Advanced Anatomy & Physiology
Exam 1
The three types of driving forces on molecules: - Answer-1) chemical 2) electrical 3) electrochemical
As change in ion concentration (increases/decreases), chemical driving force (increases/decreases) -
Answer-increases, increases
Why do cells have membrane potentials? - Answer-1) selective permeability 2)chemical driving
forces/diffusion gradients 3)electrical driving forces
What is the membrane potential (Vm)? - Answer--70mV
The Vm (resting membrane potential) is the ___________ - Answer-sum of equilibrium potentials for all
permeant ions * their relative permeabilities
Equilibrium potential - Answer-the voltage at which the chemical driving force and electrical driving
forces are equal and opposite
What does a positive or negative equilibrium potential sign mean? - Answer-If +, the electrical driving
force is going OUT of the cell, if -, the electrical driving force is going IN the cell
What does equilibrium potential magnitude depend on? - Answer-Concentration gradient (largely
influences equilibrium potential)
What is EqK+? - Answer-equilibrium potential of potassium: -90mV
,What is EqNa+? - Answer-equilibrium potential of sodium: +60mV
Magnitude of electrical driving force on an ion depends on: - Answer-1) size of the membrane potential
2) quantity of charge carried by the ion
electrochemical driving force - Answer-1) the ion's tendency to be pushed down a gradient (chemical) 2)
the ion's tendency to be pushed in a direction by membrane potential (electrical)
Nernst Equation - Answer-Ex = (+/-) 61mV * log [Co]/[Ci] --> equilibrium potential = +/-61mV times the
log of the concentration moving out over concentration moving in
Separation of charge - Answer-Unbalanced movement of an ion across the membrane; basis for
potential difference across the plasma membrane (membrane potential)
What is the concentration of ions in body fluids? - Answer-290mOsm/L (same inside and outside the
cell)
Na+-K+ ATPase - Answer-2 Na+ out, 3 K+ in
PMCA - Answer-moves Ca2+ out
Why is it important for a cell to have different charges on either side of the membrane? - Answer-The
potential energy can be utilized: ex. action potential
Why can't sodium achieve a resting membrane potential of +60? - Answer-Because there is always
potassium leaving (K+ leak channels) --> more negative
, Electrochemical driving force equals: - Answer-Vm - Ex (membrane potential - equilibrium potential of
that ion)
Electrochemical driving force of sodium given that Vm = -70 and ENa = 60? - Answer--70 - 60 = -130 so
driving force is 130mV IN
Simple diffusion depends on: - Answer-concentration, surface area, and permeability
Facilitated diffusion utilizes - Answer-channels and carriers
Primary active transport - Answer-requires energy such as ATP, ex. Na-K ATPase
Secondary active transport - Answer-utilizes electrochemical gradients, ex. glucose-Na pump
facilitated diffusion - Answer-protein-mediated, NO input of energy, ex. glucose
channels - Answer-no binding to substance being transported
simple diffusion - Answer-no protein mediator
Carrier-mediated transport is affected by: - Answer-1) saturation 2) specificity 3) competition for the
binding site
osmosis - Answer-water uses aquaporins, moves towards areas of greater solute concentration
osmolarity - Answer-ability to draw in water - the greater the solute, the more water will come
Exam 1
The three types of driving forces on molecules: - Answer-1) chemical 2) electrical 3) electrochemical
As change in ion concentration (increases/decreases), chemical driving force (increases/decreases) -
Answer-increases, increases
Why do cells have membrane potentials? - Answer-1) selective permeability 2)chemical driving
forces/diffusion gradients 3)electrical driving forces
What is the membrane potential (Vm)? - Answer--70mV
The Vm (resting membrane potential) is the ___________ - Answer-sum of equilibrium potentials for all
permeant ions * their relative permeabilities
Equilibrium potential - Answer-the voltage at which the chemical driving force and electrical driving
forces are equal and opposite
What does a positive or negative equilibrium potential sign mean? - Answer-If +, the electrical driving
force is going OUT of the cell, if -, the electrical driving force is going IN the cell
What does equilibrium potential magnitude depend on? - Answer-Concentration gradient (largely
influences equilibrium potential)
What is EqK+? - Answer-equilibrium potential of potassium: -90mV
,What is EqNa+? - Answer-equilibrium potential of sodium: +60mV
Magnitude of electrical driving force on an ion depends on: - Answer-1) size of the membrane potential
2) quantity of charge carried by the ion
electrochemical driving force - Answer-1) the ion's tendency to be pushed down a gradient (chemical) 2)
the ion's tendency to be pushed in a direction by membrane potential (electrical)
Nernst Equation - Answer-Ex = (+/-) 61mV * log [Co]/[Ci] --> equilibrium potential = +/-61mV times the
log of the concentration moving out over concentration moving in
Separation of charge - Answer-Unbalanced movement of an ion across the membrane; basis for
potential difference across the plasma membrane (membrane potential)
What is the concentration of ions in body fluids? - Answer-290mOsm/L (same inside and outside the
cell)
Na+-K+ ATPase - Answer-2 Na+ out, 3 K+ in
PMCA - Answer-moves Ca2+ out
Why is it important for a cell to have different charges on either side of the membrane? - Answer-The
potential energy can be utilized: ex. action potential
Why can't sodium achieve a resting membrane potential of +60? - Answer-Because there is always
potassium leaving (K+ leak channels) --> more negative
, Electrochemical driving force equals: - Answer-Vm - Ex (membrane potential - equilibrium potential of
that ion)
Electrochemical driving force of sodium given that Vm = -70 and ENa = 60? - Answer--70 - 60 = -130 so
driving force is 130mV IN
Simple diffusion depends on: - Answer-concentration, surface area, and permeability
Facilitated diffusion utilizes - Answer-channels and carriers
Primary active transport - Answer-requires energy such as ATP, ex. Na-K ATPase
Secondary active transport - Answer-utilizes electrochemical gradients, ex. glucose-Na pump
facilitated diffusion - Answer-protein-mediated, NO input of energy, ex. glucose
channels - Answer-no binding to substance being transported
simple diffusion - Answer-no protein mediator
Carrier-mediated transport is affected by: - Answer-1) saturation 2) specificity 3) competition for the
binding site
osmosis - Answer-water uses aquaporins, moves towards areas of greater solute concentration
osmolarity - Answer-ability to draw in water - the greater the solute, the more water will come
