Question

Assertion: Secondary immune response is always faster than the primary immune response

Reason: Memory cells produced during the primary infection are able to identify the antigen quickly

• A. Both assertion and reason are false
• B. Both assertion and reason are true, and the reason is not the correct explanation of the assertion
• C. Both assertion and reason are true, and the reason is the correct explanation of the assertion
• D. The assertion is true but reason is false

Answer 1

The correct option is C Both assertion and reason are true, and the reason is the correct explanation of the assertion

The immune system of our body tries to destroy and eliminate any foreign material (pathogens/toxins) that enters the body. The part of the pathogen that generates an immune response in the body is called antigen.

During immune response, antibodies are generated in response to the antigen. These antibodies trap the antigens and eventually the pathogens are eliminated from the body with the help of various components of the immune system.

The immune responses are of two types - primary immune response and secondary immune response.

The immune response generated by the body during the first encounter with a pathogen (bacteria, viruses, protozoans etc,) is called the primary immune response. It is slow and of low intensity.

If the same individual is subsequently exposed to the same pathogen, then the immune response generated this time is highly intensified. This is called the secondary immune response or anamnestic response. This is due to the fact that our body appears to have memories of the first encounter.
The memory B cells produced during the primary response are able to respond quickly by producing antibodies.

Hence, both assertion and reason are correct and the reason correctly explains the assertion.

Figure: The primary and secondary immune response