B3 - Movement into and out of cells Flashcards
diffusion definition
net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient as a result of their random movement
what are the 4 factors that affect diffusion?
-surface area
-temperature
-concentration gradient
-distance
osmosis definition
net movement of water molecules from a region of higher water potential to a region of lower water potential, through a partially permeable membrane
what is the effect of immersing plant cells in solutions of different concentration?
-flaccid in high concentration as water diffuses out of the plant through osmosis
-turgid in low concentration as water diffuses into the plant through osmosis
what is the importance of water potential and osmosis in the UPTAKE of water by PLANTS? [5]
-plants take in water by osmosis
-cell contents push against the inelastic cell wall
-turgor pressure (pressure inside the cell) increases
-cell becomes turgid (firm)
-firmness helps to support the plant
what is the importance of diffusion for gases and solutes in living organisms
It allows molecules to enter and leave cells into the organism or enter and leave the organism
active transport definition
movement of particles from a region of lower concentration to a region of higher concentration, up a concentration gradient using energy from respiration
why is active transport important
its a process for movement of molecules or ions across membranes including ion uptake by root hairs
whats a partially permeable membrane
membrane that chooses what gets in and out (only small things like water carbon oxygen go through, not big things like proteins)
what substances diffuse into cells for respiration
oxygen and glucose
what is the difference if the concentration gradient is steep
greater difference
passive process definition
energy not required
what toxic substance gets diffused out of respiring cells?
carbon dioxide
what toxic substance gets diffused out of liver cells?
urea
effect of diffusion distance on rate of diffusion
-shorter the distance, fast the rate of diffusion
-less time to travel a short distance
Ex) blood capillaries
effect of concentration gradient on rate of diffusion
-greater the difference in concentration, faster the net movement of particles, so faster the rate of diffusion
Ex) carbon dioxide used in photosynthesis
effect of surface area on rate of diffusion
-greater the surface area, faster the rate of diffusion
-more space for diffusion and more particles can move in a given period of time
Ex) small intestine wall
effect of temperature on rate of diffusion
-higher the temperature, more kinetic energy the particles have so the faster the rate of diffusion
what is the importance of water potential and osmosis in the UPTAKE of water by ANIMALS?
-osmosis may swell the cell and the cell may burst
-called lysis
what is the importance of water potential and osmosis in the LOSS of water by PLANTS? [5]
-when water is lost by osmosis, they become soft
-turgor pressure in side the cell decreases
-cell becomes flaccid (soft)
-plant wilts because cell is flaccid
-cel becomes plasmolysed cell (cell contents collapsed away from the cell wall
what is the importance of water potential and osmosis in the LOSS of water by ANIMALS?
-cell becomes crinkled/shriveled
-this cell is called a crenated cell
what does active transport require?
carrier proteins and energy (in the form of ATP)
2 examples of active transport
-gut wall
(in small intestine, glucose is actively transported into blood through the gut wall so that the glucose is taken by the blood to needed places)
-root hair cell
(plants use active transport to take in minerals from the soil but usually soil has a lower concentration of the minerals than the plant itself so root hair cell uses active transport to move these mienrals across the cell membrane into the root)
