Question

Haemocyanin is found in
a. Neries
b. Leech
c. Earthworm
d. Prawn

Answer 1

Haemocyanins are proteins that carry oxygen in certain invertebrate animals' bodies. Two copper atoms contain these metalloproteins, which reversibly bind to a single molecule of oxygen $(O_2)$. They are second only to hemoglobin as an oxygen transport molecule in frequency of use.

Complete answer:
• As we know that the Neries, Leech and Earthworm are the organisms which come under the phylum Annelida which are carrying Haemoglobin pigment for the transportation of nutrients and gases.
• The species that come under the phylum Annelida which carry Haemoglobin pigment for the transport of nutrients and gases are Nereis, Leech and Earthworm.
• Haemocyanins are present in molluscs, crustaceans and arthropods. Haemocyanins are proteins in the structures of invertebrate organisms that transport oxygen. Hemocyanin are not bound to the cells of the blood but are directly suspended in the hemolymph. Oxygenation induces a color change between the deoxygenated form of the colorless Cu(I) and the blue Cu(II) oxygenated form.
• Many individual subunit proteins are made of hemocyanin, each of which contains two copper atoms and can bind one molecule of oxygen $(O_2)$. The weight of each subunit is about 75 kilodaltons (kDa). Depending on the species, subunits can be organized into dimers or hexamers; the dimer or hexamer complex is often arranged in chains or clusters. Unlike the hemoglobin present in vertebrates in red blood cells, hemocyanins are not attached to blood cells but are directly retained in the hemolymph instead.

Hence, the correct answer is option (D).

Note: We need to know that the Phenol Oxidases, hexamerins, pseudo hemocyanins or cryptocyanine, (dipteran) hexamerin receptors form the arthropod hemocyanin superfamily. Phenoloxidase is a tyrosinase containing copper. These proteins are present in the arthropod cuticle sclerotization method, in tissue regeneration, and in humoral immune protection. Phenoloxidase synthesizes and is activated by zymogens.