Entry #2: PCR and Other Standard Techniques

As Told By Stephen Dixon

Overview

This week we attended a workshop on molecular biology techniques, hosted by Dr. Wendy Hutchins. The workshop consisted of a review of molecular biology, DNA transcription and translation, and an introduction to polymerase chain reaction (PCR), cloning, Beer's Law, western blots, antibiotic selection, and standard bioinformatic software.

Review of Molecular Biology

In the review of molecular biology, we covered how DNA, RNA, and proteins replicate and how they are used to create each other. DNA and RNA are related by transcription and reverse transcription. transcription occurs by unzipping the helicase of DNA using a DNA polyermase, and "copying" it to a strand of messenger RNA. Reverse transcription, usually a viral process, uses RNA Polymerase to convert RNA back to DNA. Both procedures exploit the complementarity of base pairs. We also discussed binding sites, DNA melting, stringency, and primers.

Polymerase Chain Reaction (PCR)

Polymerase Chain Reaction is a method of generating many copies of a specific DNA sequence. The main technology behind PCR's is the thermocycler, which cycles through several temperatures to ensure the optimum DNA replication. Usually, the thermocycler is run for 30-35 cycles; in theory, 2^35 strands of DNA can be produced, but in fact the number of DNA strands produced is limited because primers run out.

Other Interesting Facts

One of the things that I thought was really interesting was that the GC bond has a higher melting point than the AT bond. As a result, micro-organisms living in volcanic sea vents tended to have more GC bonds, and organisms living in the Antarctic had more AT bonds.