Question

The fluid mosaic model of membrane structure was first proposed in 1972 by Singer and Nicolson. The model describes in detail how the components of a membrane are organised.

(a) Some of the components of the cell surface membrane are:
• phospholipid molecules

• protein molecules

• cholesterol molecules.
(1) In the box below, draw a labelled diagram of a section through a cell surface membrane to show how the above components are organised within the membrane.
The diagram should include other named components of the membrane.
Label the inner and outer surfaces of the membrane.


PLEASE CREATE A DIAGRAM

Answer 1

(b) Describe the role of phospholipid molecules in the cell surface membrane.

Phospholipids are the major component of the cell surface membrane and are responsible for its physical structure and integrity. They form a bilayer, with the two layers of phospholipids arranged in a ‘mosaic’ pattern. The hydrophobic tails of the phospholipids are embedded in the centre of the membrane and their hydrophilic heads form the inner and outer surfaces of the membrane, facing the cytoplasm and the external environment respectively. This structure enables the membrane to act as a selective barrier, allowing certain molecules and ions to cross it, while preventing others from entering or leaving the cell.

Is that good?

Step-by-step explanation: