Which statement describes why red blood cells lack DNA?

Which statement describes why red blood cells lack DNA?

• A. Contains mitochondria to produce energy
• B. Has ribosomes
• C. Contains no DNA—leaves room for lots of haemoglobin
• D. Contains DNA in nucleus

Answer: (C)

Red blood cells are built to maximize their capacity to carry oxygen, so during maturation they eject their nucleus and most other organelles. In humans this leaves the mature cell anucleate, meaning it has no DNA, which frees up interior space for haemoglobin—the protein that binds and transports oxygen. With no DNA, the cell also doesn’t invest in gene transcription or protein synthesis, which fits its short, specialized lifespan. Additionally, mature red blood cells lack mitochondria, so they don’t consume the oxygen they’re carrying. Therefore, the description that best fits why these cells lack DNA is that there is no DNA, freeing room for lots of haemoglobin. The other statements don’t reflect the structure of mature red blood cells, since they do not retain mitochondria or ribosomes and they do not have DNA in a nucleus.

Red blood cells are built to maximize their capacity to carry oxygen, so during maturation they eject their nucleus and most other organelles. In humans this leaves the mature cell anucleate, meaning it has no DNA, which frees up interior space for haemoglobin—the protein that binds and transports oxygen. With no DNA, the cell also doesn’t invest in gene transcription or protein synthesis, which fits its short, specialized lifespan. Additionally, mature red blood cells lack mitochondria, so they don’t consume the oxygen they’re carrying. Therefore, the description that best fits why these cells lack DNA is that there is no DNA, freeing room for lots of haemoglobin. The other statements don’t reflect the structure of mature red blood cells, since they do not retain mitochondria or ribosomes and they do not have DNA in a nucleus.