5b Flashcards
;the internal balance of a system that keeps
conditions stable
homeostasis
the balance of
changes and motions in a system
Dynamic equilibrium:
things that can affect the homeostasis
of a cell
Optimal range
Range of tolerance
Limits of tolerance
when a substance
involved in a cellular process causes the
process to speed up
Positive feedback:
when a substance produced by a cellular process causes the process to slow down or stop
negative feedback
the diffusion of a solvent
through a semipermeable membrane
osmosis
A membrane that allows certain
things to pass through it but not
others
semipermeable
a solution that is more
concentrated than the cytoplasm of a cell
Hypertonic
a solution that is less
concentrated than the cytoplasm of a cell
Hypotonic:
the movement of molecules across a
membrane without chemical
energy
passive transport
when cells and the solution that
they are in have the same concentration
of solutes
Isotonic
Four factors determine whether a particle can be passively transported
Particle size
Particle shape
Particle polarity
Membrane composition
molecules move
through the cell membrane with the help of transport proteins
Facilitated diffusion
the movement of molecules across a
membrane using chemical energy
active transport
the cell membrane forms a
sack around the particles and then forms a vesicle
Endocytosis
