Midterm 1 Flashcards
(23 cards)
diffusion potential is caused by an _________ concentration difference on the two sides of the membrane
ion
extracellular fluid
large amounts of sodium and calcium but small amounts of potassium (opposite for intracellular fluid)
cell membrane consists of
lipid bilayer, protein molecules
penetrating proteins can constitute as ____
transport proteins
some proteins have watery spaces that allow for
free movement of water and ions and molecules
carrier proteins
bind with molecules or ions to be transported
transport through the cell membrane 2 ways
through the lipid bilayer or though the proteins
simple diffusion
ion movement across the membrane (lipid soluble or a protein channel with varying levels of specificity)
facilitated diffusion
ion movement that requires interaction with a protein to move across the membrane.
active transport
ion movement across membrane that requires interaction with a protein and energy
what properties of an ion or molecule impacts their ability to diffuse or be transported across the membrane
charge, size, shape, concentration gradient, membrane potential
what circumstance utilized active transport?
movement against a gradient
membrane potential
electrical difference when comparing the outside and inside of the cell membrane
lipid solubility
how fast a substance diffuses through the membrane
the rate of diffusion is directly proportional to its _____
lipid solubility
post synaptic integration
spatial + temporal summation
what maintains the two ion concentration gradients and helps produce the negative membrane potential in neurons?
Na+. K+ ATPase pump (but requires energy)
what is important for ion movement in neuronal cell membranes?
leak channels, Na+. K+ ATPase pump, voltage gates channels, chemically gated ligand channels
membrane potential rises high enough to block further net diffusion of sodium ions to the inside
j
what creates a membrane potential?
a concentration difference of ions across a selectively permeable membrane
Nernst Potential
the voltage required to create equilibrium for an ion with a concentration difference across a membrane
example
if the electrical membrane potential inside the cell membrane is -94 mV, the electrical gradients would be strong enough to oppose the concentration gradient and prevent K+ ions from diffusing out of the cell
neurons have ? to maintain a concentration gradient?
Na+. K+ ATPase pump, and K+ leak channels
