Question

The agarose used in electrophoresis interacts electrically with the DNA, chemically binds to the DNA, acts as a sieve, or selectively sorts recombinant DNA from host DNA?

1) interacts electrically with the DNA
2) chemically binds to the DNA
3) acts as a sieve
4) selectively sorts recombinant DNA from host DNA

Answer 1

In agarose gel electrophoresis, agarose acts as a molecular sieve that separates DNA fragments based on size, by impeding larger molecules more than smaller ones.

Step-by-step explanation:

In agarose gel electrophoresis, agarose functions as a molecular sieve. The agarose creates a network of pores through which DNA fragments can pass. Because DNA is negatively charged, it moves towards the positive electrode when an electric field is applied. However, rather than interacting electrically with the DNA or chemically binding to it, agarose gel impedes the movement of larger molecules more than smaller ones, effectively separating them by size. This separation process is not selective for recombinant DNA versus host DNA; it sorts molecules solely based on size and shape.