Question

Which does not pertain to facilitated transport?
A. Uphill transport
B. High selectivity
C. Transport saturation
D. Requirement of special membrane proteins

Answer 1

Facilitated transport is the transport of molecules along the concentration gradient through the semipermeable membrane i.e. Plasma membrane.

Complete Answer:
Facilitated transport: Facilitated transport is also known as facilitated diffusion, passive-mediated transport. Facilitated transport is a process in which the movement of molecules takes place along the concentration gradient i.e from the region of higher concentration to the region of lower concentration. The movement of molecules and ions take place until there will be equilibrium set up.

- This transport of molecules takes place through the semipermeable membrane i.e plasma membrane via some transmembrane integral proteins that are embedded in the plasma membrane. There transmembrane integral proteins are also called as carrier proteins.
- Facilitated transport is a down hill transport because it is a kind of passive transport where there will be no expenditure of ATP or energy, and it is taking place along the concentration gradient i.e. from the region of higher concentration to the region of lower concentration.
- Facilitative transport is highly selective because it requires carrier proteins for the transport of any particular molecule or ion.

Hence, option A is the correct answer for this question.

Note: Transmembrane integral proteins are also called as the channel proteins or carrier proteins. These proteins are only open to one side of the membrane at a time. These proteins bind to the molecules or ions and change their shape to carry the molecules or ions through the plasma membrane to the other side. Example – Sodium-Potassium pump.