Question

Identify a type of molecular movement which is highly selective and requires special membrane proteins, but does not require energy.

Answer 1

Facilitated diffusion :

• Facilitated diffusion is the type of molecular movement that occurs across a membrane in which certain molecules are carried by certain membrane proteins (carrier, gated channel, channel proteins) . The movement of molecules is therefore highly selective.
• The movement of molecules takes place down the concentration gradient i.e. from higher concentration to lower concentration.
• Thus it does not require energy

Final answer: Facilitated diffusion.