front 1 A microbe recovered from an environment sample grows on a medium composed of agar and a mix of salts. The agar is not digested during incubation. The growth rate increases in high CO2 conditions. The organism is likely an _______. | back 1 autotroph |
front 2 A cell that uses an organic carbon source and obtains energy from light would be called a | back 2 photoheterotroph |
front 3 A _____ organism requires oxygen for growth. | back 3 obligate aerobic |
front 4 An aquatic microbe that can grow only near the surface of the water is probably which of the following? | back 4 phototroph |
front 5 An organism that produces catalase enzyme is protected from the harmful effects of | back 5 peroxide anion |
front 6 All of the following are used to protect organisms from the toxic by-products of oxygen EXCEPT | back 6 protease |
front 7 A microbe that grows only at the bottom of a tube of thioglycollate medium is probably a | back 7 obligate anaerobe |
front 8 Nitrogen is a growth limiting nutrient for many organisms because | back 8 only a few microbes can extract it from the atmosphere, but all organisms require it for amino acid and nucleotide synthesis |
front 9 An organism that requires chemical nutrients which serve as final electron acceptors is an | back 9 chemotroph |
front 10 At temperatures higher than the maximum growth temperature for an organism, | back 10 hydrogen bonds are broken, proteins are denatured, and membranes become to fluid. |
front 11 Human pathogens are classified as | back 11 mesophiles |
front 12 In the process of _____ microbes detect the presence and density of other microbes and modify their metabolic activity in response. | back 12 quorum sensing |
front 13 Which of the following organisms would be most likely to contaminate a jar of pickles? | back 13 an acidophile |
front 14 Organisms that can grow with or without oxygen present are | back 14 either facultative anaerobes or aerotolerant anaerobes |
front 15 A fastidious organism might be grown on which of the following types of media? | back 15 enriched media |
front 16 Obligate anaerobes may be cultured in the laboratory | back 16 in a reducing medium |
front 17 Joan wants to discover a microbe capable of degrading an environment contaminant. Which of the following is the process she should use? | back 17 enrichment culture |
front 18 A microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the species is 1 hour, and there is no lag phase, how long will it be before the culture contains more than 10,000 cell/ml? | back 18 7 hours |
front 19 An epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue cells in clinical samples from victims. The scientist wants to try to isolate the bacteria in the lab. What culture conditions are most likely to be successful? | back 19 inoculation of cell cultures |
front 20 Microbial growth rates are controlled in a chemostat by | back 20 controlling the amount of a limiting nutrient |
front 21 MacConkey agar plates represent ______ medium. | back 21 both a differential and a selective |
front 22 A Petroff-Hauser counting chamber is a | back 22 glass slide containing an etched grid for counting microbes directly using a microscope |
front 23 A means of reproduction in which duplicate DNA molecules are separated by cell elongation, followed by formation of a septum to divide the cytoplasm is called | back 23 binary fission |
front 24 A device that removes wastes and adds fresh medium to bacterial cultures in order to prolong the log phase of a culture is called a | back 24 chemostat |
front 25 The ______ of a population is the time it takes for the cells to double in number. | back 25 generation time |
front 26 Which of the following is an indirect method for estimating the number of microbes in a sample? | back 26 turbidity |
front 27 During which growth phase are bacteria more susceptible to antimicrobial drugs? | back 27 log phase |
front 28 The use of salt and sugar in preserving various types of foods is an application of which of the following concepts? | back 28 osmotic pressure |
front 29 A clinical sample labeled as "sputum" was collected from | back 29 the lungs |
front 30 The method of obtaining isolated cultures that utilizes surface area to physically dilute specimens is called | back 30 the streak-plate technique |
front 31 ______ are complex communities of various types of microbes that adhere to surfaces. | back 31 Biofilms |
front 32 The ______ method provides an estimate of the CFUs (colony-forming units) in a sample | back 32 viable plate-count |
front 33 Blood agar plates are an example of _____ medium. | back 33 differential |
front 34 Sodium thioglycollate is associated with which of the following types of media? | back 34 reducing media |
front 35 Which of the following quantification techniques can distinguish living cells from dead cells in a culture? | back 35 metabolic activity |
front 36 The correct sequence for the phases indicated by the letters A,B,C and D is | back 36 lag phase, log phase, stationary phase, death phase |
front 37 The generation time of bacterial cells is shortest during the _____ phase. | back 37 log |
front 38 When cells are metabolically active but not dividing, they are in the ____ phase. | back 38 lag |
front 39 Metabolic activity is at maximum level in the _____ phase of growth. | back 39 log |
front 40 Creating conditions in the laboratory that promote the growth of some microbes while inhibiting the growth of others is called | back 40 selective enrichment culturing |
front 41 A laboratory protocol lists the following ingredients: 1 g sucrose, 16.4 g Na2HPO4, 1.5 g (NH4)3PO4, 0.02 g CaCO3, KNO3, water to 1 liter and autoclave. This recipe is for a ______ medium. | back 41 defined broth |
front 42 A capnophile is a microorganism that thrives in conditions of high | back 42 carbon dioxide levels |
front 43 A microorganism found living under conditions of high ____ is a barophile. | back 43 hydrostatic pressure |
front 44 Microaerophiles are microbes that grow best at low | back 44 oxygen levels |
front 45 A 100ul sample containing 1000 bacterial cells/ul in log phase growth is added to 9.9 ml of fresh culture medium broth. assuming no nutrients are in limited supply, and a generation time of 30 minutes, how many bacteria will be present in the entire broth culture after six hours? | back 45 4.096 x 108 |
front 46 The conversion of nitrogen gas to ammonia is called nitrogen (metabolism/ fixation). | back 46 fixation |
front 47 Organisms that require organic sources of carbon and energy are called (chemoheterotrophs/ chemoautotrophs/ auxotrophs). | back 47 chemoheterotrophs |
front 48 The (peroxide/ superoxide/ hydroxyl) radical if formed during the incomplete reduction of O2 during electron transport in aerobes. | back 48 superoxide |
front 49 The (optimum/ range/ minimum) growth temperature is the temperature at which an organism exhibits the highest growth rate. | back 49 optimum |
front 50 The preferred method for long term storage of bacteria is (freezing/ refrigeration/ lyophilization). | back 50 lyophilization |
front 51 Alkalinophiles can survive in water up to pH (11.5/ 10/ 7.0). | back 51 11.5 |
front 52 Many photosynthetic organisms produce (catalase/ carotenoids/ dismutase) to protect themselves from the damaging effects of singlet oxygen (1O2). | back 52 Cartenoids |
front 53 A (culture/ specimen/ inoculum) is a sample of microorganisms introduced into a growth medium. | back 53 inoculum |
front 54 A pure culture is composed of cells that arise from a single ( cell/inoculum/ sample). | back 54 cell |
front 55 A gelling agent derived from algae that is useful for crating solid growth media is called (broth/ agar/ starch)l | back 55 agar |
front 56 A sample placed into fresh medium is initially in the (lag/ log/ stationary) phase of microbial growth in most instances. | back 56 lag |
front 57 A growth curve plots the (number/ concentration) of viable organisms in a growing population over time. | back 57 number |
front 58 Flow (spectrohotometry/ cytometry) is a method of counting cells that have been stained or tagged with fluorescent dyes. | back 58 cytometry |
front 59 A clinical sample of (urine/ sputum/ tissue) is called a biopsy. | back 59 tissue |
front 60 A (cytometer/ spectrophotometer) can measure changes in the turbidity of a bacterial culture. | back 60 spectrophotometer |