movement of substances Flashcards
(21 cards)
what is active transport
net mov of ions/mol/ from a region of higher concentration to region of lower concentration against the concentration gradient through a partialy permeable memberane using energy released from cellular respiration
how is energy released
breaking of the bond ATP to form ADP
what is energy used for in active transport
to change shape of carrier protein to transport nutreints from region of lower concent. to region of higher concentration against the concentration gradient
dif between diffusion and active transport
- active transport need energy released from cellular repsiration, diffusion no need
- active transport need partially permeable membrane, diffusion can happen with or without
- active transport moves paricles up the concent. gradeint, diffusion transport particles down
dif bewteen simple diffusion and osmosis
- osmosis involves water molecules only, while diffusion involves gas and liquid molecules
- osmosis need partially permeable membrane, diffusion can happen with or without
factors of diffusion
- SA-VOL RATIO
- thickness of membrane
- pressure dif
- temp
- concentration gradient
- diffusion difference
- solubility of particles
how does cellulase affect rate of diffusion
breaks down cellulose, which is the material of cell wall, so cell wall is weakened, and particles can pass through cell wall more easily due to reduced resistance, rate of diffusion increase
how does heat affect rate of diffusion
- denatures proteins of membrane, so membrane become more porous, particles move across membrane faster,rate of diffusion increase
- greater heat energy converted to kinectic energy of the particles, so particles move arcross membrane faster, rate of diffusion increase
what is facilitated diffusion
a type of passive transport that allows substances to cross membrane with help of special trasnport proteins
ion channel protein
- allows specific ions to cross membrane through protein channel
- ion channels are regulated by cell, either open/closed to control movement of substances into cell
carrier proteins
carrier protein binds to specific molcules, changes its shape, deposits it across membrane, and returns back to original shape once transaction is complete
what happens when plant cell is placed in hypertonic solution
cell membrane shrinks from cell wall, cell sap and cytoplsm lose water,vacuoles decrease in shape and volume, cell becomes plasmolsyed
what happens when animal cell is placed in hypotonic solution
expands, becomes bloated and bursts-no cell wall to support its shape
what happens when plant cell is placed in hypotonic solution
cell membrane gets pressed against cell wall, cell sap and cytoplsm gain water,vacuoles increase in shape and volume, nucleus is pushed to the side,cell is turgid and bloated
what happens when animal cell is placed in hypertonic solution
shrinks becomes spiky and crenated
turgor pressure
force that water within the cell exerts that pushes cell memebrane against cell wall
turgor
measure of turgidity within a cell full of water
why is turgor important
- maintains shape of soft tissues in plant eg keep stem upright
- opens leaf up, keep leaf flat,increase exposed surface area to trap more sunlight for greater rate of photosyn.
- controls opening and closing of stomata* when guard cell gain water–swells–curve more—stomata open*
- prevents plants from wilting
define osmosis
net movement of water molecules from a region of higher water potential to a region of lower water potential down the water potential gradient across a partially permeable membrane
(simple diffusion)movement of water through cell membrane
size of water molecule permits it to pass though membrane since ts small enough, hence it moves across the cell membrane via osmosis
(faciliated diffusion) movement of water through cell membrane
cell membrane has integral proteins-aquaporin, this protein serves a water filled channel that facilitates bulk flow of waetr mocules across membrane
