Answer:

There are three types of blood cells present in our body - Red blood cells (RBCs), White blood cells (WBCs), and Platelets. Among these, the blood cell in which the nucleus is absent is the Red Blood Cell or Erythrocyte.

Red Blood Cells (RBCs)

RBCs are the most abundant type of blood cell, accounting for about 45% of the total blood volume. They are responsible for carrying oxygen from the lungs to the body tissues and carrying carbon dioxide from the body tissues to the lungs, where it is eliminated from the body. RBCs are biconcave in shape, which allows them to be flexible and squeeze through tiny capillaries.

Structure of Red Blood Cell

The RBCs are composed of a protein called hemoglobin, which gives them their red color. Hemoglobin is made up of four protein molecules (globulin chains) and four heme groups, which contain iron atoms. The iron atoms in heme bind to oxygen molecules, allowing the RBCs to carry oxygen throughout the body.

Absence of Nucleus in Red Blood Cell

RBCs do not have a nucleus, which makes them unique from other blood cells. They lose their nucleus during their development in the bone marrow, which allows them to make more space for hemoglobin. Without a nucleus, RBCs cannot divide or repair themselves, and they have a limited lifespan of about 120 days.

Conclusion

In conclusion, Red Blood Cells or Erythrocytes are the blood cells in which the nucleus is absent. They are responsible for carrying oxygen and carbon dioxide throughout the body and have a unique structure and composition that allows them to perform their functions efficiently.

In humans mature Red blood cells nucleus is absent. Mature Red blood cells are flexible and oval biconcave disks. Human mature Red blood cell can survive for 120 days.