Question

Relate the ingredients shown in the slide show test tube to the components involved in DNA replication. Why is each ingredient added to the PCR reaction?

Short slide show can be found at https://learn.genetics.utah.edu/content/labs/pcr/

I am in an intro to bio class, so please post response in simple terms so I can understand please.

Answer 1

PCR is a technique that mimics the cellular process of DNA replication. Through this technique a DNA strand of your choice of interest can be replicated and amplified. The PCR mixture and replication's components can be related as follows

1. DNA strand: a template DNA strand that has to replicated; this DNA strand will be copied

2. Primers: In the replication process a RNA primer is synthesized which is then further extended by DNA polymerase. However, in PCR, the primers are pre-synthesized depending on the DNA template. Nonetheless they play the same role of priming the replication process i.e. they first anneal to the strand and are then extended by the polymerase. they provide a platform on which dna polymerase can synthesise a new dna strand since it cannot initiate this process on its own.

3. Nucleotides: these are the substrates for the reaction by dna polymerase. ATGC are polymerized into a new DNA strand in accordance with the template. For example lets say the template sequence reads TGCAAT, a new DNA strand will be polymerized ACGTTA

4. DNA polymerase: central element to the process is an enzyme that polymerizes the nucleotides. A thermally stable polymerase is used which doesnt degrade at high temperatures