cell transport Flashcards
what is the definition of diffusion?
particles moving from a high concentration to a lower concentration.
what is the definition of osmosis?
water from a dilute solution to a concentrated solution through a partially permeable membrane.
what is the definition of active transport?
the movement of particals from a more dilute solution to a more concentrated solution using energy from respiration.
which way do the particles move in diffusion?
down the concentration gradient, from a high concentration to a low concentration.
which way do the particles move in osmosis?
water movees from an area of a lower solute concentration to an area of a higher solute concentration.
which way do the particles move in active transport?
particles move against the concentration gradient from an area of low concentration to an area of high concentration,
is energy required for diffusion?
no it’s a passive process
is energy required for osmosis?
no it’s a passive process
is energy required for active transport?
yes, energy is released by respiration.
human: nutrients in the small intestine _____ into the capillaries through the villi.
diffusion
human: oxygen _____ from the air in the alveoli into the blood in the capillaries. Carbon dioxide _____ from the blood into the capillaries into the air in the alveoli.
diffusion
human: urea _____ from cells into the blood for excretion in the kidney.
diffusion
fish: oxygen from water passing over the gills _____ into the blood in the gill filaments.
diffusion
fish: carbon dioxide _____ from the blood in the gill filaments into the water.
diffusion
plants: carbon dioxide used for photosynthesis _____ into leaves through the stomata.
diffusion
plants: oxygen produced during photosynthesis _____ out the leaves through the stomata.
diffusion
plants: water moves by _____ from a dilute solution in the soil yo a concentrated solution in the root hair cell.
osmosis
human: _____ allows sugar molecules to be absorbed from the small intestine when the sugar concentration is higher in the blood than in the small intestine.
active transport
plants: _____ is used to absorb mineral ions into the root hair cell from more dilute solutions in the soil.
active transport
what are the factors that affect the rate of diffusion?
difference in concentration ( the steeper the concentration gradient, the faster the rate of diffusion ), temperature ( the higher the temperature, the faster the rate of diffusion ), surface area of the membrane ( the larger the membrane surface area, the faster the rate of diffusion ).
what does ‘large surface area-to-volume ratio’ mean?
enough molecules can be transported across their cell membranes to meet their needs.
what does ‘small surface area-to-volume’ mean?
they need specialised organ systems and cells to allow enough molecules to be transported into and out of their cells.
when do exchange surfaces work most efficiently?
when they have a large surface area, a thin membrane, and a good blood supply.
what are the adaptations for villi in the small intestine, for absorbing nutrients?
network of capillaries, large surface area due to folding, thin wall ( only one cell thick ), good blood supply.
what are the adaptations for alveoli in the lungs, for gas exchange?
network of capillaries provides a good blood supply, the rate of diffusion is increased because the membrane of the alveoli: has a large surface area, is moist, is only one cell thick ( short diffusion pathway ).
what are the adaptations for fish gills, for gas exchange?
fish gills are made up of stacks of thin filanents with: a large surface area to increase diffusion, a network of capillaries ( good blood supply ).
what are the adaptations for root hair cells, for uptake of water and minerals?
lots of mitochondria to take in mineral ions by active transport, large surface area helps efficient absorption of water and mineral ions.
