Question

Which of the following criteria does not pertain to facilitated diffusion?

• A. Requirement of special membrane proteins
• B. High selectivity
• C. Downhill transport
• D. Uphill transport

Answer 1

The correct option is D Uphill transport

A concentration gradient must be present for molecules to diffuse even if diffusion is facilitated by the proteins. This process is called facilitated diffusion. Criteria for facilitated transport or diffusion are:

• Special proteins help move substances across membranes without the expenditure of ATP energy.
• Facilitated diffusion is very specific and highly selective. It allows cell to select substances for uptake.
• Facilitated transport does not follow uphill transport instead follow downhill transport.