Introduction to Cell Biology

1. Introduction to Cell Biology

2. The Discovery of the Cell • While we watch the YouTube clip, take notes about the scientists involved in the discovery of cells. Note the dates, people involved, and their particular discoveries. • http://www.youtube.com/watch?v=dscY_2QQbKU&feature=related

3. The Discovery of the Cell—Timeline • On a left-side sheet of notebook paper, using your notes from the video, along with your textbook, create a timeline leading up to the cell theory. Illustrate each discovery (use color). Leave enough space between events to add details later.

4. The Discovery of the Cell • Hooke-English scientist who was the first to see a dead cell while viewing cork under a microscope. • Coined the term “cell”. • Leeuwenhoek- Dutch scientist who was first to see living cells in a drop of pond water. • Considered the “Father of Microscopy”.

5. The Discovery of the Cell • Schleiden- German botanist who stated all plants are composed of cells. • Schwann-German zoologist who stated all animals are composed of cells. • Virchow-German physician who saw bacterial cells dividing under microscope.

6. The Cell Theory—The cell as the basic unit of life • All living organisms are composed of one or more cells • Cells are the basic units of structure and function in an organism • Cells come only from the reproduction of existing cells Which of the 7 characteristics of life do the parts of the Cell Theory match up with?

7. Cell Diversity • Size • Most plant and animal cells are about 10-50 micrometers (µm) in diameter. Most bacterial cells are about 1-10 µm in diameter. • Cells are limited by their surface area to volume ratio. • As a cell grows, its volume increases much faster than its surface area. • http://learn.genetics.utah.edu/content/begin/cells/scale/ • Why is surface area so important to determining the health and survival of a cell?

8. Cell Diversity • Surface Area to Volume Ratio • Everything that the cell needs or has to get rid of has to go through the cell membrane, the amount of which relates to the surface area. • The amount of food needed or waste produced depends on the volume. • As a cell gets bigger there will come a time when its surface area is insufficient to meet the demands of the cell's volume and the cell stops growing.

9. Cell Diversity • Shape • Cells come in a variety of shapes. • The diversity of form (structure) reflects a diversity of function. • How do the shapes of nerve, blood, and skin cells suit their function?

10. Common Cell Structures • Plasma membrane • Covers cell surface and acts as a boundary between inner contents of a cell and its environment • Cytoplasm • Region of the cell inside the membrane • Includes fluid, cytoskeleton, and all organelles (except the nucleus) • Control center • Region containing DNA which regulates cell construction and other processes

11. Two Basic Cell Types • Prokaryotes • Cells without a nucleus or membrane bound organelles (MBOs) • Example: E. coli

12. Two Basic Cell Types • Eukaryotes • Cells with a nucleus and membrane bound organelles (MBOs) • Examples: Human cheek cells, plant cells

13. Cellular Organization • Colonies • Colonial organisms are collections of genetically identical cells that live together in a group. • Not truly multicellular because few activities are coordinated.

14. Cellular Organization • True Multicellularity • Cells of multicellular organisms are organized further into tissues, organs, and organ systems, which have their own specific purposes.