MCB6424 Probiotics Exam 3
With Complete Solution
Microbiota - ANSWER The microorganisms which include commensal, symbiotic,
pathogenic that exist within an established environment
Microbiome - ANSWER The entire complement of microbes, their genes, and
genomes within a specific environment
200 - ANSWER The gut microbiome contains ___ trillion cells
10 - ANSWER The gut microbiome has ___ times as many cells than human cells
150 - ANSWER The gut microbiome is ___ times larger than the human genome
Colon (10^11-10^12 cfu/mL) - ANSWER Which of the following GI tracts has the
highest density of microbiota?
Stomach and duodenum (10-10^3 cfu/mL) - ANSWER Which of the following GI
tracts 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 w/o 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
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 Type of symbiosis where both benefit from each other, by
living together
E. coli - produce vitamin K in the colon - ANSWER What is a form of mutualism?
Parasitism - ANSWER A symbiotic relationship where one organisms benefits at the
expense of causing harm/damage to the
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 total absence of bacteria in the gut resulted in very
low/defective levels of which 2 things in mice models?
Butyrate - ANSWER Which metabolite is used as energy for gut epithelial cells,
lowers mucosal inflammation, and enhances epithelial barrier function?
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 Type of approach used to study microbiota where
DNA of gut microbiota is extracted, 16S rRNA is amplified/sequenced, grouped into
OTUs, identified based on phylogeny, and further identified based on sequence
databases (BLAST)
Shotgun metagenomic approach - ANSWER Type of approach used to study
microbiota where DNA of gut microbiota is extracted, sequenced, and identified
based on sequence databases (BLAST)
True - ANSWER T/F: the 16S rRNA gene is found in all bacteria and archaea
Conserved regions - ANSWER What type of regions do the primers that amplify 16S
rRNA genes bind to?
Variable region - ANSWER What region would the primers used to amplify 16S rRNA
genes target to obtain?
True - ANSWER T/F: the majority of 16S rRNA sequences have been recovered 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
Metagenomic - ANSWER Which type of sequencing is used to make functional
predictions based on gene CONTENT?
metatranscriptomic ANSWER What kind of sequencing does make functional
With Complete Solution
Microbiota - ANSWER The microorganisms which include commensal, symbiotic,
pathogenic that exist within an established environment
Microbiome - ANSWER The entire complement of microbes, their genes, and
genomes within a specific environment
200 - ANSWER The gut microbiome contains ___ trillion cells
10 - ANSWER The gut microbiome has ___ times as many cells than human cells
150 - ANSWER The gut microbiome is ___ times larger than the human genome
Colon (10^11-10^12 cfu/mL) - ANSWER Which of the following GI tracts has the
highest density of microbiota?
Stomach and duodenum (10-10^3 cfu/mL) - ANSWER Which of the following GI
tracts 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 w/o 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
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 Type of symbiosis where both benefit from each other, by
living together
E. coli - produce vitamin K in the colon - ANSWER What is a form of mutualism?
Parasitism - ANSWER A symbiotic relationship where one organisms benefits at the
expense of causing harm/damage to the
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 total absence of bacteria in the gut resulted in very
low/defective levels of which 2 things in mice models?
Butyrate - ANSWER Which metabolite is used as energy for gut epithelial cells,
lowers mucosal inflammation, and enhances epithelial barrier function?
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 Type of approach used to study microbiota where
DNA of gut microbiota is extracted, 16S rRNA is amplified/sequenced, grouped into
OTUs, identified based on phylogeny, and further identified based on sequence
databases (BLAST)
Shotgun metagenomic approach - ANSWER Type of approach used to study
microbiota where DNA of gut microbiota is extracted, sequenced, and identified
based on sequence databases (BLAST)
True - ANSWER T/F: the 16S rRNA gene is found in all bacteria and archaea
Conserved regions - ANSWER What type of regions do the primers that amplify 16S
rRNA genes bind to?
Variable region - ANSWER What region would the primers used to amplify 16S rRNA
genes target to obtain?
True - ANSWER T/F: the majority of 16S rRNA sequences have been recovered 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
Metagenomic - ANSWER Which type of sequencing is used to make functional
predictions based on gene CONTENT?
metatranscriptomic ANSWER What kind of sequencing does make functional
