CBSE 2025 · Region 1 · Set 1 · Q31 · 5 marks
Student to attempt either option-(A) or (B) :Answer the following questions :(i)State what do you understand by "MALT" ? Where it is located inside our body ?(ii)Explain cytokine barriers.(iii)Name the diagnostic test for AIDS. On what principle does it work ?(iv)Bone marrow and thymus play an important role in human immune system. Explain how are they able to achieve this.(B)Study the following table & fill 'H', 'I', 'J', 'K', 'L' and 'M' in following table with suitable words: Chemical / Bioactive Molecule Microorganism Category Use (a) Butyric acid H I Important applications in food, chemical pharma industry (b) J Monoscus purpureus K Inhibit cholesterol biosynthesis pathway (c) Cyclosporin A L Fungus M
(ii)Why are baculoviruses used as biological control agents ?
Student to attempt either option-(A) or (B) :
Answer the following questions :
(i)
State what do you understand by "MALT" ? Where it is located inside our body ?
(ii)
Explain cytokine barriers.
(iii)
Name the diagnostic test for AIDS. On what principle does it work ?
(iv)
Bone marrow and thymus play an important role in human immune system. Explain how are they able to achieve this.
(B)
Study the following table & fill 'H', 'I', 'J', 'K', 'L' and 'M' in following table with suitable words:
| Chemical / Bioactive Molecule | Microorganism | Category | Use | |
| (a) | Butyric acid | H | I | Important applications in food, chemical pharma industry |
| (b) | J | Monoscus purpureus | K | Inhibit cholesterol biosynthesis pathway |
| (c) | Cyclosporin A | L | Fungus | M |
(ii)
Why are baculoviruses used as biological control agents ?
Marking-scheme solution
(i)
$\displaystyle \star$ MALT is Mucosa Associated Lymphoid Tissue
$\displaystyle \star$ It is located within the lining of the major tracts like Respiratory or digestive or urogenital tract.
(ii)
Cytokine barriers – virus infected cells secrete proteins called interferons which protect non-infected cells from further viral infection.
(iii)
Enzyme Linked Immuno-sorbent Assay or ELISA ,ELISA is based on the principle of antigen-antibody interaction
PCR or Polymerase Chain Reaction , amplification of nucleic acid
(iv)
Both Bone marrow and thymus provide micro- environment for the development and maturation of T-lymphocytes / immature lymphocyte differentiate into antigen sensitive lymphocytes / Bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced and some lymphocytes migrate to thymus for development and maturation.
(i)
(a)
H = Clostridium butylicum
I = Bacteria
(b)
J = Statin
K = Fungi / Yeast
(c)
L = Trichoderma polysporum
M = Immunosuppressant /Suppress immune system in patients with newly transplanted organs
(ii)
Baculovirus are species specific, narrow spectrum insecticidal properties,No negative impact on non target species like plants or mammals or birds or fishes.
Human Health and DiseaseImmunityUnderstandlong_answermedium
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CBSE Class 12 Biology past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.