Coordination compound have great importance in biological systems. In this context which of the following statements is incorrect?

Option A: Chlorophylls are green pigments in plants and contains calcium

Chlorophyll is the green pigment responsible for photosynthesis in plants. Structurally, it is a coordination complex consisting of a porphyrin-like ring (a chlorin ring) coordinated to a central metal ion. However, that central metal ion is Magnesium ($$\text{Mg}^{2+}$$), not calcium. Because this statement names the wrong metal, it is factually incorrect.

Result: INCORRECT STATEMENT (Our Answer)

Option B: Carboxypeptidase-A is an enzyme and contains zinc

Carboxypeptidase-A is a metalloenzyme secreted by the pancreas that hydrolyzes peptide bonds during digestion. It contains a catalytic Zinc ($$\text{Zn}^{2+}$$) ion at its active site, which acts as a Lewis acid to polarize the carbonyl group of the substrate.

Result: CORRECT STATEMENT

Option C: Cyanocobalamin is $$\text{B}_{12}$$ and contains cobalt

Vitamin $$\text{B}_{12}$$, scientifically known as cyanocobalamin, is an essential organometallic coordination compound. It features a macrocyclic corrin ring framework that coordinates a central Cobalt ($$\text{Co}}$$) atom.

Result: CORRECT STATEMENT

Option D: Haemoglobin is the red pigment of blood and contains iron

Haemoglobin is the iron-containing oxygen-transport metalloprotein present in the red blood cells of vertebrates. It contains four subunits, each featuring a heme group where an Iron ($$\text{Fe}^{2+}$$) ion sits coordinated at the center of a porphyrin ring.

Result: CORRECT STATEMENT