B3 movement into and out of cells Flashcards
define diffusion
- net mvmt of particles
- from region of their high concentration to region of their lower concentration
- as result of their random mvmt
how do substances move into/out of cells
diffusion through cell membrane
why is diffusion important in organisms
- to deliver or removed dissolved substances (solutes) and gases though cell membranes
how does surface area influence diffusion
- as SA inc, diffusion inc
how does temperature influence diffusion
- as temp inc, diffusion inc
how does concentration gradient influence diffusion
- as inc, diffusion inc
how does distance influence diffusion
- as distance inc, diffusion dec
how does water diffuse through partially permeable membranes
osmosis
how does water move in/out of cells
through partially permeable membranes by osmosis
what happens to water in a cell if placed in concentrated solution
water will leave cell
what happens to water in a cell if placed in a dilute solution
water will enter cell
define osmosis
- net mvmt of water moelcules
- from regionof high wp (dilute solution) to low wp (concentrated solution)
- through a partially permeable membrane
what happens if plant cell is immersed in dilute solution
- gain water by osmosis
- turgor pressure increases
- high tp = turgid
what happens if plant cell is immersed in concentrated solution
- lose water by osmosis
- turgor pressure decreases
- becomes flaccid
- if lose a lot of water, cytoplasm/vacuole may shrink so much that cytoplasm pulls away from cell wall (plasmolysis)
why is osmosis important in plants
- water in soil (dilute solution)
- enter root hair cell by osmosis
why is osmosis important in animals
- body cells can be damaged if too much/little water gained/lost
- so, water concentration of blood/cytoplasm v closely controlled by kidneys
define active transport
- mvmt of particles thru cell membrane
- region of low conc to region of high conc
- using energy from respiration
active transport in plants
- conc of ions higher inside root hair cell than soil
- diffusion would cause ions to move out of plant
- AT allow take in vital ions
active transport in animals
- glucose absorbed thru intestine wall into bloodstream
- when glucose conc in intestine < bloodstream, active transport
