Feb 8thPreview.pdf - Chapter 1 General Features of Virus...

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Learning Objectives: After completing Chapter 1, students should be able to: provide a definition of the term “virus,” explain the basic structure of viruses (including genomes), explain the central dogma of molecular biology. Chapter 1 - General Features of Virus Structure 1
Chapter 1 - General Features of Virus Structure What are viruses? “Virus are tiny non-living agents with very complicated lives.” B. Marintcheva Genetic information (nucleic acid) surrounded by a protein coat. Some also contain external structures ( e.g ., spikes) and an envelope of phospholipids. Obligate intracellular parasites i.e., they require host cells to reproduce. Each type of virus infects a specific unicellular species or cell type in a multi- cellular species. 3
Chapter 1 - General Features of Virus Structure Viruses are not cells. They cannot synthesize their own ATP or amino acids or nucleotides. Cannot synthesize proteins on their own. 4 Viruses Extracellular state Intracellular state Inert particle (Protein, nucleic acid, maybe lipid) Replicating nucleic acids (Gene expression, viral proteins)
Chapter 1 - General Features of Virus Structure 5 Viruses Cells Hereditary material DNA or RNA Can be single-stranded or double-stranded Plasma membrane present No (may have an envelope) Yes Can carry out transcription independently Yes Can carry out translation independently Yes Metabolic capabilities Extensive - ATP synthesis, oxidation of reduced C, amino acid & nucleotide biosynthesis, etc. Characteristics of viruses vs . cells
Chapter 1 - General Features of Virus Structure Central dogma of molecular biology – the flow of a genetic information within a biological system. Applies to all living cells. Applies to viruses too – sometimes with a twist. 7
Chapter 1 - General Features of Virus Structure Viruses are a diverse group of infectious agents Structure (naked, enveloped, complex capsids).

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