Evolution Flashcards
How were the 3 domains discovered
By comparing ribosomal nucleotide sequences
The 3 domains are based on
Horizontal gene transfer
The endosymbiont theory
Eukaryotic cells evolved from prokaryotic cells living inside one another.
Evidence for endosymbiotic theory
Mitochondria and chloroplasts have their own genomes and can replicate independently
they have 70S ribosomes
circular single DNA
What is gene transfer
Methods
Introduction of new DNA into existing cell
Transformation
Conjugation
Transduction
Antiserum
Solution of antibody
Identifying microorganisms
Morphological
Fatty acid
Serological> slide agglutination/ ELISA
physiological
Genotyping
ELISA
Enzyme linked immunosorbent assay
Detect presence of antibodies for AIDs
Physiological
Simple» catalase/ substrate utilisation test. (citrate> citrase>oxaloaceticacid > CO2> blue (low Ph))
Modern» kits / API kit (analytic profile index)/ biolog system(carbon compounds)
Genotyping
DNA fingerprinting> bands
DNA hybridization>2 strands
DNA sequencing>nucleotide sequence
DNA chips>gene unique to pathogen
DNA fingerprinting
Genome+ restriction enzymes
Amplify markers by PCR
Compare
DNA hybridisation 70 % or more
Same species
Combining all that
Polyphasic approach
Transformation
DNA fragments of dead bacteria making a recombinant or hybrid cell
Conjugation
A donor and a recipient of opposite mating type
Doner has plasmid recipient does not
Direct cell to cell contact
1 strand of plasmid transferred
Transduction
Bacterial DNA transferred from donor to recipient inside a virus a bacteriophage originally a viral DNA that accidentally acquired a bacterial genome and transferred it
Transduction types
Generalised>all jeans in a bacteria or equally likely to be packaged in the bacteriophage
Spcialised>only certain genes transferred
Morphological
Colony(colour,shape)
Cellular(staining, inclusions)
Serologic tests
Depends on the antigenic prop of microbes
Slide agglutination (uk bacteria+known antiserum) clumping=positive
ELISA
Fatty acid profiles
Bacteria synthesise fatty acids that are constant for a species
Commercial systems separate cellular fatty acids to compare them to known ones
DNA sequencing
Determine nucleotide sequence of DNA
More accurate
Unusual and pathogenic microbes
From sequencing 1 gene to whole genome
2 closely related organisms will have
Identical or similar genes
Similar amounts of various bases in their DNA
DNA chips
Quickly detects a pathogen by identifying a gene unique to it
Fluorescent and hybridization bet probe DNA and sample DNA
