Bacterial Structure/Function Flashcards
Four steps of gram stain.
- Crystal violet
- Iodine
- Alcohol wash
- Safranin
Peptidoglycan is composed of repeating units of what two glycan molecules. What is the peptido part? Which glycan is it attached to
- NAG - N-cetylglucosamine
- NAM - N-acetylmuramic acid
- Attached to NAM is muramyl peptide that differs between bacteria. Cross-links occur between peptides to provide mesh-like structure
What part of a late peptidoglycan precursor does vancomycin bind?
D-Ala-D-Ala , preventing synthesis of peptidoglycan
What moiety can be modified in LPS to resist cationic peptide antibiotics?
Lipid A moiety
Flagellin- which TLR binds it?
Protein that makes up filament portion of flagellum
TLR5
Why are antibotics that target the ribosomes not ideal?
Ribosomes are not unique to bacteria, so these antibiotics can produce toxic effects
Endosymbiotic theory
The idea that mitochondria and chloroplasts were once prokaryotes that were engulfed by eukaryotes and became permanent organelles.
Antibiotics target mitochondrial function, especially mitochondrial ribosomes, so this can lead to toxic effects
Microbial community
Collection of microbes in a defined area - soil, human, water, etc
Microbiota
Microbial communities associated with a host, eg. Humans. Not to be confused with microflora (incorrect but often used term).
Microbiome
collection of microbial genes in a microbial community
Metagenome
A collection of genetic material isolated from an environment.
Metatranscriptome
Collection of genes expressed in an environment
Pan-genome - what two types of genes is it made up of?
Set of genes found in a particular bacterial species.
- Core genes
- Dispensable genes
Variability in what structure allows for phylogenetic identification of bacteria?
Stem/loop structure
What gene do most molecular surveys of microbial communities use to study community structure? Limitations?
16S (ribosome) - cannot identify species on 16S rRNA sequence alone
