MIC205A Exam 4 2025/2026 Exam
Questions with 100% Correct Answers |
Latest Update
Dancing with Microbes - 🧠 ANSWER ✔✔-Microbes are ubiquitous
-Microbes are breathed in, ingested, and picked up on skin
-Most do not harm us, many are beneficial
-Some colonize on skin and mucous membrane, most ingested microbes
die in stomach or excreted
-Some shed with dead epithelial cells
-Relatively few microbes evade defense and cause diseases -> distinct
characteristics allow avoidance of some body defenses
Normal microbiota - 🧠 ANSWER ✔✔-Not harmful
-Organisms that routinely reside on body's surfaces
-Relationship is delicate balance; some can cause disease if there is an
opportunity (weakness or defects n innate or adaptive defenses can leave
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PRIVACY STATEMENT. ALL RIGHTS RESERVED
,individuals vulnerable to invasion -> malnutrition, cancer, AIDS or other
disease, surgery, wounds, genetic defects, alcohol or drug abuse, and
immunosuppressive therapy)
-Permanently colonize the host
Symbiosis - 🧠 ANSWER ✔✔-Different organisms living together
-Mutualism - 🧠 ANSWER ✔✔-Kind of symbiosis
-Both partners benefit
-Example: in large intestine, some bacteria synthesize vitamin K and B
vitamins, which host can absorb; bacteria are supplied with warmth, energy
sources
Commensalism - 🧠 ANSWER ✔✔-Kind of symbiosis
-One partner benefits without harming the other partner
-Many microbes living on skin neither harmful nor helpful, but obtain food
and necessities from host
Parasitism - 🧠 ANSWER ✔✔-Type of symbiosis
-One organism benefits at expense of other
COPYRIGHT©BLAIRALISTERNEWTON 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
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PRIVACY STATEMENT. ALL RIGHTS RESERVED
,-All pathogens are parasites, but medical microbiologists often reserve for
eukaryotic pathogens (for example, protozoa, helminths)
Opportunistic pathogens - 🧠 ANSWER ✔✔-Take advantage of weakened
immune system
Microbiota/Microbiome - 🧠 ANSWER ✔✔-A collection of microbes in a
given ecological niche
-Important to human health
-Relatively little is known
-Human Microbiome Project studying microbiota using metagenomics,
analysis of DNA without culturing
Transient microbiota - 🧠 ANSWER ✔✔-May be present for days, weeks, or
months
-Inhabit temporarily
Composition of the Normal Microbiota - 🧠 ANSWER ✔✔-37 trillion human
cells
-100 trillion bacteria, 70-80% non-culturable
COPYRIGHT©BLAIRALISTERNEWTON 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
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PRIVACY STATEMENT. ALL RIGHTS RESERVED
, -Estimated bacterial species: 5,000-35,000 in intestine, 300-500 in mouth,
120 species on skin
-160-fold more gene in gut microbiome than in human genome
-We get our microbiomes at birth, during breast feeding, and from food and
the environment
-Obese people have more Firmicutes while lean people have more
Bacteroides
-Weight loss changes microbiota to resemble that of lean people
-Composition different among individuals and over time
-Changes with physiological state and life style of host
Normal Microbiota and Your Health - 🧠 ANSWER ✔✔-Microbial antagonism
or competitive exclusion: occupying sites of attachment; nutrient
competition; antibiotic compounds (bacteriocins); alter environment (lower
pH)
-Training adaptive immune system (hygiene hypothesis): activate B and T
cells; develop tolerance to routine microbes in guts, food, and on other
mucosal membranes -> insufficient exposure to microbes leads to allergies;
COPYRIGHT©BLAIRALISTERNEWTON 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
4
PRIVACY STATEMENT. ALL RIGHTS RESERVED
Questions with 100% Correct Answers |
Latest Update
Dancing with Microbes - 🧠 ANSWER ✔✔-Microbes are ubiquitous
-Microbes are breathed in, ingested, and picked up on skin
-Most do not harm us, many are beneficial
-Some colonize on skin and mucous membrane, most ingested microbes
die in stomach or excreted
-Some shed with dead epithelial cells
-Relatively few microbes evade defense and cause diseases -> distinct
characteristics allow avoidance of some body defenses
Normal microbiota - 🧠 ANSWER ✔✔-Not harmful
-Organisms that routinely reside on body's surfaces
-Relationship is delicate balance; some can cause disease if there is an
opportunity (weakness or defects n innate or adaptive defenses can leave
COPYRIGHT©BLAIRALISTERNEWTON 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
1
PRIVACY STATEMENT. ALL RIGHTS RESERVED
,individuals vulnerable to invasion -> malnutrition, cancer, AIDS or other
disease, surgery, wounds, genetic defects, alcohol or drug abuse, and
immunosuppressive therapy)
-Permanently colonize the host
Symbiosis - 🧠 ANSWER ✔✔-Different organisms living together
-Mutualism - 🧠 ANSWER ✔✔-Kind of symbiosis
-Both partners benefit
-Example: in large intestine, some bacteria synthesize vitamin K and B
vitamins, which host can absorb; bacteria are supplied with warmth, energy
sources
Commensalism - 🧠 ANSWER ✔✔-Kind of symbiosis
-One partner benefits without harming the other partner
-Many microbes living on skin neither harmful nor helpful, but obtain food
and necessities from host
Parasitism - 🧠 ANSWER ✔✔-Type of symbiosis
-One organism benefits at expense of other
COPYRIGHT©BLAIRALISTERNEWTON 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
2
PRIVACY STATEMENT. ALL RIGHTS RESERVED
,-All pathogens are parasites, but medical microbiologists often reserve for
eukaryotic pathogens (for example, protozoa, helminths)
Opportunistic pathogens - 🧠 ANSWER ✔✔-Take advantage of weakened
immune system
Microbiota/Microbiome - 🧠 ANSWER ✔✔-A collection of microbes in a
given ecological niche
-Important to human health
-Relatively little is known
-Human Microbiome Project studying microbiota using metagenomics,
analysis of DNA without culturing
Transient microbiota - 🧠 ANSWER ✔✔-May be present for days, weeks, or
months
-Inhabit temporarily
Composition of the Normal Microbiota - 🧠 ANSWER ✔✔-37 trillion human
cells
-100 trillion bacteria, 70-80% non-culturable
COPYRIGHT©BLAIRALISTERNEWTON 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
3
PRIVACY STATEMENT. ALL RIGHTS RESERVED
, -Estimated bacterial species: 5,000-35,000 in intestine, 300-500 in mouth,
120 species on skin
-160-fold more gene in gut microbiome than in human genome
-We get our microbiomes at birth, during breast feeding, and from food and
the environment
-Obese people have more Firmicutes while lean people have more
Bacteroides
-Weight loss changes microbiota to resemble that of lean people
-Composition different among individuals and over time
-Changes with physiological state and life style of host
Normal Microbiota and Your Health - 🧠 ANSWER ✔✔-Microbial antagonism
or competitive exclusion: occupying sites of attachment; nutrient
competition; antibiotic compounds (bacteriocins); alter environment (lower
pH)
-Training adaptive immune system (hygiene hypothesis): activate B and T
cells; develop tolerance to routine microbes in guts, food, and on other
mucosal membranes -> insufficient exposure to microbes leads to allergies;
COPYRIGHT©BLAIRALISTERNEWTON 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
4
PRIVACY STATEMENT. ALL RIGHTS RESERVED
