Question

The blood pigment present in earthworm is:
a. Haemocyanin
b. Haematin
c. Haemoglobin
d. Cyanin

Answer 1

As you know blood is a connective tissue that transports oxygen to the tissues of the whole body. The blood does not carry oxygen in raw form; it carries oxygen by binding it to one of its components and delivering it to the right place. The component that carries oxygen is the pigment that is present in blood. There are many types of pigments that are present in various organisms like that of haemoglobin present in humans.

Complete answer:
The earthworms exhibit a closed type of blood vascular system, consisting of blood vessels, capillaries and heart. Contractions of the body keep the blood flowing unidirectional. The blood pigment present in earthworms is haemoglobin. They produce blood cells and haemoglobin which is dissolved in blood plasma. Also, they lack red blood cells in their circulatory system as the gaseous exchange between the cells occurs through the skin.

There are three main vessels that supply blood to the body of the earthworm which are aortic arches, dorsal blood vessels and ventral blood vessels. The aortic arches work like the human heart. It has five parts which supply the blood to the dorsal and ventral blood vessels which take blood to the front part and back part of the earthworm’s body respectively.

Hemocyanin are pigments that are found only in phylum Mollusca and Arthropoda. Hemocyanin can bind to only one oxygen molecule at a time; therefore organisms have evolved another system that is a tracheal system in which the oxygen is directly transported to the organs.

Haematin, also known as hematin is a dark bluish or brownish pigment containing iron in the ferric state, which is obtained by oxidation of haem. Whereas Cyanin is a plant pigment belonging to a family of plant pigment called anthocyanins. Anthocyanins are water soluble vacuolar pigments that may appear red, purple, blue or black depending on their pH.

Hence, The correct answer is option (C).

Note: The pigments found in blood are not permanent; they lose their oxygen carrying capacity after sometime. They get renewed that is manufactured again in their specific place for better working. For example, the red blood cells that carry oxygen in humans have a lifespan of about 120 days, after that they get broken down and are manufactured in the bone marrow of the human body.