membrane physiology Flashcards
what is fluid outsid ethe cell called?
extracellular fluid
what is fluid inside the cell called?
intracellular fluid
what are the functions of the cell membrane?
act as a barrier
act as an exchange gateway
act as a communicator for environmental changes
stabilize tissue structure
what is the structure of the membrane?
lipid bilayer. hydrophilic head abd hydrophobic tail
what type of molecule is EXPLICITLY not allowed to cross the membrane without a channel, carrier or transporter?
an aqueous molecule
if a substance can cross the membrane unassisted, what does that mean for the membrane?
the membrane is permeable to it
what type of permeability does the cell membrane have?
selective permeability
what is a passive force?
forces that do not require cellular energy to produce movement across the membrane
what is active force?
forces that require the cell to use energy (ATP)
what 2 properties influence a substances permeability to the membrane?
solubility
size
can uncharged, non-polar molecules pass the membrane?
yes
can charged, polar molecules pass the membrane?
no
what 2 forces are passive molecules driven by?
chemical and electrical gradients
what is the electrochemical gradient?
when both the electrical and chemical gradients act simultaneously
what is diffusion across the lipid bilayer defined as?
simple diffusion
will more surface area on the membrane help or hinder diffusion?
help
will a thicker membrane help or hinder diffusion?
hinder
what is osmosis?
the net diffusion of water down its concentration gradient in the presence of an unequally distributed solute
what is tonicity?
the effect of a solution on cell volume
what happens to the cell in an isotonic solution
volume remains constant
what happens to cell volume in a hypotonic solution?
water rushes in the cell and the cell swells (higher solute concentration inside cel)
what happens to cell volume in a hypertonic solution?
water moves out of the cell, the cell shrinks (higher solute concentration outside cell)
what is passive transport/facilitated diffusion?
having to use a carrier protein with the concentration gradient
what is active transport?
having to use a carrier protein against the concentration gradient
