Discovery of the Cell and Cell Theory

Contributor: Elephango Editors. Lesson ID: 10715

Are you "Hooked" on science? Are you rootin' for Newton? A wacky historic video, online quiz, the R.A.F.T. method, and your little gray cells help you understand these basic blocks of living things!


Life Science

learning style
personality style
Grade Level
Middle School (6-8)
Lesson Type
Quick Query

Lesson Plan - Get It!

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It's BIG and YELLOW, and it's MOVING!

  • Should you be afraid of this living creature?

Not unless you have a fear of pine trees blowing in the wind! Organisms come in many sizes, shapes, and colors.

  • How else do creatures differ? 
  • How are they the same?

Here's a clue: Can you identify the objects in this picture?

Bazzania tricrenata

Image by HermannSchachner, via Wikimedia Commons, was made available under the CC0 1.0 Public Domain Dedication.

  • Were you able to determine what is in the picture?

They're cells; plant cells, to be specific.

plant cells

  • What kind of cells are in the picture below?

onion cells

These are also plant cells! They are the plant cells found in the skin of a red onion.

red onion

Every living organism is made up of cells, but before we get to the small picture, let's make our way down from the big picture to learn about how we know about cells today!

  • What is a cell?

human body

A cell is a living thing, but it also a building block. You are made of cells. There is no part of you that is not a cell. You are made of eye cells and stomach cells and heart cells and skin cells. Each type of cell is different, depending on its function (job).

  • How were cells discovered?

Scientist Robert Hooke used the compound microscope to look at a tiny piece of cork.

compound microscope from 1664

He saw many little boxes separated by walls. He named these boxes cells because they reminded him of little jail cells.

jail cells

Today, we use the name cells to refer to microscopic building blocks of all living things.

  • What is the cell theory?

The cell theory is a list of facts we know about cells. There are three parts to the cell theory:

Part 1: Some organisms are made of only one cell while others are made of many cells, but all living things are made of cells.

Part 2: The only way to get a new cell, is to produce it from a cell that already exists. You can just make a cell by assembling the parts.

Part 3: Cells are the basic unit of life. All living things (animals, plants, bacteria, etc.) are made of cells.

  • Can you guess which type of cell is which? [Insert image drag and drop]

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Now, it's time to test your knowledge in the Got it! section. Don't 'cell' yourself short!

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