Question

PCR is a technique that: Select one: a. can produce many exact copies of segments of DNA b. virtually eliminates operator error from DNA analysis c. provides a statistical analysis of the nitrogenous-base pairings d. produces information regarding the sequence of nitrogenous bases e. all of the above

Answer 1

Answer:

The correct answer is a. can produce many exact copies of segments of DNA.

Explanation:

Polymerase chain reaction is used to generate many copies of DNA from single DNA. It is invented by Kary Mullis in 1983. PCR consists of three steps that are denaturation, annealing and extension.

Denaturation: In this step, the double-stranded DNA is converted into single-stranded by increasing the temperature above 90°c. So DNA is thermally denatured in this step.

Annealing: In this step primers and enzymes are added which attaches to the single-stranded DNA and start making complementary strand. Temperature here is 50-60°c.

Extension: In extension, the primers are extended by a DNA polymerase called Taq polymerase to form DNA copies.

These steps are repeated several times to obtain multiple copies of DNA because detection of any sequence is easy when its multiple copy is present.

Answer 2

Answer:

a. can produce many exact copies of segments of DNA

Explanation:

PCR refers to polymerase chain reaction that replicates a gene or a DNA segment into multiple copies. For the purpose, primers, the sample DNA template to be amplified, nucleotide monomers and the heat-tolerant DNA polymerase enzyme (Taq polymerase) are mixed.

The heating of the mixture leads to the denaturation of the sample DNA. The mixture is cooled down to allow annealing of the primers to the DNA template which is then amplified by the enzyme Taq DNA polymerase. The reaction mixture is heated to allow denaturation of all the DNA molecules which in turn serve as a template and the process is repeated for several rounds according to the requirement of the copies of the sample DNA.