Question

Describe how the weakened virus is structurally different from the normal virus

Answer 1

The description is given below -

Viruses are pathogenic organisms which are weakened to use them as a vaccine. They are weakened by changing their genetic material.

Their toxins and part of their structure are also used to elicit an immune response.

They differ from the normal virus as they may have the absence of protective coating known as a capsid.

They may have altered genetic structure which causes a change in shape and structure of expressed protein.

The toxins released can also be non-virulent in comparison to unmodified virus.

Answer 2

The correct answer is given below.

Explanation:

• A normal viral particle is made up the following parts:

1. A viral particle is usually comprised of an outer covering called the capsid made up of glycoproteins.
2. These glycoproteins are essential for specifically infecting target cells.
3. A genetic material, DNA or RNA.
4. It utilise the machinery of the host that it infects to replicate and produce more virus particles.

• A weakened virus is prepared for the process of immunisation.
• It has got the following features which are different from a normal  virus in the following ways:

1. It is genetically modified.
2. Its outermost capsid covering is made such that it lacks one or more essential glycoproteins so that it is unable to infect any target cell.
3. Its genetic material is modified such that some of the essential genes necessary for its replication and assembly of new viral particles is absent.