Conjugation
Unlike other methods of genetic transfer, conjugation is unique because it requires the two bacterial cells to do this
What is touch?
Why is transformation considered horizontal rather than vertical gene transfer?
Genes are transferred between unrelated cells, not parent to offspring.
This type of bacteriophage accidentally packages fragments of host bacterial DNA during the lytic cycle.
What is generalized transducing phage?
Unlike generalized transduction, specialized transduction is carried out only by this type of temperate phage.
What is a Lysogenic Phage?
Why is horizontal gene transfer important for bacterial evolution?
It allows bacteria to gain new traits quickly without waiting for mutation or reproduction.
The donor cell uses this tiny, hair-like bridge to latch onto the recipient and pull it close.
What is a pilus?
How does transformation differ from conjugation and transduction?
Transformation uses free DNA, conjugation transfers through direct contact, transduction uses bacteriophages.
In generalized transduction, bacterial DNA is transferred during this phase of the phage life cycle, when the host cell is broken open.
What is the lytic cycle?
Specialized transduction occurs when this specific viral state, where DNA is integrated into the host genome, is induced to leave.
What is Prophage?
Transformation, conjugation, and transduction.
During the transfer process, the double- stranded piece of DNA ’unzips’ so a single strand can slide into the recipient.
What is a plasmid?
Why is free DNA in the environment important for transformation?
Without free DNA, there would be no genetic material available to absorb.
This process allows random pieces of bacterial DNA to be transferred from one bacterium to another via a virus.
What is generalized transduction?
This specific error during the ‘excising‘ process causes the phage to take a piece of the host’s DNA with it.
What is Imprecise Excision?
How does conjugation transfer DNA between bacteria?
DNA is transferred through direct cell-to-cell contact, usually by a pilus.
Once the transfer is complete, the recipient cell is officially ’converted‘ into one of these.
What is a new donor?
What would happen if bacteria lost the ability to transform?
Slower at adapting, fewer sources of genetic variation.
The DNA transferred in generalized transduction comes from this source within the infected bacterium.
What is the host bacterial chromosome?
Because the phage DNA always integrates at a specific ‘hot spot,’ only genes in this proximity can be transferred.
What are Adjacent Genes?
What role does bacteriophages play in horizontal gene transfer?
They transfer DNA from one cell to another during transduction.
These specific types of plasmids are a ‘problem for medicine’ because they carry multiple antibiotic-resistant genes.
What are R- Plasmids?
How can harmless bacteria become pathogenic through transformation?
Harmless bacteria could gain toxic genes/virulence factors from pathogenic strains.
Unlike specialized transduction, generalized transduction can tracer this type of gene.
What are any (random) bacterial genes?
In the recipient cell, the newly acquired DNA must undergo this process to be successfully incorporated into the new host’s genome.
What is Homologous Recombination?
Why can horizontal gene transfer be dangerous in medicine?
It can spread antibiotic resistance gene and virulence factor between bacteria.