The __________ are the only anuclear cells in the body.

The __________ are the only anuclear cells in the body.

• A. Red blood cells
• B. White blood cells
• C. Platelets
• D. Neurons

Answer: (A)

Red blood cells are the only anuclear cells because, during their development, they eject the nucleus to make more room for hemoglobin and maximize oxygen-carrying capacity. In mature mammals, these cells lack a nucleus (and mitochondria), which is why they cannot synthesize new proteins but can efficiently transport oxygen. White blood cells and neurons keep their nuclei, so they remain nucleated and capable of gene expression. Platelets are not complete cells; they are cytoplasmic fragments derived from megakaryocytes and do not contain a nucleus either, but they aren’t true cells.

Red blood cells are the only anuclear cells because, during their development, they eject the nucleus to make more room for hemoglobin and maximize oxygen-carrying capacity. In mature mammals, these cells lack a nucleus (and mitochondria), which is why they cannot synthesize new proteins but can efficiently transport oxygen. White blood cells and neurons keep their nuclei, so they remain nucleated and capable of gene expression. Platelets are not complete cells; they are cytoplasmic fragments derived from megakaryocytes and do not contain a nucleus either, but they aren’t true cells.