Question

What are the two main molecules that make a cell membrane?

Answer 1

Lipids and proteins.

Explanation:

Lipids include:

1. Phospholipids : This makes up the bi-layer which is the membrane's basic structure and has great control over what can enter and exit the cell, due to their hydrophobic tails and hydrophilic heads.

2. Cholesterol : This also controls entry and exit of substances as it also exhibits hydrophilic heads and hydrophobic tails. It also stabilises the membrane and affects its fluidity (the more there is, the more fluid is the membrane.)

3. Glycolipids : Those can act as receptor molecules (essential for cell-signalling), antigens and in cell-adhesion.

Proteins include:

1. Glycoproteins : Same function as glycolipids.

2. Enzymes: ( like those present in the brush border).

3. Transport proteins: (channel and carrier proteins)