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.