Movement of substances into and out of cells Flashcards
what is diffusion
the movement of molecules from a region of high concentration to a region of lower concentration down a concentration gradient
how do molecules move down a conc. gradient in humans
in the cell membrane
how does the cell membrane work
allows some molecules to cross easily but others with difficulty
what is osmosis
the net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane down a conc. gradient
what happens when an animal cell is placed into a strong sugar solution
it becomes crenated as it loses water by osmosis
animal cell into distilled water
it gains water by osmosis as it has not cell wall to create turgor pressure
- it bursts
what helps maintain optimum osmostic balance in the body
osmoregulation
plant cell into a strong sugar solution
loses water by osmosis, the vacuole gets smaller and the cell membrane shrivels away from the cell wall
- it becomes flaccid
plant cell placed into distilled water
gains water by osmosis so vacuole gets bigger, pushing the cell membrane against the cell wall
- plant cell becomes turgid containing a high turgor pressure
what happens when water enters a plant cell
makes cell rigid and firm providing support and strength for the plant
what is active transport
the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration
why is energy needed in active transport
it needs to be pushed against the conc. gradient
how does active transport help in animals
- transports food molecules
- allows glucose to be transported into bloodstream
- uptake of glucose in kidney tubules
active transport in plants
- transports minerals from a region to low to high conc.
why are magnesium ions required in plants
make chlorophyll
