Question

What is true of membrane lipids and proteins?

• A. None can flip-flop
• B. Proteins can flip-flop but lipids cannot
• C. None can flip-flop
• D. Lipids can rarely flip-flop but proteins cannot

Answer 1

The correct option is D Lipids can rarely flip-flop but proteins cannot

Plasma membrane is a selectively permeable membrane separating the cytoplasm of the cell from the extracellular environment. It is made up of three components:

1. Lipid
2. Proteins
3. Carbohydrate

The flip-flop movement in the membrane is shown by lipids. This movement is very slow and rarely occurs. In this movement, the lipid molecule gets transferred from one leaflet of the lipid bilayer to the other one.

Some proteins associated with the lipid bilayer of the cell membrane don’t exhibit flip-flop movement, rather they show lateral movement within the leaflet of the bilayer.