Microbial Taxonomy L2A Flashcards
what are examples of prokaryotic and eukaryotic?
prokaryotic: bacteria and archaea
eukaryotic: algae, fungi, protozoa, lichens, slime molds
what processes do ALL microbial cells go under?
- transcription
- translation
- metabolism
- evolve
- growth and divide
what processes do SOME microbial cells go under?
- taxes and motility
- differentiation
- neighbourly communication
- gene transfer
differences between prokaryote and eukaryote cells?
- DNA
- no lysosome, nuclear membrane, RER, SER, Golgi or mitochondria in prokaryote
- no cell wall on eukaryote
Gram Positive cell wall facts
- thick peptidoglycan
- 90% of cell
- made as several layers
- enable IMMUNE SYSTEM RECOGNITION
- PURPLE bacteria
Gram Negative cell wall facts
- thin layer of peptidoglycan
- most is second lipid bilayer called outer membrane
- outer membrane = phospholipid, polysaccharide (linked) and protein
- stain not retained - STAYS PINK
what is the endosymbiotic theory?
- mitochondria arose from the stable residency of an AEROBIC HETEROTROPHIC bacteria
- chloroplasts arose in a similar manner from a PHOTOTROPHIC BACTERIUM
- Lynn Margulis
2 key premises of the endosymbiotic theory?
- structures associating with eukarya
- at one point they became incorporated into the cell
evidence for the endosymbiotic theory?
- Mitochondria and chloroplasts contain small amounts of their own DNA -> found in closed circular form with sequences that we can relate back to a bacterium.
- Both contain their own ribosomes which are 70S and sequence of genes encoding rNA.
what does Streptomycin inhibit?
- protein synthesis by 70S ribosome ( same with mitochondria and chloroplasts)
what could the last universal common ancestor do?
- Exploit chemical energy
- Metabolise and excrete
- Shape determination
- Response to environmental challenges
what are chronometers?
the difference in nucleotide or amino acid sequence of functionally homologous macromolecules
what is molecular phylogeny?
DNA mutates therefore differences in DNA between individuals can infer evolutionary relationships
what does the idea of evolutionary chronometer state?
2 organisms separation = to number of differences in sequence of common macromolecule
what do chronometers need to be?
- universally distributed
- functionally homologous
- able to be aligned
using chronometers to measure over large distances?
rate of sequences must be very slow
what are the 3 tested and useful chronometers
- rNA
- ATPase
- Rec A
what did Carl Woese realise about rna?
- rNA molecules can infer evolutionary relationships
- rNA excellent candidate for phylogeny: universal, conserved, constant, adequate length
what did Carl woese identify?
- archaea as separate domain to bacteria and eukarya
overview of rRNA sequencing
- Isolate DNA
- Amplify 16S gene
- Check size
- Sequence
- Align and produce phylogenetic tree
2 importances of rRNA sequencing?
- Molecular biology and sequencing
- Understand and classify microbes
what are two types of molecular taxonomy?
ribotyping
genomic fingerprinting
what is ribotyping?
- based on rRNA but no sequencing
- DNA digested and probed with rRNA Probe -> restriction pattern on gel unique to each species
what is genomic fingerprinting?
- Restriction endonucleases cut DNA
- run on gel to generate specific patterns and comparison of patterns to separate strains.
what is a species?
Population of individuals that can INTERBREED to produce fertile offspring and they are reproductively isolated from other populations
do prokaryotes have species?
no
what are microbes classified as?
phylogenetic species concept
what is phylogenetic species concept
“group of strains that share certain characteristic traits and which are GENETICALLY COHESIVE and share a most recent common ancestor
why don’t prokaryotes have species?
Prokaryotes are haploid and reproduce asexually
