Haemoglobin

Haemoglobin

1. Illustrate the structure of haemoglobin?

Haemoglobin is a protein in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs. It consists of four polypeptide chains (two alpha chains and two beta chains) that are coiled together to form a globin protein. Each globin protein has a heme group attached to it, which contains iron and is responsible for binding oxygen.

The structure of haemoglobin can be divided into several parts:

• Globin protein: This is the protein part of haemoglobin that provides the framework for the heme group.
• Heme group: This is the part of haemoglobin that contains iron and is responsible for binding oxygen.
• Alpha chains: These are two of the four polypeptide chains that make up haemoglobin.
• Beta chains: These are the other two polypeptide chains that make up haemoglobin.

2. Discuss the synthesis of haemoglobin?

Haemoglobin synthesis occurs in the bone marrow, where stem cells differentiate into erythroblasts, which then mature into normoblasts, and finally, into reticulocytes, which are released into the bloodstream. The synthesis of haemoglobin involves several steps:

• Amino acids: The first step in haemoglobin synthesis is the production of amino acids, which are the building blocks of proteins.
• Globin protein: The amino acids are then combined to form the globin protein.
• Heme group: The heme group is synthesized separately and then attached to the globin protein.
• Assembly: The globin protein and heme group are then assembled together to form a haemoglobin molecule.
• Folding: The haemoglobin molecule then folds into its final shape, which is necessary for its proper function.

3. Define normal function of haemoglobin?

The normal function of haemoglobin is to carry oxygen from the lungs to the body's tissues and return carbon dioxide from the tissues back to the lungs. This process occurs through the following steps:

• Oxygen binding: Haemoglobin binds to oxygen in the lungs and forms oxyhaemoglobin.
• Oxygen transport: The oxyhaemoglobin is then transported to the body's tissues, where it releases oxygen.
• Carbon dioxide transport: Haemoglobin also binds to carbon dioxide in the body's tissues and forms carbaminohaemoglobin.
• Carbon dioxide transport: The carbaminohaemoglobin is then transported back to the lungs, where it releases carbon dioxide.

4. State normal value of different varieties of haemoglobin?

The normal values of different varieties of haemoglobin are as follows:

• Haemoglobin A (HbA): 120-150 g/L
• Haemoglobin A2 (HbA2): 2.5-3.5%
• Haemoglobin F (HbF): 0-2%

5. Explain iron metabolism?

Iron metabolism is the process by which the body absorbs, transports, and stores iron. The steps involved in iron metabolism are as follows:

• Iron absorption: Iron is absorbed from the diet in the small intestine.
• Iron transport: The absorbed iron is then transported to the bone marrow, where it is used to synthesize haemoglobin.
• Iron storage: Iron is also stored in the bone marrow, spleen, and liver in the form of ferritin and hemosiderin.
• Iron excretion: Iron is excreted from the body through the faeces, urine, and sweat.

Iron deficiency can occur if the body does not get enough iron from the diet, or if the body loses too much iron through bleeding or other means. This can lead to anaemia, which is characterized by a decrease in the number of red blood cells or the amount of haemoglobin in the blood.