| active transport | cell utilizes ATP energy |
| passive transport | does not utilize ATP energy (osmosis and diffusion) |
| diffusion | movement of molecules from a region of high concentration to low concentration (concentration gradient, temp, molecular weight, and pressure) |
| osmosis | the diffusion of water; water equalizes concentration; cell gets bigger, smaller, or stays the same (hypo, hyper, iso) |
| all molecules are | moving (randomly) |
| equilibrium | equal concentration [=] |
| concentrated kool aid vs dilute kool aid | lots of solute (kool aid) vs lots of solvent (water) |
| what happens if there is a greater concentration of oxygen outside the cell | oxygen should move into the cell until equalibrium |
| equilibrium point of oxygen in the atmosphere (why percent concentration isn't always in the middle) | 21%; atmosphere is big |
| what things pass through the membrane | small and nonpolar (hydrophobic) |
| can speed up diffusion by | increasing the temp (heating) or changing the shape |
| because of protein channels/aquaporins | all cell membrane are permeable to water |
| NaCl (salt) | can't pass through cell membrane so water goes outside the membrane to it; pulls water out of a cell and preserves food b/ bacteria needs moisture |
| cell static number of salt | 0.9% |
| water | always moves towards salt |
| hypertonic | high concentration on the outside; water moves outside; cell dehydration (smaller) |
| hypotonic | higher concentration on the inside; water moves inside; cell becomes larger |
| isotonic | same concentration on inside and outside; water moves both ways; equilibrium |
| hypertonic (animals) | Kidneys regulate; increase water consumption |
| hypotonic (animals) | Kidneys and urine; contractile vacuole (pumps water out-active transport) |
| isotonic (animals) | gatorade |
| kink in phospholipid means | unsaturated; liquid at room temp |
| membrane wants to be | fluid; viscosity is bad b/ things (O2) can't pass through; permeability of oxygen goes down |
| as temperature decreases | add more unsaturated fats |
| cholesterol (animals only) | acts as a buffer (creates barriers in the cell membrane which prevents it from moving too fast in order to maintain viscosity); too cold - prevents them from sticking together to maintain fluidity |
| why do plants not need cholesterol | plants don't need it; they make sterols and they can go dormnet at call temps |
| cholesterol and health | sticks to arteries and causes it to get smaller causing a heart attack |
| low density lipoproteins | bad; no covering |
| high density lipoproteins | good; wrapped with proteins |
| fluid | unsaturated hydrocarbon tails |
| viscous | saturated hydrocarbon tails |
| why does a cell have a receptor | when molecule sits on receptor, it sends a signal to the nucleus (makes protein channels) |
| why is oxygen continually coming in | its being used |
| CO2 | doesn't affect size of cell or oxygen; can diffuse |
| 1st question | can the molecule pass through the membrane
if it does---go from high to low until it reaches equilibrium (or doesn't because the cell is using it) |
| cell size doesn't matter | if it diffuses through |
| sodium potassium pump | 3 sodium out; 2 potassium in (nerve cell do it to have concentration gradient); goes from low to high and uses energy (against concentration gradient) |
| co-transport of sucrose | won't go through without HYDROGEN ION (which must have concentration gradient--high to low) |
| endocytosis (phago-to eat) | moves in |
| exocytosis | moves out |
