TRB PG Assistant - Structure and life history of protozoa – Entamoeba, Plasmodium species, Trypanosoma, Leishmania Online Test (MCQ Quiz)

1. Which protozoan parasite causes amoebic dysentery in humans?

A) Plasmodium vivax B) Trypanosoma brucei C) Entamoeba histolytica D) Leishmania donovani

2. What is the infective stage of Plasmodium species that is transmitted to humans by mosquito bite?

A) Merozoite B) Sporozoite C) Trophozoite D) Gametocyte

3. Which vector is responsible for transmitting Trypanosoma species that cause African sleeping sickness?

A) Anopheles mosquito B) Aedes mosquito C) Tsetse fly D) Sandfly

4. Leishmania donovani is the causative agent of which disease?

A) Malaria B) Kala-azar (Visceral leishmaniasis) C) Chagas disease D) Amoebiasis

5. In the life cycle of Entamoeba histolytica, which stage is typically found in the lumen of the large intestine and is responsible for excystation?

A) Trophozoite B) Binucleated cyst C) Quadrinucleated cyst D) Metacyst

6. Which stage of Plasmodium is responsible for the characteristic chills and fever in malaria patients due to rupture of infected erythrocytes?

A) Sporozoite B) Merozoite C) Trophozoite D) Hypnozoite

7. The relapse of malaria, especially in cases of Plasmodium vivax and Plasmodium ovale infections, is caused by the reactivation of which dormant stage in the liver?

A) Merozoites B) Sporozoites C) Hypnozoites D) Gametocytes

8. What is the primary mode of transmission for Entamoeba histolytica?

A) Blood transfusion B) Sexual contact C) Ingestion of contaminated food or water D) Insect bite

9. Trypanosoma cruzi, the causative agent of Chagas disease, is transmitted by which type of insect vector?

A) Tsetse fly B) Kissing bug (Reduviid bug) C) Sandfly D) Anopheles mosquito

10. Which form of Leishmania is found within the macrophages of the host and the sandfly vector?

A) Promastigote B) Amastigote C) Epimastigote D) Trypomastigote

11. The quadrinucleated cyst of Entamoeba histolytica is the infective stage for humans. What happens upon ingestion?

A) It directly enters the bloodstream. B) It undergoes excystation in the small intestine to form trophozoites. C) It is eliminated in the feces without causing infection. D) It develops into a gametocyte.

12. Which species of Plasmodium is responsible for the most severe and potentially fatal form of malaria?

A) Plasmodium vivax B) Plasmodium ovale C) Plasmodium malariae D) Plasmodium falciparum

13. The 'undulating membrane' is a characteristic structure found in which protozoan genus?

A) Entamoeba B) Plasmodium C) Trypanosoma D) Leishmania

14. What is the primary reservoir for Trypanosoma brucei gambiense, the cause of West African sleeping sickness?

A) Rodents B) Domestic animals C) Humans D) Wild game

15. The 'promastigote' form of Leishmania is characterized by a flagellum originating from the anterior end. Where does this form typically develop?

A) Inside the host macrophage B) In the human bloodstream C) In the gut of the sandfly D) In the liver cells

16. During the erythrocytic cycle of Plasmodium, what is the stage that invades red blood cells?

A) Sporozoite B) Trophozoite C) Merozoite D) Gametocyte

17. Which of the following is NOT a characteristic feature of Entamoeba histolytica trophozoites?

A) Irregular shape B) Single nucleus with a small, centrally located karyosome C) Inclusion of ingested red blood cells in the cytoplasm D) Presence of cilia for motility

18. The long, slender, and motile form of Trypanosoma found in the blood of the mammalian host is called:

A) Amastigote B) Epimastigote C) Trypomastigote D) Promastigote

19. The vector for Leishmania species is a:

A) Mosquito B) Tsetse fly C) Sandfly D) Tick

20. The sexual reproduction phase of Plasmodium occurs in the:

A) Human liver B) Human red blood cells C) Mosquito's midgut D) Mosquito's salivary gland

21. Entamoeba coli is a commensal protozoan that resides in the human intestine. How does it differ morphologically from Entamoeba histolytica?

A) Entamoeba coli cysts have fewer nuclei. B) Entamoeba coli trophozoites have a larger, eccentric karyosome and may contain bacteria. C) Entamoeba coli does not form cysts. D) Entamoeba histolytica trophozoites have a more regular shape.

22. Which stage of Plasmodium develops into gametocytes (male and female)?

A) Sporozoite B) Merozoite C) Trophozoite D) Hypnozoite

23. The 'salivarian' transmission mode, where the parasite is injected into the host during feeding, is characteristic of which genus?

A) Entamoeba B) Plasmodium C) Trypanosoma (e.g., T. brucei) D) Leishmania

24. The amastigote form of Leishmania is oval-shaped and lacks an external flagellum. It is the form that multiplies within:

A) The sandfly's proboscis B) The human liver cells and macrophages C) The mosquito's salivary glands D) The human red blood cells

25. The pre-erythrocytic schizogony of Plasmodium occurs in which organ?

A) Red blood cells B) Spleen C) Liver D) Lymph nodes

26. Which stage of Entamoeba histolytica is found in diarrheal stools and is responsible for the spread of infection?

A) Trophozoite B) Mature cyst C) Immature cyst D) Metacyst

27. The kinetoplast is a dense granule of mitochondrial DNA found in which protozoan genera?

A) Entamoeba and Plasmodium B) Trypanosoma and Leishmania C) Plasmodium and Leishmania D) Entamoeba and Trypanosoma

28. The 'chironomid' or 'black fly' is the vector for which species of Trypanosoma that causes disease in animals (e.g., nagana)?

A) Trypanosoma cruzi B) Trypanosoma brucei rhodesiense C) Trypanosoma brucei gambiense D) Trypanosoma theileri

29. In the life cycle of Plasmodium, the formation of sporozoites occurs within the:

A) Human liver B) Mosquito's midgut C) Mosquito's salivary glands D) Human red blood cells

30. Which of the following is a characteristic feature of the Entamoeba histolytica trophozoite found in intestinal lesions?

A) Rounded shape with a thick cyst wall B) Presence of multiple nuclei C) Inclusion of ingested red blood cells D) Motility via pseudopodia

31. The ' Romana's sign', characterized by unilateral periorbital edema, is associated with acute Chagas disease caused by:

A) Trypanosoma brucei B) Leishmania donovani C) Trypanosoma cruzi D) Plasmodium falciparum

32. The 'visceral form' of leishmaniasis (Kala-azar) is characterized by the widespread presence of amastigotes in which organs?

A) Skin and lymph nodes B) Brain and spinal cord C) Liver, spleen, and bone marrow D) Red blood cells and lungs

33. Which stage of Plasmodium is responsible for the production of merozoites in the liver during the exo-erythrocytic cycle?

A) Gametocyte B) Sporozoite C) Trophozoite D) Schizont

34. Entamoeba gingivalis is a protozoan commonly found in the human mouth. Unlike Entamoeba histolytica, it:

A) Forms cysts B) Does not ingest red blood cells C) Causes amoebic dysentery D) Is transmitted via contaminated water

35. The 'epimastigote' form of Trypanosoma, with flagellum attached along the body by an undulating membrane, is found in the:

A) Blood of the mammalian host B) Salivary glands of the tsetse fly C) Midgut and salivary glands of the kissing bug D) Liver cells of the mammalian host

36. Which Plasmodium species has a shorter incubation period and is often associated with high parasitemia and severe complications?

A) Plasmodium vivax B) Plasmodium malariae C) Plasmodium falciparum D) Plasmodium ovale

37. The 'benign tertian malaria' is caused by which Plasmodium species, characterized by fever every third day?

A) Plasmodium falciparum B) Plasmodium malariae C) Plasmodium vivax D) Plasmodium ovale

38. The most common and infective stage of Entamoeba histolytica found in formed stools is the:

A) Trophozoite B) Binucleated cyst C) Quadrinucleated cyst D) Metacyst

39. In the life cycle of Trypanosoma brucei, the parasite undergoes development in both the tsetse fly and the mammalian host. Which form multiplies by binary fission in the insect's gut?

A) Trypomastigote B) Amastigote C) Epimastigote D) Promastigote

40. The 'cutaneous leishmaniasis' (e.g., Oriental sore) is primarily caused by Leishmania species that infect which tissue?

A) Visceral organs B) Red blood cells C) Skin macrophages D) Central nervous system

41. What is the characteristic periodicity of fever in quartan malaria, caused by Plasmodium malariae?

A) Every 24 hours B) Every 48 hours C) Every 72 hours D) Irregular

42. Which protozoan genus is characterized by the absence of flagella or cilia in its adult form and reproduces asexually via binary fission?

A) Trypanosoma B) Plasmodium C) Entamoeba D) Leishmania

43. The 'African trypanosomiasis' is also known as:

A) Chagas disease B) Kala-azar C) Sleeping sickness D) Malaria

44. The 'circumventricular organs' of the brain are targeted by certain Trypanosoma species, leading to neurological symptoms. Which species is most associated with this?

A) Trypanosoma cruzi B) Trypanosoma brucei gambiense C) Trypanosoma rangeli D) Trypanosoma lewisi

45. Which stage of Plasmodium is taken up by the Anopheles mosquito when it feeds on an infected human?

A) Merozoite B) Trophozoite C) Gametocyte D) Sporozoite

46. The 'cyst wall' of Entamoeba histolytica is primarily composed of:

A) Chitin B) Cellulose C) Protein and carbohydrates D) Lipids

47. The 'Shizont' stage of Plasmodium, containing multiple merozoites, develops within which cell type in humans?

A) Liver cells B) Red blood cells C) White blood cells D) Platelets

48. Which protozoan is known for its polymorphic forms and complex life cycle involving different stages in the blood and within insect vectors?

A) Entamoeba histolytica B) Plasmodium species C) Trypanosoma species D) Leishmania species

49. The 'erythrocytic schizont' of Plasmodium contains approximately how many merozoites?

A) 6-12 B) 12-24 C) 30-50 D) 100-200

50. Which of the following is a key diagnostic feature for identifying Entamoeba histolytica in stool samples?

A) Presence of oocysts B) Encysted Giardia C) Trophozoites with ingested red blood cells D) Cysts with multiple nuclei and chromatid bodies

Structure and life history of protozoa – Entamoeba, Plasmodium species, Trypanosoma, Leishmania - Online Test

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