BIO 361 Study Questions Exam1

BIO 361 Study Questions Exam1 - BIO 361 Study Questions...

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BIO 361 Study Questions Exam #1 1. Symbionts Relationshhip? a. Phoresis: two symbionts are merely “traveling together” i. Bacteria on the legs of a fly b. Mutualism: a relationship where both symbionts benefit from the association (developed a physiological dependence to one another) i. Termite and protozoa which dwell in their hind gut c. Commensalism: One symbiont, the commensal, benefits from its relationship with the host, but the host neither benefits or is harmed i. Bacteria in our large intestine, feel on unwanted or unusual food d. Parasitic: the symbiont harms its host or in some sense lives at the host’s expense i. Protozoa/heminths eat or digests host tissues 2. Parasitic relationships? a. How do parasites harm the host? i. Kill host cells or cause mechanical injury to host tissues ii. Produce toxins that damages the host cells or tissues iii. Rob the host of nutrition iv. Eat or digest host tissues v. a combination of the above b. Do they always harm host? i. No, there is a considerable overlapped b/w mutualism, commensalism and parasitism. Some parasites colonize in areas in which they do not harm the host at all until the host become compromised, for example S. pneumoniae are carried in the nasopharynx of humans. With rabies virus, they are carried throughout animals without causing any disease c. Advantage/disadvantage? i. The parasites rely on the host for food and nutrients and can conserve its energy and metabolic activity for the sole purpose of replicating and reproducing. ii. The parasite’s development is often partly or completely controlled by the host. d. How do they maximize their chances? i. Evolved to promote their prolonged survival in the outside world (uneveloped virus, bacterial spores, protozoan cysts and worm eggs) ii. Multiply prolifically to increase the chances they can achieve 3. Infection vs disease a. Define both term i. Infection: the pathogen enters the host or the pathogen is dividing (multiplying) in the host or tissue (colonizing within the host) ii. Disease: a change or interruption of the normal structure or function of any part of the body that is manifested by a characteristics of symptoms and signs
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1. normal flora is NOT considered an infection, only if the host was compromised—if there was a small number of colonized frank pathogen then it would be b. Infectious disease? i. A change from a state of health to disease because of the presence of an infectious agent, or its product—disease can be transmitted c. Emerging infectious disease i. An infectious disease that has newly appeared in the population or existed but is rapidly increasing in incidence or geographical range 4. The ‘iceberg’ concept a. The iceberg concept explains when an organism infect a population, most
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This note was uploaded on 02/17/2010 for the course BIO 361 taught by Professor Barth during the Fall '09 term at University of Texas at Austin.

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BIO 361 Study Questions Exam1 - BIO 361 Study Questions...

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