Question

The mature mammalian red blood cells are incapable of further division because
A. DNA sequences are redundant
B. The nuclei are lobed
C. They lack nuclei
D. The mitotic apparatus is absent

Answer 1

Hint: Red blood cells or red blood corpuscles or RBCs are also known as erythrocytes. They are known as such because they are red in color due to the presence of the haemoglobin pigment. Moreover, the haemoglobin pigment acts as an oxygen carrier in the blood.

Complete answer:
The red blood cells are also known by the name of erythrocytes. An average man has around four to five million red blood cells in every millimeter cube of his blood. On the other hand, an average woman has five to six million red blood cells in every millimeter cube of her blood. Children have approximately nine million red blood cells in every millimeter cube of their blood. The shape of the red blood cells is biconcave. Moreover, red blood cells are non-nucleated. This means that they do not possess a nucleus. Due to this reason, they are incapable of performing cell division. The formation of new red blood cells is known as erythropoiesis. It occurs in the bone marrow of the adults and the liver and spleen of the children. In the case of the embryo, the red blood cells are formed by the placenta or the yolk sac, or the mesoderm. RBCs contain thirty-eight percent hemoglobin and sixty-two percent cytoplasm. They do not possess any membrane-bound organelles like mitochondria, endoplasmic reticulum, etc. Thus, based on the above information we can conclude that the mature mammalian red blood cells are incapable of further division because they lack nuclei.
Hence, the correct answer is option (C).

Note: The immature Red blood cells have a nucleus. However, it is removed from the mature red blood cells. This is done in order to accommodate more and more hemoglobin in the red blood cells. The presence of a nucleus would take up some space and volume. To use the maximum volume, the mature red blood cells lose their nucleus.