Scientists use polymerase chain reaction (PCR)
to amplify a segment of DNA into many copies.
to insert new nucleotide segments into a plasmid.
to make a complementary strand of DNA.
to link together multiple fragments of DNA
WHICH ONE WOULD YOU PICK AND MOST IMPORTANTLY, WHY?
The first answer is the correct one. PCR is done to provide copies of DNA segments (genes) from small collected samples. Larger amounts are generally needed for DNA testing.
See http://users.ugent.be/~avierstr/principles/pcr.html
I would pick the first answer, which is that scientists use polymerase chain reaction (PCR) to amplify a segment of DNA into many copies.
PCR is a technique commonly used in molecular biology to create millions or billions of copies of a specific segment of DNA. This technique enables researchers to produce large amounts of DNA from small, limited samples. This is particularly useful in various applications, such as DNA sequencing, cloning, genetic testing, and research.
PCR involves a series of repeated temperature changes that allow DNA to be copied exponentially. It requires specific components, including DNA template, DNA primers, DNA polymerase enzyme, nucleotides (the building blocks of DNA), and a thermal cycler (a machine that changes temperatures in precise cycles).
By using specific DNA primers that flank the segment of DNA of interest, PCR allows the targeted segment to be amplified. The process begins with denaturation at a high temperature, where the DNA is heated to separate the two strands. Then, the temperature is lowered to allow the DNA primers to anneal or bind to their complementary sequences on the DNA template. Finally, DNA polymerase extends the primers, synthesizing new DNA strands that are complementary to the original DNA template.
The repeated cycles of denaturation, annealing, and extension allow the targeted DNA segment to be exponentially amplified, resulting in an abundance of copies. This amplified DNA can then be used for various downstream applications, such as genetic analysis, gene expression studies, or DNA manipulation techniques, like cloning or gene sequencing.
In summary, scientists use PCR primarily to amplify a segment of DNA into many copies because it provides a reliable and efficient method for generating larger amounts of DNA from a limited sample.