Which of the following statements are correct with respect to DNA separation, isolation and visualization? Choose the correct answer from the options given below :
- A and B only
- B and D only
- A and D only
- B and C only
Answer
(1) A and B only
Solution
A: Restriction endonucleases, which cut DNA at specific sites, are called molecular scissors ⇒ correct.
B: In agarose gel electrophoresis, DNA fragments separate according to their size (smaller fragments move farther) ⇒ correct.
C: As per NCERT, separated DNA fragments can be seen only after staining with ethidium bromide followed by exposure to UV radiation ⇒ incorrect.
D: Stained DNA fragments appear as bright orange coloured bands in UV light, not in visible light ⇒ incorrect.
∴ Correct statements: A and B only.
Answer: (1)