front 1 A medium that contains yeast extract, glucose, and peptones would be a(n) | back 1 complex medium |
front 2 A bacterial suspension produces a turbidity reading that corresponds to 5 x 107 CFU/ml. A viable plate count of the same suspension produces a concentration of only 1 x 105 CFU/ml. You most correctly conclude that | back 2 Turbidity is an accurate measure of concentration, but is measures both live and dead cells. |
front 3 In metabolism, ______ reactions liberate energy used to make ATP, whereas ______ reactions require energy supplied by the hydrolysis of ATP. | back 3 catabolic, anabolic |
front 4 The ATP made by oxidative phosphorylation | back 4 is powered by chemiosmosis using a proton gradient, is made at large transmembrane proteins called ATP syntheses, represents most of the energy made during respiration. (all of the above) |
front 5 Why are both the temperatures and times involved in hot air sterilization higher than those involved in steam sterilization? | back 5 Heat transfer is more efficient when water is involved. |
front 6 At which phase of microbial growth is the growth rate identical to the death rate? | back 6 stationary phase |
front 7 A bacterial growth experiment began with 100 cells and ended with 409,600 cells. How many generations occurred? | back 7 12 [Log (409,600) – Log (100)]/log 2 = 12, see Appendix B. |
front 8 During glycolysis | back 8 ATP is generated by substrate-level phosphorylation. |
front 9 Suppose you have a suspension of C. botulinum endospores that has a decimal reduction time (DRT) of 1.5 minutes at 121 °C. If you had 1 x 10 6 endospores, how long (at 121 °C ) would it take to reduce this number to a single organism? | back 9 9 minutes |
front 10 The process of destroying vegetative pathogens on living tissue is most correctly called | back 10 antisepsis |
front 11 What type of organism would have an optimum growth temperature at about 12 °C? | back 11 psychrophile |
front 12 Plasmas, supercritical fluids, and peroxygens are all | back 12 new methods used to sterilize. |
front 13 The most important products of the Krebs cycle are | back 13 NADH and FADH2. |
front 14 The method of preserving bacterial cultures that involves sublimation is | back 14 lyophilization |
front 15 The germicidal action of chlorine is due to the formation of | back 15 hypochlorous acid |
front 16 The net yield of ATP equivalents from one turn of the Krebs cycle (starting with acetyl-CoA) is | back 16 12 |
front 17 The most common physical method of microbial control in foods is | back 17 heat treatment or low temperatures. |
front 18 The most resistant microbe (of the ones listed) to chemical biocides is | back 18 bacterial endospores |
front 19 A bacterostatic agent | back 19 inhibits the growth of bacteria. |
front 20 Flavoproteins, cytochromes, and ubiquinones are all part of | back 20 the electron transport chain. |
front 21 Phenolics, biguanides, halogens, alcohols, and probably quaternary ammonium compounds (Quats) all cause damage to the cell’s | back 21 plasma membrane. |
front 22 Radiation does most of its lethal damage by causing breaks in, or changes to the microbe’s | back 22 DNA |
front 23 Which of the following is not a common end product of a microbial fermentation? | back 23 Glucose |
front 24 Organisms that grow deep in the bottom of the ocean (no light) next to hydrogen sulfide vents (source of energy), and are able to fix CO2 in the seawater, would be referred to as | back 24 chemoautotrophs |
front 25 Which type of organism is indifferent to either the presence or absence of oxygen? | back 25 aerotolerant anaerobe |
front 26 During photosynthesis, the main products of the light-dependent reactions are ________, whereas the main products of light-independent reactions are __________. | back 26 ATP, O2, and NADPH/sugars |
front 27 Enzymes | back 27 lower the activation energy of a chemical reaction. |
front 28 Five bacterial cells with a generation time of 15 minutes were allowed to grow for 8 hours. How many cells are present? | back 28 2.15 × 1010 Number of generations = 480/15 = 32; Nt = N0 x 2number of generations, = 5 x 232 = 2.15 x 1010, see Appendix B. |
front 29 A sample of milk is diluted 1:2,000,000 and 1 ml samples of this dilution are plated in duplicate. The average plate count is 50 CFU. How many CFU/ml are present in the undiluted milk? | back 29 100,000,000 Total CFU/ml in milk = Ave. plate count x 1/dilution factor = 50 x 2,000,000 = 100,000,000 CFU/ml. |
front 30 Blood agar containing an antibiotic that inhibits gram-positive organisms, would most correctly be called | back 30 both selective and differential. |