Question 1

Some members of the Thermoplasmatales can grow at pH levels below

Accepted Answer

A) 4. 
B) 7. 
C) 0. 
D) 10. 
A) 4. 
B) 7. 
C) 0. 
D) 10.

Question 2

Pseudopeptidoglycan (pseudomurein)is part of the cell wall of some methanogens.

Accepted Answer

A) True 
 B)False

Question 3

Although the domain Archaea contains many acidophilic organisms,there are still many others within the domain that grow well in environments with a neutral pH.

Accepted Answer

A) True 
 B)False

Question 4

Most of the Archaea are phenotypically quite similar.

Accepted Answer

A) True 
 B)False

Question 5

Though the known diversity of acetotrophic methanogens is low,they are ecologically significant in nature.

Accepted Answer

A) True 
 B)False

Question 6

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

Accepted Answer

A) True 
 B)False

Question 7

The cytoplasmic proteins of Halobacterium are

Accepted Answer

A) highly acidic. 
B) highly basic. 
C) generally neutral. 
D) variable,depending on the species. 
A) highly acidic. 
B) highly basic. 
C) generally neutral. 
D) variable,depending on the species.

Question 8

Hyperthermophilic Archaea have been found to contain dibiphytanyl tetraether lipids.Why are these lipids different from lipids present in non-hyperthermophiles? What special properties and structures do they confer?

Accepted Answer

The phytanyl units confer high thermosta

Question 9

Thermoplasma contains an extremely small genome complexed with a highly basic DNA-binding protein.

Accepted Answer

A) True 
 B)False

Question 10

The rRNA gene sequences of hyperthermophilic Archaea and Bacteria have diverged ________ over time,likely due to ________.

Accepted Answer

A) relatively little / strong constraints on sequence changes at higher temperatures 
B) substantially / higher mutation rates at higher temperatures 
C) relatively little / low mutation rates in these ancient organisms 
D) substantially / DNA damage at higher temperatures 
A) relatively little / strong constraints on sequence changes at higher temperatures 
B) substantially / higher mutation rates at higher temperatures 
C) relatively little / low mutation rates in these ancient organisms 
D) substantially / DNA damage at higher temperatures

Question 11

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 12

Thermoplasma grows either aerobically or anaerobically by sulfur respiration.

Accepted Answer

A) True 
 B)False

Question 13

A chemoorganotroph growing optimally at 55°C and pH 2 in complex media would most likely be a member of the genus

Accepted Answer

A) Methanocaldococcus. 
B) Halobacterium. 
C) Methanococcus. 
D) Thermoplasma. 
A) Methanocaldococcus. 
B) Halobacterium. 
C) Methanococcus. 
D) Thermoplasma.

Question 14

Why does Halobacterium pump large quantities of K⁺ cations into its cytoplasm from the environment? What would happen if Halobacterium did not do this?

Accepted Answer

Halobacterium maintains a high intracell

Question 15

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 16

Some Archaea are chemoorganotrophs and use organic compounds as electron donors for energy metabolism.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following are NOT substrates for methanogens?

Accepted Answer

A) acetate and pyruvate 
B) carbon dioxide,carbon monoxide,and formate 
C) glucose and sucrose 
D) methanol,methylamine,and methylmercaptan 
A) acetate and pyruvate 
B) carbon dioxide,carbon monoxide,and formate 
C) glucose and sucrose 
D) methanol,methylamine,and methylmercaptan

Question 18

The presence of genes encoding RubisCO enzymes in Methanocaldococcus jannaschii and a species of Pyrococcus indicates that the organisms

Accepted Answer

A) incorporate carbon dioxide via the acetyl-CoA pathway. 
B) incorporate carbon dioxide via the Calvin cycle. 
C) incorporate carbon dioxide via the reverse citric acid cycle. 
D) utilize molecular hydrogen as an electron donor in chemolithotrophic metabolism. 
A) incorporate carbon dioxide via the acetyl-CoA pathway. 
B) incorporate carbon dioxide via the Calvin cycle. 
C) incorporate carbon dioxide via the reverse citric acid cycle. 
D) utilize molecular hydrogen as an electron donor in chemolithotrophic metabolism.

Question 19

In general,the cold-dwelling thaumarchaeotes are evolving more slowly than the hyperthermophilic crenarchaeotes.

Accepted Answer

A) True 
 B)False

Question 20

Which genus within Archaea is capable of growth at the hottest temperature recorded of 122°C?

Accepted Answer

A) Methanopyrus 
B) Thermoproteus 
C) Thermosphaera 
D) Pyrococcus 
A) Methanopyrus 
B) Thermoproteus 
C) Thermosphaera 
D) Pyrococcus

Exam 16: Diversity of Archaea

Some members of the Thermoplasmatales can grow at pH levels below

Pseudopeptidoglycan (pseudomurein)is part of the cell wall of some methanogens.

Although the domain Archaea contains many acidophilic organisms,there are still many others within the domain that grow well in environments with a neutral pH.

Most of the Archaea are phenotypically quite similar.

Though the known diversity of acetotrophic methanogens is low,they are ecologically significant in nature.

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

The cytoplasmic proteins of Halobacterium are

Hyperthermophilic Archaea have been found to contain dibiphytanyl tetraether lipids.Why are these lipids different from lipids present in non-hyperthermophiles? What special properties and structures do they confer?

Thermoplasma contains an extremely small genome complexed with a highly basic DNA-binding protein.

The rRNA gene sequences of hyperthermophilic Archaea and Bacteria have diverged ________ over time,likely due to ________.

Which of the following metabolisms is NOT found in Archaea?

Thermoplasma grows either aerobically or anaerobically by sulfur respiration.

A chemoorganotroph growing optimally at 55°C and pH 2 in complex media would most likely be a member of the genus

Why does Halobacterium pump large quantities of K⁺ cations into its cytoplasm from the environment? What would happen if Halobacterium did not do this?

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.

Some Archaea are chemoorganotrophs and use organic compounds as electron donors for energy metabolism.

Which of the following are NOT substrates for methanogens?

The presence of genes encoding RubisCO enzymes in Methanocaldococcus jannaschii and a species of Pyrococcus indicates that the organisms

In general,the cold-dwelling thaumarchaeotes are evolving more slowly than the hyperthermophilic crenarchaeotes.

Which genus within Archaea is capable of growth at the hottest temperature recorded of 122°C?

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The rRNA gene sequences of hyperthermophilic Archaea and Bacteria have diverged over time,likely due to .