Chapter 6 transformation and transduction Flashcards
________ occurs when a recipient cell takes up a fragment of donor DNA from the surrounding growth medium
Transformation
Transformation is a _______ occurring mechanism used to produce accurate maps of bacterial genes. It is also used in the _______ to introduce DNA into microbial, plant, and animal cells
naturally
laboratory
Genes that are closely linked are said to be involved in _______, the simultaneous transformation of 2 or more genes
cotransformation
What are the steps to transformation? (4)
1) Donor cell lysis
2) Double-stranded donor DNA enters the recipient cell
- one of the strands gets degraded
3) Donor strand aligns with and displaces some of the recipient strand
- forms heteroduplex
4) recipient cell divides forming 1 transformant cell and 1 non transformant cell
Double-stranded donor DNA enters the recipient cell where?
receptor site
A chromosome that contains all of the transforming strand and recipient strand is called a _______
heteroduplex
What are the 6 steps to the lytic cycle?
1) attachment
2) injection
3) replication of phage DNA
- Host DNA breaks down
4) transcription and translation of phage genes
5) assembly / packaging
6) lysis
What are the 3 additional steps that differ between the lysogenic cycle and the lytic cycle?
1) Integration: after attachment and injection, the pahge chromosome integrates with the host chromosome via recombination
2) Excision: after multiple cell divisions, the phage DNA excises from the host chromosome
3) Resumption: the phage chromosome enters the lytic cycle and starts replicating
A _______ phage is capable of integrating the phage DNA into the host chromosome, becoming lysogenic.
temperate
Once integrated into the host chromosome, the phage chromosome is called the _______ (in lysogenic cycle)
prophage
transduction is the transfer of genetic material from a donor to a recipient cell by way of a _______
bacteriophage
Bacteriophages are composed of an icosahedral _______, hollow protein _______, and sometimes a set of _______
1) head
2) sheath
3) tail fibers
Transfer of genetic material from a donor bacterium to a recipient via a phage leads to the production of a _______ bacterial strain
transductant
What are the 2 types of transduction?
1) general transduction
2) specialized transduction
_______ the transfer of RANDOM bacterial genes, is carried out by bacteriophages that cannot distinguish between phage and bacterial DNA during packing of DNA into new phage particles
generalized transduction
_______ is carried out only by temperate phages and the only genes transferred are those close to the integration site
specialized transduction
In _______ progeny phages are assembled normally but some phages receive a host DNA fragment instead of phage DNA
generalized transduction
In specialized transduction, the integration site is called _____ in the lambda phage and _______ in the E. coli host
attp
attb
After integration at the att sites, aberrant excision produces a _______ phage
- contains only galK or bioA gene
specialized transducing
The λdgal+ specialized transducing phage includes the galK gene - it can infect host cells but ________
lacks genes needed for lysis and lysogeny
The λdbio+ specialized transducing phage includes the bioA gene - it can infect host cells, but ________
lacks the genes needed for lysogeny
_______ is the transfer of genetic material between individual bacteria or archaea and other organisms
lateral gene transfer
LGT is identified by the presence of DNA-sequence features in regions of a genome that are uniquely different from the rest of the genome = _______
Genomic islands
LGT has allowed for rapid organism adaptation to changing environmental conditions by acquiring _______
antibiotic resistance
LGT in bacteria can lead to acquired _______, which contain genes for proteins that promote host invasion and genes that produce toxic compounds
pathogenicity islands
