DNA molecules of different sizes are often separated with the use of a technique called electrophoresis (see Chapter 19). With this technique, DNA molecules are placed in a gel, an electrical current is applied to the gel, and the DNA molecules migrate toward the positive (+) pole of the current. What aspect of its structure causes a DNA molecule to migrate toward the positive pole?

Question

Roberto Watkins

Biology

24 August, 12:10

DNA molecules of different sizes are often separated with the use of a technique called electrophoresis (see Chapter 19). With this technique, DNA molecules are placed in a gel, an electrical current is applied to the gel, and the DNA molecules migrate toward the positive (+) pole of the current. What aspect of its structure causes a DNA molecule to migrate toward the positive pole?

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Kristina Villarreal · Answer 1

A DNA molecule is a polymer of nucleotides, which are made up of a nitrogenous base, a sugar and a phosphate group.

The phosphate groups are negatively charged, giving the sugar-phosphate backbone a negative charge. This negative charge causes the DNA molecule to be attracted to the positive pole of the current and thus migrate towards it.