Formative Practice 3.1 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
What are the two main components of the plasma membrane?

Proteins and phospholipids

Question 2:
Explain the meaning of fluid mosaic model.

The fluid mosaic model refers to protein molecules that are suspended in the phospholipid bilayer forming an ever-changing mosaic pattern. The phospholipid bilayer, proteins and cholesterols are not static but form a dynamic and flexible structure.

Question 3:
Predict what will happen to the plasma membrane if there is no cholesterol.

Without cholesterol, the plasma membrane will become too fluid at normal body temperature and may rupture. Without cholesterol, the membrane will become too permeable to dissolved substances.

Question 4:
Explain the role of phospholipid and protein in ensuring the (Accessed on 21 August 2019) permeability of the plasma membrane.

The characteristic of phospholipid and protein molecules that only allow passage for a certain number of substances enables or limits the free movement of certain substances though the plasma membrane. This characteristic determines the selective permeability of the plasma membrane.

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