Question

1. Beginning with 3600 copies of a DNA fragment, calculate the number of copies after 45 cycles of polymerase chain reaction.

Answer 1

Answer-

According to the given question-

Polymerase chain reaction-  Polymerase chain reaction is used for getting the large quantity of DNA in pure form from the single copy in a very short period of time with the help of specific enzymes.

• This techniques was developed by Karry Mullis.
• It is a technique which is fast, inexpensive used for getting large quantity of specific DNA fragments from source DNA

According to the information given in the sample we have 3600 copies of DNA fragment and we have to calculate the number of copies after 45 cycles of polymerase chain reaction.

we know that DNA have two strand and both strand serve as template strand during synthesis. so from one molecule of double strand DNA we get two copy of double strand DNA molecule or in other word we can say that from one DNA strand we get one more DNA strand.

For example if we have 1 DNA molecule that have two strand so after one cycle of PCR we get 2 DNA molecule or 4 DNA strand or fragment or copy of DNA that can be used for the next cycle of PCR.

So considering the same information for this question also here we have 3600 fragment of DNA which means we have 3600 DNA strand or 1800 DNA molecule .

so from one DNA molecule after one PCR cycle we get 2 copy of DNA thus for n number of cycle we get= 2 ⁽ⁿ⁾ copy of DNA

so putting the valve in this equation we get number of copy.

number of copy from 3600 fragment of DNA or 1800 DNA molecule= 1800 2 ⁽⁴⁵⁾

= 3600 ⁽⁴⁵⁾  

number of copy from 3600 fragment of DNA or 1800 DNA molecule = 1 * 10^{^ 160} copy of DNA