DNA in agarose gel electrophoresis
In agarose gel electrophoresis, how do DNA fragments behave?
Answer B: explanation for every choice
A
DNA is negatively charged, so it moves away from the negative electrode.
B
Correct. DNA's phosphate backbone is negatively charged, and the gel lets smaller fragments move through it more easily.
C
Larger fragments are slowed more by the gel.
D
Charge per unit length is nearly constant, so size, not sequence, determines migration.
TakeawayDNA runs to red (positive). Small fragments run farthest.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb130.