Answer :
Answer:
Plasma membrane is a semi-permeable membrane that allows only certain molecules to enter inside the cell.
Explanation:
The movement of lipids or proteins from one leaflet to the other leaflet of the plasma membrane is known as flip flop movement or flip flop diffusion. Different phospholipids are present in different leaflets of the plasma membrane. These components of the plasma membrane does not flip flop compared to lipids and proteins which moves from one leaflet to another. This is because they are charged molecules with polar head. There movement needs more energy to cross the lipid bilayer which is hydrophobic in nature.