Exam_3_809ShortAnswerKey

Exam_3_809ShortAnswerKey - BIO 307D Exam 3 November 9 2009...

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1 BIO 307D Name ______________________________ Exam 3 November 9, 2009 Section II . Compare/contrast and define 4 of the following terms. Each answer is valued at 5 points. If you answer more than 4 of the following, your first 4 answers will be graded. If you write an answer and then decide that you do not want that answer to be graded, clearly draw a line through that answer page. [20 pts total] opportunistic pathogen A microbe that is usually not a pathogen, such as normal human microbiota (microflora), but which may cause disease (i.e., become pathogenic) under special circumstances such as when a person’s immune system is compromised or when the microbe enters tissue that is normally free of microorganisms. exotoxin and endotoxin Exotoxins are proteins that are produced by certain bacterial cells as they grow and secreted/released from the bacterium. Once released, the exotoxins act upon specific cells in the animal – generally damaging the cell or altering its function. [Examples are A-B exotoxins such as botulism toxin, cholera toxin or staphylococcus toxin that causes food poisoning.] Endotoxins are structural components of bacterial cells such as lipopolysaccharide (LPS) that when released from a dead/decomposing bacterial cell can have a range of effects on the animal’s body ranging from inducing a fever to causing septic shock. pathogenicity and virulence Pathogenicity is the ability of a microbe to cause disease in an animal/human (i.e., to damage the infected host). Virulence is the relative capacity of a pathogen to infect and/or damage an animal/human. [Virulence depends on many capabilities of the pathogen including its ability to stay in the body, avoid the animal’s host defenses, and produce molecules that damage host tissue.] lentivirus Lentiviruses are a subgroup of Retroviruses. [Like all retroviruses, they copy their RNA genomes into dsDNA and integrate this molecule into the host cell chromosome.] While they have the same basic genes found in all retroviruses ( gag, pol, env , & pro ), lentiviruses encode many additional proteins such as tat and rev, that regulate viral replication. HIV is one example of a lentivirus. provirus
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This note was uploaded on 01/23/2010 for the course BIO 307D taught by Professor Moore during the Fall '09 term at University of Texas.

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Exam_3_809ShortAnswerKey - BIO 307D Exam 3 November 9 2009...

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