QUESTION 2 Restriction enzymes work because they cut at specific palindromic seq
ID: 193500 • Letter: Q
Question
QUESTION 2 Restriction enzymes work because they cut at specific palindromic sequences of DNA. Most (but not all) restriction enzymes create "sticky ends" after cutting the DNA. What are these "sticky ends", and what purpose do they fulfill in gene characterization and cloning? Sticky ends are unpaired bases at the end of a cut site, caused by a restriction enzyme that does not cut in the middle of the restriction sequence. This makes it easier for the resulting fragment to anneal to a sticky end of another fragment and re-establish a continuous DNA strand, thus enabling scientists to efficiently remove and re-insert portions of DNA. O Sticky ends are what result when you eat a peanut butter and jelly sandwich and forget to wash your hands before you go back to work in the lab. Any DNA samples you touch become sticky. And that is the end of your experiment. So it is a sticky end. Sticky ends are when there are no unpaired bases at the end of a cut site, caused by a restriction enzyme that cuts in the middle of the restriction sequence. This makes it easier for the resulting fragment to anneal to a sticky end of another fragment and re-establish a continuous DNA strand, thus enabling scientists to efficiently remove and re-insert portions of DNA. OSticky ends are what is left when DNA is not replicated completely. They serve as an indication for the scientist that the gene cloning cycle is not yet fully complete.Explanation / Answer
There are many restriction enzymes which cleaves the DNA by straight cuts at the same site in both strands of the DNA molecule is called as blunt end. Many restriction enzymes cut the DNA in a stagger manner by leaving some nucleotides of ssDNA. The sticky ends or cohesive ends allow the separation of the two strands in a DNA molecules. These cohesive ends in fact can base pair with the two DNA ends to line up the two molecules of the DNA. The restriction enzyme which is used for the cleavage in the site of insertion and the source of the DNA that is to be inserted are the same so that it can develop the same sticky ends in both so it can be unite together. This is the ability of restriction enzymes which allows the recombination. These ends are produced by a variety of overhangs. The overhang is an extension of nucleotides (which is unpaired) at the end of a DNA molecule. The overhangs can be found in either strand of the DNA molecule and creates 3' or 5' overhangs.
So the answer is- Option A- Sticky ends are unpaired bases at the ends of a cut site, caused by a restriction enzyme that does not cut in the middle of the restriction sequence.This makes it easier for the resulting fragment to anneal to a sticky ends of another fragment and re-establish a continuous DNA strand, thus enabling scientists to efficiently remave and re-insert the portion of DNA