Biology Y9 Cellular Transport Flashcards
factors that affect the rate of diffusion
concentration gradient, temperature, diffusion distance, surface area
diffusion. + where does it occur
Diffusion is the movement of a substance from an area of
high concentration to an area of lower concentration through a partially permeable membrane until an equilibrium is reached
Diffusion occurs in (dissolved) liquids and gases when their
particles collide randomly and spread out.
Diffusion is an important process for living things - it is how
substances move in and out of cells.
what is concentration
number of particles in a given volume
egs of diffusion occurs in an animal
gas exchange at the alveoli, glucose absorption in the small intestines, glucose diffusion across the cell membrane
what is the relationship between temperature and diffusion
as temperature increases, particles diffuse faster
what is the concentration gradient
the difference in particle concentration between 2 areas
what is osmosis
the movement of water from an area of high water potential to an area of low water potential across a partially/selectively permeable membrane
in osmosis ‘water follows ______’
solutes
what water has the highest water potential
pure water
low solute concentration = ______ water potential
high
what is a partially/selectively permeable membrane
a membrane that controls the passage of different substances in and out of cells through differences in size
what is the only partially/selectively permeable membrane we use in biology
the cell membrane
what happens to a plant cell if there is equal water potential inside and out
there is no net change or equilibrium
what happens to a plant cell if there is higher water potential outside than inside
the net movement of water is into the cell, and the cell expands slightly - a turgid cell
what happens to a plant cell if there is higher water potential inside than outside
the net movement of water is out of the cell, and the cell shrinks - a flaccid cell
what happens to a plant cell if there is a very low water potential on the outside and a high water potential on the inside
lots/most of the water leaves, the cytoplasm shrinks, and the cell membrane pulls away from the cell wall - plasmolysis
what type of cell is good/bad for a plant
turgid good, flaccid bad
what is water potential
the ability for water to move from one solution to another
what are the 3 marks for in an osmosis question
1- direction of water in/out
2- it’s osmosis
3- why - water potential gradient
crenation
when a cell shrinks and has rippled edges
what is cytolysis
a cell bursting
why is an animal cell more vulnerable to bursting than a plant cell
it doesn’t have a cell wall - which maintains structure and resists pressure
why might the inside of a plant cell have a lower water potential
the permanent vacuole has lots of solutes
