polymerase chain reaction

Question 1

purpose of polymerase chian reaction

Answer 1

creates multiple copies of DNA segment

Question 2

describe PCR

Answer 2

Denaturation
• DNA sample heated to 94C for 2 mins; this breaks the H bonds in one double stranded DNA molecule, forming 2 single stranded DNA molecules (with exposed bases)
Annealing
• Cooled slightly to 55C for 2 minutes; allows primers (short segments of single stranded DNA) to anneal (form H bonds) with regions at either end of the DNA of interest with complementary bases.
• At the 3’ end of each strand
Polymerisation
• DNA polymerase binds to primers and creates polymers (ie. extends the primers)
• The DNA polymerase reads the original strand/travels in a 3’  5’ direction. At the same time, nucleotides are added to form a new DNA strand in a 5’  3’ direction (remember, these two strands are antiparallel – they’re both added in the same direction overall.
• Nucleotides must also be available.
• 72*C for one minute.
 Results in twice the amount of DNA being made.