MLS303 Part 2 – Flashcards
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What are the three types of taxonomy? |
Biologic Numeric DNA |
| What are the three elements to any biological systematics? |
Taxonomy Nomenclature Identification |
| What do the suffix's "ales" and "aceae" AWLAYS refer to? |
ales: order aceae: family |
| What is the purpose of Taxonomy? |
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; What is numeric taxonomy and what is usually used to chart it? |
Numeric taxonomy is a Phenetic system that uses observable characteristics (gram stain, cell shape, motility, size, cell wall chemistry etc....) to group organisms A Similarity Matrix is used to group the organisms by greatest number of characteristics in common and a dendogram is used to graphically display similarity coefficients.; ; |
; What is a phenon? |
it is a group of organisms with great similarity *In numeric taxonomy ;%80 similarity= same species |
| What is Phylogenetic (Genotypic) system of taxonomy? |
This groups organisms based on shared evolutionary heritage.; *DNA and RNA sequencing techniques are considered to give the most meaningful phylongenies |
| What is the G + C ratio? |
How much Guanine and Cytosine in a ;strand of DNA; Determined by:;G+C/ G+C+T+A |
| How do we determine G+C amount? |
| DNA with greater G+C content have more hydrogen bonds and the strand seperates at a higher temperaure which equals a higher melting point. When the DNA strand is slowly heated the midpoint of the rising curve gives the melting temperature, which is a direct measure of G+C content.; |
| What is the average Genome size for bacteria? |
| between 1 x 10^9 and 4 x 10^9 daltons per cell of DNA |
; What is the purpose of a thermalstability test? |
| to figure out what temperature is best to stick DNA acid and bases together |
| What are molecular species? |
o two organisms are considered to be in the same molecular species if they exhibit 70% or greater relatedness and the related sequences contain 5% or fewer unpaired bases |
What is Multilocus Sequence Typing (MLST) |
the seqeuncing and comparison of 5-7 housekeeping genes done to prevent misleading results from analysis of one gene introduced by lateral gene transfer. ** also used for microbial classification and determination of phylogenetic relationships |
| What are restriction enzymes used for? |
· use restriction enzymes to recognize specific nucleotide sequences · repetitive sequences amplified by the polymerase chain reaction o amplified fragments run on agarose gel, with each lane of gel corresponding to one microbial isolate § pattern of bands analyzed by computer |
| Why is amino acid sequencing useful? Which protiens are found useful? |
a.a. sequencing of a protien is a reflections of mRNA seqeunce and therefore of the gene which encodes that protien. [cytochrome, histones, and heatshock proteins provided relevant taxonomic and phylogentic info] |
| What are oligonucleotide signature sequences? |
| short, conserved nucleotide sequences that are specific for a phylogentically defined group of organisms. |
when comparing rRNA sequences between 2 organisms, their relatedness is represented by an associatin coefficient of Sab value, the higher the Sab value…..
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| the more closely related the two organisms are. |
| What is the difference between a "lumper"and a "splitter"...referring to dendograms... |
| splitter thinks that every difference matters and lumpers think organisms at least 92% similar are in one species. |
Who was Carl Linne (Carlus Linnaeus)? |
| He was a physician from swedan who developed the system of classification of plants based on number of stamen and carpels but one of his greatest contributions was the binomial system which we stil use today. |
| What is a colloquial name? |
| It is the informal/common name. We do not used this becuase it is unreliable and miscommicative |
| What are some of the the ways of organisms are named? |
By:
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| What does axenically pure mean? |
| less than 2 species |
| In Indentification..What are some methods of Isolation? |
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| What is the First Biochemical test in Identification? |
Gas Environment (second test in Identification) Are they strict aerobes? microaerophiles? facultative anaerobe? etc? |
| What is the next step in identification after gas enivornment identification? |
Step 3- Microscopic & Macroscopic Mophology Determine colony formation, bacterial shape, on unadulturated organisms (close to orginal environment as possible) |
| What tests are done for the Biochemical Characteristics of Microbial Identification? |
1.Carbohydrate Dissimilation: Fermentation, Voges-Prokauer, and Fermentation and Proteolysis of Milk.
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| In the Carbohydrate Dissimilation test what are the 3 things used in the test for fermentation? |
1. Durham Tube 2. Phenol Red broth base 3. Specific Carbohydrate |
| In the Carbohydrate Dissimilation test what is the voges proskauer determine? |
| Determine the amount of Acetylmethylcarbinal (AMC) using Barrits Reagent |
| In the Carbohydrate Dissimilation test what usually is used and what happens in the fermantation and proteolysis of milk? |
| litmus milk is used and it is a acid reaction with protien precipitation and lipid hydrolysis |
| In proteolysis detection how is the nutrient gelatin test preformed? |
Nutrient broth + 10% gelatin incubated at 20C or 35C (melts at this temp so always read at 20C) read as liquifiers, weak liquifiers, or non liqufiers |
In proteolysis detection How is the gelatin hydrolysis test preformed? |
petri dish with nutrient gelatin, add frazier glacial acetic acid/ HCl-HgCl2 after innoc. and incub. then look for clearing zone
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In proteolysis detection how is the H2S production test performed? |
reduction of thiol(sulfur containing) AAS add Pb or Fe, it will turn black
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In proteolysis detection how is the indole test performed? |
the trytophan will reduce to Indole + pyruciv acid detect indole with Kovacks reagent -n-amyl alcohol -HCl -PABA you will get a red color |
In proteolysis detection how is the nitrate reduction test performed? |
in a liquid media with a peptone to start it. Na, KNO2 (can organisms use nitrate as H acceptor?) |
| Why are serologic characteristics tested for in Indentification of organisms? |
· due to ultrastructure most microorganisms are capable of acting as antigens to the human immune system |
| Why are pathophysiologic characteric tests done in identification? |
even with all the previous test, sometimes the microorganisms still cant be identified so they innoculate an animal (kochs 3rd postulate) issues with this are: time, cost, and space |
| What is Phage testing in Identification of microorganisms? |
-because bacteria are able to have their own parasites, bacteriophages, this test is done **it needs to be narrowed down to 2 bacterias -bc it is very host specific, you place the bacterias in a petri dish, add the bacteriophage that targets one, and if it "eats" the bacteria, the bacteria is host specific for that bacteriophage |
What is DNA probe/Homology in Identification of microorganisms? |
to be able to tell the organisms apart by their DNA -need to have a good idea what you are looking for, a specific reason why -some tests/labs may start with this |
| List, in order of use, the methodologies used in the identification of bacteria: |
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