Chapter 5
How much ATP could be obtained from the complete oxidation of one molecule of glucose?
38 (2 from Glycolysis, 2 from Krebs Cycle, 34 from ETC)
An organism that has peroxidase and superoxide dismutase but lacks catalase is most likely an
aerotolerant anaerobe
What are the standard temperature and duration for an autoclave? What are the standard equivalents for hot-air sterilization?
autoclave: 121oC for 15 minutes
hot air: 170oC for 2 hours
What are the four main mechanisms of bacterial antibiotic resistance?
Blocking entry
Inactivating enzymes
Alteration of target molecule
Efflux of antibiotic
An electron, liberated from chlorophyll by light, is passed down an electron transport chain. What is the name of this reaction?
photophosphorylation
By deep-freezing, bacteria can be stored without harm for extended periods. Why do refrigeration and freezing preserve foods?
The growth rate of bacteria slows down with decreasing temperatures. Mesophilic bacteria will grow slowly at refrigeration temperatures and will remain dormant in a freezer. Bacteria will not spoil
food quickly in a refrigerator.
Differentiate TDP, TDR, and DRT.
Thermal death point: lowest temperature which kills all cells in 10 minutes
Thermal death rate: time to kill all cells at a designated temperature
Decimal reduction time: time to kill 90% of cells at a designated temperature
Differentiate MIC and MBC.
minimal inhibitory concentration: lowest concentration of a chemical, usually a drug, that prevents the visible growth of bacteria
minimal bactericidal concentration: lowest concentration of an antibacterial agent required to kill a bacterium over a fixed, somewhat extended period, such as 18 hours or 24 hours, under a specific set of conditions
How would you label an organism that fixes CO2 and oxidizes sulfur?
The CO2 is the carbon source, and the inorganic sulfur is the energy source. This is a chemoautotroph.
Clostridium and Streptococcus are both catalase negative. Streptococcus grows by fermentation. Why is Clostridium killed by oxygen, wheras Streptococcus is not?
Streptococcus is able to live in anaerobic conditions while Clostridium is not because it possesses SOD (superoxide dimutase) or an equivalent system that neutralizes the toxic forms of oxygen
Which of the following is most likely to be bactericidal: membrane filtration, ionizing radiation, lyophilization, deep-freezing, or all of the above?
ionizing radiation
List three common ways antibiotics are misused.
Using outdated or weakened antibiotics
Using antibiotics for the common cold and other inappropriate conditions
Using antibiotics in animal feed
Failing complete the prescribed regimen
Using someone else's leftover prescription
How many ATP are generated in the ETC per NADH? Per FADH2? Per NADPH?
NADH: 3
FADH2: 2
NADPH: 3
A pastry chef accidentally inoculated a cream pie with six S. aureus cells. If S. aureus has a generation time of 60 minutes, how many cells would be in the cream pie after 7 hours?
6(27)=768 cells
The use-dilution values for two disinfectants tested under the same conditions are as follows: Disinfectant A-1:2; Disinfectant B-1:10,000. If both disinfectants are designed for the same purpose, which would you select?
Disinfectant B is preferable because it can be diluted more and still be effective.
What are the five main mechanisms of antimicrobial drug action?
Inhibition of cell wall synthesis
Inhibition of protein synthesis
Inhibition of nucleic acid replication and transcription
Injury to plasma membrane
Inhibition of synthesis of essential metabolites
When Clostridium ferments pyruvic acid, what is one of the end products?
butyric acid, butanol, acetone, isopropyl alcohol, and CO2
If you wanted to classify bacteria based on their ability to utilize citrate as a sole source of carbon, what medium would you use?
A chemically defined medium that includes citrate as the only carbon source. Complex media would not be sufficient for this purpose.
Which of the following is not a characteristic of quaternary ammonium compounds: bactericidal against gram-positive bacteria, sporicidal, amebicidal, fungicidal, or kills enveloped viruses?
Name one antifungal drug, one antiviral, one antiprotozoan, and one antihelminthic. Categories or specific drugs covered in the lecture slides are acceptable answers.
Antifungals: polyenes (amphotericin B), echinocandins, azoles (miconazole, triazoles), allylamines
Antivirals: nucleoside/nucleotide analogs (acyclovir), protease inhibitors (idinavir), integrase inhibitors, attachment inhibitors (zanamivir), uncoating inhibitors (amantadine)
Antiprotozoans: chloroquine, metronidazole, nitazoxanide
Antihelminthics: mebendazole, ivermectin