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
Taxonomic rank from largest to smallest
Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species
[Dear King Philip Came Over for Good Soup]
What do proteolytic bacteria do?
Degrade proteins and produce bitterness and putrefaction
What is the primary classification of bacteria based on?
Peptidoglycans in their cell wall
Saccharolytic Microbes
Reside in the gut and utilize carbohydrate fermentation
Toxigenic Microbes
Produce and release toxins; ingestion of preformed toxins resulting from microbial growth within food can cause food poisoning
Which group of microorganisms are unicellular and eukaryotic with motility?
Protozoa
Bacteria are prokaryotic. Mold is the multicellular form of fungi. Parasites are multicellular.
What is the primary difference between prokaryotic and eukaryotic cells?
Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a nucleus and membrane-bound organelles.
True or False: Prokaryotic cells are generally larger than eukaryotic cells.
False
Fill in the blank: Eukaryotic cells have __________, which are absent in prokaryotic cells.
membrane-bound organelles
Which of the following is an example of a prokaryotic organism? A) Yeast B) Bacteria C) Fungi
B) Bacteria
What type of genetic material do prokaryotic cells typically possess?
Circular DNA
True or False: Eukaryotic cells reproduce only asexually.
False
What structure is responsible for controlling the entry and exit of substances in a eukaryotic cell?
Cell membrane
In which type of cell would you find ribosomes that are larger, prokaryotic or eukaryotic?
Eukaryotic
Fill in the blank: Prokaryotic cells typically reproduce through __________.
binary fission
What is the primary function of the nucleus in eukaryotic cells?
To store genetic information
Which of the following is NOT a characteristic of prokaryotic cells? A) Lack of membrane-bound organelles B) Presence of a cell wall C) Presence of a nucleus
C) Presence of a nucleus
True or False: All eukaryotic cells are multicellular.
False
What is the term for the rigid outer layer found in many prokaryotic cells?
Cell wall
Which type of cell typically has a more complex structure?
Eukaryotic cell
Fill in the blank: Eukaryotic cells can be divided into __________ and __________.
plant cells and animal cells
What is the function of mitochondria in eukaryotic cells?
To produce energy (ATP) through respiration
Which type of organism is primarily unicellular: prokaryotic or eukaryotic?
Prokaryotic
True or False: Prokaryotic cells can perform photosynthesis.
True
What is a key feature of the cell membrane in both prokaryotic and eukaryotic cells?
It is selectively permeable.
Fill in the blank: Eukaryotic cells contain __________, which are involved in protein synthesis.
ribosomes
What are the two main types of prokaryotic cells?
Bacteria and Archaea
Which type of cell has a complex cytoskeleton?
Eukaryotic cell
True or False: Prokaryotic cells have multiple linear chromosomes.
False
What is the primary method of genetic exchange in prokaryotic cells?
Conjugation
Fill in the blank: Eukaryotic cells can undergo __________, a form of cell division that produces gametes.
meiosis
