Question

many proteins have a quaternary structure which consists of more than one amino acid chain. hemoglobin, a protein found in blood has the function of carrying oxygen. it is made of multiple polypeptide chains. each chain has a heme group, which has iron. heme groups are indicated on the image in green. → count the heme groups to determine many polypeptide chains are needed to build one hemoglobin protein: a single change in an amino acid in one of these sequences leads to blood cells that have the wrong shape. what disorder is this? if you dont know, click here. source: https://en.wikipedia.org/wiki/hemoglobin 16

Explanation:

Step1: Recall hemoglobin structure

Hemoglobin has one heme group per polypeptide chain. By counting heme groups (green - colored in the image), we can determine the number of polypeptide chains.

Step2: Identify the disorder

A single - amino - acid change in hemoglobin's polypeptide chain leads to sickle - cell anemia, where red blood cells have an abnormal sickle shape.

Answer:

Number of polypeptide chains: 4
Disorder: Sickle - cell anemia