Bacterial Genetics Flashcards
What is a piece of DNA that codes for a single protein (it also includes the promoter region)?
Cistron
What codes for multiple proteins from a single promoter with its regulatory sequence?
Operon
What is the Dogma?
DNA serves as the template for making mRNA by RNA polymerase in a process called transcription.
What is translation?
Protein synthesis. Ribosomes translate the genetic language of mRNA (codons) into amino acids that make up the protein
How is translation different in Eukaryotic vs Prokaryotic?
In prokaryotes, transcription and translation are coupled (translation can begin on the unfinished mRNA as it is being transcribed from the DNA). This does not happen in Eukaryotes
Which are the elements that can do gene transferring?
- Plasmids
- Transposons
- Bacteriophages
What are transposons?
Segments of dsDNA that can move (jumping genes) within a genome, to another genome, or into a plasmid. They cannot replicate independently. They carry the genes needed for mobilization but not for replication. Transposons can transfer virulence genes, making the bacterium more dangerous.
Which are the mechanisms of genetic transfer?
- Conjugation (direct contact)
- Transformation (incorporation of free DNA. Lysed bacterial cell breaks open and releases genetic material)
- Transduction (DNA transfer mediated by bacteriophages)
What is F transfer?
If the F plasmid is extrachromosomal only the F plasmid is transferred. Now the recipient cell becomes F+
What is competence?
The ability of bacteria to incorporate free DNA (which is taken into the cell and incorporated into the genome if it carries a survival or virulence trait. If it carries nothing it gets degraded)
During what phase does competence occur?
Log phase
Which are the 2 types of indirect transfer?
Generalized: Phage DNA does not become integrated into bacterial genome. Random fragments of genomic DNA are packaged into some of the phage heads
Specialized: Phage DNA does become integrated into bacterial genome. All phage particles contain both bacterial and viral DNA. Only one type of particle is produced.
What 2 types of particles are generated in generalized transduction?
- Bacteriophages: only viral DNA
- Transducing particles: Only bacterial DNA can be any part of the genome
What is a recombinant phage?
Contains viral and bacterial DNA (always the same bacterial genes)
What is a prophage?
When viral DNA integrates into the chromosome
