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Questions and Answers

What type of genetic material do viruses possess?

  • Only single-stranded RNA
  • Only single-stranded DNA
  • Only double-stranded DNA
  • Double- or single-stranded DNA or RNA (correct)

    • What drives evolution in bacteria and archaea by generating much larger changes than mutation?

  • Horizontal gene transfer (correct)
  • Genetic exchange
  • Exponential growth
  • Spontaneous mutations

    • What type of cells have a composition of double-stranded DNA for their genetic material?

  • Only archaeal cells
  • Only prokaryotic cells
  • Only eukaryotic cells
  • Prokaryotic and eukaryotic cells (correct)

    • Which process allows quick acquisition of new characters and fuels metabolic diversity in bacteria?

    <p>Transformation</p> Signup and view all the answers

    What initiates many DNA repair processes and allows repair without a template by random incorporation of dNTPs, resulting in many mutations?

    <p>SOS repair system</p> Signup and view all the answers

    What is the typical size of DNA that can be transformed in bacteria?

    <p>Free DNA</p> Signup and view all the answers

    Which protein is a regulator of the SOS repair system in bacteria?

    <p>LexA</p> Signup and view all the answers

    What is the process that results in genetic exchange between homologous DNA from two different sources?

    <p>Homologous recombination</p> Signup and view all the answers

    Which type of radiation causes pyrimidine dimer formation in DNA?

    <p>Ultraviolet (UV)</p> Signup and view all the answers

    What is the effect of homologous recombination on genotype in bacteria?

    <p>Generates new genotypes when related but distinct sequences are involved</p> Signup and view all the answers

    What is the process of genetic transfer involving pili in bacteria?

    <p>Conjugation</p> Signup and view all the answers

    Which class of mutants requires time-consuming screening for isolation?

    <p>Auxotrophs</p> Signup and view all the answers

    What can base-pair substitutions lead to?

    <p>Silent mutations, missense mutations, and nonsense mutations</p> Signup and view all the answers

    What can chemical mutagens like nitrous acid and hydroxylamine do to DNA?

    <p>Cause mutations</p> Signup and view all the answers

    What do base analogs like 5-bromouracil and 2-aminopurine do when incorporated into DNA?

    <p>Lead to faulty pairings with other nucleotides</p> Signup and view all the answers

    What do frameshift mutations, insertion, and deletion mutations cause?

    <p>A shift in reading frame, leading to changes in the polypeptide sequence or complete loss of function of one or more genes</p> Signup and view all the answers

    What are observable properties in bacteria designated by?

    <p>A capital letter followed by two lowercase letters, then +/–</p> Signup and view all the answers

    What can be used to isolate nutritional auxotrophs?

    <p>Replica plating</p> Signup and view all the answers

    What do revertants do?

    <p>Restore the original phenotype</p> Signup and view all the answers

    What do selectable mutations confer?

    <p>An advantage</p> Signup and view all the answers

    What do mutation rates depend on?

    <p>The frequency of DNA changes and efficiency of DNA repair</p> Signup and view all the answers

    What can suppressor mutations do?

    <p>Restore the original phenotype through mutations at different sites in the genome or in other genes</p> Signup and view all the answers

    What can induce mutagenesis?

    <p>Chemical and physical mutagens</p> Signup and view all the answers

    What do nutritional auxotrophs have compared to prototrophs?

    <p>Additional nutritional requirements for growth</p> Signup and view all the answers

    What do base-pair substitutions lead to?

    <p>Silent mutations, missense mutations, and nonsense mutations</p> Signup and view all the answers

    What can alkylating agents do as mutagens?

    <p>React with DNA, causing mutations</p> Signup and view all the answers

    What is the effect of frameshift mutations, insertion, and deletion mutations?

    <p>Cause a shift in reading frame, leading to changes in the polypeptide sequence or complete loss of function of one or more genes</p> Signup and view all the answers

    What can suppressor mutations do?

    <p>Restore the original phenotype through mutations at different sites in the genome or in other genes</p> Signup and view all the answers

    What drives evolution in bacteria and archaea by generating much larger changes than mutation?

    <p>Homologous recombination</p> Signup and view all the answers

    What do revertants do?

    <p>Restore the original phenotype</p> Signup and view all the answers

    What do selectable mutations confer?

    <p>An advantage</p> Signup and view all the answers

    What do mutation rates depend on?

    <p>The frequency of DNA changes and efficiency of DNA repair</p> Signup and view all the answers

    What can base analogs like 5-bromouracil and 2-aminopurine do when incorporated into DNA?

    <p>Lead to faulty pairings with other nucleotides</p> Signup and view all the answers

    What is the typical composition of genetic material in prokaryotic and eukaryotic cells?

    <p>Double-stranded DNA</p> Signup and view all the answers

    How is the wild-type strain of a cell defined?

    <p>Isolated from nature</p> Signup and view all the answers

    What is the genotype designation for a gene involved in histidine biosynthesis in bacteria?

    <p>Three lowercase letters followed by a capital, all italicized (e.g., hisC)</p> Signup and view all the answers

    What is a mutant in the context of genetics?

    <p>A cell derived from wild type that carries a nucleotide sequence (genotype) change</p> Signup and view all the answers

    What is the effect of horizontal gene transfer (genetic exchange) in prokaryotes?

    <p>Generates much larger changes than mutation</p> Signup and view all the answers

    What does the term 'wild-type' refer to?

    <p>An organism or strain isolated from nature</p> Signup and view all the answers

    How are mutations designated in bacteria?

    <p>Three lowercase letters followed by a capital, all italicized</p> Signup and view all the answers

    What is the genotype designation for a gene involved in histidine biosynthesis in bacteria?

    <p>Three lowercase letters followed by a capital, all italicized (e.g., hisC)</p> Signup and view all the answers

    What is the composition of genetic material in viruses?

    <p>Double- or single-stranded DNA or RNA</p> Signup and view all the answers

    What is the term used for a cell derived from wild type that carries a nucleotide sequence (genotype) change?

    <p>Mutant</p> Signup and view all the answers

    What is the process that allows free DNA to be incorporated into a recipient cell, bringing about genetic exchange?

    <p>Transformation</p> Signup and view all the answers

    What is the effect of homologous recombination on genotype in bacteria?

    <p>It generates new genotypes when related but distinct homologous sequences are involved</p> Signup and view all the answers

    What is the typical size of DNA that can be transformed in bacteria?

    <p>20-30 kilobase pairs</p> Signup and view all the answers

    What initiates many DNA repair processes and allows repair without a template by random incorporation of dNTPs, resulting in many mutations?

    <p>SOS repair system</p> Signup and view all the answers

    What is the process that results in genetic exchange between homologous DNA from two different sources?

    <p>Homologous recombination</p> Signup and view all the answers

    Which type of radiation causes pyrimidine dimer formation in DNA?

    <p>Ultraviolet (UV) radiation</p> Signup and view all the answers

    What is the process of genetic transfer involving pili in bacteria?

    <p>Conjugation</p> Signup and view all the answers

    What is the horizontal movement of genes between cells that are not direct descendants, allowing quick acquisition of new characters and fueling metabolic diversity?

    <p>Horizontal gene transfer</p> Signup and view all the answers

    What is the process that allows the incorporation of new characters and fuels metabolic diversity in bacteria?

    <p>Horizontal gene transfer</p> Signup and view all the answers

    What is the process that allows genetic transfer by which free DNA is incorporated into a recipient cell, bringing about genetic exchange?

    <p>Transformation</p> Signup and view all the answers

    Study Notes

    Mutations and Genetic Mutagenesis

    • Observable properties (phenotype) in bacteria are designated by a capital letter followed by two lowercase letters, then +/–, indicating the ability to synthesize specific compounds.
    • Mutants can be isolated through selection or screening, with selectable mutations conferring an advantage and non-selectable mutations requiring time-consuming screening.
    • Common classes of mutants include auxotrophs, temperature-sensitive mutants, drug-resistant mutants, rough colony mutants, pigmentless mutants, sugar fermentation mutants, and virus-resistant mutants.
    • Nutritional auxotrophs, which have additional nutritional requirements for growth compared to prototrophs, can be isolated by screening using replica plating.
    • Mutation rates depend on the frequency of DNA changes and efficiency of DNA repair, with spontaneous mutation rates varying between prokaryotes, eukaryotes, DNA viruses, and RNA viruses.
    • Base-pair substitutions can lead to silent mutations, missense mutations, and nonsense mutations, affecting polypeptide sequences and phenotypes.
    • Frameshift mutations, insertion, and deletion mutations can cause a shift in reading frame, leading to changes in the polypeptide sequence or complete loss of function of one or more genes.
    • Revertants can restore the original phenotype, and suppressor mutations can restore the original phenotype through mutations at different sites in the genome or in other genes.
    • Mutagenesis can be induced by chemical and physical mutagens, including base analogs, chemicals that react with DNA, and alkylating agents.
    • Base analogs like 5-bromouracil and 2-aminopurine can be incorporated into DNA, leading to faulty pairings with other nucleotides.
    • Chemicals like nitrous acid, hydroxylamine, and alkylating agents can react with DNA, causing mutations.
    • Mutagenesis can also be induced by physical mutagens such as radiation.

    Mutations and Genetic Mutagenesis

    • Observable properties (phenotype) in bacteria are designated by a capital letter followed by two lowercase letters, then +/–, indicating the ability to synthesize specific compounds.
    • Mutants can be isolated through selection or screening, with selectable mutations conferring an advantage and non-selectable mutations requiring time-consuming screening.
    • Common classes of mutants include auxotrophs, temperature-sensitive mutants, drug-resistant mutants, rough colony mutants, pigmentless mutants, sugar fermentation mutants, and virus-resistant mutants.
    • Nutritional auxotrophs, which have additional nutritional requirements for growth compared to prototrophs, can be isolated by screening using replica plating.
    • Mutation rates depend on the frequency of DNA changes and efficiency of DNA repair, with spontaneous mutation rates varying between prokaryotes, eukaryotes, DNA viruses, and RNA viruses.
    • Base-pair substitutions can lead to silent mutations, missense mutations, and nonsense mutations, affecting polypeptide sequences and phenotypes.
    • Frameshift mutations, insertion, and deletion mutations can cause a shift in reading frame, leading to changes in the polypeptide sequence or complete loss of function of one or more genes.
    • Revertants can restore the original phenotype, and suppressor mutations can restore the original phenotype through mutations at different sites in the genome or in other genes.
    • Mutagenesis can be induced by chemical and physical mutagens, including base analogs, chemicals that react with DNA, and alkylating agents.
    • Base analogs like 5-bromouracil and 2-aminopurine can be incorporated into DNA, leading to faulty pairings with other nucleotides.
    • Chemicals like nitrous acid, hydroxylamine, and alkylating agents can react with DNA, causing mutations.
    • Mutagenesis can also be induced by physical mutagens such as radiation.

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    Description

    Test your knowledge of mutations and genetic mutagenesis with this quiz! Explore concepts such as observable properties in bacteria, mutant isolation methods, classes of mutants, mutation rates, types of mutations, revertants, suppressor mutations, and induced mutagenesis by chemical and physical agents.

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