37 Questions
What criteria must two organisms meet to be considered the same species based on molecular techniques?
>98.7% 16S rRNA identity AND >70% DDH
How are new organisms that cannot be cultured typically characterized?
Via molecular techniques like 16S rRNA sequencing
Which organizations are responsible for accepting and reporting new species in microbiology?
International Union of Microbiological Societies (IUMS) and International Committee on Systematics of Prokaryotes (ICSP)
What is the general correlation between 16S rRNA identities and amino acid identity (AAI) when comparing genomes?
General, but not perfect, correlation
What is the main reason for the revolutionary changes in eucaryotic microbe taxonomy mentioned in the text?
Adoption of molecular phylogenetics
Why do some influential eucaryal taxonomists refuse to discard historical groupings, even if they are proven to be polyphyletic?
Bias towards genealogical taxonomy
What concept do some eucaryotic taxonomists try to retain despite lack of evidence, as mentioned in the text?
Eucaryotes evolving from procaryotes
Which taxonomy method is now mostly used for eucaryal taxonomy based on the text?
Molecular phylogenetic analyses using SSU RNA sequences
What is the approximate number of accepted (cultured) phylogenetic divisions of Bacteria?
~41
How many candidate phyla are there in the Candidate Phyla Radiation (CPR)?
Around 70
What is the main criticism of some eucaryotic taxonomists towards the three Domain organization?
Refusal to accept it despite evidence
Are the total number of bacterial phyla estimated to be around 1000?
No, more than 100
How do many 'candidate' phyla contain no cultured species?
All of them
Considering the diversity of Bacteria, how far apart are some of the bacterial phyla evolutionarily?
As far apart as Animal and Plant kingdoms
Why is it impossible to have both five kingdoms and two kingdoms simultaneously?
They are artificial taxonomies.
What did the finding that Archaea are phylogenetically distinct from Bacteria indicate?
Monera is an artificial taxon.
Why was the Three Domain organization proposed by Woese considered significant?
It eliminated polyphyletic taxa.
What did the absence of a unifying definition of 'procaryote' lead to?
Difficulty in differentiating procaryotes from eucaryotes.
What prompted the need for the proposal of the Three Domains?
'Archaebacteria' being unrelated to other organisms.
What is the significance of 16S rRNA in species identification techniques?
It is used for molecular sequencing and comparison, aiding in species identification.
What did Woese propose in 1977 regarding bacteria?
There are two types of bacteria: Eubacteria and Archaebacteria.
What was the main reason for the confusion regarding the division of life forms according to Whittaker's Five Kingdoms model?
The inclusion of Moneres without a clear definition.
How did traditional microbial taxonomy differ from Woese's approach based on gene sequence comparisons?
Traditional taxonomy relied on cytology, morphology, and physiology.
What was the main challenge in defining what a bacterium (or procaryote) is?
The impossibility to define it in a taxonomically-sound fashion.
What does Norman Pace suggest about the term 'procaryotic'?
It should only be used historically due to its confusing nature.
Which of the following is a characteristic shared by the Three Domains Archaea, Bacteria, and Eucarya?
Use of methionine as the initiator tRNA amino acid
What does Ignicoccus hospitalis possess that suggests similarity to a nucleus?
Inner membrane compartment where DNA is found
Why might the term 'procaryotic' be misleading in a modern context?
'Taxonomic baggage' associated with the term
Which domain has multiple linear chromosomes as opposed to 'procaryotes'?
Eucarya
What is one reason TM7 was initially considered uncultivated?
No one was able to isolate TM7 cells for a decade.
Why was Candidatus Microgenomatus auricola SCGC AAA011-E14 significant?
It was obtained from a single tiny cell using microfluidic techniques.
Which technique was used to process the VERY TINY single cell ZG1 for obtaining partial genome sequence?
Microfluidic techniques
What distinguished TM7 as only the fourth known Gram-positive group?
Visual confirmation via microscopy prior to cultivation success
Why were cultures of TM7 isolated in 2014 considered no longer uncultivated?
They were successfully isolated after a decade of attempts.
What distinguishes Saccharibacteria (formerly TM7) and Microgenomates (formerly OP11) phyla?
Saccharibacteria have been isolated, unlike Microgenomates.
What made candidate phylum OP11 unique before its renaming as Microgenomates?
It was diverse and found globally.
'Candidatus Microgenomatus auricola SCGC AAA011-E14' refers to:
'Candidatus' status given to newly discovered bacteria.
Explore the key characteristics of the Three Domains: Archaea, Bacteria, and Eucarya. This quiz delves into membrane-bound organelles, presence of nuclear membrane, and cell wall composition among other distinguishing features.
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