What problem can occur if a restriction enzyme tube is kept at room temperature for a long time?

Correct answer: Enzyme activity can decrease

Restriction enzymes are proteins whose activity depends on their correct three-dimensional structure and stable storage conditions. Prolonged exposure to room temperature can accelerate denaturation, aggregation, or loss of catalytic activity, especially for enzymes supplied frozen or requiring a cold chain. A weakened enzyme may cut DNA slowly or incompletely, causing unreliable digestion results. Thus option A is correct. Keeping the tube cold helps preserve activity, although the exact storage temperature must follow the manufacturer’s instructions. DNA does not form automatically, buffer cannot become protein, and enzyme storage does not strengthen an electrophoresis gel.