how hemoglobin is a conjugated protein and explain what is conjugated protein

A conjugated protein has something called a prosthetic
group attached to it, in addition to one or more peptide chains. Simple proteins are
made up simply of chains of amino acids help together by peptide bonds and folded or
twisted in a specific way. A conjugated protein goes a step further and incorporates a
non-peptide group, the prosthetic group. This prosthetic group may include organic
components such as a lipid, sugar, or vitamin, or may be inorganic, such as a mineral or
metal ion.

Hemoglobin consists of four polypeptide chains,
two alpha chains and two beta chains. Each of the four chains also includes a heme
group, a basket-shaped ring of carbon and nitrogen atoms with an iron ion (Fe2+) in the
center. Technically each of the four subunits is a conjugated protein in its own right,
and when the four join to create a hemoglobin molecule, that is a conjugated protein
too.

There are excellent illustrations at the links below
which may help you to visualize this.