PNB 2264 EXAM 2 COMPREHENSIVE PRACTICE
TEST QUESTIONS AND SOLUTIONS
◉ outside.
Answer: is Cl higher inside or outside the cell
◉ unequally.
Answer: membranes are _____ permeable to various ions
◉ less.
Answer: membranes are more/less permeable to Na than K at rest
◉ high to low.
Answer: ion channels are always ____ concentration to ____
concentration
◉ no movement.
Answer: concentration gradient, no permeability
◉ all ions move from high to low concentration until there's no
concentration gradient left, no electrical potential.
Answer: concentration gradient, non selective permeability
,◉ + moves from high to low concentration, then some moves back
because of negative charge inside relative to outside (electric
potential).
Answer: concentration gradient, permeable to + only
◉ electric potential and concentration gradient.
Answer: two opposing forces in membrane potential
◉ equilibrium potential.
Answer: membrane potential at which the concentration gradient
and electric potential are equal and opposite (only for 1 type of ion)
◉ no net flux of K across membrane.
Answer: K at equilibrium
◉ does not change.
Answer: despite movement of ions, relative concentration of ions
◉ big changes.
Answer: small movements produce ___ in Vm
,◉ relative concentrations.
Answer: what always predicts how ions move
◉ Nernst equation- every.
Answer: calculates equilibrium potential- permeability to one ion
◉ valence (charge), concentration gradient, only applies to one
specific ion, channels must be open for this to exist.
Answer: What to know about Nernst equation
◉ 0.
Answer: if there's no concentration gradient, Ex = (according to
Nernst Equation)
◉ K = -75 mV.
Answer: most negative equilibrium potential
◉ positive.
Answer: sodium equilibrium potential
◉ negative (not as much as K).
Answer: chlorine equilibrium potential
, ◉ is there concentration gradient, does it become
larger/smaller(more equal), direction of ion movement (high to
low), charge of ion, does movement make cell positive or negative.
Answer: how to predict changes in Ek (5 ways)
◉ one.
Answer: equilibrium potential applies to __ types of ions
◉ Ek increases but is still negative since there's more inside the cell
still.
Answer: if outside potassium is increased from 5 to 10, what
happens to equilibrium potential of K?
◉ Ek is 0 because there's no more concentration gradient.
Answer: if Ko is increased from 5 to 100, what happens to Ek?
◉ becomes more negative since more K cells are leaving.
Answer: if Ki is increased from 100 to 200, what happens to Ek
◉ cells are permeable to many ions.
Answer: what is the problem with Nernst equation
TEST QUESTIONS AND SOLUTIONS
◉ outside.
Answer: is Cl higher inside or outside the cell
◉ unequally.
Answer: membranes are _____ permeable to various ions
◉ less.
Answer: membranes are more/less permeable to Na than K at rest
◉ high to low.
Answer: ion channels are always ____ concentration to ____
concentration
◉ no movement.
Answer: concentration gradient, no permeability
◉ all ions move from high to low concentration until there's no
concentration gradient left, no electrical potential.
Answer: concentration gradient, non selective permeability
,◉ + moves from high to low concentration, then some moves back
because of negative charge inside relative to outside (electric
potential).
Answer: concentration gradient, permeable to + only
◉ electric potential and concentration gradient.
Answer: two opposing forces in membrane potential
◉ equilibrium potential.
Answer: membrane potential at which the concentration gradient
and electric potential are equal and opposite (only for 1 type of ion)
◉ no net flux of K across membrane.
Answer: K at equilibrium
◉ does not change.
Answer: despite movement of ions, relative concentration of ions
◉ big changes.
Answer: small movements produce ___ in Vm
,◉ relative concentrations.
Answer: what always predicts how ions move
◉ Nernst equation- every.
Answer: calculates equilibrium potential- permeability to one ion
◉ valence (charge), concentration gradient, only applies to one
specific ion, channels must be open for this to exist.
Answer: What to know about Nernst equation
◉ 0.
Answer: if there's no concentration gradient, Ex = (according to
Nernst Equation)
◉ K = -75 mV.
Answer: most negative equilibrium potential
◉ positive.
Answer: sodium equilibrium potential
◉ negative (not as much as K).
Answer: chlorine equilibrium potential
, ◉ is there concentration gradient, does it become
larger/smaller(more equal), direction of ion movement (high to
low), charge of ion, does movement make cell positive or negative.
Answer: how to predict changes in Ek (5 ways)
◉ one.
Answer: equilibrium potential applies to __ types of ions
◉ Ek increases but is still negative since there's more inside the cell
still.
Answer: if outside potassium is increased from 5 to 10, what
happens to equilibrium potential of K?
◉ Ek is 0 because there's no more concentration gradient.
Answer: if Ko is increased from 5 to 100, what happens to Ek?
◉ becomes more negative since more K cells are leaving.
Answer: if Ki is increased from 100 to 200, what happens to Ek
◉ cells are permeable to many ions.
Answer: what is the problem with Nernst equation
