Naming, Identifying, and Classifying Microorganisms Based on their Characteristics Flashcards
What are the major classes of microorganisms in increasing complexity?
Viruses, Bacteria, Fungi, Protozoa, Multicellular animal parasites
What is the cellular structure of viruses?
Acellular, not considered a living organism
What type of genetic material do viruses contain?
Either DNA or RNA, never both
What are the characteristics used to classify viruses?
- Genetic material: DNA or RNA (Either single stranded or double stranded)
- Presence of an envelope
- Cytopathic effects
What defines bacteria as prokaryotic organisms?
No nucleus or other membrane-bound organelles
What is the main component of the bacterial cell wall?
Peptidoglycan
What is the process of Gram Staining?
Crystal violet, Iodine, Decolorizer, Safranin
What color do Gram positive bacteria retain after staining?
Purple
What color do Gram negative bacteria turn after staining?
Pink; Gram negative bacteria contain a thin layer of peptidoglycan in their cell wall, and therefore they lose the purple color when exposed to the decolorizer and the safranin stains them pink
What are the common shapes of bacteria?
- Bacilli
- Cocci
- Spirilli
What does ‘Staphyl’ refer to in bacterial arrangement?
Cluster
What does ‘Strepto’ refer to in bacterial arrangement?
Arrangement in sheets or chains
What is the cell wall composition of fungi?
Chitin
What are the two forms fungi can present as?
1) Yeast (unicellular)
2) Mold (multicellular)
Fungi can be dimorphic meaning they can take the form of yeast and mold
What are hyphae in fungi?
Tubular extensions that form mycelia
What is the temperature preference for yeast and mold?
- Yeast: ~37 degrees Celsius
- Mold: ~25 degrees Celsius
What are the characteristics used to classify protozoa?
- Motility
- Environment/infection site
- Life cycle
What are the three types of motility in protozoa?
- Pseudopods
- Cilia
- Flagella
Cilia vs Flagella
Cilia are tiny hair-like projections that move in a coordinated back and forth motion (whip-like/ wave motion).
Flagella helps cells move by rotating, which propels the cell forward.
What defines multicellular animal parasites?
Eukaryotic and multicellular (Not strictly microorganisms by definition but can have microscopic stages in their life cycles)
What are endospores?
Non-reproductive, dormant forms of bacterial cells. Sporulating bacteria are mainly Gram positive. The protective capability of endospores has been demonstrated in revival of Bacillus endospores from amber that is millions of years old.
What genera are mainly associated with endospore-forming bacteria?
- Bacillus
- Clostridium
What does ‘aureus’ represent in the name ‘Staphylococcus aureus’?
Species
What type of microorganisms are responsible for food rancidity?
Lipolytic microorganisms- These microbes, either bacteria or molds, use lipase in breaking down and decomposing vegetable and animal fats resulting in rancidity