Unit 2 Bacterial Systematics Flashcards
Why can taxonomic keys only be written after a classification scheme has been constructed?
Because a taxonomic key helps identify unknown organisms by comparing their characteristics to known organisms.
Describe a Staphyl(o) morphology
Cluster
Describe a Strept(o) morphology
Chain
Alpha Taxonomy
Classification that Involves simple descriptions of organism based on phenotypes
Beta Taxonomy
Classification that involves genetic and molecular identities
Taxonomic Groups
Domain Kingdom Phylum Class Order Family Genus Species
What is the nomenclature format?
Genus Name, Specific Epithet, Authority Bacillus Megaterium deBary
What is an authority when naming organisms
Who discovered, described, or established the taxon?
Who regulates the application of scientific Names in bacteria?
International Code of Nomenclature of Bacteria
What is the significance of the International Code of Nomenclature of Bacteria and Viruses?
It standardizes naming and classification of those organisms
What are the common morphologies in bacterial cells
Cocci Bacilli Spirilli Spirochete Vibrio Pleomorphic
Describe a Sarcinae cellular arrangement
Cube-like with layers
What is the purpose of a taxonomic (dichotomous key) and the use of pair questions/couplets to identify specimens?
Dichotomous keys help eliminate and identify organisms based on characteristics
What is the difference between Logistic and Exponential growth?
Exponential growth does not reach a carrying capacity and never ends (J-Shaped), while Logistic growth is similar, it has a carrying capacity and is more S-Shaped.
Why is harvesting a culture during the log phase preferred over other phases?
Because the Log phase is exponentially growing prior to carrying capacity or death phase. This would produce the most viable bacteria of all the phases
How is a culture sampled using spectrophotometry?
Light going through another light to the curvette to the sample
What is Agar made of?
A polysaccharide found in seaweed
What is agar used for?
Solid culture media (Slants and Plates)
Why is agar so well suited for culturing?
It is a non-nutritive media which makes it versatile and has the ability to grow multiple types of microbes. It can also be sterilized.
What is a Liquid Nutrient Media called?
A Broth
What are the two types of solid Nutrient Media?
Slants and Plates (Usually Agar)
What is the general Purpose Media used in lab?
Tryptic Soy Agar
What is the difference between General Purpose and Enriched Media?
Enriched media has Growth factors as additives to help microbes that would not usually thrive in a non-nutritive media (Can be selective and differential). NNM (TSA) has no additives and is more versatile
What is a synthetic Nutrient Media Complex?
All components known
What is a non-synthetic Nutrient Media Complex?
All components are not known (SBA)
What is a selective Media?
Compounds are added to prevent other microbes from growing
What is a differential media?
Indicator solution or compound is added to distinguish between microbes
What is a Growth Factor
Nutrients the organism cannot make itself and must be produced in the diet
What is the importance of a Growth Factor in culturing?
Growth Factors are added in cultures to promote growth and viability in the target bacteria
What is a Confluent Colony
One that takes over the medium
What is an isolated colony
One which individual colonies are visible and separated from each other
What is the ideal bacterial growth/incubation temperature (in most cases)
30-38C
What factor does pH play in Bacterial growth?
Buffers are used to prevent overly acidic or Alkaline conditions preventing growth
What is an obligate Anaerobe?
They are poisoned by Oxygen, So they gather at the bottom of the tube where the O2 concentration is the lowest.
What is a facultative Anaerobe?
They can grow with or without oxygen because they can metabolize aerobically or anaerobically
What is an aero tolerant Anaerobe?
An anaerobe that uses Fermentation to produce ATP
What is a strict Anaerobe?
They are poisoned by Oxygen, So they gather at the bottom of the tube where the O2 concentration is the lowest.
What is the importance of Inoculation in culturing?
Ensuring enough bacteria is transferred to the medium and Aseptic technique is used prior to inoculation
What is the importance of incubation in culturing?
Attempting to culture at the wrong temperatures can result in no growth, over growth, or cellular death from heat exposure.
What is the importance of identification in Culturing
Knowing the level of hazard the microbe is can save a life, and being able to determine its gram result, morphology, and biochemical tests can help positively identify the Genus of the organism.
What is the importance of isolation in Culturing?
Ensuring that a pure and isolated culture is produced will help identify and not mix cells of different species.
Photoheterotroph
organisms that use light for energy, but cannot use carbon dioxide as their sole carbon source
PhotoAutotroph
Using energy from sunlight, carbon dioxide and water are converted into organic materials to be used in cellular functions such as biosynthesis and respiration.
ChemoAutotroph
an organism, typically a bacterium, that derives energy from the oxidation of inorganic compounds.
Chemoheterotroph
biology an organism that obtains its energy from the oxidation of organic compounds
What is the significance of a Porin Protein?
It is found in the Outer Membrane of a Gram (-) Cell and have regulatory control within the cell
What is the nature of the genetic Material in prokaryotes?
Single, Small, Circular chromosome held in the Nucleoid region of a bacterial cell
What is the structure of a bacterial Ribosome?
A Large and small subunit come together to form a protein factory
What is an endospore?
A Dehydrated, Metabolically inert piece of DNA. It’s germination occurs in the presence of Water and its Germination agent.
What is an Inclusion Body?
A way to store molecules such as granules, fat, and other metabolic product in the cell.
What is the difference between cytosol and cytoplasm?
Cytosol is the gel-like fluid in the cytoplasm. The Cytoplasm is the fluid and organelles held inside the cell membrane. It is the site of many biochemical activities
How is a nutrient defined as being “Essential”
It cannot be formed in the organism and must be supplied in the diet (Also called Growth Factor)
What is a microaerophile?
Require oxygen, but at low concentrations. Sensitive to toxic forms of oxygen
What is the mode of Bacterial Growth?
Binary Fission
What is the role of Micronutrients in the life of a bacterial cell?
metal ions required by certain cells in such small amounts that it is difficult to detect (measure) them, and it is not necessary to add them to culture media as nutrients. Trace elements are required in such small amounts that they are present as “contaminants” of the water or other media components
What is the role of Macronutrients in the life of a cell?
Usually a growth Factor required by the cell to live (Protein, DNA, Lipid, Carbohydrate)
Define a Growth Factor and discuss the importance of it in Bacterial Culturing
A Growth factor must be supplied in the diet or in the medium of a Bacterial culture to show significant growth in the culture.
Lag Phase
The beginning of the S in a Log Curve
Log Phase
The Main Growth portion of the S in a Log Curve
Stationary Phase
The plateau in a Log curve (Carrying capacity)
Death Phase
Declining curve in a Log Curve
R (Growth Rate)
represents the per capita birth rate minus the per capita death rate for a population
RMax
maximum intrinsic rate of increase
What are the differences between Prokaryotic and Eukaryotic Cells
Eukaryotic: Multiple Chromosomes, Membrane-Bound Organelles, Chloroplast, Mitochondria, larger Cell Size, Nucleus Prokaryotic: Nucleoid, Single, Circular Chromosome, No organelles, Smaller Ribosomes
What is the basic Structure of a Cell membrane
Fluid Mosaic Model featuring Phospholipid Bilayer with Membrane bound proteins. Phospholipids are amphipathic with Hydrophilic heads pointing towards the inside of the cell and outside of the cell. Hydrophobic tails between the two rows of heads.
What is the difference between Active and Passive Transport?
Passive Transport (Osmosis, Diffusion, Open Channels), operate with the concentration Gradient. Active Transport goes against the concentration, and electrochemical gradient, requiring ATP (renders it active Transport)
Uniporters
Send molecules in or out of the cell (only 1)
Symporters
Send molecules In the same direction at least 2 at a time (2 in or 2 out)
Antiporters
Move molecules in and out of the cell at the same time
What is the significance of the Electrochemical Gradient across a cell membrane
The required action potential must be reached prior to any task being completed. Proton gradients are used to generate a chemiosmotic potential that is also known as a proton motive force. Which creates a difference in charge across the membrane
What is the Extracellular Matrix?
Proteins and scaffolding on the outside of the cells that support and help connect cells to each other.
What is the structure of Peptidoglycan
Alternating NAG and NAM segments connected by Peptide Chains (Crystal Lattice Structure)
What is the Peptide Chain in peptidoglycan?
Connects the opposite NAG and NAM Sequences. It is a 4-Amino Acid Chain
What is a glycocalyx
A Filamentous network of carbohydrate-rich molecules that coat cells.
What is a Capsule
Protects the cells and provides virulence (Tightly Attached)
What is a Slime Layer
A slime layer in bacteria is an easily removable (e.g. by centrifugation), unorganized layer of extracellular material that surrounds bacteria cells. (Loosely attached)
What are two functions of a Glycocalyx
Cell-to-cell recognition, Adherence, and Protection
What is the significance of Biofilm
a thin, slimy film of bacteria that adheres to a surface. Found commonly in the mouth on teeth (Plaque) and Harden with a polysaccharide Matrix
Fimbriae
Short, Numerous surface appendages on the cell that provide adhesion
Pili
Short, Small Filamentous hairlike structures that allow bacteria to attach to other cells.
Sex Pilus
Allows transfer of plasmid DNA from one bacterial cell to another.
What is the structure and motion of a Prokaryotic Flagellum?
Made of Flagellin Protein, Rotate to create the Whip motion
What is the structure and motion of a Eukaryotic Flagellum?
9+2 Arrangement, Made of Tubulin Protein (Alpha and Beta), has a Basal Body at the base.
What is the difference between a Eukaryotic Flagellum and a Eukaryotic Cilium?
Cilia move in oar-like movements in unison. They are shorter, and more numerous Flagellum move in a whip-like motion, tend to be longer, and not as numerous
Gram (+) Cell Wall
In the Gram-positive Bacteria, the cell wall is thick (15-80 nanometers), consisting of several layers of peptidoglycan. the S-layer is attached to the peptidoglycan layer.
Gram (-) Cell Wall
the cell wall is relatively thin (10 nanometers) and is composed of a single layer of peptidoglycan surrounded by an outer membrane. S-layer is attached directly to the outer membrane
Periplasmic Space
The zone between the cytoplasmic membrane and the outer membrane in Gram-negative bacteria. It contains a thin layer of peptidoglycan, has a gel-like consistency, and contains various types of proteins concerned with the cell’s metabolism (Provides Temporary Storage of Enzymes released by the cell membrane)
Gram (-) Cell wall composition
Gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins
Name This cell Morphology
Cocci
Name this cell Arrangement
Cocci/Solitary
Name This cell Arrangement
Sarcinae
Name This Cell Morphology
Spirilli
Name This Cell Morphology
Spirochete
Name This Cell Arrangement
Staphylococcus
Name this cell morphology
Bacillus
Name This cell Arrangement
Streptococcus
Name This cell Morphology
Vibrio
Name This Cell Morphology
Pleomorphic
Identify the Capsule on the Bacterial Cell
Identify the Fimbriae on the bacterial cell
