Question

Which of the following is true regarding analysis of chemical and physical properties of DNA?

a. Mixtures of different sized DNA molecules with similar charge-to-mass ratios will migrate as the same rate through an agarose gel due to the concentration of the gel.

b. The conformation of a DNA molecule does not affect its migration through a gel matrix.

c. A circular single stranded DNA molecule migrates faster than a supercoiled molecule when these when these types of DNA are contained within the same sample and run on a gel.

d. Nucleic acids generally absorb light at a wavelength of 280 nm.

Answer 1

The true statement is that the conformation of DNA affects its migration through a gel during electrophoresis, with supercoiled DNA migrating faster due to being more compact.

Step-by-step explanation:

Among the options provided, the true statement regarding the analysis of chemical and physical properties of DNA is that the conformation of a DNA molecule affects its migration through a gel matrix. This means that the shape of DNA, whether it is supercoiled, circular, or linear, will influence the rate at which it moves through an agarose gel during electrophoresis. Specifically, supercoiled DNA migrates faster than circular DNA because it is more compact and encounters less friction in the gel matrix. Additionally, the pore size of the gel also plays a role; a higher percentage agarose gel, which has smaller pores, is used to separate smaller DNA molecules due to greater friction. On the contrary, nucleic acids absorb light at a wavelength of 260 nm, not 280 nm, which is typically associated with protein absorption.