Antibiotic Resistance Transfer Flashcards
What is vertical gene transfer?
Genetic changes (like mutations) transferred from parent to offspring.
What is horizontal gene transfer?
Genetic materials acquired from foreign cells that are stabilized and transferred to offspring.
What are the three ways horizontal gene transfer can happen?
Transformation, transduction, conjugation
What is transformation?
When a competent bacterial cell acquires free DNA from the environment.
What is homologous recombination? What protein is it dependent on?
It is when acquired DNA is integrated into the bacterial chromosome. Dependent on RecA (called RecA dependent recombination).
What is transduction?
When a bacteriophage transfers genetic material from one bacterium to another.
What are the two types of transduction?
Specialized and generalized.
What is specialized transduction?
When a phage imprecisely excises itself from a bacterial genome and transfers the bacterial pieces (from next to the prophage) to new host bacteria.
How does generalized transduction occur?
Lytic phages encode a protease that chops up DNA so that it can package DNA into new phage particles. This protease also cuts up the bacterial chromosome, and sometimes bacterial genetic material is packed into a new phage particle. When this phage with bacterial DNA infects a new bacterium, that bacterium may acquire new genes via homologous recombination.
What is conjugation?
Transfer of genetic material between to bacteria through direct contact.
What type of genetic material is transferred during conjugation?
SS plasmid DNA.
Why do transposons need to integrate into the bacterial chromosome?
Transposons don’t encode replicons, which allow genetic material to be copied. Therefore, they need to integrate into the bacterial chromosome because it encodes replicon elements.
Name four things that are necessary for a plasmid to be transferrable.
- ori (origin of replication)
- rep (proteins for replication)
- tra (transfer apparatus - does not have to be on the plasmid but has to be somewhere in the bacterium)
- oriT (origin of transfer - MUST be on the plasmid)
What two genes make a replicon?
- rep protein
2. origin of replication
What is oriC?
Origin of replication on the chromosome
