A seed was taken from the bed of a pickup truck belonging to

A seed was taken from the bed of a pickup truck belonging to a suspect. In and attempt to exonerate or tie the suspect to the crime scene at the time of the crime (i.e. when the tree was seeding) and to the specific tree (by DNA fingerprinting), the DNA from the seed was isolated and subjected to PCR. A single copy of the DNA was amplified by PCR for DNA sequencing. After 21 rounds of PCR, how many copies of the DNA are present? (assume 100% efficiency)

Solution

Working principle of PCR as the name implies it is a chain reaction if small segment of the DNA section of interest needs to be identified which serves as the template for producing the primers that initiate the reaction one DNA molecule is used to produce 2 copies than 4 then 8 and so forth.

Because both strands are copied during PC are there is an exponential increase of the number of copies of the gene suppose there is only one copy of the wanted been before the cycling starts after 1 cycle there will be two copies after 2 cycles there will be 4 copies three cycles will result in 8 copies and so on

After 21 rounds 2097152 copies of Dna are present as it is exponential.