Question

During gel electrophoresis, DNA travels towards the positive charge. Including the substance agarose in the gel allows for visualization of DNA under UV light. Below is an image of a gel run with a single DNA sample (ane 2) and a DNA ladder (lane 1). Using the DNA ladder reference included to the right, it can be concluded that two fragments labeled C&D in the DNA sample are approximately 6.0 Lane 1 2 kilobases and 3.0 kilobsases, respectively. Laai Auxilwa al

Answer 1

DNA is a negatively charged molecule due to the presence phosphate groups in it's backbone and thus it moves towards the positively charged electrode electrode that is the anode, during electrophoresis.

The inclusion of a substance called ethidium bromide in the agarose gel allows the visualization of DNA under UV light. Ethidium bromide interchelates i.e gets trapped in between the double strands of DNA and on exposure to UV exhibits fluorescence. That I it absorbs UV light,gets excited and emits at a higher wavelength in the visible region,which we see as orange bands.

Band C corresponds to the third band from the well in the ladder labe which is 6 Kilobases and band D corresponds to the 6 the band in the ladder which is 3 kilobases. Dbeing smaller than C travelled further in the gel.