Diagram shows a typical agarose gel showing migration of DNA fragments .

a. Which of the bands has the largest and smallest DNA fragments ?
b. How can you make fragments of DNA for electrophoresis ?
c. Explain separation of DNA fragments using electrophoresis.
d. Point out a method to visualize the separated DNA fragments after electrophoresis .

Explanation

a. .a. is largest and .d. is smallest .
b. Using restriction endonucleases
c. DNA fragments are negatively charged molecules, They are forced to move towards anode under an electric field . DNA fragments separate according to their size .
d. They are visualised only after staining the DNA with a compound known as ethidium bromide followed by exposure UV light