Podcast
Questions and Answers
Preventing the function of light repair (photoreactivation) interferes with the repair of which of the following?
Preventing the function of light repair (photoreactivation) interferes with the repair of which of the following?
thymine dimers
The classic transformation experiment done by Griffith used:
The classic transformation experiment done by Griffith used:
harmless and virulent strains of Streptococcus pneumoniae
Recombination is defined as:
Recombination is defined as:
one bacterium donating DNA to another
In addition to transformation, the other two forms of horizontal gene transfer are:
In addition to transformation, the other two forms of horizontal gene transfer are:
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In the beginning of transformation, ______ binds to the target cell.
In the beginning of transformation, ______ binds to the target cell.
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During the entry of the donor DNA into the recipient cell, what happens?
During the entry of the donor DNA into the recipient cell, what happens?
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Mismatch repair is activated by:
Mismatch repair is activated by:
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The donor DNA pairs with a homologous region of the recipient DNA.
The donor DNA pairs with a homologous region of the recipient DNA.
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As a result of mismatch repair during transformation:
As a result of mismatch repair during transformation:
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During the process of transformation in the lab setting, cells are plated on selective media to:
During the process of transformation in the lab setting, cells are plated on selective media to:
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Cells that are capable of bringing DNA from their environment into the cell are called:
Cells that are capable of bringing DNA from their environment into the cell are called:
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Transformation is facilitated by:
Transformation is facilitated by:
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A culture of E. coli is irradiated with UV light. The UV light affects the cell's DNA by:
A culture of E. coli is irradiated with UV light. The UV light affects the cell's DNA by:
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Bacterial cells that have been genetically modified to carry an antibiotic resistance gene can be separated from susceptible microbes by using a _______ selection method using agar plates with antibiotic.
Bacterial cells that have been genetically modified to carry an antibiotic resistance gene can be separated from susceptible microbes by using a _______ selection method using agar plates with antibiotic.
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On which of the following DNA strands will UV light have the most effect?
On which of the following DNA strands will UV light have the most effect?
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A prototroph can grow on glucose-salts media.
A prototroph can grow on glucose-salts media.
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Plasmids are:
Plasmids are:
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A recombinant organism is:
A recombinant organism is:
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If you find that a particular plasmid has an R factor, the bacteria that has it will be:
If you find that a particular plasmid has an R factor, the bacteria that has it will be:
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F+ cells:
F+ cells:
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The F pilus binds to:
The F pilus binds to:
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The F pilus is:
The F pilus is:
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The plasmid is mobilized for transfer when:
The plasmid is mobilized for transfer when:
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Plasmid DNA is transferred:
Plasmid DNA is transferred:
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The F plasmid encodes for:
The F plasmid encodes for:
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The first step in conjugation is:
The first step in conjugation is:
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After the transfer of the F plasmid is complete:
After the transfer of the F plasmid is complete:
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If Gene X codes for an F pilus and transposition occurs, then the bacterium containing the plasmid would:
If Gene X codes for an F pilus and transposition occurs, then the bacterium containing the plasmid would:
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Repair mechanisms that occur during DNA synthesis are:
Repair mechanisms that occur during DNA synthesis are:
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Genes from the donor chromosome are transferred as:
Genes from the donor chromosome are transferred as:
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After the conjugation of an Hfr cell with an F- cell:
After the conjugation of an Hfr cell with an F- cell:
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During conjugation, the donor chromosome is transferred as:
During conjugation, the donor chromosome is transferred as:
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Which of the following genes are likely to be found on a plasmid rather than on the bacterial chromosome?
Which of the following genes are likely to be found on a plasmid rather than on the bacterial chromosome?
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Which of the following statements is/are TRUE?
Which of the following statements is/are TRUE?
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Study Notes
DNA Repair and Transformation
- Photoreactivation prevents the repair of thymine dimers.
- Griffith's classic transformation experiment involved harmless and virulent strains of Streptococcus pneumoniae.
- Transformation is a form of recombination involving one bacterium donating DNA to another.
Horizontal Gene Transfer
- Besides transformation, conjugation and transduction are other forms of horizontal gene transfer.
- Double-stranded DNA binds to the target cell during the initial stage of transformation.
- Nucleases break down one strand of the donor DNA during its entry into the recipient cell.
DNA Mismatch Repair
- Mismatch repair is triggered by any difference between nucleotide sequences of donor and recipient DNA.
- Donor DNA pairs with a homologous region in the recipient DNA.
Transformation Outcomes
- Following mismatch repair, cells may contain either original DNA or donor DNA.
- In laboratory settings, selective media is used to ensure that only transformants grow.
- Competent cells can uptake DNA from their surroundings through their cell walls.
DNA Damage and UV Light
- UV light effects on DNA include forming covalent bonds between thymine bases on the same strand.
- Direct selection methods using agar plates with antibiotics can separate genetically modified bacteria carrying antibiotic resistance genes from non-resistant strains.
Genetic Elements
- A prototroph can thrive on glucose-salts media.
- Plasmids can replicate independently of bacterial chromosomes and can carry antibiotic resistance genes.
- Recombinant organisms contain genes from another organism.
Conjugation Mechanisms
- F+ cells possess a plasmid and serve as donors in conjugation.
- The F pilus binds to specific receptors on the recipient cell's wall and facilitates the attachment of the two cells.
- An endonuclease cleaves the plasmid at the origin of transfer to initiate mobilization.
DNA Transfer Process
- Plasmid DNA is transferred in single-stranded form during conjugation.
- The F plasmid encodes the production of the F-pilus.
- The initial step in conjugation is contact between the donor and recipient cells.
Plasmid and Chromosome Interactions
- After the complete transfer of the F plasmid, the F- cell becomes F+.
- Transposition of Gene X, which codes for an F pilus, can disrupt a bacterium's ability to conjugate.
Repair Mechanisms
- DNA synthesis repair mechanisms include mismatch repair and proofreading by DNA polymerase.
- Genes from the donor chromosome are also transferred in single-stranded form during conjugation.
Genetic Mutations and Growth Requirements
- After an Hfr cell conjugates with an F- cell, the recipient remains F-.
- Genes such as ATP synthase and superoxide dismutase are likely found on plasmids rather than on the bacterial chromosome.
- Wild type E. coli require the amino acid histidine for growth, and missense mutations generally have more significant consequences than frameshift mutations.
Studying That Suits You
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Description
Test your knowledge with these flashcards covering key concepts from biology for Week 6. Topics include DNA repair mechanisms, transformation experiments, and bacterial recombination. Perfect for students looking to reinforce their understanding of genetics and microbiology.