Human Health and Disease: NEET PYQ, 2018–2026

Q1 · Zoology · Human Health and Disease

Chronic use of alcohol can damage the liver, causing:

• Agoitre
• Bemphysema
• Ccirrhosis
• Drickets

Q2 · Zoology · Human Health and Disease

A community's drinking water becomes contaminated, and many people develop severe watery diarrhoea that leads to dehydration. Which organism is most likely responsible, and what is the most appropriate immediate treatment?

• AVibrio cholerae; oral rehydration salts to replace lost water and electrolytes.
• BSalmonella typhi; antibiotics alone, with rehydration not needed.
• CEntamoeba histolytica; metronidazole alone, with no need for fluid replacement.
• DVibrio cholerae; antiviral drugs, since cholera is caused by a virus.

Q3 · Zoology · Human Health and Disease

A patient receiving chemotherapy for a solid tumour develops hair loss and a fall in neutrophil and platelet counts. Which statement best explains these side effects?

• AChemotherapeutic drugs bind specifically to keratin in hair and to clotting factors, so the damage is confined to those molecules.
• BChemotherapeutic drugs act on rapidly dividing cells in general, so normal dividing cells such as hair follicle cells and bone marrow precursors are also damaged.
• CChemotherapeutic drugs act mainly on cells in the resting G0 phase, so only non-dividing somatic cells are harmed.
• DChemotherapy stimulates apoptosis of mature erythrocytes directly, which is why haemoglobin falls, and this has no effect on dividing cells.

Q4 · Zoology · Human Health and Disease

Which of the following is a primary lymphoid organ?

• ASpleen
• BThymus
• CLymph node
• DPeyer's patches

Q5 · Zoology · Human Health and Disease

In rheumatoid arthritis, the body's immune system attacks the joint tissues. Which mechanism most directly explains this self-attack?

• AFailure of self-tolerance, allowing lymphocytes that react to the body's own antigens to escape deletion and become active
• BLoss of MHC class II from all antigen-presenting cells, so the immune system cannot detect any antigen
• COverproduction of histamine by mast cells, which directly destroys joint cartilage
• DPhagocytes losing the ability to engulf microbes, so pathogens damage the joints unchecked

Q6 · Zoology · Human Health and Disease

A virus has evolved to reduce surface expression of MHC class I molecules on the cells it infects, which allows it to escape recognition by CD8+ cytotoxic T lymphocytes. Which cell type is best placed to destroy such an infected cell, and why?

• ANatural killer cells, because they recognise the reduced MHC class I expression and kill the infected cell without needing prior sensitisation to that virus.
• BHelper T lymphocytes, because loss of MHC class I activates them directly, and they release perforin that lyses the infected cell.
• CCytotoxic T lymphocytes that have been sensitised to the virus, because they recognise viral antigen presented on MHC class II and then release perforin.
• DMacrophages, because they engulf the infected cell only after antibody binds to its surface, using their Fc receptors to perform complete destruction.

Q7 · Zoology · Human Health and Disease

The Widal test is a common laboratory test for typhoid fever. What does it detect?

• ASalmonella typhi bacteria directly in a blood smear
• BAntibodies in the patient's serum that react with Salmonella typhi antigens
• CPlasmodium parasites inside red blood cells
• DViral RNA of a flavivirus in the bloodstream

Q8 · Zoology · Human Health and Disease

A mutation that inactivates both copies of a tumour suppressor gene such as Rb or p53 contributes to cancer most directly because:

• AThe gene product normally restrains cell division, so losing it removes a brake on proliferation.
• BThe gene product is a growth-promoting protein whose activity is increased, so proliferation accelerates.
• CThe mutation multiplies the number of copies of the gene, amplifying a growth signal.
• DThe mutation affects only cell shape and not division, so it cannot contribute to tumour formation.

Q9 · Zoology · Human Health and Disease

Papain digestion of an IgG molecule yields two identical antigen-binding fragments and one crystallisable fragment. Which statement correctly describes where antigen specificity and effector function reside?

• AAntigen binding is carried by the Fab fragments, which contain the variable regions of both heavy and light chains; the Fc fragment, formed from heavy-chain constant regions, mediates effector functions such as binding to phagocytes and complement.
• BAntigen specificity is conferred by the constant regions of the light chains, and the variable regions form the Fc fragment that binds phagocytes.
• CAntigen binding is carried by the Fc fragment, because it contains the hinge region that allows flexible docking onto antigen, while the Fab fragments carry only constant regions that bind complement.
• DEach Fab fragment contains only one light chain, so antigen binding requires the Fc fragment to pair the two light chains; effector functions are carried by the Fab fragments through their light-chain variable regions.

Q10 · Zoology · Human Health and Disease

Which of the following drugs is classed as a hallucinogen?

• ALysergic acid diethylamide (LSD)
• BAmphetamine
• CMorphine
• DNicotine