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MICROBIOLOGY EXAM 1 NEWEST 2024-2025 ACTUAL
EXAM COMPLETE 350 QUESTIONS AND CORRECT
DETAILED ANSWERS ( VERIFIED ANSWERS )
|ALREADY GRADED A+
All of the following are associated with filtration EXCEPT:
- nitrocellulose or plastic membrane filters.
- varying thicknesses of membrane filters used.
- HEPA filters are used to filter air.
- viruses and proteins can be trapped by some filters.
- sterilization of heat-sensitive materials. - ANSWER- B) varying
thicknesses of membrane filters used.
Describe some factors that can either increase or decrease the effectiveness of antimicrobial agents. - ANSWER- duration of exposure- ->in general, longer/increased exposure time, increases efficiency of the agent
concentration of the agent-->in general increase concentration of agent increases efficiency...however saturable once agent reaches max kill, rate increases, does not drop efficiency.
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presence of organic debris-->debris may be food, feces, blood, vomit,
skin, hair, etc. it also blocks agent from receiving microbes: may need to
pre clean. in general increased debris decreases efficiency.
surface features-->in general rougher/more porous surface, decreases efficiency. ideally wants agent with low surface tension.*water has high tension surface *tension goes in to cracks/pores
temperature-->in general a temperature increases efficiency. usually increased temperature reduces time required to clean and reduces concentration level.*less to do with agent *more to do with microbe
population size(how many microbes are present)-->in general larger population/more microbes present, decreases efficiency. most agents have a defined kill rate. the larger the population the more time to kill eg.. agent-->50% per minute kill rate(pop. a. 100-50-25-12-6-3-1-0) 1 minute to kill
population composition-->in general, more diverse/mixed population, decrease efficiency. population may be diverse in many different groups of microbes present, presence of endospore forming species, age of cells(older/mature cells more difficult to kill) eg.. pop. b. (1000-500-250-125-62-31-16-8-4-2-1-0) 11 minutes to kill 2 / 4
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The spores of which of the following microbes are the most resistant to every known sterilization technique? - ANSWER- Bacillus stearothermophilus
Match the pioneer(s) in microbiology with their accomplishment(s).Fleming Snow Jenner Ehrlich Watson & Crick - ANSWER- idk
Fleming- immunologist and discovered lysosome and penicillin Snow- epidemiology and infection control (emerging infectious disease) Jenner- Immunology (Developed smallpox immunization) Ehrlich - chemotherapy Watson & Crick - discovered DNA molecule
Compare and contrast the three domains identifies by Woese-Eukarya, Bacteria, and Archaea. - ANSWER- written
A bacterial capsule
- is generally composed of polysaccharide
- facilitates nonspecific adherence 3 / 4
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- is antiphagocytic
- is external to the cell wall
- all of the above - ANSWER- E. all of the above
A bacterial cell that is moving away from a toxic pollutant in the environment during the daylight is said to exhibit - ANSWER- negative chemotaxis
If a microbiology lab technician left the safranin out of the Gram stain procedure, what would be the result? - ANSWER- Gram-positive cells would be purple, and Gram negative cells would be colorless.
The number of bacteria resulting from the growth of one bacterium
through five generations: - ANSWER- idk
Which of the following quantification techniques can distinguish between living and dead cells in a culture?
- microscopic counts
- dry weight
- metabolic activity
- a Coulter counter
- turbidity - ANSWER- C) metabolic activity
A cell that uses an organic carbon source and obtains energy from a light would be called a
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