ch 16 micro

A second mutation that occurs at a different site from the first mutation, and which returns the mutant back to the wild-type phenotype, is a(n) ______ mutation.

suppressor, reverse

Another term for the transfer of genes from parents to progeny is _____ gene transfer.

vertical

The most prevalent form of a gene, and its associated phenotype, is called the ______ type.

wild

Which three types of mutations are classified as reversion mutations? Multiple select question. A second mutation that creates a new codon that codes for the wild type amino acid. A second mutation that restores the original wild-type sequence. A second frameshift mutation that restores an original reading frame. A mutation that causes the wild type strain to become a mutant strain. A second mutation creates a codon that replaces the wild type amino acid with a similar amino acid.

A second mutation that creates a new codon that codes for the wild type amino acid. A second mutation that restores the original wild-type sequence. A second mutation creates a codon that replaces the wild type amino acid with a similar amino acid.

Which three of the following statements are correct regarding conjugation in Gram-positive bacteria such as Enterococcus faecalis. Multiple select question. Donor and recipient cells adhere directly to each other. Peptides are released to activate transfer genes. The donor cell typically dies following gene transfer. A sex pilus may not be required. The proteins involved are not related to those in Gram-negatives.

Donor and recipient cells adhere directly to each other. Peptides are released to activate transfer genes. A sex pilus may not be required.

Which of these is the defining characteristic of an Hfr strain? Multiple choice question. Multiple sex pili F plasmid in their cytoplasm Very efficient DNA replication F plasmid integrated into the host chromosome

F plasmid integrated into the host chromosome

An F plasmid that has been excised from a bacterial chromosome, and which therefore also includes some chromosomal genes, is called a(n) _____. Multiple choice question. F- plasmid F+ plasmid F' plasmid Fc plasmid

F' plasmid

Which three of the following statements regarding homologous recombination are correct? Multiple select question. Recombinases recognize specific DNA sequences. It is the most common mechanism of DNA recombination. Similar or identical DNA strands are broken and reunited. RecA protein is involved. It occurs only during meiosis.

It is the most common mechanism of DNA recombination. Similar or identical DNA strands are broken and reunited. RecA protein is involved.

Mutations that result from the activity of mobile genetic elements called transposons are considered to be which type of mutations? Multiple choice question. Point Spontaneous Induced Transition

Spontaneous

Which three of these statements are correct about nonsense mutations? Multiple select question. They cause the early termination of translation. Effects range from mild to complete loss of normal gene function. They are typically not as severe when they occur near the beginning of a gene. They involve a single base substitution that changes a codon for one amino acid to a codon for a different amino acid. By definition, they always produce stop codons.

They cause the early termination of translation. Effects range from mild to complete loss of normal gene function. By definition, they always produce stop codons.

Which two of these statements are correct about frameshift mutations? Multiple select question. They usually yield mutant phenotypes. They involve a single base substitution that changes a codon for one amino acid into another. By definition, they always produce stop codons. They usually result in the synthesis of nonfunctional proteins. They are typically not as severe when they occur near the beginning of a gene.

They usually yield mutant phenotypes. They usually result in the synthesis of nonfunctional proteins.

Which of the following statements regarding viruses is FALSE? Multiple choice question. Viral infection often results in a host cell producing hundreds of viruses. Viruses can replicate either within a host cell or autonomously. Viruses that infect bacteria are called bacteriophages. Viruses often have just a nucleic acid genome and a protein coat.

Viruses can replicate either within a host cell or autonomously.

Which of the following statements about viruses and transduction is false? Multiple choice question. Transduction is a natural consequence of the viral life cycle and requires no special host cell structures. Viruses can move genes from one bacterium to another in natural environments. Viruses escaping a bacterium can move genes to an archaeon when they find a new host cell. All cellular organisms are susceptible to viral infections.

Viruses escaping a bacterium can move genes to an archaeon when they find a new host cell.

A suppressor mutation, which returns a mutant back to its wild-type phenotype, occurs at ____________ the first mutation. Multiple choice question. a different site from the same site as

a different site from

Alternative forms of a gene are called

alleles

An organism with a mutation that affects its ability to synthesize a biochemical essential for its growth is known as a(n)

auxotroph

Select three examples of chemical mutagens. Multiple select question. base analogs intercalating agents UV radiation high temperature DNA-modifying agents

base analogs intercalating agents DNA-modifying agents

In bacteria, conjugation refers to the transfer of DNA by _____. Multiple choice question. direct uptake by the cell bacteriophages cell-to-cell contact "jumping genes"

cell-to-cell contact

Base analogues, DNA-modifying agents, and intercalating agents are three types of _______ mutagens.

chemical

horizontal transfer of bacterial DNA by the process known as _____.

conjugation

Possible causes of spontaneous mutation include Multiple select question. errors in DNA replication transposons spontaneous lesions in DNA chemical agents physical agents

errors in DNA replication transposons spontaneous lesions in DNA

True or false: Conjugation occurs only in Gram-negative bacteria

false

William Hayes' 1952 experiments demonstrated that conjugation is unidirectional and identified strains he named F+ and F-. The "F" stands for ____

fertile

A mutation that leads to a change from wild type to a mutant form is called a(n) _______ mutation.

forward

Mutations that arise from the insertion or deletion of base pairs within the coding region of a gene are specifically called ______ mutations.

frameshift

Vertical gene transfer can be best defined as the transfer of genes _____. Multiple choice question. between any two individuals of different species from parents to progeny from progeny to parents between any two individuals of the same species

from parents to progeny

The major conclusion of Hayes' 1952 experiments, which demonstrated the existence of F+ and F- strains, was that _____. Multiple choice question. gene transfer by conjugation is bidirectional gene transfer by transformation is unidirectional gene transfer by conjugation is unidirectional gene transfer by transformation is bidirectional

gene transfer by conjugation is unidirectional

The transfer of random bacterial DNA during the lytic cycle of a bacteriophage is called ________ transduction.

generalized

Hfr strains of bacteria are so named because they undergo a ________ (high/low) frequency of _________.

high Recombination

The most common type of DNA recombination (e.g., during meiosis or bacterial horizontal gene transfer) is _______ recombination between similar or identical DNA strands.

homologous

Mechanisms that result in the transfer of genes from one independent, mature organism to another are collectively called _____ gene transfer.

horizontal

Which three of the following descriptions apply to an F' plasmid? Multiple select question. A cell carrying an F' plasmid is always considered an Hfr cell. it is an erroneously excised plasmid. It has been excised from a bacterial chromosome. It is smaller than a normal F plasmid. It includes some chromosomal genes.

it is an erroneously excised plasmid. It has been excised from a bacterial chromosome. It includes some chromosomal genes.

Point mutations that involve a single base substitution and result in a change to the amino acid encoded are called _________ mutations. These mutations may or may not have a significant impact on the protein structure.

missense

A point mutation that involves a single base substitution and results in a change to the amino acid encoded by that codon is specifically called a _____. Multiple choice question. nonsense mutation conditional mutation missense mutation suppressor mutation

missense mutation

The general term for heritable changes in DNA sequence is ________

mutations

Point mutations that result in a new stop codon are called _____ mutations.

nonsense

A resistance mutant may have acquired resistance to which three of the following? Multiple select question. transformation pathogen nutrient deficiency chemical antibiotic

pathogen chemical antibiotic

The type of mutation that affects only a single base pair at a given DNA location is called a(n) _______ mutation.

point

Silent, missense, nonsense, and frameshift are all common types of ________ mutations.

point, forward

A wild-type chemoorganotroph able to grow on a minimal medium containing only salts and a carbon source is known as a(n) ________ . These wild-type stains may give rise to mutants incapable of survival without additional nutrients, like a particular amino acid.

prototroph

An allele is most likely to persist in a population if it confers a survival advantage under _________ pressure. Multiple choice question. extinction lethal reductive selective

selective

Point mutations that change the nucleotide sequence of a codon but do not change the amino acid encoded by that codon are called _________ mutations.

silent

A mutation that caused the codon CGU to change to CGC, which does not affect the amino acid encoded, could be described by which two of these terms? Multiple select question. neutral silent missense point nonsense

silent point

The transfer of specific chromosomal DNA following induction of a lysogenic phage is called _______ transduction.

specialized

In bacterial genetics, transformation is _____. Multiple choice question. the transfer of bacterial DNA by a bacteriophage another term for "jumping genes" the uptake of DNA by a bacterial cell the transfer of bacterial DNA by cell-cell contact

the uptake of DNA by a bacterial cell

Select the best definition of horizontal gene transfer. Multiple choice question. persistence of a gene that confers a survival advantage transfer of genes from parents to progeny transfer of genes from one independent, mature organism to another DNA transfer between animals that move on land

transfer of genes from one independent, mature organism to another

The process of taking up DNA from the surroundings, and maintenance of the DNA in a heritable form, is called ________.

transformation