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Grade 11 · 🧬 Biology · Cell biology · BIO-G11-C1.1

See real plant cells without a microscope (onion skin)

Peel the thin inner skin of an onion and hold it to the light to see rows of real plant cells.

⏱ 15 min🟢 EasySample guide · pending teacher review
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Why this matters

Every cup of bunna comes from coffee plant cells, and injera ferments because yeast cells divide. When doctors at Black Lion Hospital diagnose disease, they look at cells under a microscope. Ethiopian medical and crop research all starts with understanding what's inside a single cell.

Watch the demo

Video by Microbehunter

The science

Prokaryotic vs eukaryotic cells

Prokaryotes (bacteria) have no membrane-bound nucleus. Eukaryotes (plants, animals, fungi) have a true nucleus and many membrane-bound organelles.

Key organelles

  • Nucleus: stores DNA, controls the cell.
  • Mitochondria: release energy (ATP).
  • Ribosomes: build proteins.
  • Chloroplasts (plants only): photosynthesis.

Plant vs animal cells

Plant cells also have a rigid cell wall made of cellulose and a large central vacuole. That's why plant cells look like neat bricks.

You'll need

  • 1 fresh onion
  • A knife to cut it (ask an adult to help)
  • A bright window or strong lamp
  • A magnifying glass, if you have one↳ A drop of water on clear plastic also magnifies a little
  • Iodine antiseptic (optional) to stain the cells

Safety first

  • Ask an adult to cut the onion.
  • If you use iodine, don't let it touch your eyes or mouth.

Step by step

0/4 done

What you should see

Tiny rectangular cells line up like bricks in a wall. With iodine, each cell shows a darker round dot inside.

Why it happens

The clear outlines are cell walls, made of cellulose — a feature of plant cells only. The darker dot is the nucleus, which holds the cell's DNA. Onion skin cells have no chloroplasts because they grow underground, away from light.

Didn't work? Try this

I just see a blurry sheet.

Your piece is too thick or folded. Peel a smaller, thinner piece and lay it completely flat.

I can't see any nucleus.

Stain it with a drop of diluted iodine and wait one minute.

Still stuck? Ask the lab assistant

Check your understanding

  • 1. Which structure is found in plant cells but NOT animal cells?

  • 2. Why don't onion skin cells look green?

Your lab notebook

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