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What are the differences between Eukaryotic, Prokaryotic and Viral Genome?
- Eukaryotic and Prokaryotic are DNA and Viruses can be DNA or RNA.
- The genome for a prokaryote is circular.(bact.)Don't have Introns & Exons they go through transcription and translation at the same time.
- The genome for a eukaryote is multiple and linear.Ribozymes cut out the Introns and put the Exons back together. A 5'cap & polyA tail is mRNA.
- The genome for viruses is Big for DNA and Small for RNA.They transcribe multiple genes with one promoter. Their genes overlap for different proteins.
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Polycistronic mRNA
- A.K.A. Operons, a set of genes, all of which are regulated as a single unit.
- RNA polymerase can transcribe all 3 genes from the same promoter.
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2 types of operons
- Inducible operon; operon is turned ON by substrate.
- Repressible operon; genes in a series are turned OFF by the product being synthesized
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Lac Operon
- When there is no lactose the repressor protein is attached to the operator and blocks transcription.
- The repressor protein comes from the regulator gene.
- Lactose binds to the repressor and makes it come off.
- RNA polymerase can attach to the promoter and move forward with the repressor gone.
- Now we can have transcription.
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Describe a PCR (polymerase chain reaction)
- Method to amplify DNA
- Ingredients: DNA to be apmplified(primer), Taq polymerase(from thermus aquaticus), nucleotides.
- Repetitively cycled: Denaturation(94deg.C) Strands separate, Priming (50-65deg.C) Oligonucleotide primers attach at ends of strands to promote replication of amplicons, Extension(72deg.C) Heat-stable DNA polymerase synthesizes complementary strand.
- Each cycle doubles the number of copies for analysis.
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