Transport Physiology

Question 1

Thermodynamic equilibrium

Answer 1

Absence of a solute electrochemical potential difference
Passive unidirectional movement across the membrane
-no net transport

Question 2

Passive transport mechanisms

Answer 2

Channels and uniporters

Question 3

Active transport mechanisms

Answer 3

Primary- uses ATP

Secondary- uses gradient created by the primary transporter

Question 4

Vmax

Answer 4

maximal rate of solute transport
-determined by number of transporters present and time required for a transporter to undergo one complete transport cycle

Question 5

Km

Answer 5

constant described by the solute concentration where V is one-half the Vmax

• lower= greater affinity
• higher= lesser affinity

Question 6

Amiloride

Answer 6

inhibits Na channel and Na/H exchangers

Question 7

Phloridzin

Answer 7

specifically inhibits the Na-glucose cotransporter