A certain restriction enzyme digest results in DNA fragments of the following sizes: 4,000 bp, 2,500 bp, 2,000 bp, and 400 bp. Sketch the resulting separation by electrophoresis. Show starting point, positive and negative electrodes, and the resulting position of the DNA bands. ( this will all be in one column or well)

Smaller the size of the DNA fragment, farther it moves during electrophoresis. The sketch of the position of the fragments has been drawn in the figure below.

Explanation:

As we know DNA is a negatively charged molecule. So during electrophoresis the fragments move towards the positive electrode because opposite charges attract each other.

Different fragment move different distances according to their size during the electrophoresis. Smallest segment travels the largest distance in the gel medium while the largest one travels least distance.

In the question there are four DNA fragments with base pairs 4000, 2500, 2000 and 400 so the smallest segment with 400bp will be farthest from the starting point and the largest fragment with 4000bp will travel least distance in the gel medium. Their respective positions are shown in the figure below. The starting point is near the negative electrode.

Is this a question? i'm confused

The answer would be c, white eyes are homozygous recessive. in the early 1900s, morgan conducted several experiments with vinegar  flies (drosophila). one  sample revealed an anomaly: a  white-eyed, single male fly. he attempted to breed this fly with the typical red-eyed females. the offspring were all red-eyed. using flies from this new generation (brother-sister pairs)  produced some red-eyed and a few white-eyed flies. the white-eyed were all male. in later experiments, he was able to produce white-eyed females. this proved that white eyes are not lethal to either sex (ruling out a and b). since the percentage of white eyes to red eyes is so low, white eyes are not a dominant trait. it would be a recessive trait.