Enzymes tutorial Q2ciii

Q) Suggest why the lysosomal membrane remains intact? [3]

Possible Answers:

[1st mark] 
- Lysosomal enzymes hydrolyse polysaccharides, lipids, proteins, and nucleic acids.

[2nd mark] 
- These differ from the constituents of the lysosomal membrane which comprise of phospholipids, membrane-bound proteins, glycolipids, and glycoproteins. [1]
OR 
- The inner surface of the lysosomal membrane is coated with an extensive glycocalyx (refer to pictures below).
OR
- The integral and inner peripheral membrane proteins and membrane phospholipids on the inner surface of the lysosomal membrane are highly glycosylated.
OR 
- There are large numbers of glycoproteins and glycolipids on the inner surface of the lysosomal membrane.

[3rd mark]
- As the constituents of the lysosomal membrane are not complementary to the active sites of the lysosomal enzymes, they cannot fit into the active sites and thus, remain unhydrolysed. [1]
OR
- The glycosylation on the inner lysosomal membrane prevents the lysosomal enzymes from accessing the membrane phospholipids and proteins.