BIOLOGY 172 Lecture Notes - Lecture 20: Polymerase Chain Reaction, Reverse Transcriptase, Dna Replication
Document Summary
Makes use of the principles of dna replication. Rapidly makes millions of copies of a specific dna sequence. Copies gene of interest -- stretch of dna. Step 1: denaturation -- solution containing double-stranded template dna is heated to separate the two strands (heat rather than helicase in cell) Step 2: annealing -- two dna primers form base pair interactions with template strands (dna rather than rna primer because it is more stable) Step 3: extension -- dna polymerase synthesizes new dna strands by extending primers. Process continues copying all strands previously copies. You need sequence information to design primers! You need heat stable dna polymerase because we are using heat to denature (use extremophile polymerase) Components: template dna, (2) primers, a lot of dntps (atgc), taq dna polymerase (extremophile), buffer. Repeated cycles of : denaturation, annealing, extension. Tiny amounts of hair, blood, semen at crime scenes can be replicated. Dna polymerase can only use dna as a template.
