Gel electrophoresis is used to dna fragments a. separate b. join c. cut d. copy

a. separate  

Explanation:

DNA fragments are formed with the action of restriction enzymes having different sizes. The most widely used technique for separating DNA fragments is electrophoresis through agarose gels.

Agarose is a polysaccharide (such as agar and pectin) that dissolves in boiling water and then gels when it cools down like gelatin. To perform an electrophoresis, an agarose gel is prepared, DNA is introduced into small gel wells, and then an electric current is applied through the gel. Because DNA is negatively charged, it is attracted to the positive electrode. However, to reach the positive electrode, DNA must migrate through the agarose gel.

Smaller DNA fragments can migrate through an agarose gel faster than larger DNA fragments. The migration rate of linear DNA fragments through agarose is inversely proportional to log10 of their molecular weights.

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