gene technology

describe the steps involved in the production of bacteria capable of synthesizing human insulin.

1) identifying the human insulin gene

• beta cells in islet of langerhans in the pancreas produced large amounts of insulin and will therefore have large amounts of mRNA for it
• mRNA has a genetic code complementary to the exons (key portions of DNA - which are translated into proteins - useful part) of a human insulin gene
• mRNA contains more exons than DNA therefore works faster

2) isolating mRNA and making CDNA using reverse transcriptase

• mRNA is isolated from beta cells
• mRNA is incubated with a mixture of free DNA nucleotides and reverse transcriptase ( from viruses - use RNA as their genetic material)
• produces single strand of DNA - CDNA - complementary DNA

3) cloning the DNA using DNA polymerase

• single strand is made double by DNA polymerase
• cloned to make many CDA molecules using polymerase chain reaction (PCR)
• PCR makes DNA amplification possible
• heat => 'melting' - hydrogen bond breaks
• cool - hydrogen bonds begin…