2. Transport across cell membranes Flashcards
What is the cell membrane made of?
protein and phospholipids
phospholipids
fat
selectively permable
lets small molecules pass through like oxygen and glucose and stops large molecules like starch from passing through
examples of passive transport
osmosis and diffusion
does passive transport require energy?
no
passive transport
occurs due to different concentrations of substances between the cell and its external enviroment
occurs due to different concentrations of substances between the cell and its external enviroment
concentration gradient
Diffusion
movement of molecules down a concentration gradient from a high concentration to a low concentration
diffusion substance in stomata leaves
carbon dioxide
diffusion movement in stomata leaves
from a higher concentration in the air to a lower concentration in the leaf
Diffusion substance in the villi
glucose
diffusion movement in villi
higher concentration in the villus to a lower concentration in the blood capillaries
diffusion substance in the alveolus
oxygen
diffusion movement in alveolus
higher concentration in the air sac to a lower concentration in the blood capillaries
osmosis
movement of water molecules from a high water concentration to a low water concentration
osmosis calculation
% change difference over original x 100
plasmolysed
cells loose water
`Turgid
full of water, membrane pushes against cell wall
effect on plant cells with low water concentration
plasmolysed
equal water/solute concentration
normal
high water concentration
turgid
what prevents plant cells from bursting
cell wall
effect of osmosis on animal cells with low water concentration
shrivelled
equal water/solute solution
normal
high water concentration
burst
Active transport
movement of molecules and ions from a low concentration to a high concentration
what is the function of membrane proteins
responsible for moving molecules and ions against the concentration gradient
Does active transport require energy?
yes