Question 1

Biofilms in the human mouth primarily contain pathogens.

Accepted Answer

A) True 
 B)False

Question 2

Bacterial cells themselves serve as major sources of protein and vitamins in hindgut fermenting animals such as rabbits and horses.

Accepted Answer

A) True 
 B)False

Question 3

Due to the close interactions with other organisms,obligate symbionts generally have larger genome sizes compared to other non-symbiotic bacteria.

Accepted Answer

A) True 
 B)False

Question 4

Two main symbionts of termites are ________ and ________.

Accepted Answer

A) archaea / bacteria 
B) bacteria / fungi 
C) bacteria / protists 
D) fungi / protists 
A) archaea / bacteria 
B) bacteria / fungi 
C) bacteria / protists 
D) fungi / protists

Question 5

The mycelia of mycorrhizae can form underground nutrient networks where several trees are connected.

Accepted Answer

A) True 
 B)False

Question 6

The most heavily colonized human organ by bacteria is the ________,containing 10¹¹-10¹² bacterial cells per g.

Accepted Answer

A) mouth 
B) small intestine 
C) large intestine 
D) skin 
A) mouth 
B) small intestine 
C) large intestine 
D) skin

Question 7

During the Jurassic Period,several different mammalian lineages independently evolved an herbivorous lifestyle for obtaining energy.This has resulted in

Accepted Answer

A) different digestive patterns in herbivorous animals,some that depend on gut microbiota to digest plant material and some that do not. 
B) different digestive patterns in herbivorous animals that all depend on gut microbiota to digest plant material. 
C) the evolution of foregut fermentation,as seen in ruminants,as the only digestive pattern that depends on fermentative gut microbiota. 
D) horizontal gene transfer of genes for glycoside hydrolases and polysaccharide lyases from bacteria to mammals. 
A) different digestive patterns in herbivorous animals,some that depend on gut microbiota to digest plant material and some that do not. 
B) different digestive patterns in herbivorous animals that all depend on gut microbiota to digest plant material. 
C) the evolution of foregut fermentation,as seen in ruminants,as the only digestive pattern that depends on fermentative gut microbiota. 
D) horizontal gene transfer of genes for glycoside hydrolases and polysaccharide lyases from bacteria to mammals.

Question 8

Coral bleaching is primarily caused by antimicrobials that disrupt the mutualistic relationships formed between corals and their bacterial symbionts.

Accepted Answer

A) True 
 B)False

Question 9

Bacteroids are rarely found within plant cells.

Accepted Answer

A) True 
 B)False

Question 10

The microbiome contains all

Accepted Answer

A) organisms present on the skin. 
B) organisms within the digestive system. 
C) organisms present in and on the body. 
D) organisms present on the skin and in the digestive system. 
A) organisms present on the skin. 
B) organisms within the digestive system. 
C) organisms present in and on the body. 
D) organisms present on the skin and in the digestive system.

Question 11

A mutant of Rhizobium leguminosarum is able to survive and reproduce in the laboratory outside of plant roots,but can no longer initiate root nodule formation.What type of genes are most likely mutated in this mutant?

Accepted Answer

A) rhz genes 
B) myc genes 
C) nif genes 
D) nod genes 
A) rhz genes 
B) myc genes 
C) nif genes 
D) nod genes

Question 12

Plant diversity is generally lower in environments where mycorrhizae are associated with plants due to strong coevolution,which leads to competitive exclusion.

Accepted Answer

A) True 
 B)False

Question 13

Ruminants digest bacterial cells as a primary source of

Accepted Answer

A) carbohydrates. 
B) vitamins and proteins. 
C) proteins. 
D) vitamins. 
A) carbohydrates. 
B) vitamins and proteins. 
C) proteins. 
D) vitamins.

Question 14

Why was Escherichia coli thought to be a dominant member of the human gut microbial community in the past? What populations ARE important in the human gut and what evidence do we have that the specific bacteria present are important for human health?

Accepted Answer

Escherichia coli was thought to be a dom

Question 15

How do Hawaiian bobtail squids prevent all bacteria except Allivibrio fischeri from colonizing their light organ?

Accepted Answer

Firstly,the mucus produced in the light

Question 16

Leguminous plants such as alfalfa,beans,clover,peas,and soybeans all benefit from symbiotic bacteria that leach vitamins into the plant roots.

Accepted Answer

A) True 
 B)False

Question 17

The following quote is taken from a university extension publication for farmers:
"Grain poisoning,also known as grain overload or lactic acidosis,is usually the result of stock consuming large quantities of grain or pellets to which they are unaccustomed.Pasture-fed cows or feedlot cattle not yet adapted to grain may become acutely ill or die after eating only moderate amounts of grain,whereas stock accustomed to diets high in grain content may consume large amounts of grain with little or no effect."
What is happening in the digestive system of the livestock that causes grain poisoning and why does a gradual shift in diet avoid this problem?

Accepted Answer

A major shift in diet,where the rumen fl

Question 18

Horizontal gene transfer between host organisms and their symbionts

Accepted Answer

A) happens frequently because of coevolution. 
B) causes genome reduction in the symbiont and genome expansion in the host. 
C) causes genome reduction in both the host and the symbiont. 
D) has been observed,but is considered a rare event. 
A) happens frequently because of coevolution. 
B) causes genome reduction in the symbiont and genome expansion in the host. 
C) causes genome reduction in both the host and the symbiont. 
D) has been observed,but is considered a rare event.

Question 19

How do arbuscular mycorrhizae (AM)help plants obtain more nutrients from the soil?

Accepted Answer

A) Byproducts of AM metabolism serve as primary nutrient sources for the plants. 
B) The AM increase the total surface area to absorb more nutrients. 
C) The hyphae develop as specialized nodules that directly produce nutrients for the plant. 
D) Signaling molecules in the plant are passed to the AM to initiate electron flow,which is in turn used to create ATP. 
A) Byproducts of AM metabolism serve as primary nutrient sources for the plants. 
B) The AM increase the total surface area to absorb more nutrients. 
C) The hyphae develop as specialized nodules that directly produce nutrients for the plant. 
D) Signaling molecules in the plant are passed to the AM to initiate electron flow,which is in turn used to create ATP.

Question 20

The specificity of certain rhizobia to infect only particular plants is in part due to the

Accepted Answer

A) abundance of nutrients present in the soil. 
B) nifH genes they possess. 
C) rhizobial lipids that act as signaling molecules. 
D) season (time of year). 
A) abundance of nutrients present in the soil. 
B) nifH genes they possess. 
C) rhizobial lipids that act as signaling molecules. 
D) season (time of year).

Exam 22: Microbial Symbioses

Biofilms in the human mouth primarily contain pathogens.

Bacterial cells themselves serve as major sources of protein and vitamins in hindgut fermenting animals such as rabbits and horses.

Due to the close interactions with other organisms,obligate symbionts generally have larger genome sizes compared to other non-symbiotic bacteria.

Two main symbionts of termites are ________ and ________.

The mycelia of mycorrhizae can form underground nutrient networks where several trees are connected.

The most heavily colonized human organ by bacteria is the ________,containing 10¹¹-10¹² bacterial cells per g.

During the Jurassic Period,several different mammalian lineages independently evolved an herbivorous lifestyle for obtaining energy.This has resulted in

Coral bleaching is primarily caused by antimicrobials that disrupt the mutualistic relationships formed between corals and their bacterial symbionts.

Bacteroids are rarely found within plant cells.

The microbiome contains all

A mutant of Rhizobium leguminosarum is able to survive and reproduce in the laboratory outside of plant roots,but can no longer initiate root nodule formation.What type of genes are most likely mutated in this mutant?

Plant diversity is generally lower in environments where mycorrhizae are associated with plants due to strong coevolution,which leads to competitive exclusion.

Ruminants digest bacterial cells as a primary source of

Why was Escherichia coli thought to be a dominant member of the human gut microbial community in the past? What populations ARE important in the human gut and what evidence do we have that the specific bacteria present are important for human health?

How do Hawaiian bobtail squids prevent all bacteria except Allivibrio fischeri from colonizing their light organ?

Leguminous plants such as alfalfa,beans,clover,peas,and soybeans all benefit from symbiotic bacteria that leach vitamins into the plant roots.

Horizontal gene transfer between host organisms and their symbionts

How do arbuscular mycorrhizae (AM)help plants obtain more nutrients from the soil?

The specificity of certain rhizobia to infect only particular plants is in part due to the

Microorganisms and Microbiology

Microbial Cell Structure and Function

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Molecular Biology

Microbial Growth and Control

Microbial Genomics

Metabolic Regulation

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Viral Genomes and Diversity

Genetics of Bacteria and Archaea

Genetic Engineering and Biotechnology

Microbial Evolution and Systematics

Metabolic Diversity of Microorganisms

Functional Diversity of Bacteria

Diversity of Bacteria

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Diversity of Eukaryotic Microorganisms

Methods in Microbial Ecology

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Microbiology of the Built Environment

Microbial Interactions With Humans

Immunity and Host Defense

Immune Mechanisms

Molecular Immunology

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Person-To-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

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Two main symbionts of termites are and .