Classification and Identification of Microorganisms

Taxonomy

The science of classify and naming organisms, consists of classification, identification, and nomenclature

Classification

The assigning of organisms to taxa based on similarities

Identification

Determining that an isolated organism belongs to a particular taxon or group

Nomenclature

Rules of naming an organism

Carlos Linnaeus

Created a system that classified and named organisms based on characteristics they have in common. Initially only proposed two kingdoms, Plantae and Animalia

Genus

Similar species are grouped into this, then this is grouped into larger taxonomic categories

Binomial Nomenclature

Genus species

First letter of the genus is alwasy capitalized. First letter of species is aways lower case. If it is printed it is in italics, if handwritten than it is underlined

Five Kingdoms

Animalia, Plantae, Fungi, Protista, and Prokaryotae

Past Goal of Naming System

Classify organisms to catalog them using physical characteristics

Modern Goal of Naming System

Understanding relationships among organisms and is often based on similarities in DNA sequence

Carl Woese

Compared nucleotide sequences of Ribosomal RNA subunits because changes rarely occur in the sequence of

Found that Bacteria and Archaea were different from each other

Three Domain System

Bacteria, Archaea, and Eukarya

Physical Characteristics

Shape, Arrangement, Cell Wall Type, Cellular Structure, etc.

Biochemical Tests

Carbohydrate usage, presence/absence of enzymes, gas production, etc.

Serological Tests

Whether or not an antibody binds to an antigen found on the cell surface. An antigen is a biochemical on the surface of a cell. AN antibody is a specific protein that only binds to one particular antigen

Phage Typing

Bacteriophage is a virus that only infects bacteria cells. A test that determines whether a species of bacteria is susceptible or resistant to a particular bacteriophage

Genome

All of the DNA found in a bacteria cell, can be sequenced and compared. Are relatively small and can be sequenced quickly and inexpensively