Question | Answer |
Turgor pressure | rigidity or stiffness of plants because of water pressure in central vacuole |
what does hypertonic do | shrink |
what does hypotonic do | swell |
what does isotonic do | no change |
facilitated diffusion | diffusion with aid of channel and carrier proteins |
diffusion | high to low concentration |
equilibrium | molecules equally distribute across available area |
the ability of a molecule or atom to diffuse through a membrane depend on what three factors? | size, charge, polar/nonpolar |
osmosis | water diffusing from high to low concentration across a membrane |
active transport | moves molecules across membrane using ATP energy |
what does active transport require | ATP energy |
active transport moves atoms or molecules against... | concentration gradient |
how does active transport change solute concentration on either side of the membrane? | maintains the difference in concentration |
hypotonic | high water low solute concentration |
hypertonic | high solute low water concentration |
isotonic | equal water and solute concentration |
channel protein | provide a pathway through the lipid bilayer for a charged substance to pass |
what ions or molecules pass through a channel protein and why? | charged substances because the fatty acid tails don't have a charge so they don't like them |
what are the two parts of the phospholipid bilayer? | phosphate group head, and 2 fatty acid tails |
describe the phosphate head of the phospolipid bilayer | it is polar and hydrophilic |
describe the fatty acid tails of the phospholipid bilayer | it is non polar and hydrophobic |
receptor proteins | receive and transmit messages from outside the cell and transport this signal into the cell |
permeable membrane | membrane which things can pass through |
semipermeable membrane | only some things can pass through |
endocytosis | cells import large particles |
pinocytosis | cell drinking. brings in droplets of extracellular fluid |
phagocytosis | cell eating. moves large particles or whole organisms into cell |
exocytosis | vesicles join the membrane dumping out contents |
why is fresh water sprayed on vegetables in a supermarket | because the water makes the cells become turgid and look healthy and fresh |
what are some molecules that can pass through the lipid bilayer and why? | O2 CO2 NH3. because they are small and nonpolar |
what is the purpose of the sodium potassium pump? | to maintain original concentration for signals |
how does the sodium potassium pump change the concentration of ions on either side of the membrane? | pushes Na out, and pulls K in |
how does the sodium potassium pump work? | pushes out 3 Na and pulls in 2 K |
how does a coupled channel work? | two molecules will enter the cell together while one moves up concentration gradient and one moves down concentration gradient |
amphipathic | a molecule with difference in polarity between 2 ends resulting in a difference in water solubility |
concentration gradient | 2 different areas of solute |
electrical gradient | concentration gradient of ions |
extracellular fluid | fluid outside cell |
glycoprotein | membrane carbohydrates covalently bonded to proteins |
hydrophilic | water loving |
hydrophobic | water hating |
integral protein | protein that is the entire width of bilayer (transport/channel protein) |
interstitual fluid (IF) | fluid in between cells |
intracellular fluid (ICF) | fluid inside cell |
passive transport | substances move down their concentration gradient with no expended energy |
receptor mediated endocytosis | protein receptors will collect and move specific molecules into cell |
selective permeable | chooses what passes through |
vesicle | helps dump things out of membrane in exocytosis |
functions of plasma membrane | isolate cell contents from environment, regulate exchange of essential substances, communicate with other cells, creates attachments within and between other cells, regulates biochemical reactions |
why do phospholipids take the bilayer form when placed in water? | because of hydrophobic and hydrophilic interactions |
what in animal membranes keeps them flexible? | cholesterol |
what feature makes the membrane fluid? | unsaturated fatty acids with double bonds creating kinks |
why do caribous hooves have more unsaturated fatty acids? | to keep the cell membrane fluid when it is cold |
what are the roles that proteins in the cell play? | transport important substances, membrane structure, cell identification, acquire food, remove waste |
fluid | substance that can move or change shape in response to external forces |
solute | substance that can be dissolved in a solvent |
solvent | fluid capable of dissolving a solute |
concentration | number of something in a given volume unit |
gradient | physical difference in temperature, pressure, charge, or concentration in two adjacent regions |
what do substances move in response to? | concentration gradient |
the greater the concentration gradient the faster... | the rate of diffusion |
membrane proteins and phospholipids can limit the things that can cross but not.... | the direction of movement |
what kind of hings do cell membrane let cross? examples | small nonpolar O2 CO2 NH3 |
what kinds of things do cell membranes not let cross? examples | large polar sugars, ions, water |
what does the flow of water across a membrane depend on? | the concentration of solutes in the internal or external solutions |
aquaporins | special protein channels water crosses the cell membrane in |
what is it called when a plant cell is in a hypotonic solution | turgid |
what is it called when a plant cell is in an isotonic solution | flaccid |
what is it called when a plant cell is in a hypertonic solution | plasmolyzed |
what are the 6 major functions of membrane proteins? | transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining attachment to the cytoskeleton and extracellular matrix. |
what stops the central vacuole from swelling? | cell wall |
what 2 factors decided which way water will move through a membrane? | solute concentration, difference between solute concentration |
recognition proteins | protein that marks and identifies an unknown cell |