🩺 NEET🧬 Biology

Human Health and Disease

5 solved NEET Biology previous year questions on Human Health and Disease, each with the correct answer and a full explanation.

Identify the site where Wuchereria bancrofti is normally found in the human body.

aMuscles of the legs

bBlood vessels of the thigh region

cSkin between the fingers

dLymphatic vessels of the lower limbs

✓ Correct answer: d) Lymphatic vessels of the lower limbs

ExplanationWuchereria bancrofti is a filarial parasite causing lymphatic filariasis.It resides in the lymphatic vessels, commonly affecting lower limbs.This leads to swelling and elephantiasis.Transmitted via mosquitoes, it's a major tropical disease.Symptoms include lymphedema and swelling.

The cell-mediated immunity inside the human body is carried out by:

aErythrocytes

bT-lymphocytes

cB-lymphocytes

dThrombocytes

✓ Correct answer: b) T-lymphocytes

ExplanationThe correct answer is B: T-lymphocytes.Cell-mediated immunity is the branch of adaptive immunity that does not involve antibodies.It is carried out by T-lymphocytes (T- cells), which: Recognize antigen-presenting cells Directly kill infected or cancerous cells Release cytokines to activate other immune cells B-lymphocytes are responsible for humoral (antibody-mediated) immunity, not cell-mediated immunity.Erythrocytes (red blood cells) and thrombocytes (platelets) have no role in adaptive immunity.

At which stage of HIV infection does one usually show symptoms of AIDS?

aWithin 15 days of sexual contact with an infected person.

bWhen the infected retrovirus enters host cells.

cWhen HIV damages large number of helper T lymphocytes.

dWhen the viral DNA is produced by reverse transcriptase.

✓ Correct answer: c) When HIV damages large number of helper T lymphocytes.

ExplanationThere is always a time lag between the infection and the appearance of AIDS symptoms.This period may vary from a few months to many years.

Drug called Heroin is synthesised by [NEET 2019]

aMethylation of morphine

bAcetylation of morphine

cGlycosylation of morphine

dNitration of morphine

✓ Correct answer: b) Acetylation of morphine

Explanation(2) Heroin is an Opioid drug.Frequently referred to as smack.It is obtained from the diacetylation of morphine.Morphine as such is an alkaloid obtained from the Poppy plant.Papaver somniferum or poppy is the source to many alkaloids with pharmacological properties.While methylation of morphine yields codeine.

Which of the following immune responses is responsible for rejection of kidney graft?

aAuto-immune response

bHumoral immune response

cInflammatory immune response

dCell-mediated immune response

✓ Correct answer: d) Cell-mediated immune response

ExplanationThe answer is D – Cell-mediated immune response.Graft rejection is primarily driven by T lymphocytes (T cells) that recognize the transplanted kidney as foreign (non-self).These T cells activate and proliferate, triggering an immune attack against the graft tissue.This is a classic example of a cell- mediated immune response (Type IV hypersensitivity).Humoral immune response (option B) also contributes to rejection (via antibodies), but cell-mediated immunity is the main mechanism.Auto-immune response (option A) refers to the immune system attacking self-antigens, which is different from graft rejection.Inflammatory immune response (option C) is a broader term and not specific to graft rejection.

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