Question

The plasma membrane acts as a barrier in cells of all types to control the movement of substances into and out of the cell.

a.explain how the plasma membrane acts as a semi-permeable barrier to various types of molecules based on its molecular structure.
b.describe, in detail, three ways in which large molecules such as proteins can cross the plasma membrane.

Answer 1

A) plasma membranes are made up of phospholipid bilayer. They contain hydrophilic heads and hydrophobic tails. This means only lipid soluble substance will be able to pass through the plasma membrane.