Micro 7.B HW

Which of the following is required for transposition?

?

Based on the animation, what is transferred during bacterial conjugation?

A bacterial plasmid

Insertion sequences target which areas on a target DNA sequence?

A sequence of nucleotides identical to the inverted repeat sequence found on the insertion sequence itself

Which of the following is a characteristic of an F+ cell?

Ability to synthesize sex pili, presence of a fertility factor, and ability to mate with an F- cell

What is the key difference between donor cells and recipient cells?

An F plasmid

Which type of transposon would contain a gene for transposase?

Both simple and complex transposons

How do complex transposons differ from simple transposons?

Complex transposons code for additional genetic elements, such as antibiotic resistance genes; simple transposons only code for the transposase gene essential for the tranposon itself.

Bacterial conjugation is often referred to as bacterial sex. Why is this term inaccurate?

Conjugation does not result in the formation of new offspring.

Which statement about conjugation is false?

Conjugation is a process of bacterial reproduction.

Why does conjugation between an Hfr strain and an F- strain not result in two Hfr strains?

Conjugation is typically disrupted before the fertility factor can be transferred

In conjugation, F+ cells

Contain an F plasmid.

What is required by an F- cell to become an F+ cell?

F plasmid

Which of the following is capable of conjugation?

F+ and Hfr cells

T/F: Most bacteria have a natural ability to take up DNA from their environment.

False

At which point does a recipient cell become an F+ cell?

Formation of the complementary strand of the F factor

How is generalized transduction different from specialized transduction?

Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.

What was the scientific result of Frederick Griffith's experiments with Streptococcus pneumoniae?

He showed that the DNA from strain S cells could transform strain R cells.

How does an F+ cell differ from an Hfr cell?

Hfr strains have the F plasmid integrated into the chromosome

How can hospital personnel prevent the spread of resistant Enterococcus faecium throughout the hospital?

Hospital personnel should wash their hands when entering and leaving a patient's room.

How would you be able to determine if the Tn5 transposon you put into a bacterium integrated into the host genome?

If the Tn5 transposon integrated into the host genome, the cells would show resistance to the antibiotic kanamycin.

What benefit does the F- strain receive from mating with an Hfr strain?

It acquires new, potentially beneficial genes from the Hfr strain

What is a nosocomial infection?

It is a hospital-acquired infection.

Why does a complex transposon often contain an extra piece of DNA between the two insertion elements?

It is often a gene that confers a survival advantage to the host, such as antibiotic resistance.

What is the function of the conjugation pilus?

It pulls the F+ and F- cells together.

What cellular macromolecule is the fertility factor comprised of?

Nucleic acid

How does replicative transposition differ from cut-and-paste transposition?

Replicative transposition results in the transposon being copied to a new location; in cut-and-paste transposition, the entire transposon moves to the new location.

Which finding is most surprising from Griffith's experiments?

S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.

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?

The R strain picked up the S strain DNA, enabling it to produce a capsule.

What characteristic of the S strain allows it to evade the immune system of the mice?

The cells have a capsule

What must occur for bacterial conjugation to take place?

The cells must come into contact with each other.

What happens to the packaged DNA of a specialized transduced phage when it infects a new recipient cell?

The host DNA integrates, with the prophage, into the new recipient chromosome

If the gene that codes for transposase is mutated so that it no longer produces the fully functional enzyme, how will the insertion sequence be affected?

The insertion sequence would lose its ability to effect its own movement.

How does specialized transduction differ from regular lysogeny?

The prophage in specialized transduction carries with it pieces of the host chromosomal DNA.

How can specialized transduction contribute to the transfer of antibiotic resistance genes in a bacterial population?

The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA.

What makes an insertion sequence different from other DNA sequences found in a cell?

They are capable of effecting their own movement from one location to another on DNA.

How is a complex transposon different from a simple transposon?

They have two simple transposons with another DNA sequence between them.

What is unique about transduction compared to normal bacteriophage infection?

Transduction transfers DNA from the chromosome of one cell to another.

Which of the following is an example of horizontal gene transfer in bacteria?

Transduction, conjugation, and transformation

What is the hallmark of all horizontal gene transfers?

Transfer of DNA between organisms of the same generation

T/F: In generalized transduction, viruses carry random DNA sequences from one cell to another.

True

Competent cells are cells that

can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination.

What term is used to describe bacterial cells that can naturally take up DNA from their environment?

competent cells

A mutation that causes production of a defective pilus in a bacterium will prevent __________.

conjugation

A transducing phage

contains fragments of the host chromosome instead of the viral genome

Which of the following is NOT used by bacteria to acquire new genetic material?

crossing over

The effects of a transposition event are equivalent to a(n)

frameshift mutation

Transfer of random pieces of DNA mediated by phage is known as

generalized transduction.

The horizontal transfer process known as transduction

involves a virus.

A recombinant cell

is a cell that receives DNA from an outside source and incorporates it into its own.

What does MDR mean?

multi-drug-resistant

Mice that are injected with only the R strain of Streptococcus pneumoniae

stay healthy, because their immune systems can kill this strain easily.

When a transducing phage interacts with a new host cell,

the DNA from the previous host can recombine with the new host chromosome

Bacteriophages are important for which of the following processes?

transduction

Transfer of DNA between bacterial cells by viruses is called

transduction

Frederick Griffith discovered

transformation.

While studying a bacterial strain, a scientist notes a short DNA sequence between inverted repeats is present in both the chromosome and a plasmid within the cell. This sequence is most likely a(n)

transposon