Chapter 5- Membrane and Action Potentials

Question 1

what do all cells have …

Answer 1

a plasma membrane

Question 2

what is in the plasma membrane

Answer 2

-lipid bilayer

Question 3

how do fat soluble molecule pass through the plasma membrane

Answer 3

diffusion

Question 4

how do water soluble molecule pass through the plasma membrane

Answer 4

require a protein channel inserted in the membrane to pass

Question 5

what do all cells have a difference in

Answer 5

electrical potential between the ICF and the ECF

Question 6

what can change these electrical potentials

Answer 6

• nerve and muscles can change potential rapidly
• profound change in potential
• excitable cells
• able to produce an action potential

Question 7

what do non excitable cells use

Answer 7

changes in membrane voltage for signaling, but not via an action

Question 8

what is voltage

Answer 8

this is a relative phenomenon

Question 9

how do you measure voltage

Answer 9

with 2 electrode for recording

Question 10

how is RMP established

Answer 10

the balance of electrical and chemical properties of the cell

Question 11

what laws do ions follow

Answer 11

the the law of diffusion down a concentration gradient and they are also subject to electrical forces such as charges, repel, opposites attract

Question 12

what is the only way you can measure voltages

Answer 12

charges must be going through a resister

Question 13

what happens when a positive charge leaves the cells

Answer 13

the inside becomes more relatively negative which creates a more negative electrical potential inside

Question 14

where is voltage generated in a cell

Answer 14

across the membrane

Question 15

when will positive charges stop leaving the cell

Answer 15

when the diffusion gradient equals the electrical gradient

Question 16

when is there no net movement of an ion

Answer 16

when the electrical and diffusion forces are equal and opposite

Question 17

what is the equilibrium

Answer 17

this is when an ion stops its movement

Question 18

what is the nernst potential

Answer 18

the potential across a membrane that exactly opposes the net diffusion of a particular ion through the membrane

NEED TO KNOW the equations

Question 19

what is the magnitude of the nernst potential determined

Answer 19

by the ratio of the concentrations of the specific ion on the both sides of the membrane

Question 20

what happen when the nernst potential has a greater ratio

Answer 20

the greater the ratio the greater the tendency for the ions to diffuse in one direction and is required to prevent additional net diffusion

Question 21

what is the potential in extracellular fluid

Answer 21

this is outside the membrane an its has a zero potential

Question 22

what is the potential for the nernst

Answer 22

this potential is on the inside of the membrane

Question 23

when is the sign of the nernst potential is positive (+)

Answer 23

if the ion diffusion form inside of outside is a negative ion

Question 24

when is the sing of the nernst potential is negative (-)

Answer 24

if the ion diffusion from inside to outside is positive