Question

In which form would chromatoid bodies in Entamoeba histolytica be produced?
a. In minute form
b. In metacyst
c. In trophozoite
d. In cyst

Answer 1

Hint: The chromatoid bodies or chromatoid bars are present in the form of Entamoeba histolytica that can survive outside the body of the host, in extreme environmental conditions. This form of the Entamoeba is inactive and it only becomes active when it enters the host organism and sheds its layers. This dormant structure contains within itself the active form of Entamoeba.

Complete answer:
The chromatoid bodies are present in the cyst form of Entamoeba histolytica.
Chromatoid structures or bars are present on the cysts as elongated bars with rounded edges. They are crystallized ribonucleoproteins and are visible when the parasite is stained with trichrome or iodine. They get formed when ribosomes arrange themselves in helices and aggregate. They may not always be present, but they are a characteristic feature of Entamoeba histolytica.

The cyst of this parasite contains the active form with, i.e. the trophozoites. Trophozoites are the active forms of Entamoeba histolytica. Cysts are present outside the body of the host, in soil, water, and food. They thrive in moist and humid environments. Once the cysts enter the body of the host organism, they form trophozoites in the small intestine. These trophozoites then enter the large intestine and invade the cell, thereby causing the disease Amoebiasis.

Hence, the correct answer is option (D).

Note: Chromatoid bars are present in the early stages of the cyst and contain mainly ribonucleic acid and proteins.
During the formation of chromatoid bodies, there is a rise in the rate of RNA production in the cell. So, even though the ribonucleic acid is being used for creating the chromatoidal bars, the total amount remains constant.