The Cell Theory states that all living things are made of cells and they are produced from other living cells. At this time, there is no accurate way to determine the number of cells in the body. Estimates range from 10 to 100 trillion in an adult. As you may or may not know, cells are very small with the larger cell being about the diameter of a human hair.
Living things are made of two kinds of cells, prokaryotic (no nucleus) and eukaryotic (having a nucleus.) Humans are made of eukaryotic cells.
The basic structure of a cell includes:
A. Cell Membrane- Encloses the cell and allows materials to pass into and out of the cell.
B. Cytoplasm: A jellylike substance inside that cell that is mostly water with the other parts of the cell in this substance.
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1. Nucleus- The brain of the cell, contains the genetic material DNA arranged in chromosomes.
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2. Mitochondria - Energy production for the cell.
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3. Lysomes - Destroys harmful substances or worn-out cell parts.
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4. Endoplasmic reticulum - Makes protein.
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5. Golgi bodies - Stores the proteins.
If you are a teacher in the New Haven, and perhaps in other areas, you have access to the videos on United Streaming.com. There are several videos on the cell and at this time I would suggest the viewing of either:
The Living Cell - 20 Minutes - Grades 4-8
Structure and Function of Plant and Animals Cells
Or
Assignment Discovery: Cells - 24:40 Minutes - Grades 6-8
Microscopic Viewing of Cells
For this unit, viewing and discussing the parts and functions of the cell is adequate but, because we are interested in the growth of cancerous cells, we will look at the cell a little differently.
Under normal conditions, the cells divide producing new cells exactly alike. However, sometime cells multiply unchecked and damage surrounding tissues. This is what we define as cancer. This would be a good time to view the video:
Life Science: Cells - 20 Minutes - Grades 6-8
Segment shows growth or cancerous cells.