Consider the following statements regarding the separation of DNA fragments by gel electrophoresis: I. DNA fragments are negatively charged molecules and are forced to move towards the cathode under an electric field. II. The sieving properties of agarose gel allow smaller DNA fragments to move farther away from the wells than larger fragments. III. The separated DNA fragments can be visualized as bright orange bands

Step-by-step solution

DNA fragments are negatively charged molecules due to the presence of phosphate groups. Under an electric field in gel electrophoresis, they move towards the positive electrode, which is the anode, not the cathode. Thus, Statement I is incorrect. The agarose gel acts as a sieve, and the movement of DNA fragments depends on their size. Smaller DNA fragments experience less resistance and move farther away from the wells compared to larger fragments. Thus, Statement II is correct. DNA fragments cannot be seen in visi