All living things are made of one or more CELLS.

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The Cell Theory Cell Theory Video https://youtu.be/4OpBylwH9DU

Transcript of All living things are made of one or more CELLS.

Page 1: All living things are made of one or more CELLS.

The Cell Theory Cell Theory Video

https://youtu.be/4OpBylwH9DU

Page 2: All living things are made of one or more CELLS.

All living things are made of one or

more CELLS.

Page 3: All living things are made of one or more CELLS.

Some organisms consist of ONE cell

while others have MANY cells.

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Regardless of the number of cells, living things must carry on all the life PROCESSES.

This cell is in the process of cell REPRODUCTION.

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Since cells cannot be seen with the naked eye, the invention of the…..MICROSCOPE was very important to the discovery of cells.

It was not until the mid-1600’s that microscopes were used to examine the parts of living things.

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One of the first scientists to use a compound microscope was…..

ROBERT HOOKE who examined thin slices of CORK and other plant tissues.

He found that they contained BOXLIKE structures which he called CELLS.

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What Hooke saw, however, were the walls of….

…DEAD cells.

He never observed the cells of living things.

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Anton van Leeuwenhoek examined drops of….

POND water using a very powerful single-lens microscope.

Leeuwenhoek also observed human BLOOD cells and BACTERIA which are the smallest kinds of cells.

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It was not until the early 1800’s that the cellular nature of living things began to gain attention. 1824 – Henry

Dutrochet

Proposed that all living things were made from cells.

1831 – Robert Brown

Observed and named the NUCLEUS

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Schleiden and Schwann

1838 – Matthias Schleiden

Developed the theory that all plants contained cells.

1839 – Theodor Schwann

Proposed that all animals contained cells.

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Purkinje and Virchow

1839 – Johannes Purkinje

Used the term “protoplasm” to refer to the jelly-like material in a cell.

1855 – Rudolf Virchow

Stated that all living cells came from other cells.

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Schultze and Dujardin

1861 – Max Schultze

Defined “protoplasm” as the physical basis of life.

1861 – Felix Dujardin

Recognized the existence of one-celled organisms.

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By the end of the 1800’s scientists discovered many structures that lie WITHIN a cell. They were also able to describe the events of cell DIVISION in which one cell splits to form TWO cells.

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As a result of the work of these scientists, the main points of the CELL THEORY were stated.

The Cell Theory states that….

› All organisms are made of ONE or more CELLS

› All cells carry on LIFE ACTIVITIES

› New cells ARISE only from other LIVING cells by the process of CELL DIVISION.

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There are THREE (3) exceptions to the cell theory.

The first cell could not have come from a pre-existing cell.

Although viruses can carry on many life processes, they DO NOT contain cells

Mitochondria and chloroplasts contain their own DNA and can reproduce within a cell.