Final answer:
The uncut control appears larger in size than the cut plasmid because the cut plasmid is linearized, while the uncut plasmid remains circular. Linear DNA migrates more slowly in agarose gel electrophoresis, resulting in the cut plasmid appearing smaller in size compared to the uncut control.
Step-by-step explanation:
When comparing a cut plasmid with an uncut control, it is normal for the uncut control to appear larger in size than the cut plasmid. This is because the cut plasmid is linearized, while the uncut plasmid remains circular. Plasmids are naturally circular DNA molecules found in bacteria. When the plasmid is cut at a restriction site, the circular shape is disrupted, and the plasmid becomes linear.
Linear DNA molecules migrate more slowly in agarose gel electrophoresis compared to circular DNA molecules, which results in the cut plasmid appearing smaller in size. Therefore, the difference in size between the cut plasmid and the uncut control is due to the change in shape from circular to linear, resulting in different migration rates in the agarose gel.