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Among mammals, nucleus is absent in :
- a)lymphocytes and RBCs
- b)immature RBCs and platelets
- c)mature RBCs and platelets
- d)only RBCs
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
Among mammals, nucleus is absent in :a)lymphocytes and RBCsb)immature ...
The nucleus is absent in mature sieve tube cells and mammalian erythrocytes. Sieve tube is described as the cells of the phloem tissue present in vascular plants. Their function is to translocate and distribute the food material to different parts of the plants. The nucleus of the sieve tube fragmented and disappeared.
On the other side, the mammalian erythrocytes are also known as red blood cells and a major component of the blood. They are formed in the bone marrow. During the process of formation of erythrocytes, the nucleus and mitochondria disappear and are converted to the mature erythrocyte. They possess a red coloured pigment which is known as haemoglobin. Erythrocytes are unable to multiply because they lack a nucleus, and they can survive for 100-120 days.
On the other side, the mammalian erythrocytes are also known as red blood cells and a major component of the blood. They are formed in the bone marrow. During the process of formation of erythrocytes, the nucleus and mitochondria disappear and are converted to the mature erythrocyte. They possess a red coloured pigment which is known as haemoglobin. Erythrocytes are unable to multiply because they lack a nucleus, and they can survive for 100-120 days.
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Most Upvoted Answer
Among mammals, nucleus is absent in :a)lymphocytes and RBCsb)immature ...
Explanation:
Mature RBCs and platelets are the only mammalian cells that lack nuclei. Here's why:
Mature RBCs:
RBCs, also called erythrocytes, are the most abundant type of cell in the human body. They transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Mature RBCs lack nuclei because they need to make room for the oxygen-carrying protein hemoglobin. Without a nucleus, RBCs are unable to synthesize new proteins or repair damaged ones. Therefore, mature RBCs have a limited lifespan of about 120 days.
Platelets:
Platelets, also called thrombocytes, are small cell fragments that are essential for blood clotting. Like RBCs, mature platelets lack nuclei. This is because the absence of a nucleus allows them to be more flexible and better able to change shape, which is necessary for clot formation.
Lymphocytes:
Lymphocytes are a type of white blood cell that plays an important role in the immune system. Unlike RBCs and platelets, lymphocytes have nuclei. Therefore, option A is incorrect.
Immature RBCs:
Immature RBCs, also called reticulocytes, do have nuclei. As they mature, their nuclei are extruded, and they become mature RBCs. Therefore, option B is incorrect.
In summary, the only mammalian cells that lack nuclei are mature RBCs and platelets.
Mature RBCs and platelets are the only mammalian cells that lack nuclei. Here's why:
Mature RBCs:
RBCs, also called erythrocytes, are the most abundant type of cell in the human body. They transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Mature RBCs lack nuclei because they need to make room for the oxygen-carrying protein hemoglobin. Without a nucleus, RBCs are unable to synthesize new proteins or repair damaged ones. Therefore, mature RBCs have a limited lifespan of about 120 days.
Platelets:
Platelets, also called thrombocytes, are small cell fragments that are essential for blood clotting. Like RBCs, mature platelets lack nuclei. This is because the absence of a nucleus allows them to be more flexible and better able to change shape, which is necessary for clot formation.
Lymphocytes:
Lymphocytes are a type of white blood cell that plays an important role in the immune system. Unlike RBCs and platelets, lymphocytes have nuclei. Therefore, option A is incorrect.
Immature RBCs:
Immature RBCs, also called reticulocytes, do have nuclei. As they mature, their nuclei are extruded, and they become mature RBCs. Therefore, option B is incorrect.
In summary, the only mammalian cells that lack nuclei are mature RBCs and platelets.
Community Answer
Among mammals, nucleus is absent in :a)lymphocytes and RBCsb)immature ...
Nucleus is absent in RBC and platelets.... but lama is exceptional case... in rbc, nucleus is present
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Among mammals, nucleus is absent in :a)lymphocytes and RBCsb)immature RBCs and plateletsc)mature RBCs and plateletsd)only RBCsCorrect answer is option 'C'. Can you explain this answer?
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