Ultraviolet light can damage a DNA strand causing:: (A) Two adjacent purine residue to form a covalently bounded dimer, (B) Two adjacent pyrimidine residues to form covalently bonded dimer, (C) Disruption of phosphodiesterase linkage, (D) Disruption of non-covalent linkage
Answer is B. Ans. B. Two adjacent pyrimidine residues to form covalently bonded dimerDamage to DNA during its replication can occur from ultra violet irradiations that causes thymine dimer formation.