You have a piece of DNA that includes the sequence 5GATGAGGA

You have a piece of DNA that includes the sequence: 5\'GATGAGGATGAGGAGAAGTACCGGCCGCCGCCTGCGCATCACAATATGTTCAGT 3\' To amplify this DNA by PCR, you would use a pair of primers One primer sequence is 5’ - 5\' – GATGAGGATGAGGAGAAG - 3\' Which of the following primer do you need to amplify this piece of DNA

A. 5\' - CTACTCCTACTCCTCTTC - 3\'

B. 5\' – CTTCTCCTCATCCTCATC - 3\'

C. 5\' - GAAGAGGAGTAGGAGTAG - 3\'

D. 5\' – ACTGAACATATTGTGATG - 3\'

E. 5\' – TGACTTGTATAACACTAC - 3’

Solution

Given Sequence of DNA:

5\' GAT GAG GAT GAG GAG AAG TAC CGG CCG CCG CCT GCG CAT CAC AAT ATG TTC AGT 3\'

Required Primer as per question 3\' GTA GTG TTA TAC AAG TCA 5\'   

ANSWER IS D. 5\' – ACTGAACATATTGTGATG - 3\'

Complementary strand of DNA:

3\' CTA CTC CTA CTC CTC TTA ATG GCC GGC GGC GGA CGC GTA GTG TTA TAC AAG TCA 5\'

5\' – GATGAGGATGAGGAGAAG - 3\' = Given Primer in Question

Concepet used:

1. Both strands of DNA unwind.

2. On both DNA strands Primer binds with 3\'. Primer is read from 5-> 3\' direction.

3. In one strand if primer reads from left to right then in other strand it reads from right to left.

4. Primer binding with DNA follows complementary rule: A-T, T-A, G-C,C-G