Question 1

It is difficult to estimate when cyanobacteria appeared on Earth using evidence from the oxidation state of the Earth's crust,because

Accepted Answer

A)  several abiotic reactions could have formed Fe³⁺. 
B)  there are multiple forms of anoxygenic photosynthesis. 
C)  there are multiple groups of oxygenic photosynthetic bacteria. 
D)  several ancient anaerobic metabolisms form Fe³⁺. 
A)  several abiotic reactions could have formed Fe³⁺. 
B)  there are multiple forms of anoxygenic photosynthesis. 
C)  there are multiple groups of oxygenic photosynthetic bacteria. 
D)  several ancient anaerobic metabolisms form Fe³⁺.

Question 2

The factor that MOST affects the thermostability of a protein is its

Accepted Answer

A)  highly hydrophobic core regions. 
B)  folding pattern. 
C)  ionic surface interactions. 
D)  number of hydrogen bonds. 
A)  highly hydrophobic core regions. 
B)  folding pattern. 
C)  ionic surface interactions. 
D)  number of hydrogen bonds.

Question 3

When retinal in bacteriorhodopsin becomes excited,it directly catalyzes the formation of ATP.

Accepted Answer

A) True 
 B)False

Question 4

Some of the largest naturally occurring plasmids occur in the

Accepted Answer

A)  methanogens. 
B)  genus Thermoplasma. 
C)  extreme halophiles. 
D)  genus Picrophilus. 
A)  methanogens. 
B)  genus Thermoplasma. 
C)  extreme halophiles. 
D)  genus Picrophilus.

Question 5

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 6

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

Accepted Answer

A) True 
 B)False

Question 7

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 8

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 9

What do MOST halobacteria use for carbon substrates?

Accepted Answer

A)  amino and organic acids 
B)  carbohydrates 
C)  lipids 
D)  nucleic acids 
A)  amino and organic acids 
B)  carbohydrates 
C)  lipids 
D)  nucleic acids

Question 10

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

Accepted Answer

A) True 
 B)False

Exam 16: Diversity of Archaea

It is difficult to estimate when cyanobacteria appeared on Earth using evidence from the oxidation state of the Earth's crust,because

The factor that MOST affects the thermostability of a protein is its

When retinal in bacteriorhodopsin becomes excited,it directly catalyzes the formation of ATP.

Some of the largest naturally occurring plasmids occur in the

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

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

Most known methanogens are nonhalophilic

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

What do MOST halobacteria use for carbon substrates?

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

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Microbial Evolution and Systematics

Metabolic Diversity of Microorganisms

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