PROBIOTICS MCB6424 EXAM 3 QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
LATEST UPDATE
Microbiota
The microorganisms (commensal, symbiotic, and pathogenic) that live in an established
environment
Microbiome
The full complement of microbes, their genes, and genomes in a particular environment
200
The gut microbiome contains ___ trillion cells
10
The gut microbiome has __ times the number of human cells
150
The gut microbiome is ___ times larger than the human genome
Colon (10^11-10^12 cfu/mL)
Which part of the GI tract has the highest density of microbiota?
Stomach and duodenum (10-10^3 cfu/mL)
Which part of the GI tract has the lowest density of microbiota?
True
T/F: the gut microbiota is generally non-pathogenic
,1-3%
The gut microbiota is __% of our total body mass
True (this concept is has changed recently)
T/F: humans and animals are usually germfree in utero
Normal microbiota
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
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
The long-term interaction between 2+ different biological species; "living together;" 3
types: commensalism, mutualism, and parasitism
Commensalism
The type of symbiosis in which one organism benefits and the other is unaffected
Mycobacteria (in the ear)
What is an example of commensalism?
Mutualism
The type of symbiosis in which both organisms benefit from living together
E. coli (synthesize vitamin K in the colon)
What is an example of mutualism?
Parasitism
, 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
What is an example of parasitism?
Oppostunistic pathogen
Which type of pathogen only causes disease under special circumstances (and
normally are not harmful in their natural environment)?
S. pneumoniae and E. coli
What are 2 examples of opportunistic pathogens?
IgA and GALT
The complete absence of bacteria in the gut (mice models) resulted in very
low/defective levels of which 2 things?
Butyrate
Which metabolite is used as energy for gut epithelial cells, lowers mucosal
inflammation, and strengthens epithelial barrier function?
Acetate and propionate
Which 2 metabolites are used for lipogenesis and gluconeogenesis in the host's gut?
10 million
How many prokaryotic species are there estimated to be?
Operational taxonomic unit (OTU)
A term used to categorize bacteria based on sequence similarity (97% rRNA gene
sequence identity)
16S-based approach
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
LATEST UPDATE
Microbiota
The microorganisms (commensal, symbiotic, and pathogenic) that live in an established
environment
Microbiome
The full complement of microbes, their genes, and genomes in a particular environment
200
The gut microbiome contains ___ trillion cells
10
The gut microbiome has __ times the number of human cells
150
The gut microbiome is ___ times larger than the human genome
Colon (10^11-10^12 cfu/mL)
Which part of the GI tract has the highest density of microbiota?
Stomach and duodenum (10-10^3 cfu/mL)
Which part of the GI tract has the lowest density of microbiota?
True
T/F: the gut microbiota is generally non-pathogenic
,1-3%
The gut microbiota is __% of our total body mass
True (this concept is has changed recently)
T/F: humans and animals are usually germfree in utero
Normal microbiota
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
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
The long-term interaction between 2+ different biological species; "living together;" 3
types: commensalism, mutualism, and parasitism
Commensalism
The type of symbiosis in which one organism benefits and the other is unaffected
Mycobacteria (in the ear)
What is an example of commensalism?
Mutualism
The type of symbiosis in which both organisms benefit from living together
E. coli (synthesize vitamin K in the colon)
What is an example of mutualism?
Parasitism
, 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
What is an example of parasitism?
Oppostunistic pathogen
Which type of pathogen only causes disease under special circumstances (and
normally are not harmful in their natural environment)?
S. pneumoniae and E. coli
What are 2 examples of opportunistic pathogens?
IgA and GALT
The complete absence of bacteria in the gut (mice models) resulted in very
low/defective levels of which 2 things?
Butyrate
Which metabolite is used as energy for gut epithelial cells, lowers mucosal
inflammation, and strengthens epithelial barrier function?
Acetate and propionate
Which 2 metabolites are used for lipogenesis and gluconeogenesis in the host's gut?
10 million
How many prokaryotic species are there estimated to be?
Operational taxonomic unit (OTU)
A term used to categorize bacteria based on sequence similarity (97% rRNA gene
sequence identity)
16S-based approach
