Mesnage - Microbial Diversity

Question 1

name 3 processes that influence genetic plasticity thereby generating microbial diveristy

Answer 1

1) rapid multiplication via binary fission = diversification through mutations
2) haploid genome = mutations are always passed on
3) horizontal gene transfer = transformation/transduction and conjugation of (viral) DNA influence microbial diveristy

Question 2

define phylogeny

Answer 2

evolutionary relationships measured by compared DNA

Question 3

name 2 methods of showing phylogenetic relationships

Answer 3

cladograms and phylogenetic trees

Question 4

what is a molecular clock?

Answer 4

a comparison between mutation rates of species using DNA seq of rDNA to find a common ancestor and when they diverged - the number of sequence differences between two species should be proportional to the time of divergence between them.

Question 5

define taxonomy

Answer 5

classification using binomial nomenclature and the domain kingdom phylum (etc) system

Question 6

name 5 methods of phenotypic analysis which are used to classify organisms via taxonomy

Answer 6

1) morphology/differential staining
2) metabolic properties (series of tests which have specific combinations relating to different bacterial species)
3) phage typing - specific phages lyse specific bacteria
4) f/a (fatty acid) profiling using gas chromatography
5) mass spectrometry

Question 7

name 5 methods of genotypic analysis which are used to classify organisms via taxonomy

Answer 7

1) DNA-DNA hybridisation (there’s a flashcard explaining this)
2) Fluorescence In Situ Hybridisation - fluorescent DNA markers are used to identify unknown genomes (bind to known complementary seq’s)
3) 16S rDNA sequencing - v highly conserved seq DNA but with hypervariable regions which are specific to each bacteria
4) Multi Locus Sequencing Typing - multiply and sequence a number of housekeeping genes (difference in alleles at multiple loci is v specific to bacteria)
5) whole genome sequencing

Question 8

Describe DNA-DNA hybridisation

Answer 8

unlabeled and labeled DNA are mixed and incubated allowing the DNA strands to dissociate and re-associate (forming hybrid dsDNA). the mixture is then heated, the stronger the hybrid dsDNA has bound the more heat (energy) is required meaning the DNA is more similar

Question 9

name the 3 domains and who defined them

Answer 9

eukarya
archaea
bacteria
Carl Woese

Question 10

who came up with binomial nomenclature

Answer 10

carl linnaeus

Question 11

who came up with the 5 kingdoms

Answer 11

robert whittaker