Straighterline Micro 250 final prep Questions & Answers with 100% Verified Answers

Straighterline Micro 250 final prep Questions & Answers with 100% Verified Answers _____ solution was introduced in the late 19th century for preventing gonococcal infections in a newborn's eyes after exposure to the mother's infected birth canal. Select one: a. Merthiolate b. Triclosan c. Betadine d. Silver nitrate e. Zinc oxide - Silver nitrate A bacterium that you isolated from pond water appears to use light for energy. Based upon this information, you inoculate the organism into fresh media, infused with lots of carbon dioxide. Even after incubation at the correct temperature (of pond water), the organism is not growing. Your best explanation of what might have happened is Select one: a. there was no sulfur compound added to the medium, that could be used as an electron donor. b. no oxygen was added to the medium so the organism died. c. there is some inhibitory chemical that is preventing the growth of the bacterium. d. you were using the wrong type of sunlight as the energy source for the bacterium. - there was no sulfur compound added to the medium, that could be used as an electron donor. A diagram of the three domains (Bacteria, Archaea, Eukarya) proceeding from the Last Universal Common Ancestor would show Archaea Select one: a. as the original cells from which the others derived. b. branching off the Domain Eukarya. c. branching off the Domain Bacteria. - branching off the Domain Eukarya A fat is called _____ if all carbons of the fatty acid chain are single-bonded to 2 other carbons and 2 hydrogens. - saturated A group of protozoa that are not motile are the ______. Select one: a. amoebas b. ciliates c. trophozoites d. Plasmodium sp. e. dimorphics - Plasmodium sp. A microaerophile Select one: a. grows best in an anaerobic jar. b. grows with or without oxygen. c. needs normal atmospheric levels of oxygen. d. requires a small amount of oxygen but won't grow at normal atmospheric levels of oxygen. - requires a small amount of oxygen but won't grow at normal atmospheric levels of oxygen. A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium. Following incubation, only the E. coli grows in the culture. What is the most likely explanation? Select one: a. The microbiologist used too much inoculum. b. The culture was contaminated. c. The incubation temperature was incorrect. d. The culture medium was selective. e. The culture medium was differential. - The culture medium was selective. A microbiologist must culture a patient's feces for intestinal pathogens. Which of the following components would likely be present in a selective medium for this purpose? Select one: a. NaCl b. Sheep red blood cells c. Bile salts d. Thioglycolic acid e. Peptone - Bile salts A microorganism that does not have catalase or superoxide dismutase would find it difficult to live in an environment with ______. Select one: a. carbon dioxide b. oxygen c. high salt d. temperatures above 37° C e. high acidity - oxygen A mutation that changes a normal codon to a stop codon is called a ______ mutation. Select one: a. point b. silent c. back d. missense e. nonsense - nonsense A nutrient medium that contains at least one ingredient that is not chemically defined is termed ______. Select one: a. complex b. reducing c. enriched d. synthetic - complex A nutrient medium that contains at least one ingredient that is not chemically defined is termed ______. Select one: a. complex b. reducing c. enriched d. synthetic - complex A pure culture contains Select one: a. only one identified species of microorganism. b. only bacteria. c. microbes from a single source. d. a variety of species from the same genus. - only one identified species of microorganism. e. aerator - starter culture A pure or mixed sample of known microbes added to food is a(n) ______. Select one: a. leavening b. fermenter c. starter culture d. flavor inducer A reducing medium contains Select one: a. sugars that can be fermented. b. extra oxygen. c. hemoglobin, vitamins, or other growth factors. d. substances that remove oxygen. e. inhibiting agents. - substances that remove oxygen. A reducing medium is used to culture ______ organisms. Select one: a. fastidious b. aerobic c. anaerobic d. pathogenic - anaerobic