Question: What is considered to be the average natural mutation rate that occurs during DNA replication?
Answer: One in every billion nucleotides replicated.
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Question: A mutation that affects the genotype of the organism but not the phenotype is called a
Answer: silent mutation.
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Question: A base insertion or deletion in the translated region of the gene may lead to
Answer: frameshift mutation.
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Question: A base substitution that changes a codon coding for an amino acid to a stop codon is called a
Answer: nonsense mutation
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Question: How frequently do silent mutations occur?
Answer: One out of every three mutations
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Question: How is DNA methylation used in DNA repair?
Answer: The mismatch-repair enzymes can use a lack of methylation to identify and remove newly synthesized DNA.
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Question: Which of the following repair enzymes cannot repair thymine dimers?
Answer: Mismatch-repair enzymes
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Question: Why is light required for photolyases?
Answer: The light provides the energy to break the bonds between the thymine dimers.
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Question: Which of the following repair mechanism(s) does not involve DNA polymerase?
Answer: Light-repair mechanism
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Question: Thymine dimers result from
Answer: nonionizing radiation
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Question: Which of the following might result in a frameshift mutation?
Answer: Benzopyrene
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Question: Which of the following describes how 5-bromouracil might create a mutation?
Answer: It can replace the base thymine, and can base pair with guanine rather than adenine.
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Question: Mutagens
Answer: increase the likelihood of mutations in DNA.
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Question: A nucleotide-altering chemical
Answer: can alter nitrogenous bases of DNA, resulting in incorrect base pairing
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Question: A silent mutation is so named because ________
Answer: it has no effect on the overall amino acid sequence
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Question: A new chemotherapeutic agent is developed that alters the structure of all thymines in DNA. These thymines are then misread during the production of mRNA. Which of the following could NOT result from this type of mutation?
Answer: frameshift mutation
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Question: While studying protein synthesis in the lab, you experimentally induce a mutation in a bacterium's DNA. You assess the proteins in the mutated bacterium and find that one of them is significantly shorter than its wild-type counterpart. Based on this information, what type of mutation did you induce?
Answer: nonsense mutation
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Question: Bacterial conjugation is often referred to as bacterial sex. Why is this term inaccurate?
Answer: Conjugation does not result in the formation of new offspring.
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Question: What must occur for bacterial conjugation to take place?
Answer: The cells must come into contact with each other.
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Question: Which statement about conjugation is false?
Answer: Conjugation is a process of bacterial reproduction.
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Question: Based on the animation, what is transferred during bacterial conjugation?
Answer: A bacterial plasmid
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Question: A recombinant cell
Answer: is a cell that receives DNA from an outside source and incorporates it into its own.
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Question: What is the hallmark of all horizontal gene transfers?
Answer: Transfer of DNA between organisms of the same generation
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Question: Which of the following is an example of horizontal gene transfer in bacteria?
Answer: Transduction, conjugation, and transformation
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Question: How does an F+ cell differ from an Hfr cell?
Answer: Hfr strains have the F plasmid integrated into the chromosome.
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Question: Why does conjugation between an Hfr strain and an F- strain not result in two Hfr strains?
Answer: Conjugation is typically disrupted before the fertility factor can be transferred.
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Question: Which of the following is a characteristic of an F+ cell?
Answer: Ability to synthesize sex pili, presence of a fertility factor, and ability to mate with an F- cell.
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Question: What benefit does the F- strain receive from mating with an Hfr strain?
Answer: It acquires new, potentially beneficial genes from the Hfr strain
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Question: What is the function of the conjugation pilus?
Answer: It pulls the F+ and F- cells together
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Question: what is required by an F- cell to become an F+ cell?
Answer: F plasmid
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Question: What is the key difference between donor cells and recipient cells?
Answer: an F plasmid
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Question: What cellular macromolecule is the fertility factor comprised of?
Answer: Nucleic acid
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Question: At which point does a recipient cell become an F+ cell?
1.Fusion of the cell membranes
2.Attachment of the sex pilus
3.Transfer of the single stranded F factor
4.Pulling of donor and recipient cells together
5.Formation of the complementary strand of the F factor
Answer: 5
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Question: What is unique about transduction compared to normal bacteriophage infection?
Answer: Transduction transfers DNA from the chromosome of one cell to another.
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Question: How is generalized transduction different from specialized transduction?
Answer: Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.
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Question: A transducing phage
Answer: contains fragments of the host chromosome instead of the viral genome.
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Question: When a transducing phage interacts with a new host cell,
Answer: the DNA from the previous host can recombine with the new host chromosome.
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Question: Competent cells are cells that
Answer: can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombinat
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Question: Mice that are injected with only the R strain of Streptococcus pneumoniae
Answer: stay healthy, because their immune systems can kill this strain easily.
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Question: What characteristic of the S strain allows it to evade the immune system of the mice?
Answer: The cells have a capsule.
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Question: What most likely explains the recovery of live S strain cells from a mouse injected with heat-killed S strain mixed with live R strain cells?
Answer: The R strain picked up the S strain DNA, enabling it to produce a capsule.
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Question: Which finding is most surprising from Griffith's experiments?
Answer: S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.
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Question: Deleting or inserting one nucleotide pair in the middle of a gene is an example of which of the following?
Answer: frameshift mutation
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Question: Which of the following statements concerning sugar utilization in E. coli is true?
Answer: Bacteria growing on glucose as the sole carbon source grow faster than on lactose.
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