Multiple Choice
In agarose gel electrophoresis used for DNA analysis, which DNA fragments move faster through the gel toward the positive electrode?
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18. Molecular Genetic Tools
Methods for Analyzing DNA
Multiple Choice
In agarose gel electrophoresis, how are DNA or RNA molecules typically visualized on the gel after separation?
A
By staining the gel with a nucleic acid–binding dye (e.g., ethidium bromide or SYBR Safe) and viewing bands under UV or blue light
B
By detecting radioactivity emitted spontaneously by DNA or RNA without any labeling or staining
C
By adding DNA polymerase to the gel so it synthesizes complementary strands that become visible to the naked eye
D
By measuring the temperature increase of the gel caused by nucleic acid migration and converting it into an image
Verified step by step guidance1
Understand that agarose gel electrophoresis separates DNA or RNA molecules based on size by applying an electric field to the gel.
Recognize that nucleic acids themselves are not visible to the naked eye after separation, so a method to visualize them is necessary.
Learn that visualization is typically achieved by staining the gel with a dye that binds specifically to nucleic acids, such as ethidium bromide or SYBR Safe.
Know that these dyes fluoresce when exposed to UV or blue light, allowing the separated DNA or RNA bands to be seen as bright bands on the gel.
Conclude that the correct visualization method involves staining the gel with a nucleic acid–binding dye and viewing the bands under UV or blue light.
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