Micro.Review.Part1

Micro.Review.Part1 - MCB 5252 Exam FOUR Review Questions;...

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Unformatted text preview: MCB 5252 Exam FOUR Review Questions; Part ONE 1. What are the general characteristics of viruses? List stages in virus replication cycle a. Obligate intracellular parasites b. Require host machinery for energy and protein synthesis c. Genome may be DNA or RNA d. Composed of Nucleic Acid and Protein Coat Replication Cycle (General Lytic Cycle) Adsorption; Penetration (uncoating); Eclipse; shut down of host protein, DNA, and RNA synthesis; Synthesis of viral macromolecule; Synthesis of early viral proteins before replication of the viral genome (replicase); synthesis of late proteins after the genome has been replicated (structural proteins); assembly of virus components; release of virus particles. Adsorption Penetration Uncoating Transcription Translation Synthesis of Virus Nucleic Acid Assembly of new virus particles. 2. Compare and contrast the characteristics of viruses and other microbes a. Microbes adhere to the following characteristics: Invasion, Attachment, procurement of nutrients, survival of host defenses, and replication (spreading of pathogen). b. In general, viruses must: i. Enter the Cell ii. Grow (replicate) within the cell iii. Evade host defenses (interferons, fever, etc) iv. Illicit dmage to host via: Cell Lysis, production of toxic substances, cellular transformation, indirect production of toxic substances, and host cell alterations (nuclear and cytoplasmic). 3. List virus virulence factors. List routes by which viruses may gain retry into host tissue a. All virus are covered by a protein coat called a capsid charged with the purpose of protecting the genome (RNA or DNA) from: physical damage and chemical damage (enzymatic. i. The outer surface of the capsid is responsible for recognition and binding via virus attachment protein to a cellular receptacle molecule. ii. Capsid responsible for delivery of virus genome inside the cells of the host. b. Adsorption is important in determining host and t issue specificity and pathogenesis. For example: i. Influenza-infect mucosal cells, but not basal cells ii. Rotavirus-infect intestinal cells only iii. Poliovirus-wild type infects intestinal cells/neurons Note: Most virus gain entry to the body via the respiratory pathway (lungs). Ent ry may also be gained via: t rauma and/or insect bite; Alimentary Tract; the skin; Genital Tract; and Conjunctiva. 4. List type of host damage caused by viral infection a. Cell Lysis b. Production of Toxic Substances c. Cell Transformation d. Suppression of Immune mechanisms e. Induction of non-normal host specified products (antigens, illicit immune response inflammation). f. Alterations in structural features of host cell 5. What are the four types of allergic reactions resulted from viral infection a. Type I Allergic Reaction: IgE antibodies fixed to mast cells react with the complete virus or with viral components b. Type II Allergic Reaction: Involvement of IgG and/or IgM: c. Virus (or viral component)-Complement fixation to the cell. Results in complement Virus (or viral component)-Complement fixation to the cell....
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Micro.Review.Part1 - MCB 5252 Exam FOUR Review Questions;...

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