Which of the following are SHORT TERM stepwise effects of radiation exposure? 1) life-span shortening 2) primary radiochemical reactions 3) functional damage of cells

• A. 1 and 2
• B. 1 and 3
• C. 2 and 3
• D. 1, 2, and 3

Answer: (C)

Short-term effects come from immediate chemical and cellular changes after exposure. The very first events are primary radiochemical reactions—ionization and radiolysis—which generate reactive free radicals in the cell in an unimaginably short time. These radicals quickly attack vital molecules, especially DNA, proteins, and membranes, causing onward functional disturbances. The resulting functional damage to cells—altered metabolism, membrane dysfunction, enzyme inhibition, and potential cell death or mitotic arrest—appears soon after exposure. Life-span shortening, by contrast, is a late effect that develops over time as accumulated damage and repair errors influence aging and cancer risk; it has a latency period rather than an immediate, stepwise progression. So the short-term, stepwise effects are the primary radiochemical reactions and the immediate functional damage of cells.