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Cell Theory |
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Cell Theory |
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History
- Van Leeuwenhoek- invented the microscope
- Hooke- used the microscope to examine cork and other
things. He saw rows and rows of empty compartments and called them cells.
- Schleiden- botanist (studies plants)
- Schwann- zoologist (studies animals)
Cell Theory
1. cells are the basic units of structure of all living
things
2. cells are the basic units of function of all living things
3. all cells arise from pre-existing cells (no- might not be
true, because were did the first cell come from)
(Virchow- first to observe cell
division- added the 3 part of the cell theory)
Exceptions to the Cell Theory
1. Viruses- a package of genetic material (DNA or RNA) enclosed in a protein envelope. Ex: a parasite- lives in another person or organism (host). It is alive because it can produce (can�t do it alone).
2. Slime Mold- can be and shape, like Jell-O, brownish. You would see cells under a microscope only. Sometime in its life cycle there is no cell division and you just see nuclei floating around in the membrane.
Organelles- sub units in cells
1. mitochondria-
�power house of cell�- energy released
2. ribosome- site of protein synthesis
3. endoplasmic reticulum- series of canals used for intracellular transport
4. nucleolus- functions in protein synthesis
5. nucleus- control center of call (controls all activities)
6. cell wall- (only in plant cells) outer boundary, for protection, maintains
the shape of the cell
7. cell membrane- (only in animal cells) outer boundary, regulates the movement
of substances into and out of the cell (semi-permeable)
8. lysosomes- breaks down some cellular wastes
9. vacuoles- stores various substances
10. cytoplasm- gel like substance (main ingredient is water), site of most
chemical reactions in the cell
11. chromosomes- function in hereditary, collection of genes
12. genes- individual units or hereditary
13. chloroplasts- (only in plant) contains chlorophyll, used in photosynthesis
14. gulgi bodies- package and transports certain substances
15. centriole/ cetrosome- (only in animals), function in cell division
16. nuclear membrane- outer boundary of the nucleus, protects it by regulating
the movement of substances into and out of the nucleus
Levels of Organization
1. cells
2. tissues- a group of cells specialized for a specific function
3. organs- a group of tissues specialized for a specific purpose
4. organ system- a group specialized for a specific function
Life Functions
1. respiration
2. locomotion-movement
3. excretion
4. nutrition
a) ingestion- to eat
b) digestion- breaking down food
c) absorption- moving
d) egestion/elimination- getting rid of wastes
5. regulation- 5 senses
6. transport
7. reproduction
8. growth
9. synthesis- to produce (molecules)
Homeostasis- the tendency of
an organism to maintain a constant internal environment
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