Week 10 / Microbiology 2 Flashcards
what is biological systematics?
Studies how life changes through time and how living things
relate to one another
what is taxonomy?
define systems by shared characteristics
what is classification ?
arrange organisms into groups
What is nomenclature?
assign names
What are biological entities?
What are they split into?
basically every plant , animal , bacteria
cellular: Eukarya, Bacteria, Archea
Acellular: viruses , prions
Describe the development of classification systems ?
Linnaeus: 2 kingdoms/ vegetablia , animalia 1735
Haeckel: 3 kingdoms / protista /plantae / anamalia 1866
chatton : 2 empires / prokaryota , eukaryota 1925
whittaker : 5 kingdoms / monera, protista,plantae,fungi,animalia 1969
woese: 3 kingdoms / bacteria , archaea,eucarya 1977
What are viruses and prions described as?
anomalous entities
Non-living
Viruses are parasitic (require hosts and Viruses are parasitic (require hosts and
resources to reproduce)
How are viruses classified?
(acellular)
Baltimore or ictv
but generally on the phenotype and nucleic acid
What are prions ?
How do they cause disease?
Misfolded proteins
By causing proteins to fold in the brain
examples of species Eukaryota and bacteria?
H.sapiens
E.coli
What is a species?
A group of living organisms capable of interbreeding, even if
geographically isolated;geographically isolated
What is strain ? in the context of microbiology
is a genetic variant or subtype of a bacterial species
that varies slightly from other members of the same species
What is species ? in the context of microbiology
example
collection of strains that share stable properties
but differ significantly from other groups of strains but differ significantly from other groups of strains
What are the different criteria used to assign species or strains in microbiology? [3]
Phenotype: an organism’s observable characteristics or traits (e.g: an organism’s observable characteristics or traits (e.g
morphology, development, biochemical or physiological properties)morphology, development, biochemical or physiological properties)
Serotype: distinct variations in cell surface antigens within a species:
Genotype:is the part of the genetic makeup of a cell, which is the part of the genetic makeup of a cell, which
determines one of its characteristics
How can species be phenotypically classified ? [7]
Morphology
** Cell shape (bacilli or cocci)Cell shape (bacilli or cocci)
** Cell structure (gram staining)Cell structure (gram staining)
Biochemistry
** Enzyme production
** Transport proteins activity
** Life cycle
Vegetative or spore forming
Ecological niche
Temperature
Thermophile
Psychrophile
Interactions with other organisms
Susceptibility to bacteriophages
Pathogenicity (ability to cause disease)
What is a serotype
distinct variations in cell surface antigens within a species
What is a genotype?
How can species be genotypically classified ? [3]
part of the genetic makeup of a cell which determines one of its characteristics (phenotype)
Genomics
** PCR
** Amplification of selected region of interest (specific genes)
Base composition (%G/C)
Nucleic acid sequencing
** 16S rRNA
** Used in phylogenetics due to
slow rate of evolution
phylogenetics due to slow
rate of evolution
**Can also be used in diagnosis
** Whole genome sequencing
what is a way we can define bacteria species ?
if genome sequences are at least 95% identical
what can taxonomy based on genetics be confused by?
horizontal gene transfer
What is vertical transmission?
What is horizontal transmission ?
passage of genetic information from parent to offspring
the acquisition of genetic information by transfer from an organism that is not its parent
What is genome sequencing?
How can we characterise with this information
determines the complete DNA sequence of an organism at a single time
Presence/absence of genes
Gene mutations
Point mutations (SNPs)
Can change protein encoding
Gene insertions/deletions
Acquired genes from horizontal transfer
Phylogenetics
What is phylogenetics?
How can we use it to classify?
To make it easier what is the results converted to?
the study of evolutionary relationships among biological entities (within species)
Produces clusters (clades) of similar organisms based on DNA or protein sequences
For 2 or more sequences, multiple sequence alignments (MSA can be produced)
More closely related = more similar the genetic sequences
percentages
What are phylogenetic trees?
What is the rooted tree?
What is the unrooted tree?
visualise evolutionary relationships between organisms
the tree where each time it branches it assumes the branch is the common ancestor
only how each leaf relates to others (no inference on ancestry)
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