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Multiple Choice
Which method uses an electric current to separate DNA fragments by size?
A
Gel electrophoresis
B
Chromatography
C
Centrifugation
D
Spectrophotometry
Verified step by step guidance
1
Identify the key concept: The problem is asking about a method that separates DNA fragments by size using an electric current.
Understand the principle of gel electrophoresis: This technique uses an electric field to move DNA fragments through a gel matrix. Smaller fragments move faster and travel further than larger ones.
Consider the role of the gel: The gel acts as a sieve, allowing smaller DNA fragments to pass through more easily than larger ones, thus separating them by size.
Recognize the role of the electric current: The electric current causes the negatively charged DNA fragments to migrate towards the positive electrode, facilitating their separation based on size.
Compare with other methods: Chromatography, centrifugation, and spectrophotometry do not use an electric current to separate DNA fragments by size, making gel electrophoresis the correct method.