Ch. 8-3 Flashcards
to study for part of the final (56 cards)
Every living cell lives in a ______ environment
liquid
How do cell membranes maintain homeostasis?
by regulating molecule movement from one side of the membrane to the other
Do solutes move all the time or stay still?
They move all the time
Particles naturally move from ____ to _____ concentration. This is known as _______.
high to low;
diffusion
Molecules move from an area of high to low concentration until they reach…
equilibrium
True or False: Because molecules move after equilibrium is reached, the concentration of one side of the membrane changes.
FALSE: The molecules move in opposite directions across the membrane at the same rate, so there’s no net change in concentration.
The movement of molecules across the cell membrane without using cellular energy
Passive transport
What kinds of molecules can go directly through the cell membrane?
small and uncharged molecules
What kinds of molecules CAN’T go directly through the cell membrane?
Also give an example
ions (which are charged) & large molecules
e.g., Chloride, glucose
What carbon compound lets certain molecules go through facilitated diffusion?
Proteins acting as carriers
How many kinds of proteins can help with facilitated diffusion?
Can a protein work with any molecule?
Hundreds;
No, they are specific to certain molecules
Does facilitated diffusion require cellular energy
No
Why can’t water molecules directly go through the cell membrane?
Because parts of the membrane (the lipid’s tails) are hydrophobic.
The channel protein that helps water go through the membrane
aquaporins
Define osmosis
the facilitated diffusion of water through a selectively permeable membrane
In osmosis, water moves from _____ to ____ concentration
Hint: how is it like in diffusion normally?
high to low
Higher solute concentration means there is a ______ water concentration (assuming the solute is dissolved in water) and vice versa
lower
In osmosis, water moves from one side to another or to both sides?
Both, but there’s a net movement to wherever there’s a higher solute concentration
When will water stop moving across the membrane?
When equilibrium is reached
When the concentration of water & a solute is the same on both sides of a membrane, the solutions are…
isotonic (same strength/solute)
To have a greater solute concentration than the other solution
hypertonic (above strength/solute)
To have a smaller solute concentration than the other solution
hypotonic (below strength/solute)
Osmotic pressure
The net movement of water out of or into a cell
In what solution will an animal cell shrink?
Hypertonic solution
