Which process describes the creation of cross-links between macromolecules or portions of the same molecule due to radiation?

• A. Cross-linking
• B. Polymerization
• C. Deoxyribosylation
• D. Fragmentation

Answer: (A)

Ionizing radiation generates reactive free radicals that can form covalent bonds between two different macromolecules or between distant parts of the same molecule. This linking creates cross-links, which stiffen and disrupt the normal function of the macromolecule, such as DNA or proteins, by restricting movement and interfering with processes like replication and transcription. This is different from fragmentation, where the molecular backbone is broken into smaller pieces, or from polymerization, which would build longer chains from monomers. Deoxyribosylation isn’t a typical radiation-induced cross-linking effect in this context.