Follow-Up Questions restriction enzymes cut the DNA so that the double-stranded
ID: 213697 • Letter: F
Question
Follow-Up Questions restriction enzymes cut the DNA so that the double-stranded DNA molecule is intact. However, some restriction enzymes leave "sticky ends. What is meant by the phrase "sticky ends? 2. Using your knowledge of DNA, what overall charge does the DNA molecule have? What is this charge a result of Based on your answers, what pole would you expect the DNA you loaded to move toward? Why? Which fragments of DNA would you expect to move the shortest distance from the loading well? Explain. 3. 4. A scientist cuts a large amount of DNA using a restriction enzyme that she believes will produce a range of DNA pieces that are relatively similar in size. Scientists can vary the density of the agar gels by varying the amount of agar in the gel. Would she want to make an agarose gel with a higher bands? A higher amount of agarose in the gel makes it stiffer. Explain. or lower amount of agarose in order to resolve the DNA 5. You are given two samples of DNA with the following sequences Strand 1: CAGTGATCTCGAATTCGCTAGTAACGTT GTCACTAGAGCTTAAGCGATCATTGCAA Strand 2: TCATGAATTCCTGGAATCAGCAAATGCA AGTACTTAAGGACCTTAGTCGTTTACGT If you treat both strands with an enzyme that recognizes the sequence GAATTC, record the number and size (in base pairs) of fragments from each sample of DNA.Explanation / Answer
Answer:
1. On a piece of two-stranded DNA, short, complementary, one-stranded regions produced by the action of a restriction endonuclease are called sticky ends. Sticky ends facilitate the joining of segments of DNA from different sources.
2. DNA has an overall negative charge.
Phosphate groups in the DNA backbone carry negatively-charged oxygen molecules giving the phosphate-sugar backbone of DNA an overall negative charge.
Because of the overall negative charge, I expect that the DNA would move towards the positive pole.
3. The long fragments because they are entangled more in the agarose gel. Also because they're larger.
4. A higher percentage agarose (up to 2%) gel would help to separate the similar sized fragments.
(Since there are multiple questions, the first 4 questions have been answered according to the rules of Chegg)