Microbiology
Homework Assignment – Microbial/Bacteria/Viral Diseases

Directions: Answer each question. Be sure to answer the ENTIRE question. See numbers in parentheses ( ) for point values. You must handwrite your answers in the space provided. In addition to answering the questions, you will be graded 5 points based on the neatness of your submitted work (including your handwriting). If I cannot read the answer, you will get 0 points for the question. If you use another source (website, journal article, etc.) to help you answer a question, you must cite it. 1. Name and describe the 3 types of symbiosis. (6) * Mutualism- a relationship between two species of organisms in which both benefit from the association. * Commensalism- a type of relationship between two species of a plant, animal, fungus, etc., in which one lives with, on, or in another without damage to either. * Parasitism- a relation between organisms in which one lives as a parasite on another.

2. Pick one of the types of symbiosis and find an example and describe it (using your textbook or the internet). (2) * Example of Commensalism: Remarkable cases occur of commensalism between certain crabs and sea-anemones, and they betoken much intelligence.

3. You want to prove that the Mycoplasma bacterium is the cause of tuberculosis. Describe how you would prove this using Koch’s postulates. (4) * The microorganism or other pathogen must be present in all cases of disease * The pathogen can be isolated from the diseased host and grown in pure culture * The pathogen from the pure culture must cause the disease when inoculated into a healthy susceptible laboratory animal * The pathogen must be re-isolated from the new host and shown to be same as the originally inoculated pathogen.

4. What is virulence? (1) * The relative ability of a