Question 1

The most ancient CO2 fixation pathway in anaerobic phototrophic bacteria and archaea is:

Accepted Answer

A)   the reverse TCA cycle
B)   the 3-hydroxypropionate cycle
C)   the Calvin cycle
D)   the reductive acetyl-CoA pathway
E)   none of the aboveF) A) and B)
G) None of the above

Question 2

What techniques and technical advances allowed Melvin Calvin to study carbon fixation? Why did he choose the unicellular alga Chlorella?

Accepted Answer

Melvin Calvin and his group used ¹⁴C, whic...

Question 3

Briefly describe the reductive acetyl-CoA pathway. What is its relevance for methanogens?

Accepted Answer

The reductive acetyl-CoA pathway seems t...

Question 4

In the reductive TCA cycle, four or five ATPs are used to produce one oxaloacetate. How many molecules of CO2 are fixed in this cycle?

Accepted Answer

A)   two
B)   three
C)   four
D)   five
E)   sixF) A) and E)
G) A) and B) C

Question 5

The term "genome degeneration" refers to:

Accepted Answer

A)   the loss of a particular biosynthetic pathway when an organism becomes dependent on other species in the environment
B)   catabolic
C)   the genetic regulatory mechanisms triggered after bacteria are exposed to UV
D)   irreversible
E)   none of the aboveF) A) and E)
G) D) and E) A

Question 6

What is the health risk of having nitrates in drinking water? What conditions favor the accumulation of nitrates and nitrites in bodies of water?

Accepted Answer

In natural environments most nitrogen so...

Question 7

The incorporation of NH4+ into 2-oxoglutarate is the first step in nitrogen assimilation in bacterial cells. This reaction is catalyzed by the enzyme ________ and produces __________.

Accepted Answer

A)   glutamate dehydrogenase (GDH) ; glutamate
B)   glutamine synthase (GS) ; glutamine
C)   glutamate synthase (GOGAT) ; glutamate
D)   all of the above
E)   none of the aboveF) C) and D)
G) B) and E)

Question 8

Which of the following pathways is NOT a route for CO2 assimilation?

Accepted Answer

A)   reductive acetyl-CoA pathway
B)   gluconeogenesis pathway
C)   hydroxypropionate cycle
D)   reductive pentose phosphate cycle
E)   reverse TCA cycleF) C) and D)
G) A) and D)

Question 9

Based on the number of enzymes involved in its biosynthesis, which of the following is the most complex amino acid specified by the genetic code?

Accepted Answer

A)   tryptophan
B)   tyrosine
C)   phenylalanine
D)   leucine
E)   isoleucineF) A) and E)
G) B) and D)

Question 10

How many turns of the Calvin cycle does it take to provide one molecule of glyceraldehyde-3-phosphate into the biosynthesis of glucose?

Accepted Answer

A)   1
B)   2
C)   3
D)   6
E)   none of the aboveF) C) and D)
G) B) and C)

Question 11

Which of the following is correct regarding the biosynthesis of purines and pyrimidines?

Accepted Answer

A)   5-phosphoribosyl-1-pyrophosphate (PRPP)  is a precursor to both purines and pyrimidines.
B)   The pyrimidine ring is synthesized first, and then linked to 5-phosphoribosyl-1-pyrophosphate.
C)   The purine ring is built around the C1 of 5-phosphoribosyl-1-pyrophosphate.
D)   All of the above.
E)   None of the above.F) B) and E)
G) A) and E)

Question 12

Microbial biosynthetic processes require:

Accepted Answer

A)   essential elements
B)   reduction
C)   energy
D)   all of the above
E)   none of the aboveF) A) and C)
G) C) and D)

Question 13

Which of the following statements is NOT true about Rubisco?

Accepted Answer

A)   It catalyzes the addition of CO2 to ribulose 1,5-bisphosphate.
B)   It is present in all organisms that use the Calvin cycle to fix CO2.
C)   It is found in the carboxysomes of autotrophic bacteria.
D)   All species contain the same number of large and small subunits.
E)   Its structure is highly conserved across bacterial groups and chloroplasts.F) B) and D)
G) A) and E)

Question 14

What is denitrification?

Accepted Answer

A)   conversion of nitrate or nitrite to N2 by anaerobic respirers
B)   oxidation of NH4+ to nitrate or nitrite by lithotrophs
C)   conversion of N2 to NH4+
D)   all of the above
E)   none of the aboveF) B) and E)
G) A) and E) A

Question 15

Which of the following is NOT correct about fatty acid biosynthesis?

Accepted Answer

A)   It involves successive condensations of malonyl-ACP.
B)   A dehydratase is used to generate an unsaturated bond.
C)   It is regulated by the stringent response of carbon starvation.
D)   NADPH is generally involved in hydrogenation.
E)   Many single-component enzymes are involved.F) B) and D)
G) B) and C)

Question 16

Which pair is NOT matched correctly?

Accepted Answer

A)   coenzyme B12-cobalt
B)   chlorophyll a-magnesium
C)   bacteriochlorophyll-magnesium
D)   heme-iron
E)   none of the aboveF) A) and B)
G) C) and E)

Question 17

Industrial nitrogen fixation is achieved through the Haber process in which:

Accepted Answer

A)   N2 is reduced catalytically by H2 at ambient temperature
B)   N2 is hydrogenated by CH4 at extreme temperature and pressure
C)   nitrate and nitrite are chemically converted to NH at ambient temperature
D)   all of the above
E)   none of the aboveF) B) and E)
G) A) and E)

Question 18

How is fatty acid biosynthesis regulated in bacteria?

Accepted Answer

Because fatty acid biosynthesis consumes...

Question 19

__________ and __________ are unique in that they fix CO2 as their sole carbon source.

Accepted Answer

A)   Organotrophs; iron oxidizers
B)   Photoheterotrophs; chemiolithotrophs
C)   Photoautotrophs; lithotrophs
D)   all of the above
E)   none of the aboveF) B) and E)
G) A) and C)

Question 20

Briefly describe how NH4+ is assimilated into biomass by bacteria.

Accepted Answer

The assimilable ammonium ion (NH₄⁺) is pro...

Exam 15: Biosynthesis

The most ancient CO2 fixation pathway in anaerobic phototrophic bacteria and archaea is:

Correct AnswerverifiedShow Answer

What techniques and technical advances allowed Melvin Calvin to study carbon fixation? Why did he choose the unicellular alga Chlorella?

Correct AnswerverifiedMelvin Calvin and his group used 14C, whic...View AnswerShow Answer

Briefly describe the reductive acetyl-CoA pathway. What is its relevance for methanogens?

Correct AnswerverifiedThe reductive acetyl-CoA pathway seems t...View AnswerShow Answer

In the reductive TCA cycle, four or five ATPs are used to produce one oxaloacetate. How many molecules of CO2 are fixed in this cycle?

Correct AnswerverifiedC

The term "genome degeneration" refers to:

Correct AnswerverifiedA

What is the health risk of having nitrates in drinking water? What conditions favor the accumulation of nitrates and nitrites in bodies of water?

Correct AnswerverifiedIn natural environments most nitrogen so...View AnswerShow Answer

The incorporation of NH4+ into 2-oxoglutarate is the first step in nitrogen assimilation in bacterial cells. This reaction is catalyzed by the enzyme ________ and produces __________.

Correct AnswerverifiedShow Answer

Which of the following pathways is NOT a route for CO2 assimilation?

Correct AnswerverifiedShow Answer

Based on the number of enzymes involved in its biosynthesis, which of the following is the most complex amino acid specified by the genetic code?

Correct AnswerverifiedShow Answer

How many turns of the Calvin cycle does it take to provide one molecule of glyceraldehyde-3-phosphate into the biosynthesis of glucose?

Correct AnswerverifiedShow Answer

Which of the following is correct regarding the biosynthesis of purines and pyrimidines?

Correct AnswerverifiedShow Answer

Microbial biosynthetic processes require:

Correct AnswerverifiedShow Answer

Which of the following statements is NOT true about Rubisco?

Correct AnswerverifiedShow Answer

What is denitrification?

Correct AnswerverifiedA

Which of the following is NOT correct about fatty acid biosynthesis?

Correct AnswerverifiedShow Answer

Which pair is NOT matched correctly?

Correct AnswerverifiedShow Answer

Industrial nitrogen fixation is achieved through the Haber process in which:

Correct AnswerverifiedShow Answer

How is fatty acid biosynthesis regulated in bacteria?

Correct AnswerverifiedBecause fatty acid biosynthesis consumes...View AnswerShow Answer

__________ and __________ are unique in that they fix CO2 as their sole carbon source.

Correct AnswerverifiedShow Answer

Briefly describe how NH4+ is assimilated into biomass by bacteria.

Correct AnswerverifiedThe assimilable ammonium ion (NH4+) is pro...View AnswerShow Answer

The most ancient CO₂ fixation pathway in anaerobic phototrophic bacteria and archaea is:

Correct Answer
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Melvin Calvin and his group used ¹⁴C, whic...
View Answer

Correct Answer
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The reductive acetyl-CoA pathway seems t...
View Answer

In the reductive TCA cycle, four or five ATPs are used to produce one oxaloacetate. How many molecules of CO₂ are fixed in this cycle?

Correct Answer
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C

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A

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In natural environments most nitrogen so...
View Answer

The incorporation of NH₄⁺ into 2-oxoglutarate is the first step in nitrogen assimilation in bacterial cells. This reaction is catalyzed by the enzyme and produces __.

Correct Answer
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Which of the following pathways is NOT a route for CO₂ assimilation?

Correct Answer
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A

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Because fatty acid biosynthesis consumes...
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and are unique in that they fix CO₂ as their sole carbon source.

Correct Answer
verified

Briefly describe how NH₄⁺ is assimilated into biomass by bacteria.

Correct Answer
verified
The assimilable ammonium ion (NH₄⁺) is pro...
View Answer