Question 1

What are the key enzymes, intermediates, and products of heme catalysis?

Accepted Answer

As shown in Figure 17.54 in the text,  @#LAT-DLM&-

Question 2

If there was a loss of efficiency in the urea cycle, there would be a buildup of

Accepted Answer

A)  fumarate. 
B)  urea. 
C)  glutamine. 
D)  glucose. 
A)  fumarate. 
B)  urea. 
C)  glutamine. 
D)  glucose.

Question 3

Alanine, cysteine, glycine, and serine are all considered amino acids.

Accepted Answer

A)  glucogenic 
B)  ketogenic 
C)  nonessential 
D)  urea 
A)  glucogenic 
B)  ketogenic 
C)  nonessential 
D)  urea

Question 4

Differentiate between proteins being degraded by an ATP-dependent process compared with the ATP-independent process.

Accepted Answer

An ATP-independent process deg

Question 5

Using the figure below, determine which of the following is NOT a final product from group 1 amino acid degradation.

Accepted Answer

A)  glycine 
B)  pyruvate 
C)  acetoacetyl-CoA 
D)  acetyl-CoA 
A)  glycine 
B)  pyruvate 
C)  acetoacetyl-CoA 
D)  acetyl-CoA

Question 6

How does atmospheric fixation occur given the high energy barrier to convert nitrogen to nitrogen oxides?

Accepted Answer

A)  through the oceans that break the triple bond of nitrogen and allow for the combination with water 
B)  through clouds that allow for nitrogen to combine with oxygen 
C)  in the soil by bacteria that reduce nitrogen to ammonia 
D)  through lightning that breaks the triple bond of nitrogen and allows for the combination with oxygen 
A)  through the oceans that break the triple bond of nitrogen and allow for the combination with water 
B)  through clouds that allow for nitrogen to combine with oxygen 
C)  in the soil by bacteria that reduce nitrogen to ammonia 
D)  through lightning that breaks the triple bond of nitrogen and allows for the combination with oxygen

Question 7

What specific characteristic must a target protein have to be recognized by an ubiquitinating protein?

Accepted Answer

A)  "phosphorylated residue" 
B)  "N terminus" 
C)  "C terminus" 
D)  "$\alpha$-helix" 
A)  "phosphorylated residue" 
B)  "N terminus" 
C)  "C terminus" 
D)  "$\alpha$-helix"

Question 8

Adenylylation of Try397 regulates glutamine synthetase by

Accepted Answer

A)  lowering activation energy. 
B)  inhibiting activity. 
C)  increasing activation energy. 
D)  increasing rate of reaction. 
A)  lowering activation energy. 
B)  inhibiting activity. 
C)  increasing activation energy. 
D)  increasing rate of reaction.

Question 9

It is important that proteolytic enzymes in the lysosome are optimized to work at low pH because low pH

Accepted Answer

A)  enhances protein denaturing. 
B)  deactivates cysteine proteases. 
C)  makes it easier for ATP to be converted to ADP + Pi. 
D)  enhances the degradation of ubiquitinated proteins. 
A)  enhances protein denaturing. 
B)  deactivates cysteine proteases. 
C)  makes it easier for ATP to be converted to ADP + Pi. 
D)  enhances the degradation of ubiquitinated proteins.

Question 10

What is the mechanism by which Roundup works?

Accepted Answer

A)  Glyphosate is a competitive inhibitor to plant EPSP synthase. 
B)  Urea is a competitive inhibitor to plant chorismate synthase. 
C)  Glyphosate is an activator to plant EPSP synthase. 
D)  Anthranilate is an activator to chorismate synthase. 
A)  Glyphosate is a competitive inhibitor to plant EPSP synthase. 
B)  Urea is a competitive inhibitor to plant chorismate synthase. 
C)  Glyphosate is an activator to plant EPSP synthase. 
D)  Anthranilate is an activator to chorismate synthase.

Question 11

Glutamine synthetase uses ammonia to covert glutamate into

Accepted Answer

A)  "glutamine. 
B)  "nitrate." 
C)  "$\alpha$-ketoglutarate." 
D)  "histidine." 
A)  "glutamine. 
B)  "nitrate." 
C)  "$\alpha$-ketoglutarate." 
D)  "histidine."

Question 12

What are the four key enzymes in nitrogen fixation and assimilation in plants and bacteria?

Accepted Answer

A)  nitrogenase synthetase, glutamine complex, glutamate synthase, glutamate dehydrogenase 
B)  nitrogenase complex, glutamine synthetase, glutamate synthase, glutamate dehydrogenase 
C)  glutamine synthetase, glutamate synthase, glutamate dehydrogenase, glutamate oxidase 
D)  nitrogenase complex, glutamine synthetase, glycine synthase, glutamine dehydrogenase 
A)  nitrogenase synthetase, glutamine complex, glutamate synthase, glutamate dehydrogenase 
B)  nitrogenase complex, glutamine synthetase, glutamate synthase, glutamate dehydrogenase 
C)  glutamine synthetase, glutamate synthase, glutamate dehydrogenase, glutamate oxidase 
D)  nitrogenase complex, glutamine synthetase, glycine synthase, glutamine dehydrogenase

Question 13

Cells cannot store amino acids that accumulate as a result of protein degradation. The carbon skeletons that remain

Accepted Answer

A)  enter the urea cycle. 
B)  are used to produce new amino acids. 
C)  enter the citrate cycle. 
D)  are used to produce DNA and RNA. 
A)  enter the urea cycle. 
B)  are used to produce new amino acids. 
C)  enter the citrate cycle. 
D)  are used to produce DNA and RNA.

Question 14

What are the allosteric regulators of glutamine synthetase?

Accepted Answer

Glucosamine-6-phosphate, carba

Question 15

Which of the following is the correct net reaction of nitrogen fixation in bacteria?

Accepted Answer

A)  N2 + 8H+ + 8e -  + 16 ATP + 16 H2O $\rightarrow$ 2NH3 + H2 + 16 ADP + 16 Pi 
B)  N2 + 8H+ + 8e - + 16 ADP + 16 H2O $\rightarrow$ 2NH3 + H2 + 16 ATP + 16 Pi 
C)  2N2 + 8H+ + 8e - + 16 ATP + 16 H2O $\rightarrow$ NH3 + 4H2 + 16 ADP + 16 Pi 
D)  2NH3 + H2 + 16 ADP + 16 Pi $\rightarrow$ N2 + 8H+ + 8e -  + 16 ATP + 16 H2O 
A)  N2 + 8H+ + 8e -  + 16 ATP + 16 H2O $\rightarrow$ 2NH3 + H2 + 16 ADP + 16 Pi 
B)  N2 + 8H+ + 8e - + 16 ADP + 16 H2O $\rightarrow$ 2NH3 + H2 + 16 ATP + 16 Pi 
C)  2N2 + 8H+ + 8e - + 16 ATP + 16 H2O $\rightarrow$ NH3 + 4H2 + 16 ADP + 16 Pi 
D)  2NH3 + H2 + 16 ADP + 16 Pi $\rightarrow$ N2 + 8H+ + 8e -  + 16 ATP + 16 H2O

Question 16

A possible outcome if E. coli was depleted in NADPH would be

Accepted Answer

A)  buildup of lysine. 
B)  depletion of asparagine. 
C)  buildup of aspartate. 
D)  depletion of methionine. 
A)  buildup of lysine. 
B)  depletion of asparagine. 
C)  buildup of aspartate. 
D)  depletion of methionine.

Question 17

If no NAD+ was available, the group 2 amino acid degradation pathway would experience a

Accepted Answer

A)  buildup of urea. 
B)  buildup of glutamate. 
C)  depletion of proline. 
D)  depletion of histidine. 
A)  buildup of urea. 
B)  buildup of glutamate. 
C)  depletion of proline. 
D)  depletion of histidine.

Question 18

Using nitrogenase to reduce N2 should require 2 ATP to be invested, but it actually takes 16 ATP. Why?

Accepted Answer

A)  It is harder to break the nitrogen triple bond than expected and requires more energy input. 
B)  Extra energy is required to produce H2. 
C)  To regenerate the MoFe protein requires the input of ATP. 
D)  To keep the nitrogenase complex associated requires an input of 4 ATP. 
A)  It is harder to break the nitrogen triple bond than expected and requires more energy input. 
B)  Extra energy is required to produce H2. 
C)  To regenerate the MoFe protein requires the input of ATP. 
D)  To keep the nitrogenase complex associated requires an input of 4 ATP.

Question 19

How is the synthetic pathway for nonessential amino acids different than for essential amino acids?

Accepted Answer

The nonessential amino acids have carbon

Question 20

For the figure below, summarize the interdependent regulation of glutamine synthetase and glutamine synthetase adenylyltransferase.

Accepted Answer

Covalent modification of glutamine synth

Exam 17: Amino Acid Metabolism

What are the key enzymes, intermediates, and products of heme catalysis?

If there was a loss of efficiency in the urea cycle, there would be a buildup of

Alanine, cysteine, glycine, and serine are all considered amino acids.

Differentiate between proteins being degraded by an ATP-dependent process compared with the ATP-independent process.

Using the figure below, determine which of the following is NOT a final product from group 1 amino acid degradation.

How does atmospheric fixation occur given the high energy barrier to convert nitrogen to nitrogen oxides?

What specific characteristic must a target protein have to be recognized by an ubiquitinating protein?

Adenylylation of Try397 regulates glutamine synthetase by

It is important that proteolytic enzymes in the lysosome are optimized to work at low pH because low pH

What is the mechanism by which Roundup works?

Glutamine synthetase uses ammonia to covert glutamate into

What are the four key enzymes in nitrogen fixation and assimilation in plants and bacteria?

Cells cannot store amino acids that accumulate as a result of protein degradation. The carbon skeletons that remain

What are the allosteric regulators of glutamine synthetase?

Which of the following is the correct net reaction of nitrogen fixation in bacteria?

A possible outcome if E. coli was depleted in NADPH would be

If no NAD+ was available, the group 2 amino acid degradation pathway would experience a

Using nitrogenase to reduce N2 should require 2 ATP to be invested, but it actually takes 16 ATP. Why?

How is the synthetic pathway for nonessential amino acids different than for essential amino acids?

For the figure below, summarize the interdependent regulation of glutamine synthetase and glutamine synthetase adenylyltransferase.

Principles of Biochemistry

Physical Biochemistry: Energy Conversion, Water, and Membranes

Nucleic Acid Structure and Function

Protein Structure

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Cell Signaling Systems

Glycolysis: a Paradigm of Metabolic Regulation

The Citrate Cycle

Oxidative Phosphorylation

Photosynthesis

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Lipid Metabolism

Nucleotide Metabolism

Metabolic Integration

DNA Replication, Repair, and Recombination

RNA Synthesis, Processing, and Gene Silencing

Protein Synthesis, Posttranslational Modification, and Transport

Gene Regulation

Filters

If no NAD⁺was available, the group 2 amino acid degradation pathway would experience a

Using nitrogenase to reduce N₂ should require 2 ATP to be invested, but it actually takes 16 ATP. Why?