Question

Digestion in the enteron of Hydra starts with
a. Proteolytic enzymes
b. Amylolytic enzymes
c. Lipolytic enzymes
d. None of the above

Answer 1

Hint: Hydra belongs to the kingdom coelenterate of Animalia. The body of coelenterates bear a central gastrovascular cavity which opens to the outside through a single opening called mouth. Mouth is an aperture present on the hypostome. Hypostome is a conical elevation present on the free (non-attached) end of the body Entry of food and exit of waste material takes place through this single opening mouth.

Complete answer:
- Hydra flourishes well in cool, clean and stagnant water.
- Number of tentacles surrounding the mouth in Hydra is 6-10. Tentacles of Hydra are hollow while that of obelia are solid.
- Food of Hydra is water fleas (Daphnia and Cyclops). Thus, it is carnivorous. It cannot digest starch.
- No free larval stage in development of Hydra. Hence, development is direct.
- Most species of Hydra are dioecious/unisexual.
- Male Hydra bears 1-8 conical testes towards distal end whereas female Hydra bears 1-2 rounded ovaries towards proximal end of the body

Now let us match this with given options:-
> Proteolytic enzymes :- Food of Hydra is water fleas (Daphnia and Cyclops) . They are proteinaceous in nature. So, proteolytic enzymes act on proteins thus this option is correct.

> Amylolytic enzyme :- to digest starch that is grasses the organisms must have longer intestines but they do not have this much long intestine m they do not digest starch.

> Lipolytic enzyme :- this enzyme mainly acts on fat. But food of hydra does not contain fat as it consists of proteins. Thus, this enzyme does not act.

Hence, the correct answer is option (A).

Note: A piece of Hydra will regenerate into full Hydra if it contains a part of epidermis, gastrodermis and interstitial cells. If the body stalk of hydra is cut transversely into several segments, then in these segments, tentacles would regenerate at the end that was close to hypostome. Regeneration in Hydra was discovered by AbrahamTrembley