7. Genetic Transfer and Mapping in Bacteria Flashcards
the transfer of genetic material from one bacterial cell to another.
Genetic Transfer
a form of genetic transfer between bacteria that involves direct physical interaction between two bacterial cells. One bacterium acts as donor and transfers genetic material to a recipient cell.
Conjugation
1) when a bacterial cell takes up a plasmid vector or segment of chromosomal DNA from the environment; (2) when a normal cell is converted into a malignant cell.
Transformation
a form of genetic transfer between bacterial cells in which a virus (bacteriophage) transfers bacterial DNA from one bacterium to another.
Transduction
a type of growth medium for microorganisms that contains a mixture of nutrients that are required for growth; nothing additional has been added.
Minimal Medium
a strain that cannot synthesize a particular nutrient and needs that nutrient to be added to its growth medium.
Auxotroph
a strain that does not need a particular nutrient included in its growth medium.
Prototroph
a fertility factor that is found in certain strains of bacteria and carries genes that allow the bacteria to conjugate. Strains of bacteria that contain an F factor are designated F+; strains without any F factor are designated F−.
F Factor
a structure on the surface of bacterial cells that acts as an attachment site to promote the binding of bacteria to each other.
Sex Pilus (Pili)
a connection between two bacterial cells that provides a passageway for DNA during conjugation.
Conjugation Bridge
a protein complex that recognizes the origin of transfer in F factors and other conjugative plasmids, cuts one DNA strand, and aids in the transfer of the T DNA.
Relaxosome
the location on an F factor or within the chromosome of an Hfr strain that is the initiation site for the transfer of DNA from one bacterium to another during conjugation.
Origin of Transfer
(1) during conjugation, the strand of F-factor DNA that is transferred to a recipient cell; (2) a segment of DNA found within a Ti plasmid that is transferred from a bacterium to an infected plant cell.
T DNA
a complex of DNA (or RNA) and a protein.
Nucleoprotein
a general term for a DNA molecule (most often circular) that exists independently of the chromosomal DNA. Some are used as vectors in cloning experiments.
Plasmids
a genetic element that can replicate independently of the chromosomal DNA but can also occasionally integrate into the chromosomal DNA.
Episome
a bacterial strain in which an F factor has become integrated into the bacterial chromosome. During conjugation, an Hfr strain can transfer segments of the bacterial chromosome
Hfr (High frequency of recombination) Strain
an F factor that also carries genes derived from the bacterial chromosome.
F’ (prime) Factors
a method used in conjugation experiments in which the length of time that the bacteria spend conjugating is stopped by a blender treatment or other type of harsh agitation.
Interrupted Mating
a unit of measure used in bacterial conjugation experiments; refers to the relative time it takes for genes to first enter a recipient strain during conjugation.
Minute
a virus that infects bacteria.
Bacteriophage (Phage)
a type of growth cycle for a bacteriophage in which the phage directs the synthesis of many copies of its genetic material and coat proteins. These components then assemble to make new phages. When synthesis and assembly are completed, the bacterial host cell is lysed, and the newly made phages are released into the environment.
Lytic Cycle
a natural process of transformation that occurs in certain species of bacteria.
Natural Transformation
cells that can take up DNA from the environment or an extracellular medium.
Competent Cells
proteins that are needed for bacterial cells to become naturally transformed by extracellular DNA.
Competence Factors
the exchange of identical or similar DNA segments between homologous chromosomes.
Homologous Recombination
a region of double-stranded DNA that contains one or more base mismatches.
Heteroduplex
the exchange of DNA between nonhomologous segments of chromosomes or plasmids.
Nonhomologous Recombination
transformation of bacteria that occurs via experimental treatments.
Artificial Transformation
a peptide secreted by certain species of bacteria that allows them to become competent for transformation.
Competence-Stimulating Peptide (CSP)
DNA sequences found in certain species of bacteria that are needed for a DNA fragment to be taken up during transformation.
DNA Uptake Signal Sequences
the transfer of genes from one individual to another individual that is not its offspring.
Horizontal Gene Transfer
the acquisition of antibiotic resistance by a bacterial strain, which may result from genetic alterations in the bacterial genome, but often occurs because a bacterium has taken up a gene or plasmid from another bacterial strain.
Acquired Antibiotic Resistance
