Multiple Choice
Why do the fragments of DNA in gel electrophoresis move away from the negative cathode?
17. Biotechnology
Gel Electrophoresis
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Gel electrophoresis separates fragments of DNA based on which characteristic?
A
Sequence.
B
Level of methylation.
C
Size.
D
All of the above.
Verified step by step guidance1
Understand the principle of gel electrophoresis: It is a technique used to separate DNA fragments based on their size. DNA molecules are negatively charged due to their phosphate backbone, and when an electric field is applied, they migrate towards the positive electrode.
Consider the structure of the gel: Typically, agarose or polyacrylamide gels are used. These gels act as a sieve, allowing smaller fragments to move faster and further than larger ones.
Recognize the role of size in separation: As DNA fragments move through the gel, their size determines how easily they can navigate through the pores of the gel matrix. Smaller fragments encounter less resistance and thus travel further.
Sequence and methylation level do not affect migration: While sequence and methylation can affect other properties of DNA, they do not influence the migration speed in gel electrophoresis. The primary factor is size.
Conclude that size is the correct characteristic for separation: Based on the principles of gel electrophoresis, size is the key characteristic that determines how DNA fragments are separated during the process.
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