Cells

Cell Theory

Foundations of Modern Biology: Understanding the Building Blocks of Life

Discovery of the basic unit of life

Do you know what all living things are made of? For most of human

history, we did not know the answer to this question. It was not until 1665 that people realized that all living things are made up of tiny cells, and that cells perform all of the functions that keep organisms alive. Below is a picture of one such cell that constitutes most of your blood. What do you know about cells? How big do you think they are? How many do you think are in the human body?

These are human red blood cells shown under a powerful microscope. What other types of cells are

found in humans and how do they differ from red blood cells?

Red Blood Cells

The discovery of cells was made when Robert Hooke looked through his microscope at the bark of a cork tree. He saw the spaces created by the cells of the cork tree’s bark and began to form a theory. Without this amazing discovery, many scientific breakthroughs would not have been possible. For example, we would not be able to treat most diseases such as cancer effectively. People would not understand heredity and genetics. The discovery of cells has been the basis for much of what we know about life science today.

By building upon the work of Robert Hooke, German scientists Theodor Schwann, Matthias Schleiden, and Rudolf Virchow developed the cell theory. This theory is one of the fundamental principles of biology. But what exactly is the cell theory and why is it important to understand the structure and function of organisms? In this concept, you will learn about the importance of cells and the cell theory.

Open Ended

As time progressed and technology improved, microscopes were able to give clearer images of extremely tiny objects. How did this development advance the cell theory?

Open Ended

An Elephant and a Mouse both are made up of cells. Compare the sizes of the cells found in an elephant to those found in a mouse. Why is an elephant so much larger than a mouse? Use scientific reasoning to support your claims.

The Introduction to Cell Structure

Draw

Draw a diagram of a cell that shows:

- Cell membrane

- Cytoplasm

- Nucleus.

Label each part.

You may ask AI to find information.

Hotspot

Which one is a plant cell?

Open Ended

Find information about Prokaryotic cells and Eukaryotic cells. Write down what you get!

Categorize

Options (7)

cell wall contain peptidoglican

have a nucleus

have membrane-bound organelles

contain cytoplasm

contain DNS

are produced by division of another cell

Virus

Living cells are classed as either prokaryotic or eukaryotic. Identify the following as characteristics of prokaryotic cells, eukaryotic cells, or both. Drag each characteristic into the correct column.

You may use AI to find information.

Prokaryotic cells

Eukariptic cells

Both

Not a cell

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Animal cells

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• ...

• ...

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Plant cells

Plant and Animal Cell