Quiz 1 Flashcards
_________________ uses ATP to pump sodium out and potassium into the cell
active transport
What is the concentration gradient of the cell
- sodium outside
- potassium inside
what is the electrochemical potential difference of the cell
Negative -70mv
- more positive outside
- more negative inside
____________ the balancing of the forces of charge and concentration gradient
electrochemical gradient
___________ is the axon used in the experiment. It is unmylinated and very thick
giant squid axon
What are the three steps of an action potential
- depolarization
- repolarization
- hyperpolarization
_____________________ sodium channels open allowing sodium to flow in and increase membrane potential to about +40 mv
depolarization
___________________ potassium channels open because of strong positive, allowing membrane potential to return to its negative value
depolarization
______________ sudden decrease to potassium equilibrium (-93 mv) and then a slow return to -70mv via sodium potassium pump
hyper polarization
Hodkins and huskily used a ____________ to mimic depolarization to determine the shape of the conducted atoms and amounts of what is exchanged
voltage clamp
During depolarization sodium permeability rose to a peak and then returned to zero potassium rose but did not inactivate
depolarization
_________________ block sodium channels
tetrodotoxin
_________ blocks potassium channels
tetraethyl Ammonium
Why are ion channels able to discriminate agains singling charged ions
- size: molecules must be less than 3A
- oxygen lining: only molecules that can make hydrogen bonds can pass
- can remove their water shell
The introduction of chemicals allowed the scientists to measure
what molecules (sodium and potassium) enter and leave the cell during an action potential
tetrodotoxin plus the ion channel and allows ___________________
current of ions to be measure without hindering the opening and closing of the ion
the article discussion why we can not study potassium what are the reasons for this
- no blocking agent like tetrodxin
- potassium channels open 10 slower thus it is harder to detect
- 1/10 potassium to sodium pump radio
