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Cell Notes

 

            
             What observations were used to develop the cell theory?.
            
             • German botanist, Schleiden - cells compose not only the stems and roots but every part of a plant.
            
             • German zoologist, Schwann - made same claim about animals.
            
             • German physician, Virchow - observed that cells come only from other cells.
             2. What function do organelles serve?.
            
             • Eukaryotic cells possess organelles.
            
             • Their small, specific membrane-bound internal compartments, that carry out specific functions in the cell.
             3. Explain why cells must be small.
            
             • 2 limits that affect how efficiently cells work and that govern cell size.
            
             • One is related to the exchange between the inside and the outside of the cell.
             - All info and materials entering or leaving the cell must pass through .
             "doors" in the cell membrane. The efficiency of this exchange depends on the ratio of the cell's surface area to its volume.
             - Large cells have far less membrane surface per unit of volume with which .
             to supply materials to the cells interior and to rid it of wastes.
            
             • The other reason is that as the cell size increases, it takes longer for information and materials to reach their destination.
            
             • SMALL CELLS ARE MORE EFFICIENT THAN LARGER CELLS.
             4. Explain prokaryotes and eukaryotes.
            
             • Prokaryotic cells are single-celled organisms that lack internal membrane-bound compartments.
            
             • Eukaryotic cells are complex cells that have a nucleus and organelles,.
            
             • Bacteria is the only prokaryote, all other living cells are eukaryotes.
            
             • Many biologists think that eukaryotes evolved from prokaryotes.
             5. The three parts of the cell theory.
            
             • All living things are composed of one or more cells.
            
             • In organisms, cells are the basic units of structure and function.


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