Question

Respiratory pigment present in cockroach is
A. Malpadin
B. Vanadium
C. Haemocyanin
D. None of these

Answer 1

Trachea is the respiratory organ found in cockroach. The trachea is a dense arrangement of a network of air tubes found in the internal system. When air enters into the body of the cockroach through spiracles into the tracheal tubes and it further diffuses into various tissues and cells of the body.

Complete answer:
- A cockroach belongs to the class insecta of phylum Arthropoda.
- They are brown or black bodied animals.
- The size of cockroach ranges from 0.6-7.6 cm.
- It consists of a long antenna, legs and flat extension of the upper body wall that conceals the head.

The body of cockroach is segmented and divisible into three distinct regions:
1. Head
2. Thorax
3. Abdomen

- The whole body of the cockroach is covered by the hard chitinous exoskeleton which is brown in colour.
- So, according to the question, the respiratory system of cockroaches consists of a network of trachea that open through 10 pairs of small holes known as spiracles that are present on the lateral side of the body.
- Tracheoles carry oxygen from the air and distribute it to all parts of the body.
- The opening of these spiracles is guided by the sphincters.
- Exchange of gases takes place at the tracheoles with the help of diffusion.
- Haemolymph is a colorless pigment present in the blood.
- There is no respiratory pigment found in the cockroaches.
- Malpani is the just the malpighian tubule system which is a type of excretory and osmoregulatory system found in cockroaches.
- Haemocyanin is a blue, copper-containing respiratory pigment found in crustaceans and molluscs.

Hence, the correct answer is option (D).

Note: Haemocyanin is a protein which transports oxygen in the bodies of some invertebrates. Their active centre has two copper atoms which reversibly bind a single oxygen molecule. Unlike the hemoglobin in red blood cells found in vertebrates, hemocyanins are not bound to blood cells.