Quiz 1

Question 1

_________________ uses ATP to pump sodium out and potassium into the cell

Answer 1

active transport

Question 2

What is the concentration gradient of the cell

Answer 2

• sodium outside

- potassium inside

Question 3

what is the electrochemical potential difference of the cell

Answer 3

Negative -70mv

• more positive outside
• more negative inside

Question 4

____________ the balancing of the forces of charge and concentration gradient

Answer 4

electrochemical gradient

Question 5

___________ is the axon used in the experiment. It is unmylinated and very thick

Answer 5

giant squid axon

Question 6

What are the three steps of an action potential

Answer 6

• depolarization
• repolarization
• hyperpolarization

Question 7

_____________________ sodium channels open allowing sodium to flow in and increase membrane potential to about +40 mv

Answer 7

depolarization

Question 8

___________________ potassium channels open because of strong positive, allowing membrane potential to return to its negative value

Answer 8

depolarization

Question 9

______________ sudden decrease to potassium equilibrium (-93 mv) and then a slow return to -70mv via sodium potassium pump

Answer 9

hyper polarization

Question 10

Hodkins and huskily used a ____________ to mimic depolarization to determine the shape of the conducted atoms and amounts of what is exchanged

Answer 10

voltage clamp

Question 11

During depolarization sodium permeability rose to a peak and then returned to zero potassium rose but did not inactivate

Answer 11

depolarization

Question 12

_________________ block sodium channels

Answer 12

tetrodotoxin

Question 13

_________ blocks potassium channels

Answer 13

tetraethyl Ammonium

Question 14

Why are ion channels able to discriminate agains singling charged ions

Answer 14

• size: molecules must be less than 3A
• oxygen lining: only molecules that can make hydrogen bonds can pass
• can remove their water shell

Question 15

The introduction of chemicals allowed the scientists to measure

Answer 15

what molecules (sodium and potassium) enter and leave the cell during an action potential

Question 16

tetrodotoxin plus the ion channel and allows ___________________

Answer 16

current of ions to be measure without hindering the opening and closing of the ion

Question 17

the article discussion why we can not study potassium what are the reasons for this

Answer 17

• no blocking agent like tetrodxin
• potassium channels open 10 slower thus it is harder to detect
• 1/10 potassium to sodium pump radio