Question

ASSERTION: Trichonympha is a cellular-digesting insect- gut zooflagellate.
REASON: The protozoan secretes glucosidases which convert cellulose into glucose.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Hint: The referred organism is a protozoan, which lives in symbiotic association in the hindgut of wood roaches and lower termites. Its association with the other organism is mutually beneficial for both these as one of these helps the host to digest cellulose and in return, it receives a constant food supply and shelter.

Complete step by step answer:
Features of Trichonympha are –
1. It is bell-shaped and has haploid adult stage
2. In termites, Trichonympha dies at the time of molting.
3. It can reproduce by both sexually and asexually (binary fission) methods.
4. Trichonympha also live as a symbiont in the alimentary canal of wood roaches and encysted itself before 6 days of molting and reproduces sexually.
5. Encystment helps in sexual reproduction during favorable conditions by helping the organism survive through the unfavorable conditions in a state of minimal activity that requires minimum nutrition. Therefore, the organism survives the harsh conditions by minimizing its metabolic activities.

Hence, the correct answer is option A.

Additional information: Encystment in termites and wood roaches can be explained by two hypotheses - During molting time the gut environment becomes hostile which includes lack of food and oxygen bubble formation which may result in widespread encystment. Due to hormonal changes of lower termites.

Note: Trichonympha lives suitably in termites and wood roaches because hosts have a diet containing wood and wood related items and hosts are unable to digest these cellulose-rich items because of the absence of digesting metabolism. They survive unfavorable environmental conditions by forming cysts which are capable of keeping the organism viable even during extreme climatic conditions.