homeostasis and transport systems Flashcards
what is homeostasis?
every cell needs to maintain a steady environment in order to efficiently carry out life functions
what are the three types of passive transport?
diffusion
osmosis
facilitated diffusion
osmosis
what is isotonic?
water outside cell = water inside cell
equal amounts of water move in and out
osmosis
what is hypotonic?
water outside cell > water inside cell
water moves into cell
what does hypotonic lead to?
lysis
osmosis
what is hypertonic?
water outside cell < water inside cell
water exits cell
what does hypertonic lead to?
plasmolysis in plant cells
crenation in animal cells
what is facilitated diffusion?
passive movement of a substance into or out of the cell by means of carrier proteins or channel proteins embedded in the cell membrane
what is diffusion?
the movement of a substance from an area of high concentration to an area of low concentration [H] -> [L]
what is active transport?
moving substances against the concentration gradient (energy is required)
why is active transport used?
diffusion alone is not sufficient to provide the cell with its needs
how much energy do many cells use on active transport?
about 40%
what is passive transport?
[H] -> [L]
no energy input in terms of ATP
what is active transport?
[L] -> [H]
energy needed in terms of ATP
what are the two types of bulk transport and where do they take place?
endocytosis (inside cell)
exocytosis (outside cell)
