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Human Health and Disease — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYHuman Health and Disease4 Marks
Question
Explain innate immunity in detail
✓

Answer

→Innate immunity is non-specific immunity, which is present at the time of birth.
1) Physical barrier :
→Our skin is the main physical barrier that prevents the entry of microorganisms.
→Mucous membrane lining the respiratory tract, gastrointestinal tract and urinary tract also helps to prevent germs from entering the body.
2) Physiological barrier:
→Acid in the stomach, saliva in the mouth, tears in the eyes etc. inhibit the growth of pathogens.
3) Cellular Barrier :
→Some white blood cells [WBCs] in our body, such as polymorphonuclear leukocytes and natural killer cells, a type of lymphoid cell in the blood, can feed on and destroy microbes.
(4)Cytokine barrier:
→Virus-infected cells secrete proteins called interferons, which protect other uninfected cells from virus infection.

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mRNA triplet
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UUU
Lysine
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Polypeptide produced
UUUAAAUUUAAA
Phenylalanine-Iysine-phenylalanine-Iysine

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AAA
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CCC
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Y
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Amnion
Chorion
(b)
Uterine wall
Placenta
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Placenta
Uterine wall
(d)
Uterine wall
Amnion
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  4. None of these
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  1. Assertion: Amniocentesis is legally banned for sex determination.

Reason: Amniocentesis was being misused for aborting normal female fetus.

  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
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