Emerging VirusesViruses that make a sudden appearance – they emerge and get theattention of the medical communityNot new – but have evolved and expanded their range/ hostMany come from tropics Ebola Virus Hantavirus
PrionsInfections proteinsMisfolded protein that is normally presentMisfolded protein converts normal proteinsExample – Mad Cow Disease
Bacterial Genome• Circular DNA• No introns• Replication – Begins at origin – Works its way around – Result – 2 circles – Happens prior to binary fission
Plasmids• Small circular pieces of DNA outside of bacterial genome• Self-replicating• Used in DNA technology to introduce foreign DNA into bacteria
Genetic Recombination in Bacteria• Transformation – Uptake of naked DNA from environment• Conjugation – Transfer of DNA from one bacterial cell to another – Sex pili• Transduction – Transfer of DNA from bacteriophage to bacteria (bacteriophage got DNA from previous host cell)
Operon: on/ off switch for prokaryotic genes• trp operon - represses enzymes – In absence of tryptophan • Operon is on • Inactive repressor – In presence of tryptophan • Operon is off • Tryptophan activates repressor which binds operator
lac operon - Inducible Enzymes• In absence of lactose, no enzymes made• In presence of lactose, – Lactose binds and inactivates the repressor – Enzymes to digest lactose are made
Development of colorectal cancer• Multiple mutations lead to carcinoma – Loss APC gene – Activation of ras oncogene – Loss of tumor-suppressor gene DCC – Loss of tumor-suppressor gene p53 – More mutations
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.