Question

Stinging capsules (nematocysts) are found in
A) Scypha and brain coral
B) Cliona and chalina
C) Sea pen and sea fan
D) Grantia and Velella

Answer 1

Hint: Nematocysts have specific capsules known as cnidoblast. They have most common intracellular secretion products. Nematocysts belong to the phylum Coelenterate. Stinging capsules help them to catch prey. Scypha is a sponge while Brain coral belongs to the coral family. Sea pen and sea fan both belong to Coelenterate.

Complete answer:
Stinging capsules (nematocysts) are the organs which act as offence and defense. They belong to phylum Coelenterata. Phylum Cnidarians have specialized cells. Specialized neural cells are also known as stinging cells. Cnidocyst is important to capture prey and also used for defence. They have complexity in their structure and functions. Transcriptomes have unique organelles. Cnidocyst is the product of Golgi secretion. These are composed of a complex capsule polymer characterized by cysteine-rich peptides. They have coiled; hollow, usually barbed thread which contains poison and used to ward off enemies or to capture prey.
Scypha includes sponge. Brain corals are the members of corals. They have spheroid shape and grooved surface which resembles a brain. Cliona celata are also called red boring sponge. It belongs to the family of Clionaidae. Grantia is also sponge and velella is a cnidarian. Sea pen and sea fan are members of the phylum nematocysts. These both belong to Coelenterates.
From the above information we have found that stinging capsules are found in sea pens and sea fans.

So, option C is the correct answer.

Note: Nematostella vectensis, a rising model organism for the study and characterization of the cnidocyte. The presence of cnidae separates jellyfish and other cnidarians from other animals. The effect of stings is very dangerous for humans and may cause paralysis, shock, and even death. Capsules can be divided into three main categories: (i) nematocysts (ii) spirocysts (ptychocysts). It can be divided into 25 subcategories. It has several genetic and biochemical molecular mechanisms.