CHP 9- GENE TRANFER

The transfer of DNA from one bacteria to another

conjugation

Passing of genes to a cell in the same generation

Horizontal gene transfer

DNA is passed from

Conjugation, sex, F

What process requires contact between donor and recipient cells in the same generation?

Conjugation

In a culture containing both F- and F+ cells, which of the following will occur if we wait long enough?

All F- will become F+ cells

virulent phage

A phage that reproduces only by a lytic cycle.

What is known by bacterial competence?

Taking in DNA from an environment

a virus which incorporates DNA into the DNA of its host organism is existing as a

Prophage

High frequency recombination cells arise when

a portion of the cell's F plasmid has been incorporated into the bacterial chromosome

The genetic information needed for a cell to participate in conjugation resides in the DNA of a cell's

F plasmid

If an organism has a vancomycin resistant gene on its plasmid and a streptomycin resistant gene on its chromosome, what happens?

In Griffith's experience, the "transforming substance" that allowed the rough bacteria to become smooth is

DNA

E coli grows on a plate treated with ampicillin and dies on a plate treated with streptomycin. In this case, E.coli is what to ampicillin and what to streptomycin?

Resistant; Susceptible

HFR

A high-frequency recombination bacterial strain, caused by the presence of a chromosomally integrated F factor.

Vertical gene transfer (VGT)

transfer of genetic material from parent cell to daughter cell

when the plasmid becomes incorporated into the chromosome

the cell is call an Hfr (high frequency of recombination) cell

When viral DNA is incorporated into the bacterial chromosome

prophage

Genes that move one location to another

Transduction

horizontal gene transfer

What is the difference between vertical and lateral gene transfer?

Vertical transfer is from parent to offspring; lateral (horizontal) transfer is between organisms in the same generation.

What is transformation in bacteria?

The process where a bacterium takes up naked DNA from its surroundings.

What is a 'competence factor' in bacteria?

A substance released into the medium that allows a bacterium to take up naked DNA fragments.

How does transduction differ from transformation?

Transduction involves the transfer of genetic material via bacteriophages (viruses) rather than direct uptake of naked DNA.

What is the difference between a virulent and a temperate phage?

Virulent phage cause immediate lysis of the host cell, while temperate phage can enter a lysogenic phase where they integrate into the chromosome.

What is a prophage?

The viral DNA that has been inserted into the bacterial chromosome during the lysogenic cycle.

What is conjugation in bacteria?

The transfer of genetic material between neighboring bacterial cells requiring direct physical contact.

What structure facilitates bacterial conjugation?

The F pilus, also known as the sex pilus or conjugation pilus.

What is the role of an F plasmid?

It directs the synthesis of conjugation pili and can provide antibiotic resistance.

What distinguishes an Hfr strain from a standard F+ strain?

In Hfr strains, the F plasmid is incorporated into the bacterial chromosome, allowing for the transfer of chromosomal DNA.

What is an F' (F prime) plasmid?

An F plasmid that has detached from the chromosome and carries a piece of chromosomal DNA with it.

What are transposable elements?

Genetic sequences that can move from one location to another within a genome.

What two components make up a transposon?

Transposable elements and an additional unrelated gene.

What is genetic fusion?

The transposition of DNA that moves the control genes of one operon in front of another operon.

What is gene amplification?

The rapid production of plasmids or bacteriophages within a bacterial cell to increase the yield of products like enzymes or antibiotics.

What defines a transgenic or recombinant organism?

An organism that contains DNA integrated from a different species.

What is the function of a restriction endonuclease?

To cut DNA at specific sequences, originally serving to restrict bacteriophage division.

What is the role of ligase in recombinant DNA technology?

It incorporates the target DNA segment into the vector.

What are two common methods for transforming bacterial cells with a vector?

Heat-shock and electroporation.

What is gene therapy?

The insertion of functional genes into cells to cure a genetic disease.

Name two industrial applications of recombinant DNA technology.

Fermentation processes (beer/wine) and the degradation of environmental pollutants.

What are two agricultural benefits of recombinant DNA?

Increased crop yield and resistance to insects or herbicides.

Why is the use of recombinant E. coli considered safe?

Lab strains do not infect humans, and incorporating mammalian genes often makes the bacteria less adaptable.

What is the definition of a recombinant cell?

A cell that has successfully combined DNA from a donor organism.

Define a transposon.

•Resistance genes are often found on resistance plasmids

What is genetic recombination?

The process by which genetic material from different sources is combined into a single DNA molecule.

What is the difference between vertical and horizontal gene transfer?

Vertical transfer is the transmission of genes from parent to offspring; horizontal transfer is the movement of genes between organisms within the same generation.

How did Griffith's experiment demonstrate bacterial transformation?

He showed that non-virulent bacteria could be transformed into virulent strains by taking up genetic material from heat-killed virulent bacteria.

What is bacterial competence?

The physiological state in which a bacterial cell is capable of taking up exogenous DNA from its environment.

What is the difference between a temperate and a virulent phage?

A virulent phage causes immediate lysis of the host cell, while a temperate phage can integrate its DNA into the host genome and remain dormant.

What distinguishes generalized transduction from specialized transduction?

Generalized transduction involves the random packaging of host DNA into a phage, while specialized transduction involves the transfer of specific host genes adjacent to the phage integration site.

What defines the roles of F+ and F- cells in conjugation?

An F+ cell contains the fertility plasmid and acts as the donor, while an F- cell lacks the plasmid and acts as the recipient.

What are bacterial plasmids and what do they provide?

Small, extrachromosomal DNA molecules that can provide advantageous traits such as antibiotic resistance or metabolic capabilities.

What is high frequency recombination (Hfr)?

A state where the F plasmid is integrated into the bacterial chromosome, allowing the cell to transfer chromosomal genes to a recipient at a high frequency.

What is a transposon?

A mobile genetic element capable of moving from one location to another within a genome.

What is the difference between an F plasmid and an F' plasmid?

An F plasmid is an independent fertility factor, while an F' plasmid is an F plasmid that has incorporated some host chromosomal DNA.

What is the process of transduction in bacteria?

The transfer of bacterial DNA from one cell to another via a bacteriophage (virus).

What is the process of conjugation?

The direct transfer of DNA between two bacterial cells that are temporarily joined, usually via a pilus.

What is the difference between resistance and susceptibility in bacteria?

Resistance is the ability of a bacterium to survive exposure to an antibiotic, while susceptibility is the inability to survive or grow in the presence of that antibiotic.

How do you identify the donor and recipient in the transfer of antibiotic resistance genes?

The donor is the cell that possesses and transfers the resistance gene (often via a plasmid), while the recipient is the cell that receives the gene and acquires the resistance.

What is the difference between an F plasmid and an F' plasmid?

An F plasmid is a standard fertility factor that allows a cell to act as a donor; an F' plasmid is an F plasmid that has incorporated some chromosomal DNA from the host cell.

What is the purpose of recombination and gene amplification in a laboratory setting?

Recombination is used to combine DNA from different sources to create new genetic combinations, while gene amplification is used to increase the number of copies of a specific DNA sequence.

What are common applications of DNA recombination?

Production of therapeutic proteins (like insulin), creation of genetically modified organisms, gene therapy, and the development of vaccines.