PM-149 Lecture 7. Viruses and Bacteria PDF
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Uploaded by PerfectLepidolite3494
Swansea University
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This document is a lecture on the genetics of viruses and bacteria. It covers topics such as viral structure, host range, the life cycle of a virus, and bacterial evolution. The lecture also touches upon antibiotic resistance.
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Lecture 7 The Genetics of Viruses & Bacteria & Learning Objectives Introduction to viruses why viruses are classed as “non-living. The life-cycle of a virus. Eg. HIV/AIDS Introduction to bacteria Appreciate the large number of species How high m...
Lecture 7 The Genetics of Viruses & Bacteria & Learning Objectives Introduction to viruses why viruses are classed as “non-living. The life-cycle of a virus. Eg. HIV/AIDS Introduction to bacteria Appreciate the large number of species How high mutation rate drives evolution How bacteria acquire antibiotic resistance Clinical relevance of antibiotic-resistant bacteria. Viruses Non-living particles (nucleic acid and protein) Not composed of cells Do not carry out metabolism Do not use energy Do not maintain homeostasis Do not reproduce OBLIGATE parasites! The biggest known viruses are mimiviruses, which are 400 nanometers (0.0004 millimeters) in diameter. The viral genome is 1,200,000 nucleotides in length and codes for over 900 proteins. The smallest known viruses are circoviruses, which are 20 nanometers (0.00002 millimeters) in diameter. The viral genome is 1,700 nucleotides in length and codes for two proteins. Influenza virus - lung Influenza virus - RBC Structure of viruses Genomic material – DNA or RNA Protein shell – capsid Rod-shaped, polyhedral Protein subunits called capsomeres Structure of Different Viruses Diversity among viruses Host range Broad host range Narrow host range Viral infection of eukaryotes limited to specific tissues. Viral infections and Human Disease Viral Reproductive cycle Basic steps: – 1. Attachment: binding of the virus to the host cell membrane – 2. Entry: viral genome enters the host cell – 3. Integration: Viruses capable of integration into the host carry the enzyme integrase – 4.Synthesis of viral components: replication of viral genome and protein coat synthesis – 5. Viral assembly: self-assembly (spontaneously bind to each other) or helped by additional proteins. – 6. Release: release of new viruses either by lysis or budding ytic and Lysogenic cycles of a bacterioph Click on the link to watch an animation of the replicative cycle of a bacteriophage - https://www.youtube.com/watch?v=hFwA0aBX5bE ~ 40 million people worldwide living with HIV/AIDS in 2019. Of these, 1.8 million were children (
