Module 1: Basic Characteristics Flashcards
Define: Taxonomy
Science of biological classification; consists of classification, nomenclature, and identification
Define: Classification
Arrangement of organisms into groups based on mutual similarity or evolutionary relatedness
Define: Nomenclature
The assignment of names to taxonomic groups and members of groups
Define: Identification
The process of determining that a particular organism or isolate belongs in a taxonomic classification; based on various cellular characteristics
Eucaryotic Characteristics:
Nuclear Membrane
Present
Eucaryotic Characteristics:
Chromosomes
Multiple, Linear
Eucaryotic Characteristics: Cell Replication (Membrane attachment)
Mitosis
Define: Mitosis
Process of single cell division resulting in generally two identical cells, each containing the same number of chromosomes and genetic content as that of the original cell.
Eucaryotic Characteristics:
Energy Production
Mitochondria
Eucaryotic Characteristics:
Specialized Organelles
Several (Golgi Apparatus, endoplasmic reticulum, etc..)
Procaryotic Characteristics:
Nuclear Membrane
Absent
Procaryotic Characteristics:
Chromosomes
One, Circular
Procaryotic Characteristics: Cell Replication (Membrane attachment)
Binary Fission
Define: Binary Fission
Type of asexual reproduction common among prokaryotes wherein a cell divides giving rise to two cells, each having the potential to grow to the size of the original cell.
Procaryotic Characteristics:
Energy Production
On Cytoplasmic Membrane (No Mitochondria)
Specialized Organelles
Few (e.g. ribosomes)
What classification (Eucaryotic or Procaryotic) do Parasitic Worms (“Animal Kingdom”) fall into?
Eucaryotic
What classification (Eucaryotic or Procaryotic) do Protozoa and Algae fall into?
Eucaryotic
What classification (Eucaryotic or Procaryotic) do Fungi (Molds and Yeast) fall into?
Eucaryotic
What classification (Eucaryotic or Procaryotic) Do Bacteria fall into?
Procaryotic
What microorganisms of medical significance do not fit into any official kingdom and are classified separately?
Viruses- They are not considered living organisms
What is the nomenclature GENUS?
- Classification level of common usage (Subdivision of Family)
- Contains members with many similarities
- Written/spoken first; Underline if not italicized
What nomenclature is a subdivision of Family?
Genus
What is the nomenclature SPECIES?
- Subdivision of Genus
- Members have many similarities, but enough differences to be distinctly different
- Written/Spoken last (after genus); Underline if not italicized
- Written as “species” or “spp.” if referring to several/all members of the genus
What nomenclature contains members with many similarities, but enough differences to be distinctly different?
Species
What is the nomenclature Strain, variety, group, or type?
Subdivision or alternate forms of genus or species
(Slight genetic differences lead to slightly altered differences in Antigens and Biochemical Characteristics
What is a significant surface molecule against which antibodies are made and which can be used for identification?
Antigen
These are subdivisions of genus or species based on antigenic differences such as possession of antigens common to multiple members of the genus or species.
Groups & Types
What is an Antigenic Group?
Organisms possessing a major antigen that may be common to more than one species of the genus; Usually designated by capital letters. (ex. Group A Streptococcus or Streptococcus Group A)
This nomenclature is usually designated by numbers and refers to organisms possessing a specific antigen that is common to only very limited, closely related organisms (Members of an antigenic group)
Antigenic Type (ex. Streptococcus pyogenes, group A, type 12)
Describe the Cell Type of a “Typical” Bacteria.
Procaryotic- Single cell organisms without formed nucleus (no nuclear membrane) or organelles such as possessed by higher organisms
What is the cell size (Diameter and Length) of “Typical” Bacteria?
(Approximate & Usual)
Diameter: 0.5 to 0.8 micrometers, up to 1.5 micrometers
Length: 1 to 6 micrometers; most about 1-2 micrometers
Define: Morphology.
Study of the forms of thing
-External appearance of the cell, colony, or other item.
Observation of cells is easier after performing a…… on the slide and at what magnification?
Gram Stain and magnification of 1000 power
A gram stain of blue to purple indicates what kind of “Typical” bacteria?
Gram-Positive
A Pink to red coloration after performing a gram stain indicates what kind of “typical” bacteria?
Gram-Negative
What “typical” bacteria has a cell shape that is spherical?
Coccus (pl.= cocci)
What cell shape (in general) will Bacillus (pl. Baciilli) have? (Note: variations include coccobacillus, diphtheroid, and other shapes)
Rod or Cylindrical
What variation in cell shape is seen in coccobacillus?
Short, plump bacillus (which resembles a coccus)
This variation of cell shape, club shaped; resembling diphtheria bacillus is seen in what “typical” bacteria?
Coryneform or diphtheroid
What is a pleomorphic cell shape?
Single organism or species having various distinct forms. (e.g. same organism being short and plump as well as long and slender, may even be in the same field of view)
A Spirochete or spirillum will have an observed cell shape of what?
Spiral or corkscrew shape
This “typical” bacteria is very thin and stains poorly. It is not usually visible by the Gram Stain method.
Spirochete or spirillum
This cell arrangement has no particular arrangement.
Single
Cell arrangement: Division on one plane; daughter cells remain paired.
Pairs
Describe the cell arrangement of CHAINS.
Division on one plane, perpendicular to the long axis of the chain; Cells remain attached “end-to-end”
Describe the cell arrangement of Clusters.
Division on three planes
Describe the cell arrangement of Palisades.
“Picket Fence”, division on one plane perpendicular to the short axis of the chain.
Palisades “Picket Fence” cell arrangement is only seen in what “typical” bacterial cell?
Bacilli
Describe and give the function of the cell structure “Cytoplasm” of a “Typical” Bacterial cell.
Thick, aqueous, elastic
-Cell sap (e.g. water, nutrients, storage granules)-Genetic material & mechanisms (DNA,RNA, Ribosomes)Function: Metabolism & replication
What is the composition of the cell structure “Cytoplasmic” membrane of a “Typical” Bacterial cell.
- 8-10% of dry weight
- Phospholipid bilayer
- Proteins (Function as Porins (channels large molecules can pass through and others enzymes)
What is the function of the Cytoplasmic membrane of a “Typical” Bacterial Cell?
- Selective permeability- Controls transport in & out of cell
- Site of energy production
- Site of synthesis & transport of peptidoglycan, teichoic acids, & outer membrane components
- Site of secretion of extracellular hydrolytic enzymes
What is the function of the Cell Wall of “Typical” Bacterial cells?
- Shape & rigidity
- Provides protection from the environment & some antimicrobic agents
- Site of antibody attachment to major cell antigens
What is the structure of the gram-positive cell wall?
Peptidoglycan (60-80%) Teichoic acids (connect to cytoplasmic membrane) Protein inclusions are less frequent than in Gram-negative
A Gram-Positive bacteria will stain what color on a Gram Stain?
Purple to Blue
What is the structure of the gram-negative cell wall?
Peptidoglycan (10-20%)
Lipoprotein layer creates a periplasmic space
-Outer Membrane (Lipoproteins, lipopolysaccharides, & phospholipids)
-Site of Lipid A (endotoxin molecule)
-Site of “o” antigen in Escherichia, Salmonella, & Shigella antigenic tests
Give the two general characteristics pertaining to an Endospore (Spore).
- Highly resistant (dehydrated form resistant to environmental effects)
- Metabolically Dormant (one spore germinates to form one vegetative cell)
What is the composition of an Endospore?
Concentrated, dehydrated, densely packed nucleic acids and metabolic proteins within a thick spore coat
What is the function of an Endospore?
Survival under adverse environment conditions.
(Resists heat, chemicals, & irradiation)
-May be viable for years
What other names might a Capsule be referred to as?
Glycocalyx or Slime Layer
What is the composition of a Capsule?
Polysaccharides
What is the function of a Capsule?
- Resistant to Phagocytosis
- May “hide” surface antigens
- Assists in attachment (Sometimes, i.e. dental plaque)
What is the long slender threadlike appendage several times the length of the bacterial cell called?
Flagellum (pl. Flagella)
What is the composition of a Flagellum?
Protein
Name the two functions of a flagellum?
- Motility (propel/provide locomotion for bacterium)
- Movement towards favorable environment & away from adverse one. (Types: Chemotaxis & Phototaxis)
What is Chemotaxis?
Movement of motile cell or organism, or part, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance.
What is Phototaxis?
Movement of motile cell or organism in response to light. Can be either toward (Positive Phototaxis) or away (Negative Phototaxis)
By what means are Spirochetes able to move?
Axial Filaments (bundle of fibrils arising at ends of cell beneath outer sheath & spiral around the cell
A Spirochetes movement is characterized how?
Corkscrew Motion
