| A | B |
|---|
| transport | movement across membrane without use of energy |
| homeostasis | a steady state producing a constant internal environment |
| cell membrane | helps maintain homeostasis by controlling and regulating what goes into and out of the cell |
| molecules that are in constant motion travel in ___________ lines | straight |
| molecules that are in constant motion bump into ___________ | something |
| molecules that are in constant motion travel in straight lines in different directions or ___________ | random motion |
| molecules tend to move ______________ | into areas of less concentration |
| cytolysis | reverse cells take in so much H2O and burst |
| an example of cytolysis is ______________ | red blood cells |
| single celled organisms: ______________ environment | hypotonic |
| single celled organisms are hypotonic in relationship - H2O ________ into cell | diffuses |
| contractile vacuoles | removes excess H2O - contracting and squeezing water out |
| cells in multicellular organisms respond to hypotonic environments ______________ | pumping solutes out of cytosol |
| facilitated diffusion | molecules that cannot diffuse rapidly through membrane - not soluble in lipids or too large |
| molecules that cannot diffuse rapidly through membrane are assisted by _____________- | specific proteins - carrier proteins |
| Three steps to facilitated diffusion: | bind, change, release |
| carrier proteins binds __________________ | to a molecule on one side of a membrane |
| carrier proteins change ___________ | shape - shielding from nonpolar molecules |
| carrier proteins are released ____________- | from one side |
| transport of glucose has two properties to __________________ | help substances move in either direction and specific for one type of molecule |
| ion channels | protein - passageway which an ion can diffuse |
| important ions: | Na+, K+, Ca2+, Cl+ |
| some ions are open...others have ______- | gates |
| Three kinds of stimuli (of ions) | stretching of membrane, electrical signals, chemicals |
| diffusion | movement of molecules from an area of greater to an area of lesser concentration |
| concentration gradient | difference in concentration of a substance across a space |
| substances then to move down a concentration gradient toward ___________________- | an area of lower concentration |
| equilibrium | a state that exists when concentration of a substance is the same throughout the space |
| diffusion across a membrane - dissolve in ___________ | lipids |
| nonpolar examples | CO2, O2 |
| permeable | allowing substances to pass through |
| ability of a molecule to pass through a membrane depends _________________ | on the size and type of molecule |
| osmosis | diffusion of H2O through a membrane from an area where H2O is more concentrated |
| net direction of H2O molecules depends ___________ | on concentration of solutes on two sides of membrane |
| when concentration of solute molecules outside cell is lower than concentration in cytosol _______________ | solution outside is hypotonic |
| hypo = _____________ | lower |
| lower concentration of solutes and _______________ | higher concentration of H2O molecules |
| in osmosis, a cell in this type of solution ______ | H2O will diffuse out of cell until equilibrium is reached |
| concentration of solutes outside and inside are ___________ | equal |
| when the concentration of solutes outside and inside are equal - outside _______________ | solution is isotonic to cytosol |
| ISO = ____________ | equal/no net movement of water |
| the prefixes hypo-, hyper- and iso- refer to the __________ | concentration of solutes |
| cell - no control over _________ | osmosis |
| direction H2O diffuses depends _____- | on H2O concentration |
| Tungor pressure ____________ | pressure that builds up within cell as H2O diffuses into cell |
| With Tungor pressure, pressure forces contents ________ | against cell wall - cell firm |
| With Tungor pressure, pressure is _____________ | maintained - hypotonic environment |
| in a hypotonic environment, water ____________ | moves in |
| in a hypotonic environment, it loses ___________ | H2O or gains solutes - hypertonic - condition - plasmolysis occurs |
| Plasmolysis | shrinking of cell due to water loss (wilting) |
| in plasmolysis, H2O _____________ | leaves cell/tungar pressure is lost |
