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Biology · 2023 · 2 marks
CBSE 2023 · Region 5 · Set 3 · Q19
(a) Certain specific bacterial spores are mixed in water and sprayed over Brassica crop to control butterfly catterpillars. Name this bacterium and…
Certain specific bacterial spores are mixed in water and sprayed over Brassica crop to control butterfly catterpillars. Name this bacterium and its mode of action on the butterfly catterpillars.
Immunotherapy these days is one of the most efficient way of treatment of cancer. The therapy involved activates the immune system and destroys the tumour.
(i)
Write an example of one such biological response modifier used in immunotherapy.
(ii)
Why do patients need such substances if immune system is already working in body ?
(iii)
State what is 'Contact inhibition'.
Marking-scheme solution
(a)
Bacillus thuringiensis
In the gut of the larva the toxin is released/activated and larva get killed.
OR
(b) (i) \(\displaystyle \alpha\) - Interferons
(ii) Activates immune system to destroy cancer cells / tumor.
(iii) The property of normal cell by virtue of which contact with other cells inhibits their uncontrolled growth.
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CBSE Class 12 Biology past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.