Health and Hygiene – Diseases, Bacteria, Viruses, Parasites Quiz - ICSE Class 9 Biology
Free practice quiz: Health and Hygiene – Diseases, Bacteria, Viruses, Parasites (ICSE Class 9 Biology). 49 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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Which of the following diseases is primarily transmitted through contaminated water and sanitation, often leading to severe dehydration due to profuse watery diarrhea?
- Tuberculosis
- Malaria
- Cholera
- Dengue Fever
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Answer: C. Cholera
Cholera is an acute diarrheal illness caused by infection of the intestine with Vibrio cholerae bacteria. The infection is often associated with consuming contaminated water or food, leading to severe dehydration. Tuberculosis is airborne, Malaria is mosquito-borne, and Dengue Fever is also mosquito-borne.
The life cycle of *Schistosoma mansoni*, a parasitic flatworm causing schistosomiasis, involves an aquatic snail as an intermediate host. Humans are infected when:
- Consuming undercooked fish containing cercariae.
- Inhaling airborne spores from infected snails.
- Larval forms (cercariae) penetrate the skin during contact with contaminated water.
- Ingesting eggs passed in the feces of infected animals.
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Answer: C. Larval forms (cercariae) penetrate the skin during contact with contaminated water.
Schistosomiasis is contracted when free-swimming larval forms of the parasite (cercariae), released from infected freshwater snails, penetrate the skin of humans during contact with infested water. Consuming undercooked fish might transmit other parasites. Inhaling spores is related to fungi. Ingesting eggs is a route for some roundworms and tapeworms, but not the primary route for Schistosoma.
The antibiotic penicillin works by inhibiting:
- Bacterial protein synthesis
- Bacterial DNA replication
- Bacterial cell wall synthesis
- Viral RNA polymerase
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Answer: C. Bacterial cell wall synthesis
Penicillin and its derivatives are beta-lactam antibiotics that interfere with the synthesis of peptidoglycan, a crucial component of bacterial cell walls. This weakens the cell wall, leading to cell lysis. Bacterial protein synthesis is targeted by drugs like tetracyclines and macrolides. DNA replication is targeted by quinolones. Viral RNA polymerase is a target for some antiviral drugs.
Which of these diseases is caused by a rickettsia bacterium and transmitted by ticks, characterized by fever, headache, and a rash that often starts on the extremities?
- Malaria
- Lyme Disease
- Rocky Mountain Spotted Fever
- Plague
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Answer: C. Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever (RMSF) is caused by *Rickettsia rickettsii*, a bacterium transmitted by ticks. Symptoms typically include fever, headache, and a rash that often appears on the wrists and ankles. Lyme disease is caused by *Borrelia burgdorferi* and transmitted by ticks. Malaria is caused by *Plasmodium* protozoa and transmitted by mosquitoes. Plague is caused by *Yersinia pestis* and transmitted by fleas.
Which of the following is a protozoan parasite that causes malaria and is transmitted to humans by the bite of an infected female *Anopheles* mosquito?
- *Trypanosoma brucei*
- *Plasmodium falciparum*
- *Leishmania donovani*
- *Giardia lamblia*
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Answer: B. *Plasmodium falciparum*
*Plasmodium falciparum* is one of the species of *Plasmodium* that causes malaria in humans. The other parasites listed cause different diseases: *Trypanosoma brucei* causes sleeping sickness, *Leishmania donovani* causes visceral leishmaniasis (kala-azar), and *Giardia lamblia* causes giardiasis.