MBIOS 101 1nd Edition Lecture 33 Outline of Last Lecture - Lines of Defense1. Examples of Viruses2. Common Characteristics of Viruses Outline of Current Lecture – 1. History of Viruses 2. Virus Characteristics Current Lecture – Viruses1. History of Virusesa. 1898 – microbiologist Dutch Martinus W. Beijerinck i. found disease in tobacco leafii. called agent filterable virus iii. Did a filter experiment on the tobacco leaf and discovered that the virus could pass through the filter 2. Virusesa. Have their own DNAb. Examples –i. Wartsii. HPViii. Herpes Simplex iv. Parovirus 3. Virus characteristicsa. Obligate intracellular parasites of bacteria, protozoa, fungi, algae, plants, and animalsb. Ultramicroscopicc. Are not cells – very compact and economical d. Do not independently fulfill the characteristics of lifee. Need host cell to replicatef. Are inactive macromolecules outside of the host cell and active inside the hostg. Are geometrich. Basic structure consists of protein shell surrounding nucleic acid corei. Nucleic acid can be either DNA or RNA not bothThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.j. Nucleic acid can be double stranded DNA, single stranded DNA, single stranded RNA and double stranded RNA k. Molecules on virus surface impart high specificity for attachemtn to host cell l. Multiply by taking control of host’s cells genetic material and regulating the synthesis and assembly of new virusm. Lack of enzymes for metabolic processesn. Lack machinery for synthesizing proteins4. Viral Anatomy a. Non-enveloped virus (naked virus) i. All it has is a structure called the capsomere and the nucleic acid b. Enveloped virus i. Spikes on the outside of the envelope for attachment c. Bacteriophage i. Inject DNA into celld. Life cycle i. Injection into cellii. Host cell1. Disease of host cella. Productive infection (more virus produced)b. Lysis of cell (cell dies) or release of cell (host cell multiplies)2. Genetic alteration of host cella. Latent state i. Nucleic acid of virus becomes a part of the host cellDNA b. Host cell is often modified and continues to
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