Bacterial Genetics And Macrophage Interactions Flashcards
What are the two ways in which bacteria generate genetic diversity? And which one is most responsible for the spread of antibiotic resistance?
Replication errors and horizontal gene transfer.
What are some differences between prokaryotic and eukaryotic transcription and translation?
In prokaryotes:
- transcription and translation are coupled
- ribosomal subunits are 30s and 50s
- there are no introns and exons
- there is only 1 RNA polymerase (opposed to 3 in eukaryotes)
What are the three mechanisms of gene transfer?
transformation, transduction and conjugation
- What are the three exchangeable genetic elements?
- Which one can replicate on its own?
- Which one can be a part of a bacteriophage genome?
- Plasmids, transposons/insertion sequences, and pathogenicity islands.
- Plasmids
- Transposon (Mu bacteriophage)
What is phase variation?
It is a site-specific inversion to allow switching in the expression of a gene. Ex: UPEC switching between fimbriated and non-fimbriated.
What must happen to double stranded DNA before it is internalized into the bacteria during transformation?
It must be processed into single stranded DNA.
Which exchange mechanism requires physical contact between two bacterial cells?
Conjugation
What are the two virulence determinants that are actually encoded on a bacteriophage’s genome?
Cholera toxin and Shiga toxin
What two types of bacteria secrete shiga toxin?
EHEC and shigella dysenteriae
What are the 5 steps of phagocytosis?
Recognition, Bacterial uptake, Phagosome maturation, Bacterial killing by lysosomes and Processing of the antigens
What are the 4 methods of altering phagosome trafficking and which bacteria are examples of each method?
1) surviving in the lysosome - coxrella
2) escaping into cytosol - rickettsia, shigella, E.coli and listeria
3) modulating endocytic pathway - mycobacterium and salmonella
4) alternative pathway - legionella, chlamydia and brucella
