Question

is a nucleus the sole source of DNA in a eukaryotic cell?

WORKSHEET: EXERCISE 10 NAME: DATE: SECTION Twenty microliters (20 ㎕) of each sample was loaded into your gel. Convert 2OuL to milliliters (mL). I. 2. Describe the charge on the DNA molecule and specify which component of the molecule is responsible for contributing to that charge. Why do some DNA samples travel further in the gel than others? 3.

Answer 1

1. 1000 micro litre = 1mL

Or, 20 micro L = (1/1000)*20 = 0.02 mL

2. The charge on DNA molecule is Negative i.e., DNA is negatively charged .The negative charge is due to presence of the phosphoric acid in the DNA backbone.

3. The gel has pores of uniform specific size .If the DNA sample has size more , then it travels slowly via the pores and hence do not go farther than the gel but if the DNA sample is small, it passes easily through the pores and hence can go farther from the gel. So, less the size, the more farther it goes and vice versa.

4. Before putting the DNA sample into the wells, they are mixed with a dye of a specific colour ( orange, blue etc). After electrophoresis when the gel is seen under UV light, the Band fluoresces due to the dye mixed earlier and this is how we can visualise the DNA sample.