Final answer:
The statement that products of restriction digestion can be visualized by gel electrophoresis, which separates fragments based on size, is true. This method uses agarose gel and a fluorescent dye to visualize DNA fragments after being cut by restriction enzymes.
Step-by-step explanation:
The statement is true: the products of restriction digestion can indeed be visualized by gel electrophoresis, which separates DNA fragments based on their size. This technique is commonly used in molecular biology to analyze DNA. During restriction mapping, DNA is cut by restriction enzymes into fragments. These fragments are then separated by size on an agarose gel during electrophoresis. The gel has a gelatin-like consistency, and an electric field is applied to cause the DNA fragments to migrate through the gel matrix; the larger fragments will migrate more slowly than the smaller ones. After the electrophoresis is completed, the DNA fragments can be visualized using a fluorescent dye like ethidium bromide, yielding a distinct pattern of bands that corresponds to DNA molecules of varying lengths. This banding pattern can be compared to a DNA ladder, which contains DNA fragments of known lengths, to determine the size of the separated fragments. Such analysis can be used for various purposes, like comparing DNA from different samples in what is known as Restriction Fragment Length Polymorphism (RFLP) analysis.