Question 1

The Archaea are

Accepted Answer

A) primarily ancient organisms that have not evolved very much in the last billion years. 
B) phylogenetically diverse,but functionally restricted to extremophiles and chemolithotrophs. 
C) diverse microorganisms that inhabit almost every environment on Earth,including the colon of humans and other mammals. 
D) functionally diverse,but restricted to thermophilic or hyperthermophilic environments. 
A) primarily ancient organisms that have not evolved very much in the last billion years. 
B) phylogenetically diverse,but functionally restricted to extremophiles and chemolithotrophs. 
C) diverse microorganisms that inhabit almost every environment on Earth,including the colon of humans and other mammals. 
D) functionally diverse,but restricted to thermophilic or hyperthermophilic environments.

Question 2

Most known methanogens are nonhalophilic

Accepted Answer

A) psychrophiles. 
B) mesophiles. 
C) thermophiles. 
D) extremophiles (at either the psychrophilic or thermophilic end). 
A) psychrophiles. 
B) mesophiles. 
C) thermophiles. 
D) extremophiles (at either the psychrophilic or thermophilic end).

Question 3

Despite GC pairs having an additional hydrogen bond than AT pairs,hyperthermophilic Archaea generally have a lower GC ratio in their genomes when compared to other heat-sensitive prokaryotes.

Accepted Answer

A) True 
 B)False

Question 4

While many Archaea are bacilli or cocci,unusual morphologies such as square,flattened and irregular discs have also been identified in certain species.

Accepted Answer

A) True 
 B)False

Question 5

The bioenergetics of anaerobic respiring Archaea such as those of the Crenarchaeota involve ________ from which ________ is synthesized.

Accepted Answer

A) proton translocation / ATP 
B) substrate level phosphorylation / ATP 
C) sodium translocation / ATP 
D) substrate level phosphorylation / GTP 
A) proton translocation / ATP 
B) substrate level phosphorylation / ATP 
C) sodium translocation / ATP 
D) substrate level phosphorylation / GTP

Question 6

Some strains of haloarchaea exhibit

Accepted Answer

A) anoxic growth at the expense of sugar fermentation. 
B) anaerobic respiration. 
C) anoxygenic photosynthesis. 
D) light-driven ATP synthesis under oxygen-limiting conditions. 
A) anoxic growth at the expense of sugar fermentation. 
B) anaerobic respiration. 
C) anoxygenic photosynthesis. 
D) light-driven ATP synthesis under oxygen-limiting conditions.

Question 7

What is thought to be the maximum temperature for life to exist?

Accepted Answer

A) 125°C 
B) 150°C 
C) 250°C 
D) 500°C 
A) 125°C 
B) 150°C 
C) 250°C 
D) 500°C

Question 8

What makes the metabolism of Ferroglobus interesting in the context of evolution?

Accepted Answer

A) Ferroglobus is an anaerobic iron-oxidizing chemolithotrophic autotroph that may represent a key metabolism that allowed for the oxidation of ferrous iron without molecular oxygen. 
B) Ferroglobus can use H₂ or H₂S as electron donors in its energy metabolism and is thermophilic,thus representing the earliest hypothesized forms of life. 
C) Ferroglobus lacks cells wall and becomes encrusted in oxidized iron. 
D) Ferroglobus is both an iron- and nitrate-reducer and is probably the last common ancestor of all iron- and nitrate-reducing organisms. 
A) Ferroglobus is an anaerobic iron-oxidizing chemolithotrophic autotroph that may represent a key metabolism that allowed for the oxidation of ferrous iron without molecular oxygen. 
B) Ferroglobus can use H₂ or H₂S as electron donors in its energy metabolism and is thermophilic,thus representing the earliest hypothesized forms of life. 
C) Ferroglobus lacks cells wall and becomes encrusted in oxidized iron. 
D) Ferroglobus is both an iron- and nitrate-reducer and is probably the last common ancestor of all iron- and nitrate-reducing organisms.

Question 9

Describe two mechanisms that Archaea use to avoid their DNA melting at temperatures above 100°C.

Accepted Answer

The answer of Describe two mechanisms that Archaea use to...

Question 10

The microorganisms that are thought to resemble the first cellular forms of life on Earth are

Accepted Answer

A) H₂-oxidizing hyperthermophiles. 
B) acidophilic Archaea. 
C) the Nanoarchaeota. 
D) fermentative thermophiles. 
A) H₂-oxidizing hyperthermophiles. 
B) acidophilic Archaea. 
C) the Nanoarchaeota. 
D) fermentative thermophiles.

Question 11

In chemolithotrophic Archaea,H₂ is a common electron donor.

Accepted Answer

A) True 
 B)False

Question 12

What makes the lifestyle and genome of Nanoarchaeum equitans unique?

Accepted Answer

N.equitans is the only identified intrac

Question 13

What special adaptation(s)has/have Thermoplasma evolved to survive in hot acidic environments?

Accepted Answer

A) Thermoplasma stabilize their cytoplasmic membrane by incorporation of tetraether lipoglycans in the cytoplasmic membrane. 
B) Thermoplasma have a reinforced cell wall containing basic amino linkers in the peptidoglycan. 
C) Thermoplasma excrete hydrogen ions and import hydroxyl ions. 
D) Thermoplasma are highly motile to avoid destruction. 
A) Thermoplasma stabilize their cytoplasmic membrane by incorporation of tetraether lipoglycans in the cytoplasmic membrane. 
B) Thermoplasma have a reinforced cell wall containing basic amino linkers in the peptidoglycan. 
C) Thermoplasma excrete hydrogen ions and import hydroxyl ions. 
D) Thermoplasma are highly motile to avoid destruction.

Question 14

Most halobacteria are motile by means of lophotrichous flagella.

Accepted Answer

A) True 
 B)False

Question 15

Archaeal histones assist in maintaining the DNA in a double-stranded form at very high temperatures in species of Euryarchaeota.

Accepted Answer

A) True 
 B)False

Question 16

Archaea is divided into three phyla.

Accepted Answer

A) True 
 B)False

Question 17

The cytoplasmic membrane of Thermoplasma contains a lipopolysaccharide-like material called lipoglycan which

Accepted Answer

A) behaves like peptidoglycan and creates a strong cell wall. 
B) forms a monolayer that stabilizes the cytoplasmic membrane. 
C) contains ether linkages. 
D) contains ether linkages and forms a monolayer that stabilizes the cytoplasmic membrane. 
A) behaves like peptidoglycan and creates a strong cell wall. 
B) forms a monolayer that stabilizes the cytoplasmic membrane. 
C) contains ether linkages. 
D) contains ether linkages and forms a monolayer that stabilizes the cytoplasmic membrane.

Question 18

Approximately ________ of the Methanocaldococcus jannaschii genes have no counterparts in known genes from other sequenced organisms.

Accepted Answer

A) 10% 
B) 25% 
C) 40% 
D) 70% 
A) 10% 
B) 25% 
C) 40% 
D) 70%

Question 19

Replacing sodium with potassium can satisfy the requirement for sodium in the halobacteria.

Accepted Answer

A) True 
 B)False

Question 20

The light-stimulated proton pump of Halobacterium salinarum indirectly functions to pump sodium out of the cell by the activity of a Na⁺/H⁺ antiport system.

Accepted Answer

A) True 
 B)False

Exam 16: Diversity of Archaea

The Archaea are

Most known methanogens are nonhalophilic

Despite GC pairs having an additional hydrogen bond than AT pairs,hyperthermophilic Archaea generally have a lower GC ratio in their genomes when compared to other heat-sensitive prokaryotes.

While many Archaea are bacilli or cocci,unusual morphologies such as square,flattened and irregular discs have also been identified in certain species.

The bioenergetics of anaerobic respiring Archaea such as those of the Crenarchaeota involve ________ from which ________ is synthesized.

Some strains of haloarchaea exhibit

What is thought to be the maximum temperature for life to exist?

What makes the metabolism of Ferroglobus interesting in the context of evolution?

Describe two mechanisms that Archaea use to avoid their DNA melting at temperatures above 100°C.

The microorganisms that are thought to resemble the first cellular forms of life on Earth are

In chemolithotrophic Archaea,H₂ is a common electron donor.

What makes the lifestyle and genome of Nanoarchaeum equitans unique?

What special adaptation(s)has/have Thermoplasma evolved to survive in hot acidic environments?

Most halobacteria are motile by means of lophotrichous flagella.

Archaeal histones assist in maintaining the DNA in a double-stranded form at very high temperatures in species of Euryarchaeota.

Archaea is divided into three phyla.

The cytoplasmic membrane of Thermoplasma contains a lipopolysaccharide-like material called lipoglycan which

Approximately ________ of the Methanocaldococcus jannaschii genes have no counterparts in known genes from other sequenced organisms.

Replacing sodium with potassium can satisfy the requirement for sodium in the halobacteria.

The light-stimulated proton pump of Halobacterium salinarum indirectly functions to pump sodium out of the cell by the activity of a Na⁺/H⁺ antiport system.

Microorganisms and Microbiology

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Molecular Biology

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Microbial Genomics

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Viral Genomes and Diversity

Genetics of Bacteria and Archaea

Genetic Engineering and Biotechnology

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Methods in Microbial Ecology

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Nutrient Cycles

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Microbial Interactions With Humans

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