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40 Cards in this Set

  • Front
  • Back
the stable internal conditions of a living thing
homeostasis
an example of this is... BODY TEMP98.6*
homeostasis
cell membranes help organisms maintain homeostasis by...
controlling what substances may enter or leave cells
the movement of substances that can cross the cell membrane without any input of energy by the cell membrane is called..
passive transport
the simplest type of passive transport is
diffusion
the movement of molecules from an area of higher concentration to an area of lower concentration
diffusion
the difference in the concentration of molecules across a space is called a...
concentration gradient
molecules tend to move DOWN their concentration gradient from areas where they are mor concentrated to areas where they are...
less concentrated
diffusion will eventually cause the concentration of molecules to be the _____ throughout the space the molecules occupy
same
wen the concentration of the molecules of a substance is the same throughout a space a state of _____ exists
equilibrium
beaker with sugar will eventually reach...
equilibrium
the ability of a molecule to diffuse across a cell membrane depends on..
the size and type of molecule
molecules that can dissolve in lipids may pass thru the membrane by
diffusion
small molecules that are not soluble in lipids may diffuse across the membrane by..
moving through the pores in the membrane
..the process by which water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration is called
OSMOSIS!
since water moves down its concentration gradient osmosis does not requier...
cells to expend energy
osmosis is a type of....
passive transport
the net directions of osmosis depends on..
the relative concentration of solutes on the two sides of the membrane
when the concentration of solute molecules outside the cell is lower than the concentration inside the cytosol the solition outside is...
HYPOTONIC to the cytosol
when the concentration of the solute molecules outside the cell is HIGHER than the concentration in the cytolsol the solution outside is...
hypERtonic to the cytosol
water tends to diffuse from HYPOtonic solutions to...
HYPERtonic solutions
contractile vacuoles ...
organelles that remove water
contractile vacuoles collect
the excess water and then contract pumping te water out of the cell
most of the time, plant scells also live in a
hypotonicenviroment
water moves by osmosis into plant cells which swell as they fill with water the swelling stops when..
the cell membrane is pressed against the inside of a cell wall
the cell wall is strong enough to resist..
the pressure exerted by water inside the expanding cell
turger pressure is the pressure that water molecules exert against..
the cell wall
in a hypertonic environment water leaves the cell thru the osmosis the cell shrinks away from the cell wls and turgur pressure is lost. this condition is called...
plasmolysis
the reason that plants wilt if they do not receive enough water
plasmolisis
facilitated diffusion is used for...
molecules that cannot diffuse thru cell membranes even when there is a concentration gradient across the membrane
the carrier proteins that serve in facilitated diffusion transport molecules from an area of higher concentration on one side of the membrane to an area of
lower concentration on the other side
steps of facilitated difusion..3
1-binds to the molecule
2-changes shape
3-molecule is realeased into the cell
facilitated difusion can help cells move in or out of the cell depending on the..
concentration gradient
unlike passive transport active transport requires a cell to
expend energy
the carrier protiens that serve in active transport are often called cell membrane pumps because they move substances ...
up the concentration gradient
the sodium potassium pump pumps
sodium and pottasium ions up their concentration gradient
at top speed the sodium potassium pump can transport about ___sodium ions and ____potassium ions per second
450, 300
the process by which cells ingest external fluid, macromolecules and large particles including other cells is called
ENDOCYTOSIS
2 types of endocytosis
pinocytosis, phagocytosis
exocytosis is the reverse of
endocytosis