Question

The poisonous fluid present in nematocyst of Hydra is

• A. venom
• B. haematin
• C. toxin
• D. hypnotoxin

Answer 1

The correct option is D hypnotoxin

Nematocysts are venom-containing stinging organelles located in cnidocytes in cnidarians. The nematocyst is filled with a poisonous fluid called hypnotoxin. This is a mixture of proteins and phenols. The nematocyst is used for defence response of Hydra.

Any poisonous substance is called a toxin. Venom is a toxin which is present in some animals such as snakes, bees, scorpion, salamander, etc.

Haematin is a dark bluish or brownish pigment which is derived from the hemoglobin by the removal of the protein part and oxidation of haem resulting in the ferric state of iron.