Which cell type is least sensitive to ionizing radiation damage?

Which cell type is least sensitive to ionizing radiation damage?

• A. Cells that divide quickly
• B. Red blood cells
• C. Cells that divide slowly
• D. Muscle cells

Answer: (C)

Radiosensitivity tracks how actively a cell is dividing and how differentiated it is. Ionizing radiation mainly damages DNA, and cells that are actively replicating or preparing to divide are more likely to incur lethal chromosome breaks during replication and mitosis. Cells that divide slowly spend more time in a resting, non-dividing state and have more opportunities for DNA repair, so they tend to withstand radiation with less lethal impact. Therefore, among the options, those that divide slowly are the least sensitive to radiation damage. Rapidly dividing cells, by contrast, are the most sensitive targets, while highly differentiated or non-dividing cells (like muscle cells) are relatively more resistant due to their low mitotic activity.

Radiosensitivity tracks how actively a cell is dividing and how differentiated it is. Ionizing radiation mainly damages DNA, and cells that are actively replicating or preparing to divide are more likely to incur lethal chromosome breaks during replication and mitosis. Cells that divide slowly spend more time in a resting, non-dividing state and have more opportunities for DNA repair, so they tend to withstand radiation with less lethal impact. Therefore, among the options, those that divide slowly are the least sensitive to radiation damage. Rapidly dividing cells, by contrast, are the most sensitive targets, while highly differentiated or non-dividing cells (like muscle cells) are relatively more resistant due to their low mitotic activity.