Question

Define the ? 1. Hemoglobin :

Answer 1

It is a protein that helps red blood cells carry oxygen.

Explanation:

Haemoglobin is a special protein inside red blood cells which maximises the efficiency of those red blood cells to carry oxygen. It is also responsible for the red colour of the blood.

It contains an iron(II) `(Fe^(2+))` atom in the center, and a heme group around it, which is defined as a coordination complex "consisting of an iron ion coordinated to a porphyrin acting as a tetradentate ligand, and to one or two axial ligands." (From here.)

Source:

https://www.ebi.ac.uk/interpro/potm/2005_10/Page1.htm