Question 1

What makes the lifestyle and genome of Nanoarchaeum equitans unique?

Accepted Answer

N.equitans is the only identified intracellular parasite within the Archaea.It lives within the periplasm of Ignicoccus.N.equitans depends upon its host for the biosynthesis of many essential amino acids and cofactors and may not even be able to make its own ATP.The genome of N.equitans,is one of the smallest ever described and is the smallest among Archaea.It is also the most dense genome,with over 95% of the genome predicted to encode for proteins.Based on the genes that are missing from the genome,N.equitans may depend on Ignococcus for both carbon and energy.The key enzymes for DNA repair,DNA replication,transcription,and translation are present in N.equitans genome.

Question 2

Nitrifying Thaumarchaeota outcompete nitrifying bacteria in many aquatic and terrestrial environments because Thaumarchaeota

Accepted Answer

A)  are well-adapted to high salinity and extreme UV irradiation. 
B)  are well-adapted to temperature extremes. 
C)  are well-adapted to very low nutrient and electron donor concentrations. 
D)  have very resistant specialized cells that survive long periods of dehydration and nutrient starvation. 
A)  are well-adapted to high salinity and extreme UV irradiation. 
B)  are well-adapted to temperature extremes. 
C)  are well-adapted to very low nutrient and electron donor concentrations. 
D)  have very resistant specialized cells that survive long periods of dehydration and nutrient starvation. C

Question 3

Laboratory isolation of Nanoarchaeum equitans requires the presence of

Accepted Answer

A)  fatty acids. 
B)  oxygen. 
C)  Ignicoccus. 
D)  sunlight. 
A)  fatty acids. 
B)  oxygen. 
C)  Ignicoccus. 
D)  sunlight. C

Question 4

Many hyperthermophiles of Archaea are ________; however,Staphylothermus is a chemoorganotroph.

Accepted Answer

A)  chemolithotrophs 
B)  mixotrophs 
C)  parasites 
D)  photoheterotrophs 
A)  chemolithotrophs 
B)  mixotrophs 
C)  parasites 
D)  photoheterotrophs

Question 5

Which of the following metabolisms is NOT found in Archaea?

Accepted Answer

A)  photosynthesis 
B)  chemolithotrophy 
C)  chemoorganotrophy 
D)  aerobic respiration 
A)  photosynthesis 
B)  chemolithotrophy 
C)  chemoorganotrophy 
D)  aerobic respiration

Question 6

Cyclic 2,3-diphosphoglycerate (cDPG)is present in molar quantities in the cytoplasm of many hyperthermophilic methanogens.The function of this compound is to

Accepted Answer

A)  prevent rRNA misfolding. 
B)  prevent chemical damage to DNA at high temperatures. 
C)  counteract the effects of high osmotic environments. 
D)  activate hydrogen gas. 
A)  prevent rRNA misfolding. 
B)  prevent chemical damage to DNA at high temperatures. 
C)  counteract the effects of high osmotic environments. 
D)  activate hydrogen gas.

Question 7

What characteristic do mycoplasmas (Bacteria)and Thermoplasma and Ferroplasma (Archaea)have in common?

Accepted Answer

A)  contain plasmids 
B)  hyperthermophilic 
C)  lack cell walls 
D)  relatively large genomes from duplicated genes 
A)  contain plasmids 
B)  hyperthermophilic 
C)  lack cell walls 
D)  relatively large genomes from duplicated genes

Question 8

The ribosomes of Halobacterium require high ________ levels for stability and activity.

Accepted Answer

A)  KCl 
B)  NaCl 
C)  NaSO₄ 
D)  acidic amino acids 
A)  KCl 
B)  NaCl 
C)  NaSO₄ 
D)  acidic amino acids

Question 9

Ignicoccus has several unique structural features that have lead scientists to propose that it may be the modern descendent of the ancestral cell type that gave rise to the origin of eukaryotic cells.What are the unique features of Ignicoccus and why do they support this hypothesis?

Accepted Answer

Ignicoccus lacks a cell wall,but has bot

Question 10

Most of the Archaea are phenotypically quite similar.

Accepted Answer

A) True 
 B)False

Question 11

Which microbial grouping is the major oxygenic phototroph in most salt lakes?

Accepted Answer

A)  cyanobacteria 
B)  Dunaliella, a eukaryotic alga 
C)  halophilic Archaea 
D)  purple nonsulfur bacteria 
A)  cyanobacteria 
B)  Dunaliella, a eukaryotic alga 
C)  halophilic Archaea 
D)  purple nonsulfur bacteria

Question 12

Methanogenesis is coupled with proton motive force formation and ATP synthesis through the activity of ATPases.

Accepted Answer

A) True 
 B)False

Question 13

A small,heat-stable DNA-binding protein present in the cells of some Archaea,called Sac7d,binds to the minor groove of DNA in a very specific manner and increases its melting temperature by 40°C.

Accepted Answer

A) True 
 B)False

Question 14

Extremely halophilic Archaea often form ________ in order to access ________.

Accepted Answer

A)  stalks / nutrients 
B)  intracellular inclusions / elemental sulfur 
C)  gas vesicles / oxygen 
D)  intracellular membranes / sunlight 
A)  stalks / nutrients 
B)  intracellular inclusions / elemental sulfur 
C)  gas vesicles / oxygen 
D)  intracellular membranes / sunlight

Question 15

Thermoplasma metabolizes organic compounds leached from hot coal refuse.

Accepted Answer

A) True 
 B)False

Question 16

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 17

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 18

Halobacterium salinarum and certain other extreme halophiles carry out light-driven synthesis of ATP under what condition?

Accepted Answer

A)  low oxygen concentrations 
B)  low light 
C)  high oxygen concentrations 
D)  high carbon dioxide concentrations 
A)  low oxygen concentrations 
B)  low light 
C)  high oxygen concentrations 
D)  high carbon dioxide concentrations

Question 19

The amino acid composition of thermostable proteins is not particularly unusual,except for a bias for increased levels of amino acids that form α-helices.

Accepted Answer

A) True 
 B)False

Question 20

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

Exam 16: Diversity of Archaea

What makes the lifestyle and genome of Nanoarchaeum equitans unique?

Nitrifying Thaumarchaeota outcompete nitrifying bacteria in many aquatic and terrestrial environments because Thaumarchaeota

Laboratory isolation of Nanoarchaeum equitans requires the presence of

Many hyperthermophiles of Archaea are ________; however,Staphylothermus is a chemoorganotroph.

Which of the following metabolisms is NOT found in Archaea?

Cyclic 2,3-diphosphoglycerate (cDPG)is present in molar quantities in the cytoplasm of many hyperthermophilic methanogens.The function of this compound is to

What characteristic do mycoplasmas (Bacteria)and Thermoplasma and Ferroplasma (Archaea)have in common?

The ribosomes of Halobacterium require high ________ levels for stability and activity.

Ignicoccus has several unique structural features that have lead scientists to propose that it may be the modern descendent of the ancestral cell type that gave rise to the origin of eukaryotic cells.What are the unique features of Ignicoccus and why do they support this hypothesis?

Most of the Archaea are phenotypically quite similar.

Which microbial grouping is the major oxygenic phototroph in most salt lakes?

Methanogenesis is coupled with proton motive force formation and ATP synthesis through the activity of ATPases.

A small,heat-stable DNA-binding protein present in the cells of some Archaea,called Sac7d,binds to the minor groove of DNA in a very specific manner and increases its melting temperature by 40°C.

Extremely halophilic Archaea often form ________ in order to access ________.

Thermoplasma metabolizes organic compounds leached from hot coal refuse.

Some strains of haloarchaea exhibit

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

Halobacterium salinarum and certain other extreme halophiles carry out light-driven synthesis of ATP under what condition?

The amino acid composition of thermostable proteins is not particularly unusual,except for a bias for increased levels of amino acids that form α-helices.

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

Microorganisms and Microbiology

Microbial Cell Structure and Function

Microbial Metabolism

Molecular Biology

Microbial Growth and Control

Microbial Genomics

Metabolic Regulation

Viruses and Virology

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

Diversity of Eukaryotic Microorganisms

Methods in Microbial Ecology

Microbial Ecosystems

Nutrient Cycles

Microbiology of the Built Environment

Microbial Symbioses

Microbial Interactions With Humans

Immunity and Host Defense

Immune Mechanisms

Molecular Immunology

Diagnostic Microbiology

Epidemiology

Person-To-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

Water and Food As Vehicles of Bacterial Diseases

Eukaryotic Pathogens: Fungal and Parasitic Diseases

Filters

Extremely halophilic Archaea often form in order to access .