Carrier Mediated Transport

Question 1

Facilitated Diffusion

Answer 1

A carried mediated transport of a non-charged molecule down its chemical gradient (or an ion down its electrochemical gradient) by means of a specific membrane bound integral protein
Moves at a rate faster than predicted by Fick’s 1st law of diffusion

Question 2

Differences in mode of energy utilization between facilitated diffusion and passive diffusion

Answer 2

Facilitated diffusion - the solute’s electrochemical potential energy (for an ion) or chemical potential energy (for a neutral molecule) is utilized by the carrier molecule for movement of the transported solute down its gradient
Uses energy more efficiently thus increase in flux

Question 3

Flux Properties

Answer 3

1. The direction of net flux across the cell membrane is dependent upon the direction of the concentration gradient
2. Net flux will cease when the concentration of the solute becomes equal on both sides of the membrane

Question 4

Primary Active Transport

Answer 4

1. The direction of transmembrane flux is always opposite to that due to spontaneous passive diffusion down a concentration gradient
2. Work is always done on the transported molecule or ion thus raising its chemical (or electrochemical) potential energy.

Question 5

Secondary Active Transport

Answer 5

transports uncharged molecules up their chemical gradient or ions up their electrochemical gradient
Energy derived from the chemical potential energy released upon passive movement of a coupled “driver” molecul or ion down its own electrochemical gradient
- Not derived from ATP

Question 6

Co-Transport

Answer 6

movement of the coupled molecule or ion that is driven up its gradient is in the same direction as that of the “driver” ion that moves down its electrochemical gradient

Question 7

Exchange-transport

Answer 7

movement of the couple solute that is drive up its electrochemical gradient is in the direction opposite to that of the driver solute, that moves down its electrochemical gradient