cell is a plant cell, and that structure is your evidence. Second, if none of the three appears, check whether the description is complete enough to rule them out. A round cell with no wall and no chloroplasts, sitting in a description that lists many organelles, is an animal cell. Third, state your evidence in a full sentence: "This is a plant cell because it has chloroplasts, and only plant cells carry out photosynthesis."
A weak answer says "plant, because it looks like one." A complete answer names the structure and says what that structure does. Your teacher is looking for the link between the part and its job.
Be careful with shape alone. Shape is a hint, not proof, because a cell can be squashed on a slide or drawn sloppily. The straight edges of plant cells come from the cell wall, so if you use shape as your reason, connect it back to the wall: "the straight, rigid edges suggest a cell wall."
Also watch the absence trap. Saying "it has no chloroplasts, so it is an animal cell" works only when you can actually see the whole cell. Root cells and cells deep inside a potato are plant cells with very few or no chloroplasts, because they never get light. Those cells still have a cell wall and a central vacuole, so the wall is usually the safest single piece of evidence.
Misconceptions Worth Clearing Up
"Plant cells don't have mitochondria because they have chloroplasts." They have both. Chloroplasts capture light energy and store it in sugar; mitochondria release that stored energy so the cell can use it. A plant cell that only had chloroplasts would make food it could never spend.
"Plant cells don't need a cell membrane because they have a wall." The wall is a stiff outer support with pores that let many substances through. The membrane, just inside it, is what actually selects what enters and leaves. Remove the membrane and the cell loses control of its contents.
"Anything with a cell wall is a plant." Bacteria and fungi have cell walls too, made of different materials, and neither has chloroplasts. In this unit you are comparing plant cells to animal cells, so cell wall is reliable evidence — but the reason a wall is not the whole story in biology is that walls appear in several groups.
"Animal cells have no vacuoles." They have small ones used for temporary storage and transport. The plant-only feature is the single large central vacuole, not vacuoles in general. Losing that word "central" is a common source of wrong answers.
"Green means plant." Green is caused by chlorophyll inside chloroplasts, so green cells are plant cells — but plenty of plant cells are not green, including root cells, stem interior cells, and the cells of a white potato.
Finally, remember that a description listing only shared parts is not enough information to decide. If a question gives you a nucleus, cytoplasm, and a membrane and nothing else, the honest answer is that it could be either, and you should say what additional structure you would look for.
"Plant cells don't need a cell membrane because they have a wall." The wall is a stiff outer support with pores that let many substances through. The membrane, just inside it, is what actually selects what enters and leaves. Remove the membrane and the cell loses control of its contents.
"Anything with a cell wall is a plant." Bacteria and fungi have cell walls too, made of different materials, and neither has chloroplasts. In this unit you are comparing plant cells to animal cells, so cell wall is reliable evidence — but the reason a wall is not the whole story in biology is that walls appear in several groups.
"Animal cells have no vacuoles." They have small ones used for temporary storage and transport. The plant-only feature is the single large central vacuole, not vacuoles in general. Losing that word "central" is a common source of wrong answers.
"Green means plant." Green is caused by chlorophyll inside chloroplasts, so green cells are plant cells — but plenty of plant cells are not green, including root cells, stem interior cells, and the cells of a white potato.
Finally, remember that a description listing only shared parts is not enough information to decide. If a question gives you a nucleus, cytoplasm, and a membrane and nothing else, the honest answer is that it could be either, and you should say what additional structure you would look for.
Key terms
- Cell wall.
- A rigid layer of cellulose outside the cell membrane in plant cells. It gives the cell a fixed boxy shape and supports the plant. Animal cells do not have one.
- Chloroplast.
- A green organelle found only in plant cells. It contains chlorophyll and carries out photosynthesis, using light energy to make sugar from carbon dioxide and water.
- Large central vacuole.
- A single big fluid-filled sac that fills most of a mature plant cell. It stores water and creates internal pressure that keeps the cell and the plant firm.
- Cell membrane.
- The thin flexible boundary around every cell, plant or animal, that controls which substances enter and leave.
- Mitochondrion.
- The organelle that releases usable energy from sugar. Found in both plant and animal cells, so it is never evidence for one or the other.
- Eukaryotic cell.
- A cell whose DNA is enclosed in a nucleus. Both plant cells and animal cells are eukaryotic, which is why they share so many organelles.
- Cytoplasm.
- The jelly-like fluid filling the inside of a cell, where organelles are suspended and most chemical reactions occur.
- Chlorophyll.
- The green pigment inside chloroplasts that absorbs light energy for photosynthesis. It is what makes leaves look green.
Worked example
A student looks at an unlabeled slide and writes this description: "The cells form a neat grid with straight edges. Each cell has a nucleus pushed to one side, cytoplasm, mitochondria, and one enormous clear sac taking up the middle. No green color is visible anywhere." Identify the cell type and defend your answer with evidence. Explain the missing green.
Step 1 — List the shared parts and set them aside. The description mentions a nucleus, cytoplasm, and mitochondria. All three are in plant cells and animal cells, so none of them helps identify the cell. They cannot be your evidence.
Step 2 — Scan for the three plant-only structures. Cell wall: the cells form a neat grid with straight edges, and that rigid boxy shape comes from a cell wall. Large central vacuole: "one enormous clear sac taking up the middle" is exactly that structure, and it also explains why the nucleus is pushed to one side. Chloroplasts: not mentioned, and no green is visible.
Step 3 — Weigh the evidence. Two plant-only structures are present. One is absent. Presence beats absence here, because a plant cell can lack chloroplasts but an animal cell can never have a cell wall or a large central vacuole.
Step 4 — State the conclusion with evidence attached. This is a plant cell. The evidence is the large central vacuole squeezing the nucleus to the edge and the straight rigid borders showing a cell wall, and neither structure exists in animal cells.
Step 5 — Explain the missing green. Chloroplasts only develop and fill with chlorophyll in cells that receive light. This slide is most likely from a root, an onion bulb, or the inside of a stem — plant tissue that grows in the dark. No chlorophyll means no green, but the wall and the central vacuole still identify it as plant tissue.
Step 2 — Scan for the three plant-only structures. Cell wall: the cells form a neat grid with straight edges, and that rigid boxy shape comes from a cell wall. Large central vacuole: "one enormous clear sac taking up the middle" is exactly that structure, and it also explains why the nucleus is pushed to one side. Chloroplasts: not mentioned, and no green is visible.
Step 3 — Weigh the evidence. Two plant-only structures are present. One is absent. Presence beats absence here, because a plant cell can lack chloroplasts but an animal cell can never have a cell wall or a large central vacuole.
Step 4 — State the conclusion with evidence attached. This is a plant cell. The evidence is the large central vacuole squeezing the nucleus to the edge and the straight rigid borders showing a cell wall, and neither structure exists in animal cells.
Step 5 — Explain the missing green. Chloroplasts only develop and fill with chlorophyll in cells that receive light. This slide is most likely from a root, an onion bulb, or the inside of a stem — plant tissue that grows in the dark. No chlorophyll means no green, but the wall and the central vacuole still identify it as plant tissue.
Practice questions
A cell is described as having a cell membrane, cytoplasm, a nucleus, ribosomes, and many mitochondria. Which conclusion is best supported by this description?
- It must be an animal cell, because it has mitochondria.
- It must be a plant cell, because it has a nucleus.
- There is not enough information, because every part listed is found in both plant and animal cells.
- It must be an animal cell, because no cell wall is mentioned.
Answer: There is not enough information, because every part listed is found in both plant and animal cells.
Membrane, cytoplasm, nucleus, ribosomes, and mitochondria are shared equipment. Shared parts can never separate the two cell types. The fourth option is tempting, but the description simply does not mention a wall one way or the other — not mentioning something is different from observing that it is absent. To decide, you would need to look for a cell wall, chloroplasts, or a large central vacuole.
A leaf cell and a muscle cell both contain mitochondria. Explain why the leaf cell needs mitochondria even though it also has chloroplasts.
Answer: Chloroplasts capture light energy and store it in sugar, but the cell cannot use sugar directly. Mitochondria break that sugar down and release the energy in a form the cell can use for its activities, so a plant cell needs both organelles.
Students often treat chloroplasts as a replacement for mitochondria, as if making food and using food were the same job. They are two different steps. Chloroplasts are the factory that stores energy in sugar; mitochondria are the engine that spends it. Plant cells also need energy at night and in parts of the plant that never see light, such as roots, where mitochondria are doing all the energy work.
Two students argue about a round cell on a slide. Ana says it is an animal cell because it is round. Ben says shape is not good enough evidence. Who is reasoning better, and what should they look for?
Answer: Ben is reasoning better. Shape is only a hint, since cells can be squashed or drawn poorly. They should look for the three plant-only structures — a cell wall, chloroplasts, or a large central vacuole. If none of the three is present in a clear view of the whole cell, it is an animal cell, and the absent cell wall explains the round shape.
This question is about the difference between an observation and evidence. Roundness is a real observation, but it becomes evidence only when it is connected to a cause: animal cells are round because they have no rigid cell wall. Naming the structure behind the observation turns a guess into a defended claim, which is what a complete answer looks like.
FAQ
- Do plant cells have a cell membrane if they already have a cell wall?
- Yes, they have both. The cell wall is the stiff outer layer that gives shape and support, and it lets most substances pass through its pores. Just inside it is the cell membrane, which is the layer that actually controls what enters and leaves the cell. The wall supports; the membrane selects.
- What are the three main differences between plant and animal cells?
- Plant cells have a cell wall, chloroplasts, and one large central vacuole. Animal cells have none of these — no wall, no chloroplasts, and only small scattered vacuoles instead of a big central one. Everything else, including the nucleus, cytoplasm, membrane, ribosomes, and mitochondria, is found in both.
- If a plant cell has no chloroplasts, is it still a plant cell?
- Yes. Chloroplasts develop in cells that receive light, so root cells, cells deep inside stems, and the cells of a white potato have few or none. Those cells still have a cell wall and a large central vacuole, which is why the cell wall is usually the most reliable single piece of evidence for identifying plant tissue.
- Why do plant cells look like rectangles and animal cells look like blobs?
- The rigid cellulose cell wall holds a plant cell in a fixed boxy shape, and water pressure from the central vacuole pushes outward against it. Animal cells have only a flexible membrane on the outside, so they take on rounded or irregular shapes and can change shape as they move or get pressed against neighbors.
Learn this with a teacher, not a page
The Crimsora tutor teaches Plant Cells & Animal Cells live — explaining on a whiteboard, asking you questions, and adapting to where you get stuck.