Question

"1)It is generallyobserved that the children who suffered from chickn poxin their chiodhood may not contain the same disease in their adulthood . Explain giving reason the basis of such an immunity in an individual . Name the kind of immunity?
2)What are interferons? mention their role?

class 12th CBSE Biology sample paper

Answer 1

1) If the pathogen  (chickenpox) succeed in causing disease first time, specific antibodies ( by humoral immune response) are produced to counter he first attack.

The immune system has memory cells .

Due to this , on subsequent exposure to the chickenpox does not cause disease due to the humoral immune response of the body.

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2)Interferons are special kind of proteins secreted by virus infected cells .

These protect the healthy cells from the virus attack.