Neurobio 2 exam practice questions

Which of the following best describes the second law of thermodynamics?

In a closed system, entropy tends to increase over time

-the second law states that entropy increases in closed systems over time, making some energy unavailable for work

In the context of free energy, and endergonic reaction is characterized by:

+G and requires energy input

-Endergonic reaction consume free energy (G) and do not occur spontaneously

The chemical potential (u) of a molecule A is given by

uA=uA0 + RTln [A]

At chemical equilibrium. which is true?

G=0

-Forward and reverse rates are equal

The electrochemical potential for a charged solute includes a term for:

voltage

If K+-0= 5 mM and K+i = 140mM, at 37*C, E_K is approximately:

-98 mV

-E_K = 61.5 log (5/140)

A secondary active transporter moves a solute against its gradient using

the electrochemical gradient of another solute

-Secondary transport couple the movement of one solute to the gradient of another

The goldman equation accounts for:

relative permeabilities of Na+, K+, and Cl-

In a typical mammalian neuron, which ion has the highest intracellular concentration?

K+

Na+/K+ ATPase transports:

3 Na+ out, 2 K+ in

if E_NA = 60 mV and Vm= -70 mV, Na+ is:

being actively transported in

-Since Vm < E_NA, Na+ will tend to enter; active transport (pump) moves it out

osmolarity depends on

the number of solute particles

-Osmolarity is a colligative property, dependent on particle number

The donnan effect occrs because of

Presence of impermeant ions inside the cell

-impermeant intracellular anions attract cations and cause osmotic imbalance

In the nernst-planck equation, flux depends on

concentration and electrical gradients

the permeability (P) of a membrane to a solute is given by

P=D*B/change in x (x=membrane thickness)

the time constant t for solute equilibration across a membrane depends on:

permeability and surface area to volume ratio

Aquaporins facilitate the movement of

water

Cryo-EM is used to primarily determine

Protein structures

The stokes-einstein equation relates diffusion coefficient D to:

Temperature and radius

In a hypertonic solution, a cell will

shrink

-hypertonic = higher solute outside