Exam 3 Lectures 20-22

Exam 3 Lectures - Viruses and Bacterial Genetics(Lectures 20-21 Vocabulary Bacteriophage a prokaryotic virus Capsid protein coat surrounding

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Viruses and Bacterial Genetics (Lectures 20-21) Vocabulary Bacteriophage - a prokaryotic virus Capsid - protein coat surrounding nucleic acid Enveloped virus - mostly found in animals, but also a few bacterial forms are known Virion - a virus genome and its outer components such as proteins and other material. Capsomers - formed by assembled proteins and then aggregate into protein coat Nucleocapsid - the entire capsid + nucleic acid. Is often icosahedral and is surrounded by a lipid bilayer and associated proteins. Lysis - host cell destruction Lysogen - cell containing prophage. Is immune to infection by the same virus . Prophage - a latent stated formed by the incorporation of phage genome into the host E.Coli genome. Complex virus - composed of separate subassemblies which then assemble into virus. Ex T4 phage. Segmented genome - example is seen in the virus influenza where the RNA genome exits in 8 fragments. Antigenic shift - occurs because a segmented genome allows for shuffling of RNA segments in cells infected with 2 different influenza virus particles. The shift makes changed, recombined envelope proteins that create new viruses. Oncogene - cancer associated genes Homologous - region is very similar, but not necessarily identical DNA sequence Holiday junction - it’s a crossover and it forms a crossed-strand structure. Heteroduplex DNA - segments originating from different DNA molecules Pilus - used in conjugation, the F+ plasmid is transferred through the sex pilus to the F- plasmid recipient. Hfr - H igh F requency of R ecombination. Some E. coli strains with integrated F plasmid are known as Hfr IS sequences - Insertion Sequences where an F plasmid can integrate in several specific locations in the genome. oriT - is the origin of transfer Gene - segment of DNA that codes for polypeptide, tRNA, or rRNA Transposon - (Tn) has transposase gene + others (such as antibiotic resistance) Complementation - Inversions - orientation of a segment of DNA is reversed; sometimes, large portions of genomes involved. Transolocations - rearrangements of regions of DNA; large segments of DNA move to another location on the genome. Reversions - restoration of a wild-type phenotype, usually involving a single point mutation; can occur two ways: 1. Same site reversion- base pair mutates back to original 2. Second site reversion- mutation at a different site restores the wild-type phenotype (frameshift).
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Concepts 1. A combination of two experimental AIDS drugs can help control the deadly virus in people who are infected with highly resistant forms. The two drugs are called etravirine, or TMC125, and darunavir, or TMC114. 2. Complex viruses are composed of separate subassemblies which then assemble into a virus. They have a tail, head, and tail fibers (ex T4 phage). Filamentous have a helical shape with a nucleocapsid structure. Structural subunits (proteins) combine together with virus RNA inside. Icosahedral have nucleocapsid structure that is surrounded by a lipid bilayer and associated proteins. A type of enveloped
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This note was uploaded on 04/02/2008 for the course PSY 101 taught by Professor Jackson during the Fall '08 term at Michigan State University.

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Exam 3 Lectures - Viruses and Bacterial Genetics(Lectures 20-21 Vocabulary Bacteriophage a prokaryotic virus Capsid protein coat surrounding

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