Probiotics MCB6424 Exam 3 Questions With Complete Solutions
Microbiota - (ANSWER)The microorganisms (commensal, symbiotic, and pathogenic) that live in an
established environment
Microbiome - (ANSWER)The full complement of microbes, their genes, and genomes in a particular
environment
200 - (ANSWER)The gut microbiome contains ___ trillion cells
10 - (ANSWER)The gut microbiome has __ times the number of human cells
150 - (ANSWER)The gut microbiome is ___ times larger than the human genome
Colon (10^11-10^12 cfu/mL) - (ANSWER)Which part of the GI tract has the highest density of
microbiota?
Stomach and duodenum (10-10^3 cfu/mL) - (ANSWER)Which part of the GI tract has the lowest density
of microbiota?
True - (ANSWER)T/F: the gut microbiota is generally non-pathogenic
1-3% - (ANSWER)The gut microbiota is __% of our total body mass
True (this concept is has changed recently) - (ANSWER)T/F: humans and animals are usually germfree in
utero
Normal microbiota - (ANSWER)The type of microbiota that establish permanent colonies inside/on the
body without producing disease; ex: Staphylococcus (skin/mucous membranes) and E. coli (colon); live
in symbiosis with the host
Transient microbiota - (ANSWER)The type of microbiota that are present for various periods of time and
then disappear because the host's defenses don't allow them to become permanent
,Probiotics MCB6424 Exam 3 Questions With Complete Solutions
Symbiosis - (ANSWER)The long-term interaction between 2+ different biological species; "living
together;" 3 types: commensalism, mutualism, and parasitism
Commensalism - (ANSWER)The type of symbiosis in which one organism benefits and the other is
unaffected
Mycobacteria (in the ear) - (ANSWER)What is an example of commensalism?
Mutualism - (ANSWER)The type of symbiosis in which both organisms benefit from living together
E. coli (synthesize vitamin K in the colon) - (ANSWER)What is an example of mutualism?
Parasitism - (ANSWER)The type of symbiosis in which one organisms benefits at the expense of the
other by causing harm/damage
Any pathogenic bacteria in the body - (ANSWER)What is an example of parasitism?
Oppostunistic pathogen - (ANSWER)Which type of pathogen only causes disease under special
circumstances (and normally are not harmful in their natural environment)?
S. pneumoniae and E. coli - (ANSWER)What are 2 examples of opportunistic pathogens?
IgA and GALT - (ANSWER)The complete absence of bacteria in the gut (mice models) resulted in very
low/defective levels of which 2 things?
Butyrate - (ANSWER)Which metabolite is used as energy for gut epithelial cells, lowers mucosal
inflammation, and strengthens epithelial barrier function?
, Probiotics MCB6424 Exam 3 Questions With Complete Solutions
Acetate and propionate - (ANSWER)Which 2 metabolites are used for lipogenesis and gluconeogenesis
in the host's gut?
10 million - (ANSWER)How many prokaryotic species are there estimated to be?
Operational taxonomic unit (OTU) - (ANSWER)A term used to categorize bacteria based on sequence
similarity (97% rRNA gene sequence identity)
16S-based approach - (ANSWER)The type of method for studying microbiota in which the gut microbiota
DNA is extracted, the 16S rRNA is amplified/sequenced, grouped into OTUs, identified based on
phylogeny, and further identified based on sequence databases (BLAST)
Shotgun metagenomic approach - (ANSWER)The type of method for studying microbiota in which the
gut microbiota DNA is extracted, sequenced, and identified based on sequence databases (BLAST)
True - (ANSWER)T/F: the 16S rRNA gene is present in all bacteria and archaea
Conserved regions - (ANSWER)The primers used to amplify 16S rRNA genes attach to which regions?
Variable region - (ANSWER)The primers used to amplify 16S rRNA genes target which region for
amplification
True - (ANSWER)T/F: most 16S rRNA sequences come from previously undescribed microbes
False - (ANSWER)T/F: strains of the same species always have the same phenotype and functional
capabilities
True - (ANSWER)T/F: many genomes have nearly-identical copies of 16S rRNA operons
True - (ANSWER)T/F: conservation of the 16S gene sequence can mask sequence diversity in the rest of
the genome
Microbiota - (ANSWER)The microorganisms (commensal, symbiotic, and pathogenic) that live in an
established environment
Microbiome - (ANSWER)The full complement of microbes, their genes, and genomes in a particular
environment
200 - (ANSWER)The gut microbiome contains ___ trillion cells
10 - (ANSWER)The gut microbiome has __ times the number of human cells
150 - (ANSWER)The gut microbiome is ___ times larger than the human genome
Colon (10^11-10^12 cfu/mL) - (ANSWER)Which part of the GI tract has the highest density of
microbiota?
Stomach and duodenum (10-10^3 cfu/mL) - (ANSWER)Which part of the GI tract has the lowest density
of microbiota?
True - (ANSWER)T/F: the gut microbiota is generally non-pathogenic
1-3% - (ANSWER)The gut microbiota is __% of our total body mass
True (this concept is has changed recently) - (ANSWER)T/F: humans and animals are usually germfree in
utero
Normal microbiota - (ANSWER)The type of microbiota that establish permanent colonies inside/on the
body without producing disease; ex: Staphylococcus (skin/mucous membranes) and E. coli (colon); live
in symbiosis with the host
Transient microbiota - (ANSWER)The type of microbiota that are present for various periods of time and
then disappear because the host's defenses don't allow them to become permanent
,Probiotics MCB6424 Exam 3 Questions With Complete Solutions
Symbiosis - (ANSWER)The long-term interaction between 2+ different biological species; "living
together;" 3 types: commensalism, mutualism, and parasitism
Commensalism - (ANSWER)The type of symbiosis in which one organism benefits and the other is
unaffected
Mycobacteria (in the ear) - (ANSWER)What is an example of commensalism?
Mutualism - (ANSWER)The type of symbiosis in which both organisms benefit from living together
E. coli (synthesize vitamin K in the colon) - (ANSWER)What is an example of mutualism?
Parasitism - (ANSWER)The type of symbiosis in which one organisms benefits at the expense of the
other by causing harm/damage
Any pathogenic bacteria in the body - (ANSWER)What is an example of parasitism?
Oppostunistic pathogen - (ANSWER)Which type of pathogen only causes disease under special
circumstances (and normally are not harmful in their natural environment)?
S. pneumoniae and E. coli - (ANSWER)What are 2 examples of opportunistic pathogens?
IgA and GALT - (ANSWER)The complete absence of bacteria in the gut (mice models) resulted in very
low/defective levels of which 2 things?
Butyrate - (ANSWER)Which metabolite is used as energy for gut epithelial cells, lowers mucosal
inflammation, and strengthens epithelial barrier function?
, Probiotics MCB6424 Exam 3 Questions With Complete Solutions
Acetate and propionate - (ANSWER)Which 2 metabolites are used for lipogenesis and gluconeogenesis
in the host's gut?
10 million - (ANSWER)How many prokaryotic species are there estimated to be?
Operational taxonomic unit (OTU) - (ANSWER)A term used to categorize bacteria based on sequence
similarity (97% rRNA gene sequence identity)
16S-based approach - (ANSWER)The type of method for studying microbiota in which the gut microbiota
DNA is extracted, the 16S rRNA is amplified/sequenced, grouped into OTUs, identified based on
phylogeny, and further identified based on sequence databases (BLAST)
Shotgun metagenomic approach - (ANSWER)The type of method for studying microbiota in which the
gut microbiota DNA is extracted, sequenced, and identified based on sequence databases (BLAST)
True - (ANSWER)T/F: the 16S rRNA gene is present in all bacteria and archaea
Conserved regions - (ANSWER)The primers used to amplify 16S rRNA genes attach to which regions?
Variable region - (ANSWER)The primers used to amplify 16S rRNA genes target which region for
amplification
True - (ANSWER)T/F: most 16S rRNA sequences come from previously undescribed microbes
False - (ANSWER)T/F: strains of the same species always have the same phenotype and functional
capabilities
True - (ANSWER)T/F: many genomes have nearly-identical copies of 16S rRNA operons
True - (ANSWER)T/F: conservation of the 16S gene sequence can mask sequence diversity in the rest of
the genome
