NEETZoologyBiotechnology - Principles and Processes
During agarose gel electrophoresis, a mixture of DNA fragments is loaded into the wells. Which of the following correctly describes the nature of DNA molecules and their direction of movement under an electric field?
Options
- APositively charged; move towards the cathode
- BNegatively charged; move towards the anode
- CNegatively charged; move towards the cathode
- DPositively charged; move towards the anode
Correct answer
B. Negatively charged; move towards the anode
Step-by-step solution
DNA molecules possess a sugar-phosphate backbone, which imparts a net negative charge to them. During gel electrophoresis, when an electric field is applied, these negatively charged DNA fragments are forced to migrate towards the positive electrode, which is the anode. Options 1 and 4 are incorrect because DNA is not positively charged. Option 3 is incorrect because negatively charged molecules move towards the anode, not the cathode. Answer: Negatively charged; move towards the anode