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Warm-Up Cell Theory

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Words to Know

Write the letter of the definition next to the matching word as you work through the lesson. You may use the glossary to help you.

microscopic A. the process of making something look larger by using a microscope

lens B. so small that it can only be seen with a microscope

magnification C. an instrument used to see things that are too small to see with the naked eye

microscope D. a curved piece of glass or other transparent material that is used to focus light rays

WK2

Lesson Goals

Describe the cell theory.

Identify the three components of the cell

theory.

Analyze the contributions of different

of the cell theory.

scientists to the

Lesson Question

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Warm-Up Cell Theory

Cells

• Cells make up all living things.

• organisms

• Multicellular organisms

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Instruction Cell Theory

2Slide

Magnification

• The process of making something look larger by using a is called magnification.

• Magnification is achieved through the use of at least one .

• A lens is a curved piece of glass or other transparent material that is used to focus light rays.

Microscopes

• Most cells are microscopic, so they need to be observed using a microscope.

• A microscope is used to see things that are too to see with the naked eye.

The First “Microscope”

• In 1590, Hans and Zacharias Janssen created the first microscope.

• The microscope was made of three tubes.

• The two end tubes had lenses that worked together to make things look larger.

Robert Hooke

In , Robert Hooke was the first to observe “cells” using a microscope.

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Cell Theory

4Slide

The Birth of the Word “Cell”

• Robert Hooke was the first to use the word “ .”

Instruction

Anton van Leeuwenhoek

In , Anton van Leeuwenhoek observed small organisms, which he

called “ ,” by using his version of a .

Matthias Schleiden

In 1838, Matthias Schleiden concluded that are made of cells.

Theodor Schwann

• In 1839, Theodor Schwann believed that:

• are also made of cells.

• the cell is responsible for making up the organism and making the

organism .

Rudolf Virchow

In 1855, Rudolf Virchow confirmed that must come from other pre-existing cells.

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Instruction Cell Theory

9Slide

The Cell Theory

All living things are made of cells.

•

• Protozoan

• Fungi and plants

• Animals

• Cells are the basic unit of and of all living things.

• Cells are the part of a living thing that is alive and keeps the

organism alive.

• All cells come from other cells.

• Cells are damaged or , so they need replacing.

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Summary Cell Theory

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2Slide

Review: Development of the Cell Theory

Matthias Schleidenconcluded that

1855Virchow confirmedthat cells comefrom other cells.

1676Anton vanLeeuwenhoekobserved“animalcules” byusing a microscopewith a polishedlens.

1600 1650 1750 1900

1650Robert Hooke wasthe first to use theword “cell.”

1700 1800 1850are made of cells.

Theodor Schwannbelieved thatanimals are madeof cells and thatcells make uporganisms andmake organismswork.

Hans andZachariasJanssencreated the first

.

Answer

Lesson Question What is the cell theory?

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Summary Cell Theory

Review: Key Concepts

• The cell theory

• All things are made of cells.

• The cell is the basic structure and function of living things.

• All cells come from other cells.

2Slide

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