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BIO 120 Chapter 7
Membrane Structure and Function
| Term | Definition |
|---|---|
| Tails- | made of fatty acids, hydrophobic |
| Heads- | hydrophilic |
| Membrane contains- | proteins and enzymes |
| Cooler temperature means- | membrane is less fluid |
| Warmer temperature means- | membrane is more fluid |
| Proteins function- | transport and receive information and signals |
| Saturated fatty tails mean- | less fluid, thicker |
| Unsaturated fatty tails mean- | more fluid, thinner |
| Effect of cholesterol- | reduces fluidity at moderate temperature, prevents solidification at low temperatures |
| Diffusion- | molecules cross membrane moving from high to low |
| Passive transport: | simple diffusion and facilitated diffusion |
| Simple diffusion- | moves from high to low, no energy needed, no protein helper |
| Facilitated diffusion- | moves from high to low, no energy needed, has a protein helper |
| Active transport- | moves from low to high, ATP required, protein helper, pumps protons into lysosome |
| Bulk transportation- | moves from low to high, needs energy, endocytic or exocytic vesicle helps with entrance or exit from cell |
| Hypertonic- | Concentration of solute is higher outside the cell |
| Hypotonic- | concentration of solute is higher inside the cell |
| Isotonic- | concentration of solute is the same on both sides |
| Q: what kinds of molecules can pass through membrane? | small, non-charges, non-polar molecules |
| Q: can water pass through membrane? | yes, water is small enough to pass through aquapain or membrane with a protein helper, plays a role in osmosis |
| Osmosis- | the passive movement of water from areas with low to high concentrations of solute |
| Carrier protein- | change shape, help facilitate diffusion across membrane |
| Channel protein- | maintains shape, helps facilitate diffusion across membrane |