Protozoa

Here are 11 Multiple Choice Questions (MCQs) on protozoa:

Question 1: Which of the following protozoan causes amoebic dysentery?

a) Plasmodium vivax

b) Entamoeba histolytica

c) Giardia lamblia

d) Trypanosoma cruzi 

Correct Answer: b) Entamoeba histolytica

Explanation: Entamoeba histolytica is responsible for amoebic dysentery, which involves the invasion of the gut lining, causing diarrhea and potential liver abscesses.

Question 2: What is the primary mode of transmission for malaria?

a) Contaminated water

b) Mosquito bite

c) Direct contact

d) Fecal-oral route 

Correct Answer: b) Mosquito bite

Explanation: Malaria is transmitted through the bite of infected female Anopheles mosquitoes, which introduce Plasmodium parasites into the human bloodstream.

Question 3: Which protozoan is known for causing African Sleeping Sickness?

a) Leishmania donovani

b) Trypanosoma brucei

c) Toxoplasma gondii

d) Trichomonas vaginalis 

Correct Answer: b) Trypanosoma brucei

Explanation: Trypanosoma brucei gambiense and T. brucei rhodesiense are the subspecies that cause African trypanosomiasis, known as sleeping sickness.

Question 4: The life cycle of Plasmodium includes:

a) Only asexual reproduction

b) Both sexual and asexual reproduction

c) Only sexual reproduction

d) Binary fission 

Correct Answer: b) Both sexual and asexual reproduction

Explanation: Plasmodium undergoes asexual reproduction in humans and sexual reproduction in the mosquito vector, completing its complex life cycle.

Question 5: Which protozoan infection is commonly transmitted through cat feces?

a) Cryptosporidiosis

b) Giardiasis

c) Toxoplasmosis

d) Leishmaniasis 

Correct Answer: c) Toxoplasmosis

Explanation: Toxoplasma gondii infection, or toxoplasmosis, can be transmitted through oocysts shed in cat feces, posing risks particularly to pregnant women and immunocompromised individuals.

Question 6: What is the characteristic motility of Giardia lamblia?

a) Gliding

b) Jerky, twitching movements

c) Flagellar

d) Amoeboid 

Correct Answer: c) Flagellar

Explanation: Giardia lamblia uses flagella for motility, giving it a characteristic "falling leaf" motion in wet mounts.

Question 7: Which of these protozoa is known for causing a sexually transmitted infection?

a) Entamoeba histolytica

b) Plasmodium falciparum

c) Trichomonas vaginalis

d) Leishmania tropica 

Correct Answer: c) Trichomonas vaginalis

Explanation: Trichomonas vaginalis is the causative agent of trichomoniasis, a common sexually transmitted infection affecting the urogenital tract.

Question 8: The cyst stage in protozoa is associated with:

a) Active metabolism

b) Motility

c) Survival under harsh conditions

d) Sexual reproduction 

Correct Answer: c) Survival under harsh conditions

Explanation: Cysts are dormant, resistant forms of protozoa that allow survival outside the host, in environments lacking nutrients or with unfavorable conditions.

Question 9: Which protozoan is responsible for kala-azar, a severe form of leishmaniasis?

a) Leishmania tropica

b) Leishmania major

c) Leishmania donovani

d) Leishmania mexicana 

Correct Answer: c) Leishmania donovani

Explanation: Leishmania donovani causes visceral leishmaniasis, also known as kala-azar, which affects the internal organs and can be fatal if untreated.

Question 10: What is the vector for Chagas disease?

a) Mosquito

b) Sandfly

c) Triatomine bug (kissing bug)

d) Tsetse fly 

Correct Answer: c) Triatomine bug (kissing bug)

Explanation: Trypanosoma cruzi, the causative agent of Chagas disease, is transmitted by the triatomine bug, commonly known as the kissing bug.

Question 11: Which protozoan infection can result in heart disease over the long term?

a) Malaria

b) Amoebiasis

c) Chagas disease

d) Giardiasis 

Correct Answer: c) Chagas disease

Explanation: Chronic Chagas disease, caused by Trypanosoma cruzi, can lead to cardiac complications including cardiomyopathy due to the damage of heart muscle cells.