Read plant and animal cell micrographs
Use visible evidence to identify cell structures and compare typical plant and animal cells without assuming every cell contains every organelle.
AS Level · Cambridge International Biology 9700, 2028–2030. Interpret only the structures supported by the provided image or description. Written practice is self-checked; it does not demonstrate practical microscopy competence.
Before you begin
- Recognise that organisms are made of cells and that a light microscope produces a magnified image.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which structure is outside the cell-surface membrane in a typical plant cell?
What you will learn
- Interpret drawings, photomicrographs and electron micrographs of typical plant and animal cells
- Compare typical plant and animal cell structures using shared and distinguishing features
Start with the cell boundary and overall context
Locate the cell surface membrane and, in plant cells, the cell wall outside it. Look for a nucleus and cytoplasm, then identify structures only when the image provides enough visible evidence. An electron micrograph can resolve finer detail than a light micrograph, but section angle and contrast affect what is visible.
A typical plant cell has a cellulose cell wall, chloroplasts in photosynthetic cells, and a large permanent vacuole bounded by a tonoplast. A typical animal cell lacks these plant features. Both typical plant and animal cells have a cell-surface membrane, nucleus, cytoplasm, mitochondria and other eukaryotic organelles.
Interpret evidence, not assumptions
Describe structures that can be seen and use the scale or magnification supplied with the image. A cell may not show every organelle in one section. For example, the plane of a thin section may miss a chloroplast or make a mitochondrion appear round rather than elongated.
“Typical” means a representative pattern, not a rule about every specialised cell. Mature mammalian red blood cells are a familiar exception to the generalisation that animal cells contain a nucleus and mitochondria. Do not identify a structure from its expected function alone when the image is unclear.
Pause and explain
Which feature distinguishes a typical plant cell from a typical animal cell?
Worked example
A micrograph shows a rigid outer boundary, a thinner boundary just inside it, a nucleus and several oval structures with internal folds. Interpret the evidence.
Show the worked solution
- Distinguish the wall from the membrane.
- Use the internal folds to identify mitochondria.
- Compare the observed features with a typical cell type.
Answer The rigid outer boundary is consistent with a cell wall and the thinner inner boundary with a cell-surface membrane. The nucleus and folded oval organelles are consistent with a eukaryotic cell containing mitochondria. A wall suggests a plant cell, but this description alone does not establish that chloroplasts are present.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A drawing shows a cell wall, cell-surface membrane, nucleus and large vacuole. State the best-supported cell type and one limitation.
Give me a hint
Use the distinguishing plant feature, then avoid overclaiming.
Compare my reasoning
- A cell wall and large vacuole support a plant-cell interpretation.
- A drawing may omit structures or show only one section.
The cell is consistent with a plant cell because a cell wall and large vacuole are shown. The drawing does not establish that all plant cells have the same visible features, and an omitted chloroplast may simply be outside the section or absent in that cell type.
Look for these in your work
- Plant evidence used
- Limitation stated
Give two structures usually shared by typical plant and animal cells and two that distinguish a typical plant cell.
Give me a hint
Separate shared eukaryotic structures from plant features.
Compare my reasoning
- Both have a cell-surface membrane and nucleus.
- A typical plant cell has a cell wall and large permanent vacuole.
Typical plant and animal cells both have a cell-surface membrane and a nucleus. A typical plant cell has a cellulose cell wall and a large permanent vacuole, which are not features of a typical animal cell.
Look for these in your work
- Two shared structures
- Two distinguishing structures
An electron micrograph shows a round profile with internal membrane folds but no visible cell wall. What can you infer, and what should remain uncertain?
Give me a hint
Use structure for a cautious identification.
Compare my reasoning
- The folds are consistent with a mitochondrion.
- The absence of a wall in this image does not alone prove an animal cell.
The profile is consistent with a mitochondrion because it contains internal membrane folds. The image alone does not prove the whole cell is an animal cell: the viewed section may omit the wall, and other evidence is needed.
Look for these in your work
- Evidence-based identification
- Inference limit explained
Common mistakes
- Calling the cell wall the cell membrane
- Assuming every plant cell contains chloroplasts
- Naming an organelle that the image does not resolve
What can you explain now?
Which structure is outside the cell-surface membrane in a typical plant cell?
Compare with the explanation
Cell wall
The wall lies outside the membrane.
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Make it stick
Which structures are shared by typical plant and animal cells, and how should a micrograph limit your claims?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.