Bacterial Genetics Cont'd Part (3)

Transduction

Transduction is the process by which a virus transfers genetic material from one bacterium to another. Later, when one of these bacteriophages infects a new host cell, this piece of bacterial DNA may be incorporated into the genome of the new host. between cells.

Virulence

degree of pathogenicity; ability to produce disease.

Conjugation F factor

fertility factor; F+ replicated its F factor and donates the copy to the recipient cell F-.

Excision can be imprecise with host genes being captured by the F Factor to produce what is called

the F prime factor

Antibiotic resistance.

the ability of bacteria to withstand the effects of an antibiotic.

Generalized Recombination

(also called homologous recombination) allows large sections of the DNA double helix to move from one chromosome to another.

Recombination

(genetics) a combining of genes or characters different from what they were in the parents.

Transposons

(jumping genes) short strands of DNA capable of moving from one location to another within a cell's genetic material.

F prime factor

A fertility factor plasmid that contains some chromosomal DNA; these capture host genes can be transfer to another cell by conjugation.

Sex Pilus

A thin connection between two bacteria through which genetic material passes during conjugation. "mating pairs."

TRANSFER OF GENETIC INFORMATION

Bacteria can shuffle genes This is called genetic recombination. Four ways that new DNA can be added to the Transposition - within the same cell. Transformation - between cells. Conjugation - between cells. Transduction - between cells.

Once a new piece of DNA has entered a cell, what happens to it?

If the new DNA is in the form of a plasmid capable of autonomous replication, the plasmid will coexist in the cell separate from the host chromosome. If the foreign DNA is not capable of autonomous replication, it is either degraded by nucleases or incorporated into the chromosome through recombination.

Jumping Genes

Insertion Sequences or Transposons.

Transduction Cont'd

Movement of DNA from one cell to another requires a viral (bacteriophage) vector. Two Types Generalized Transduction Specialized Transduction.

Recombination can be

Site-Specific or Generalized.

Transposition

a DNA recombination reaction that results in the translocation of a discrete DNA segment called a transposable element or transposon from a donor site to one of many nonhomologous target sites. within the same cell.

Specialized Transduction

a highly specific part of the host genome is regularly incorporated into the virus.

Specialized Transduction by Temperate Phage

a phage that is capable of replicating by either a lytic or lysogenic cycle.

Transformation

a process by which the genetic material carried by an individual cell is altered by the incorporation of foreign (exogenous) DNA into its genome. between cells.

Toxin production

a toxin is a poisonous substance produced within living cells or organisms; exotoxins and endotoxins.

Bacteriophage

a virus that infects bacteria.

Examples of traits that can be encoded on plasmids

antibiotic resistance. synthesis of pilus. utilization of unusual nutrients. virulence. toxin production. antibiotic synthesis.

Two Component Regulation

bacteria cells are able to sense and response to changes in their environment.

The F factor can integrate into the chromosome as well as

be excised (exit).

Insertion Sequences

code for transposase that cuts and reseals DNA.

Site-Specific Recombination

is an exchange that occurs between pairs of defined sequences (target sites) residing on the same DNA molecule or on two different DNA molecules.

Conjugation

is the process by which one bacterium transfers genetic material to another through direct contact. During conjugation, one bacterium serves as the donor of the genetic material, and the other serves as the recipient. The donor bacterium carries a DNA sequence called the fertility factor, or F-factor. between cells.

If the foreign DNA is not capable of autonomous replication,

it is either degraded by nucleases or incorporated into the chromosome through recombination.

Synthesis of pilus

protein structures that extend from the bacterial cell envelope, they function to attach the cells to surfaces.

Generalized Transduction

random bacterial DNA is packaged inside a phage and transferred to a recipient cell.

Lysogenic cycle

replicates the phage genome without destroying the host.

If the new DNA is in the form of a plasmid capable of autonomous replication,

the plasmid will coexist in the cell separate from the host chromosome.

Genetic recombination

the regrouping of genes in an offspring that results in a genetic makeup that is different from that of the parents.

Bacterial Conjugation through

transfer of a Plasmid. during this process, DNA plasmid is transferred from one bacterium (the donor) of a mating pair into another (the recipient) via a pilus. During wall-to-wall contact of the mating bacteria, DNA transfer takes place.

Composite Transposon

type of transposable element in bacteria that consists of two insertion sequences flanking a segment of DNA; also carry genes for antibiotic resistance or other useful properties.