ch 8 bacterial genetics
Once donor DNA is in a recipient cell, it integrates into that cell's chromosome by ______.
homologous recombination
How many strands of donor DNA integrate into a recipient chromosome during transformation?
one
In transformation, only one daughter cell inherits donor DNA. This is because ______.
only a single strand of donor DNA integrates into the recipient chromosome
A(n) ________ mutation occurs if a single base pair is changed during DNA synthesis.
point
The process of bacterial __________ involves the uptake of "naked" DNA by competent bacterial recipient cells
transformation
Which mechanism of gene transfer involves the uptake of "naked" DNA by competent bacterial recipient cells?
transformation
This figure shows a cell with an integrated F plasmid. If this plasmid is incorrectly excised, the result could be an F plasmid that carries along a portion of the bacterial chromosome. Such a cell would then be called a(n) ______ cell
Blank 1: F' or F prime
a _________ is a virus that infects bacteria, and some can transfer bacterial genes from a donor cell to a recipient cell.
Blank 1: bacteriophage or phage
A plasmid that can directs its own transfer from donor to recipient cells is called a(n) __________ plasmid.
Blank 1: conjugative
is the nucleotide sequence in the DNA of a cell or an organism.
Blank 1: genotype or genome
During transduction, donor DNA is injected into a recipient cell by a phage. This DNA integrates into the recipient's chromosome by ___________ _________________
Blank 1: homologous Blank 2: recombination
Organisms most fit to survive in a given environment will predominate because they can reproduce more rapidly than others. This phenomenon is called ______ _______
Blank 1: natural Blank 2: selection
The structure connecting these two cells is called an F ____________ and is formed during the mechanism of DNA transfer called ______________
Blank 1: pilus Blank 2: conjugation
A base substitution in a protein-encoding gene results in one of three possible mutation outcomes: _______mutation, _________ mutation, or __________ mutation.
Blank 1: silent or synonymous Blank 2: missense Blank 3: nonsense
In generalized transduction, donor DNA is mistakenly packaged into a phage coat, forming a ___________ particle.
Blank 1: transducing
The mechanism by which bacterial DNA is moved from one bacterium to another by a bacteriophage is called
Blank 1: transduction
The genetic transfer mechanism shown here is called
Blank 1: transformation
Conjugation in bacteria requires ______.
contact between donor and recipient cell
A(n) _______ is a change in the nucleotide sequence of DNA that is passed on to daughter cells.
mutation
When describing conjugation in Gram-negative bacteria, a donor cell with an F ______ is considered F+, while that without this structure are termed F-.
plasmid
True or false: A point mutation involves any substitution of a single nucleotide.
true
A(n) _________ mutation is a base substitution that changes the codon to one that specifies a different amino acid.
missense
After new virus particles have assembled in the bacterial host cell, they are usually ______.
released as a result of host cell lysis
________ mutation results from an insertion or deletion of nucleotides, leading to a shift of the reading frame from the point of mutation downstream.
frameshift
Consider a population of bacteria susceptible to an antimicrobial. If a bacterium acquires a spontaneous mutation that gives resistance to the antimicrobial, this bacterium will ______ if the population is exposed to the antimicrobial.
grow without competition
Some prokaryotes are naturally competent ______.
-only under specific conditions -all the time
The native or _______ _________ strain describes cells that carry non-mutated DNA.
Blank 1: wild Blank 2: type
Which of the following statements about transformation is correct?
Transformation is the uptake of naked DNA from the environment.
The F or fertility plasmid contains genes that are required for bacterial ______.
conjugation
DNA in the environment that is not contained within a cell or virus is called
naked DNA
The process by which organisms best adapted to a given environment will predominate in that environment is called _______.
natural selection
The return of a gene from a mutated state to its original, non-mutated state is called a ______.
reversion
is the change of a mutated genetic sequence back to its original, non-mutated form.
reversion
The majority of transposons contain _______ terminators.
transcriptional
A base substitution that results in a codon that still codes for the wild type amino acid is called a(n) ______ mutation.
synonymous
Chromosomal DNA is transferred with F plasmid DNA in an Hfr cell because ______.
the plasmid DNA is integrated into the chromosome in these cells
True or false: The native or wild type strain describes the typical phenotype of strains isolated from nature.
true
Place the steps of DNA-mediated transformation into the correct order. Start with the earliest at the top.
- double stranded DNA molecule binds to surface receptor -Nucleases at the cell surface degrade one strand of the DNA; the other strand enters the cell -sing stranded DNA integrates into the genome after entering the cell -strand being replaced by donor DNA is degraded
A base substitution that leads to the creation of a stop codon is called a(n) ________ mutation.
nonsense
A base substitution that leads to the creation of a stop codon is called a(n) _________ mutation.
nonsense
If a base substitution changes an amino acid-encoding codon to a stop codon what would it be called?
nonsense mutation
the __________ is the observed characteristics of an organism.
phenotype
Mutations that arise naturally during cellular metabolism, and not as a result of exposure to mutation-causing agents, are called ______ mutations.
spontaneous
Mutations that arise naturally during cellular metabolism, and not as a result of exposure to mutation-causing agents, are called ________ mutations.
spontaneous
This image shows two steps in a mechanism of DNA transfer called
conjugation
Which term refers to an organism that has a mutation?
mutant
Which of the following are characteristics of recombinants?
-They result from horizontal gene transfer. -The have properties of both donor and recipient cells.
An organism that has a mutation is called a
mutant
A transducing particle carries ______.
donor cell DNA
When bacteriophages replicate, phage components are synthesized in the host cell and assemble into new viruses ______.
within that cell before being released
In conjugation in E. coli, an Hfr cell refers to ______.
a cell in which the F plasmid has been integrated into the cell chromosome
A base substitution that results in a change in the amino acid encoded is called a(n) ______ mutation.
missense
Segments of DNA that can move to new positions within the genome of a single cell are called ________
transposons
_______ is the transfer of bacterial DNA from a donor to recipient via a bacteriophage.
Transduction
In this diagram, step 5 was left out on purpose. You would expect it to show the formation of a _______.
transducing particle
Place the steps of F plasmid transfer in the correct order. Start with the earliest at the top.
-f pilus makes contact with recipient cell -one strand of F plasmid is cut in origin of transfer -single strand of f plasmid is transferred to the recipient cell -complement of the transferred strand is synthesized
There are two types of transduction: ________, which transfers any genes of the donor cell, and ___________, which transfers only a few specific genes.
-generalized -specialized
Transduction exists in two kinds. What are they?
-generalized -specialized
Genetic change in bacteria occurs through which two mechanisms?
-horizontal gene transfer -mutation
Which of the following are possible outcomes of a base substitution?
-nonsense mutation -missense mutation -synonymous mutation
Which of the following are the three main methods of gene transfer in bacteria?
-transduction -transformation -conjugation
Examples of conditions where bacteria can become naturally competent in the environment include ______.
-when there is a high density of bacteria -when certain nutrients are scarce
In the most thoroughly studied example of bacterial conjugation, the term ____________ designates a donor cell with an F plasmid, whereas those cells who lack the F plasmid are termed _______________
Blank 1: F+, F plus, Fplus, or Hfr Blank 2: F-, F minus, or Fminus
_________ transduction results from a packaging error during the virus replication cycle, when a piece of bacterial DNA is included in the new virus particle.
Blank 1: Generalized
Which of the following terms describes the sequence of nucleotides (genetic makeup) of an organism or a cell?
Genotype
This figure depicts the interconversion between an F+ cell and a(n)
Hfr
Which of the following describes an organism's observable characteristics?
Phenotype
During bacterial conjugation, synthesis of a new strand of F plasmid DNA occurs in ______.
both the donor and recipient
A bacterial cell described as _________ can take up DNA from the surrounding environment.
competent
Cells that have the ability to take up DNA from the environment are called ______ cells.
competent
In bacteria, _____________ refers to DNA transfer requiring cell to cell contact.
conjugation
True or false: A point mutation always leads to a shift of the reading frame from the point of mutation downstream.
false
True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells.
false
True or false: Vertical gene transfer is the transfer of genes from one organism to another in a population, while horizontal gene transfer is the transfer of genes from parent cell to progeny.
false
True or false: When an Hfr cell transfers chromosomal DNA to a recipient cell, it does not need to produce an F pilus.
false
Which of the following mutations frequently results in the production of a shortened and non-functional protein because a different set of codons is translated?
frameshift
______ are segments of DNA that can move from one location to another in a cell's genome.
tansposons
Spontaneous mutations are important because ______.
they allow populations of bacteria to adapt to a changing environment
Which of the following can be found in a bacteriophage?
-DNA or RNA genome -protein coat
Which of the following are sources of "naked" DNA?
-Lysed (burst) bacterial cells -Secreted into the environment by bacteria
Neither strain A (His-/Trp-) nor strain B (Leu-/Thr-) can grow on minimal media on their own because they cannot synthesize the indicated amino acids. If the strains are mixed and then plated onto minimal media, any colonies that form ______.
should be a result of horizontal gene transfer
This figure illustrates the potential outcomes of base substitution mutations. The column labeled with a zero (far left) indicates the wild type. Match each Arabic numeral to its correct designation.
1 matches synonymous substitution 2 matches missense mutation 3 matches nonsense mutation
A bacteriophage consists of a genome made up of DNA or _________ , surrounded by a coat made up of __________
Blank 1: RNA Blank 2: protein, polypeptides, or proteins
When an excision errors produces a plasmid containing both chromosomal and F plasmid DNA, the resulting plasmid is called a(n) ________ plasmid.
Blank 1: F' or F prime
When integrated F plasmid DNA in an Hfr cell is excised from the chromosome, an excision error can result in the removal of chromosomal DNA along with the F plasmid DNA, creating a plasmid called ______.
F'
Genes into which transposons "jump" are usually ______ by the event.
inactivated
A bacterial virus is known as a(n) _______.
phage
a(n) ________ mutation is a base substitution that does not change the encoded amino acid.
silent or synonymous
During conjugation, the F plasmid nucleic acid that transfers is ______.
single-stranded DNA
If a scientist is working with bacteria that have the typical phenotype of those isolated from nature, the bacteria are considered to be ______ type.
wild
A(n) _________ mutation is a base substitution that changes the codon to one that specifies a different amino acid.
Blank 1: missense
In ______ gene transfer, DNA moves from one organism to another, while in _______ gene transfer, DNA is passed from a parent cell to its progeny.
Blank 1: horizontal Blank 2: vertical
Consider a base substitution mutation that occurs in a codon that specifies the amino acid tryptophan. If it leads to a different amino acid, the mutation is called _________ mutation, and if the resultant codon is a stop codon, then the mutation is termed a(n) ________ mutation.
Blank 1: missense Blank 2: nonsense
When horizontal gene transfer occurs between a donor and recipient cells, the resulting cells are called
Blank 1: recombinants
When horizontal gene transfer occurs between a donor and recipient cells, the resulting cells are called ________
Blank 1: recombinants
_________ mutations are generally the most harmful to cells because they change all of the codons downstream of the mutation.
frameshift
Random genetic changes that result from normal cellular processes are ______.
spontaneous mutations
Base ______ mutations occur when an incorrect nucleotide is incorporated in place of another during DNA synthesis.
substitution
The most common type of mutation is base ____________, where an incorrect nucleotide is incorporated during DNA replication.
substitution
When two bacterial strains that are His-/Trp- (require his and trp for growth) and Leu-/Thr- (require leu and thr for growth) are mixed together and plated on minimal media, any colonies that form are likely due to one strain acquiring genes from another strain. This is called _______ gene transfer.
horizontal
Donor and recipient bacterial cells are connected by a sex ______ during conjugation.
pilus