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Back to category: Sports Limited version - please login or register to view the entire paper. Cells Cell membrane A cell membrane is made of fats. What does it do ? • Holds cell content together. • Partially permeable • Controls chemicals entering and leaving the cell. • The proper name for a cell membrane is plasma membrane. Diffusion gaseous exchange. • All cells need to take in oxygen, and excrete carbon dioxide. • It is easy for these small molecules to fit through the tiny pores of the cell membrane. • This is called diffusion. • The overall movement of substances diffusing across the membrane is from of region of their high concentration to a region of their low concentration. • We say the movement is down the concentration gradient. Osmosis • osmosis is a special kind of diffusion for water only. • Needed as a solvent for chemical reactions. • Needed to transport dissolve chemicals onto and out of the cell and across t... Posted by: Helene Hannah Limited version - please login or register to view the entire paper. |
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