TALAROS Foundation Microbiology Chapter 002, Exam 1 Study Guide Complete Solution 2023

TALAROS Foundation Microbiology Chapter 002, Exam 1 Study Guide Complete Solution 2023 The term culture refers to the ______ growth of microorganisms in ________. A) rapid, incubator B) macroscopic, media C) microscopic, the body D) artificial, colonies correct answers A A mixed culture is A) the same as a contaminated culture B) one that has been adequately stirred C) one that contains two or more known species D) a pond sample containing algae and protozoa correct answers C Agar is superior to gelatin as a solidifying agent because agar A) does not melt at room temperature B) solidifies at 75C C) is not usually decomposed by microorganisms D) both a and c correct answers D The process that most accounts for magnification is A) a curved glass surface B) refraction of light C) illumination D) resolution correct answers B A subculture is a A) colony growing beneath the media surface B) culture made from a contaminant C) culture made in an embryo D) culture made from an isolated colony correct answers D Resolution is ______ with a longer wavelength of light A) improved B) worsened C) not changed D) not possible correct answers B A real image is produced by the A) ocular B) objective C) condenser D) eye correct answers B A microscope that has a total magnification of 1500X with the oil immersion lens has an ocular of what power? A) 150X B) 1.5X C) 15X D) 30X correct answers C The specimen for an electron microscope is always A) stained with dyes B) sliced into thin sections C) killed D) viewed directly correct answers C Motility is best seen with a A) hanging drop preparation B) negative stain C) streak plate D) flagellar stain correct answers A Bacteria tend to stain more readily with positively charged dyes because bacteria A) contain large amounts of alkaline substances B) contain large amount of acidic substances C) are neutral D) have thick cell walls correct answers B Explain what is involved in isolating microorganisms and why it is necessary to do this. correct answers Isolation is when a strain of bacteria is separated and cultivated in a petri dish-creation of a pure culture. Usually bacteria are isolated so that you can determine which bacteria is responsible for a particular activity such as illness. Compare and contrast two common laboratory techniques for separating bacteria in a mixed sample. correct answers The streak plate method spreads a small droplet of the sample across the medium so that it thins out and separates the cells spatially all over the plate. The pour plate technique dilutes the mixed culture by pouring them into a series of agar tubes. The tubes are then poured into individual agar plates to incubate. The spread plate method is almost the same as the streak plate but the sample is spread evenly across the agar instead of streaked. How can one obtain 2000X magnification with a 100X objective? correct answers The ocular lens would have to be 20x since the objective lens is 100x. Differentiate among the ingredients and functions of enriched, selective, and differential media. correct answers Selective media: MacConkey agar for Gram-negative bacteria Differential media: Blood agar (used in strep tests), which contains bovine heart blood that becomes transparent in the presence of hemolytic Streptococcus Enriched media: Blood agar, Chocolate blood agar What kind of medium might you make to selectively grow a bacterium that lives in the ocean? correct answers There are enriched marine agar media for heterotrophic bacteria that can be used. What kind of medium might you make to selectively grow a bacterium that lives in the human stomach? correct answers MacConkey agar is usually used to differentiate gut bacteria such as E. coli and S. entera. It is selective and differential.