Question 1

Briefly discuss how carbon molecules of different sizes can be made for biosynthesis. What else is needed and how is it obtained?

Accepted Answer

Molecules with varying numbers of carbon...

Question 2

In the mechanism of nitrogen reduction, ________ directly takes the place of the H₂ in the FeMo subunit of the enzyme nitrogenase.

Accepted Answer

A)   NH3
B)   N2
C)   HN=NH
D)   H2N-NH2
E)   NADPHF) B) and D)
G) A) and D)

Question 3

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) A) and B)
G) B) and D)

Question 4

Describe how modular enzymes function in polyketide biosynthesis. Why might this be of use medically?

Accepted Answer

Modular enzymes consist of multiple modu...

Question 5

Which of the following does NOT serve as an intermediate in the biosynthesis of amino acids?

Accepted Answer

A)   citrate
B)   2-oxoglutarate
C)   pyruvate
D)   3-phosphoglycerate
E)   pentose phosphateF) A) and B)
G) B) and D)

Question 6

Which of the following is NOT a tetrapyrrole?

Accepted Answer

A)   cytochrome
B)   chlorophyll
C)   vitamin B12
D)   tryptophan
E)   hemoglobinF) C) and D)
G) D) and E)

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)   2-oxoglutarate aminase (2-O
A)  ; glutamine
E)   2-oxoglutarate dehydrogenase (2-ODH) ; glutamineF) None of the above
G) A) and E)

Question 8

Briefly describe the biosynthetic pathway for arginine.

Accepted Answer

Arginine biosynthesis in bacteria is a c...

Question 9

How do cyanobacteria benefit from their heterocysts attracting heterotrophic bacteria?

Accepted Answer

Some cyanobacterial heterocysts leak org...

Question 10

The enzyme that carries out this reaction shown in the diagram below is ________, and the end product is ________.

Accepted Answer

A)   3-phosphoglycerate synthetase; added to another carbon dioxide
B)   3-phosphoglycerate synthetase; reduced to glyceraldehyde-3-phosphate
C)   nitrogenase; reduced to glyceraldehyde-3-phosphate
D)   Rubisco; reduced to glyceraldehyde-3-phosphate
E)   Rubisco; added to another carbon dioxideF) A) and D)
G) A) and C)

Question 11

The ________ pathway is utilized for carbon fixation in chloroplasts and cyanobacteria.

Accepted Answer

A)   acetyl-CoA
B)   reverse tricarboxylic acid cycle
C)   3-hydroxypropionate cycle
D)   reductive pentose phosphate cycle
E)   Krebs cycleF) B) and D)
G) A) and E)

Question 12

The structures marked with arrows in the photo below are ________ and are used to ________.

Accepted Answer

A)   polyhydroxyalkanoates; sequester reactions using bicarbonate or carbon dioxide and Rubisco
B)   polyhydroxyalkanoates; store carbon for energy
C)   carboxysomes; store carbon for energy
D)   carboxysomes; sequester reactions using bicarbonate or carbon dioxide and Rubisco
E)   heterocysts; sequester reactions using bicarbonate or carbon dioxide and RubiscoF) C) and D)
G) A) and C)

Question 13

Denitrification is the

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)   removal of nitro groups from organic molecules.
E)   removal of amino groups from organic molecules.F) B) and D)
G) C) and E)

Question 14

Which of the following is NOT 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)   Both purines and pyrimidines use inosine monophosphate as a precursor.
E)   Both purines and pyrimidines are built by adding carbon components to ribose 5-phosphate.F) A) and D)
G) C) and D)

Question 15

What types of bacteria perform the reductive pentose phosphate cycle to fix CO₂?

Accepted Answer

A)   cyanobacteria
B)   purple phototrophs
C)   lithotrophs
D)   heterotrophs
E)   methanogensF) All of the above
G) B) and E)

Question 16

The most ancient CO₂ fixation pathway in methanogens is the

Accepted Answer

A)   reverse TCA cycle.
B)   3-hydroxypropionate cycle.
C)   Calvin cycle.
D)   reductive acetyl-CoA pathway.
E)   Krebs cycle.F) C) and D)
G) A) and E)

Question 17

What is the most sensitive method to determine the presence of an isotope such as ¹⁴C in a sample?

Accepted Answer

A)   nuclear magnetic resonance (NMR)  spectroscopy
B)   radioactive decay
C)   mass spectroscopy
D)   polymerase chain reaction
E)   high-performance liquid chromatographyF) All of the above
G) A) and E)

Question 18

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 C)
G) C) and E)

Question 19

What kind of reaction is the formation of oxaloacetate from phosphoenolpyruvate?

Accepted Answer

A)   catabolic
B)   anaplerotic
C)   decarboxylation
D)   dehydrogenation
E)   co-factor inducedF) C) and D)
G) B) and C)

Question 20

Which of the following drugs is a nonribosomal peptide antibiotic?

Accepted Answer

A)   erythromycin
B)   penicillin
C)   tetracycline
D)   vancomycin
E)   ciprofloxacinF) B) and C)
G) A) and B)

Exam 15: Biosynthesis

How do cyanobacteria benefit from their heterocysts attracting heterotrophic bacteria?

Correct AnswerverifiedSome cyanobacterial heterocysts leak org...View AnswerShow Answer

The enzyme that carries out this reaction shown in the diagram below is ________, and the end product is ________.

Correct AnswerverifiedShow Answer

Which of the following drugs is a nonribosomal peptide antibiotic?

Correct AnswerverifiedShow 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 does NOT serve as an intermediate in the biosynthesis of amino acids?

Correct AnswerverifiedShow Answer

Which of the following is NOT correct regarding the biosynthesis of purines and pyrimidines?

Correct AnswerverifiedShow Answer

What types of bacteria perform the reductive pentose phosphate cycle to fix CO₂?

Correct AnswerverifiedShow Answer

The ________ pathway is utilized for carbon fixation in chloroplasts and cyanobacteria.

Correct AnswerverifiedShow Answer

Which of the following statements is NOT true about Rubisco?

Correct AnswerverifiedShow Answer

The most ancient CO₂ fixation pathway in methanogens is the

Correct AnswerverifiedShow Answer

In the mechanism of nitrogen reduction, ________ directly takes the place of the H₂ in the FeMo subunit of the enzyme nitrogenase.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Describe how modular enzymes function in polyketide biosynthesis. Why might this be of use medically?

Correct AnswerverifiedModular enzymes consist of multiple modu...View AnswerShow Answer

Briefly discuss how carbon molecules of different sizes can be made for biosynthesis. What else is needed and how is it obtained?

Correct AnswerverifiedMolecules with varying numbers of carbon...View AnswerShow Answer

What is the most sensitive method to determine the presence of an isotope such as ¹⁴C in a sample?

Correct AnswerverifiedShow Answer

What kind of reaction is the formation of oxaloacetate from phosphoenolpyruvate?

Correct AnswerverifiedShow Answer

Denitrification is the

Correct AnswerverifiedShow Answer

The structures marked with arrows in the photo below are ________ and are used to ________.

Correct AnswerverifiedShow Answer

Briefly describe the biosynthetic pathway for arginine.

Correct AnswerverifiedArginine biosynthesis in bacteria is a c...View AnswerShow Answer

Which of the following is NOT a tetrapyrrole?

Correct AnswerverifiedShow Answer

Correct Answer
verified
Some cyanobacterial heterocysts leak org...
View Answer

The enzyme that carries out this reaction shown in the diagram below is , and the end product is .

Correct Answer
verified

Correct Answer
verified

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
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Modular enzymes consist of multiple modu...
View Answer

Correct Answer
verified
Molecules with varying numbers of carbon...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The structures marked with arrows in the photo below are and are used to .

Correct Answer
verified

Correct Answer
verified
Arginine biosynthesis in bacteria is a c...
View Answer

Correct Answer
verified