HSCI 100 Lecture Notes - Lecture 4: Fluid Mosaic Model, Cell Membrane, Lipid Bilayer
20 Apr 2016
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Document Summary
A cell is the basic unit of life. Size: small-> in order to function, they need to move in the membrane. In crease of volume changes the surface area of the membrane. Thought to be the first cells to evolve. What does the cell membrane do: receiving information. Contains carbohydrates on proteins and lipids on the outer layer. The membrane allows some things in while keeping other substances out. Diffusion: is the random movement of molecules from a higher to lower concentration (requires no energy) Osmosis: diffusion of water through a deferentially permeable membrane. Hypertonic: solutions have more solute than the inside of the cell. Cell shriveling (high salt concentration in surrounding fluid, water travels out of cell to dilute) Hypotonic: have less solute than the inside of the cell. Isotonic: have equal amounts of solute inside and outside the cell and thus does not affect the cell.
