Look at the Plant Cells

Lesson 3: Onion Dissection & “Look at the Plant Cells”

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The goal of this lesson is to look at the plant cells. An onion is very easy to get and it is also easy to collect cells from. Therefore, let’s look at onion cells under a microscope! Below are steps showing how to do it.

Onion skin slide preparation

Preparing onion cells slide for a microscope

  1. Peel the brown skin away from the outside of the onion. Take one layer of the onion flesh and carefully cut out a piece.

    peel onion skin away

  2. On the inside of this piece is a thin sheet of the membrane. Use tweezers or dissection needle to peel the membrane away.

    onion membrane

  3. Place the specimen in a small dish of stain (Eosin Y) and leave it for about 3 minutes.

    eosin Y stain onion skin

  4. Use tweezers to transfer the specimen out of the dish. Rinse it well in a dish containing clean water.

    wash staining

  5. Make a wet mount and look at your stained section under the microscope. See if you can find onion cell under a microscope.

    make a wet mount slide

What will you see?

onion cell under the microscope eosin Y

[In this figure] Microscopic view of onion skin.
Without stains, you can only see the cell walls of onion cells. With the staining of Eosin Y, now you can see a nucleus inside an onion cell.


What do your onion cells look like under the microscope? Please share it with us below!

Anatomy of the plant cell

Structurally, plant and animal cells are very similar because they are both eukaryotic cells. However, plant cells have three additional structures including chloroplasts, the cell wall, and vacuoles.

Chloroplasts

Chloroplasts are the center of photosynthesis, where the green pigment chlorophyll captures energy from sunlight and stores it in the energy storage molecules, like sugar.

Cell wall

A cell wall is a structural layer surrounding plant cells (also bacteria and fungi), just outside the cell membrane. It is tough and rigid providing the cell with both structural support and protection.

Vacuoles

Vacuoles are like storage rooms for the cells.

Related posts

Lesson 4: How to Use a Microtome & “Amazing Cross-section of a Stem”

Lesson 2: Mount a Slide & “Look at Your Cheek Cells“

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