1. Cell Structure and Function Biology 103

2. I. The Development of the Cell Theory
1. Robert Hooke (1665) - observed cork
2. Anton van Leeuwenhoek (1673) saw microscopic life - blood cells, single cell organisms
3. Mathias Schleiden, Botanist & Theodor Schwann, Zoologist, (1839) published their cell theory …"The cells are organisms, and animals as well as plants are aggregates of these organisms arranged in accordance with definite laws."
4. Rudolph Virchow (1858) "omnis cellula e cellula" --all cells come from cells

3. II. Cell History
1.The first cells were prokaryotic (= “before nucleus”) cells that appeared on the earth about 3.5 to 4.0 BYA.
2. More complex eukaryotic (=“true nucleus”) cells appeared about 1.5 BYA.

4. III. Eukaryotic Cell Structure
1. Cell membrane: surrounds cell, controls the movement of substances in and out, structure:
phospholipid bilayer with protein carrier proteins and receptors embedded (a fluid mosaic)
2. Nucleus: information storage: DNA synthesis, surrounded by nuclear envelope. May contain a nucleolus - indicates active protein synthesis
3. The Cytoplasm is everything in the cell except the nucleus,
4. Mitochondrion (plural = Mitochondria)
converts carbohydrates into ATP (high energy molecules) Maternal origin, two compartments

5. The cell membrane surrounds the cell
The fluid mosaic model of the cell membrane
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7. DNA is stored as chromatin
When not dividing, the nucleus is filled with threads of chromatin
Chromosomes condense before cellular division
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8. Nuclear Envelop surrounds the chromatin
The nuclear envelop is a double-walled membrane studded with nuclear pores
Most DNA is inside the nucleus
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9. Large Molecules leave the nucleus through nuclear pores
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The information in the nuclear DNA is copied to mRNA (messenger RNA). mRNA leaves the nucleus via nuclear pores
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Once in the cytoplasm mRNA is used to direct protein synthesis in the rough endoplasmic reticulum
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12. Mitpchondria make most of the ATP in the body

13. 5. Special Mention: Chloroplasts chlorophyll and are the site of photosynthesis. Why are chloroplasts important?
6. Ribosomes: help make proteins during RNA translation, made of protein and RNA - give rough ER its appearance
7. Endoplasmic reticulum (two types):
smooth - lipid synthesis
rough - protein sorting processing

14. ER and membrane cycling
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16. 8. Golgi Apparatus: Packages and sorts proteins from rough ER for export from cell or to other cell compartments
9. Lysosomes and Peroxisomes: contain digestive enzymes
10. Cilia and Flagella: create movement
11. Centrioles: organize Cilia and Flagella
12.Cytoskeleton: supports cell: a),microtubules; b) microfilaments; and c) intermediate fibers
13. Plants have a cell wall, animal cells do not. Cell walls resist osmotic forces.

18. IV. Cell Junctions
1. Tight junctions
2. Gap junctions
3. Desmosomes

19. V. Transport functions
1. Diffusion
2. Facilitated Diffusion
3. Osmosis
4. Active Transport: requires ATP
5. Vesicular Transport: Endocytosis and Exocytosis

20. Diffusion equalizes solute concentrations
Molecules diffuse down their concentration gradient from areas of high concentration to areas of low concentration.
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Facilitated diffusion allows water soluble molecules to cross the membrane with transport proteins that use no energy
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22. Osmosis: movement of water
Hypotonic solutions
Cells swell
Hypertonic solutions
cells shrink
Isotonic solutions
cells neither shrink nor swell
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23. Active transport takes ATP
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Endocytosis (two types)
a. Pinocytosis (cell drinking)
b. Phagocytosis (cell eating)
Exocytosis
Removes products from the cell
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25. VI. Surface to Volume Ratio