Chapter 10 - Classification of Microorganisms Flashcards
(18 cards)
Taxonomy
Science of classifying organisms
Total Number of Species
- 1.7 Million Discovered
- 10-100 Million Estimated
The Three Domains
- Archea
- Bacteria
- Eukarya
Archea
- Prokaryotic
- Found in extreme enviroments
- No Peptidoglycan (wall)
- Membrane has branched C chains
- 1st Amino Acid ~ Methionine
Bacteria
- Prokaryotic
- All pathogens are Bacteria
- Peptidoglycan (wall)
- Membrane has straight C chains
- 1st Amino Acid ~ Formylmethionine
- Has rRNA loop and common arm of tRNA
Eukarya
- Eukaryotic (Includes Animals, Plants, Fungi)
- Carbohydrates (wall)
- Membrane has straight C chains
- 1st Amino Acid ~ Methionine
- Has common arm of tRNA
Eukaryotic Species
Closely related organisms that breed among themselves
Prokaryotic Species
1. Clone 2. Strain
- A group of cells with similar characteristics
1. Population of cells derived from a single cell
2. Genetically different cells within a clone or species
Viral Species
A population of viruses with similar characteristics that occupy a specific ecological niche
Methods of Classifying Organisms
- Morphological Characteristics
- Differential Staining
- Biochemical Tests
Morphological Characteristics
- Useful for identifying eukaryotes
- Classification by structure (appearance)
Differential Staining
- Includes Gram and Acid-Fast Staining
- Classification based on cell wall composition
Biochemical Tests
- Differentiates between closely related organisms
- Represented by a dichotomous key (if yes than… if no then…)
Serology
1. Antiserum
Study of immune responses evident in serums
1. Solution of antibodies to identify microbes
Serology Tests
- Slide Agglunation Test (known antiserum + unknown bacterium)
- ELISA Test (enzyme-linked immunosorbent assay)
- Western Blotting Test (identifies antibodies in patient’s serum)
Phage Typing
- Tests which phages a bacterium is susceptible to
- Used to find similarities among bacteria
Genetic Tests
- DNA Based Composition (% G+C)
- DNA Fingerprint (comparison of two bacteria)
- Nucleic Acid Hybridization
- DNA Probe (fragment hybridization)
- DNA Chip (identification using species specific genes)
Nucleic Acid Hybridization
- Extent of similarity between two organisms
- Combination of complimentary DNA strands
