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Test #2 Ch. 6,7,9
Microbiology Test #2
| Question | Answer |
|---|---|
| Which of the following can grow in a Petri plate on a laboratory table? | An aerobic bacterium |
| This statement, "In the laboratory, a sterile inoculating loop is moved across the agar surface in a culture dish, thinning a sample and isolating individuals," describes which of the following? | Streak Plate |
| Superoxide dismutase ________. | Detoxifies superoxide radicals |
| The most reactive of the four toxic forms of oxygen is _______. | The Hydroxyl radical |
| Microaerophiles that grow best with a high concentration of carbon dioxide in addition to a low level of oxygen are called ___________. | Capnophiles |
| Which of the following is not a growth factor for various microbes? | Water |
| Organisms that preferentially may thrive in icy waters are described as ________. | Psychrophiles |
| Barophiles ________. | Cannot cause diseases in humans. |
| Which of the following terms best describes an organism that cannot exist in the presence of oxygen? | Obligate anaerobe |
| In a defined medium, __________. | The exact chemical composition of the medium is known |
| Which of the following is most useful in representing population growth on a graph? | A semilogarithmic graph using a log scale on the y-axis |
| Which of the following methods is best for counting fecal bacteria from a stream to determine the safety of the water for drinking? | Membrane filtration |
| A Coulter counter is _________. | A device that directly counts microbes as they pass through a tube in front of an electronic detector. |
| Lyophilization can be described as __________. | Freeze drying |
| Quorum sensing is ___________. | The ability to respond to changes in population density. |
| All cells require a source of ___________ for redox reactions. | Electrons |
| A toxic form of oxygen, _________ oxygen, is molecular oxygen with electrons that have been boosted to a higher energy state. | Singlet |
| All cells recycle the essential element _________ from amino acids and nucleotides. | Nitrogen |
| _______ are small organic molecules that are required in minute amounts for metabolism. | Growth Factors |
| The lowest temperature at which a microbe continues to metabolize is called its __________. | Minimum Growth Temperatures |
| Cells that shrink in hypertonic solutions such as salt water are responding to _______ pressure. | Osmotic |
| Obligate __________ exist in salt ponds because of their ability to withstand high osmotic pressure. | Halophiles |
| __________ pigments protect many phototrophic organisms from photochemically produced singlet oxygen. | Carotenoid |
| Microbes that reduce N2 to NH3 engage in nitrogen ____________. | Fixation |
| A student observes a researcher streaking a plate numerous times, flaming the loop between streaks. The researcher is likely using the _________ method to isolate microorganisms. | Streak Plate |
| Chemolithotrophs acquire electrons from _________ compounds. | Inorganic |
| Which of the following is most likely the number of base pairs in a bacterial chromosomes? | |
| Which of the following is a true statement concerning prokaryotic chromosomes? | |
| A plasmid is _________. | |
| Which of the following forms ionic bonds with Eukaryotic DNA and stabilizes it? | |
| Nucleotides used in the replication of DNA _________. | |
| Which of the following molecules functions as a "proofreader" for a newly replicated strand of DNA? | |
| The addition of ----CH3 to a cytosine nucleotide after DNA replication is called _________. | |
| In translation, the site through which tRNA molecules leave a ribosome is called the _________. | |
| The Ames Test _________. | |
| Which of the following methods of DNA repair involves enzymes that recognize and correct nucleotide errors in unmethylated strands of DNA? | |
| Which of the following is NOT a mechanism of natural genetic transfer and recombination? | |
| Cells that have the ability to take up DNA from their environment are said to be ___________. | |
| Which of the following statements is true? | |
| Which of the following are called "jumping genes"? | |
| Although two cells are totally unrelated, one cell receives DNA from the other cell and incorporates this new DNA into its chromosome. This process is __________. | |
| Transcription produces ___________. | |
| A nucleotide is composed of ____________. | |
| In DNA, adenine forms __________ hydrogen bonds with ____________. | |
| A sequence of nucleotides formed during replication of lagging DNA strand is _________. | |
| Which of the following is NOT part of an operon? | |
| Repressible operons are important in regulating prokaryotic __________. | |
| Which of the following is part of each molecule of mRNA? | |
| Ligase plays a major role in ___________. | |
| Before mutations can affect a population permanently, they must be ______. | |
| The trp operon is repressible. This means it is usually ________ and is directly controlled by ___________. | |
| The three steps in RNA transcription are ____________, _____________, and ____________. | Initiation of transcriptions, Elongation of the RNA transcript, Termination of transcription |
| A triplet of mRNA nucleotides that specifies a particular amino acid is called a __________. | codon |
| Three effects of point mutations are ___________, _____________, and ______________. | Silence, Missense, Nonsense |
| Insertions and deletions in the genetic code are also called _______ mutations. | |
| An operon consists of _________, __________, and ___________ and is associated with a regulatory gene. | |
| In general, __________ operons are inactive until the substrate of their genes' polypeptides is present. | |
| A daughter DNA molecule is composed of one original strand and one new strand because DNA replication is ___________. | |
| A gene for antibiotic resistance can move horizontally among bacterial cells by __________, __________, and _____________. | |
| ___________ are nucleotide sequences containing palindromes and genes for proteins that cut DNA strands. | |
| _________ _________ is a recombination event that occurs during gamete formation in eukaryotes. | |
| __________ RNA carries amino acids. | |
| _________ RNA and __________ RNA are antisense; that is, they are complementary to another nucleic acid molecule. |