By What Technique Can Individual DNA Molecules Be Visualized

Question

By what technique can individual DNA molecules be visualized?
A)electron microscopy and metal shadowing
B)light microscopy only
C)agarose gel electrophoresis
D)Northern blot

Accepted Answer

Individual DNA molecules can be visualized with the help of electron microscopy and metal shadowing, where the DNA molecule is coated with a thin layer of metal and then viewed under an electron microscope. Light microscopy only allows visualization of larger structures and is not suitable for visualizing individual DNA molecules. Agarose gel electrophoresis can be used to separate DNA fragments based on their size, but does not visualize individual DNA molecules. Northern blot is a technique used to detect specific RNA molecules in a mixture, and is not used for visualizing DNA molecules.