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Microbio ch9
| Question | Answer |
|---|---|
| Microbial growth represents an increase in ______, not size. | Numbers |
| Understand the basic steps of binary fission. | DNA replicates/ Division (septum) in middle of cell/ Two separate cells |
| Understand generation time. | Amount of time it takes for what ever population you currently have to double in size |
| Understand the phases of the bacterial growth curve. | Lag phase: No increase in number of living bacterial cells/ Log Phase: Exponential increase in number of living bacterial cells |
| Understand the phases of the bacterial growth curve. | Stationary phase: Plateau in number of living bacterial cells' rate of cell division and death roughly equal |
| Understand the phases of the bacterial growth curve. | Death or decline phase: Exponential decrease in number of living bacterial cells |
| Understand the DIRECT and indirect methods of quantification discussed in the notes. | Quantify cell numbers/ plate counts (serial dilutions)/ Filtration/ MPN(most probable number)/ Direct microscopic count |
| Understand the direct and INDIRECT methods of quantification discussed in the notes. | Quantify factors that depend on cell numbers/ Turbidity/ Metabolic activity/ dry weight |
| What is a biofilm and how does it form? | Microbial communities/ Form slime or hydrogels/ Share nutrients/ Sheltered from harmful factors |
| Define: obligate aerobe | Mostly resembling of humans/ Needs oxygen |
| obligate anaerobe | Organisms that cannot tolerate oxygen/ dies in the presence of O2/ Cannot break down O2 |
| facultative anaerobe | Grown better with oxygen but can also live in environments without it |
| aerotolerant anaerobes | No preference |
| microaerophiles | Happy with very small amounts of oxygen |
| acidophile | Lactic acid in bacteria grows optimally in pH less than 5.55/ |
| neutrophile | Bacteria grow optimally at a pH within one or two pH units/ Ex: staphylococci, salmonella spp |
| alkaliphile | Microorganisms that grow best at pH btwn 8.0 and 10.5/ Ex: Vibrio cholerae, Natronobacterium |
| psychrophile | Microorganisms that can grow at 0°C and below/ Found in permanently cold environments/ Important decomposers |
| psychrotroph | Organisms that prefer cooler environments, 25°C to 4°C/ Found in natural temperate climate environments/ Spoilage of refrigerated food |
| mesophile | "Middle loving", adapted to moderate temps 20°C to 45°C/ Ex: E.coli, salmonella spp, lactobacillus spp |
| thermophile | Organisms that grow in temps from 50°C to 80°C/ "Heat loving"/ found in hot springs, geothermal soils, garden compost/ Ex: Thermus aquaticus, geobacillus spp |
| hyperthermophile | Organisms grow in temps from 80°C to 110°C/ Found at hydrothermal vents/ Ex: Pyrobolus, pyrodicitium |
| What are chemically defined and complex media? | Exact chemical composition is known (less used) |
| What are chemically defined and COMPLEX media? | Extracts and digests of yeasts, meat, or plants/ Ex: NB, NA, TSB, TSA |
| Understand SELECTIVE and differential media. | Suppresses unwanted microbes |
| Understand selective and DIFFERENTIAL media. | Makes it easy to distinguish colonies of different microbes: colonies get a unique appearance |
| Understand quorum sensing. | Mechanism by which cells in a biofilm coordinate their activities in response to environmental stimuli/ chemical' autoinducers, provoke gene expression/ Gram+&- have diff signaling molecules |
Created by:
Clinton Perdue
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