Question 1

Pyruvate dehydrogenase complex connects glycolysis to respiration. Which is a correct mechanism for how the activity of this enzyme complex is regulated?

Accepted Answer

The pyruvate dehydrogenase complex is regulated by feedback inhibition and covalent modification. Gene expression can be repressed by conditions like carbon starvation and low oxygen levels, which are signals of low energy availability.

Question 2

Pathways involving both anabolic and catabolic reactions are referred to as

Accepted Answer

Pathways involving both anabolic (building up) and catabolic (breaking down) reactions are referred to as amphibolic pathways.

Question 3

Species of Pseudomonas and Rhodococcus can degrade benzoate and other aromatic molecules, either aerobically or anaerobically. Which of the following is NOT correct regarding anaerobic degradation of aromatic molecules?

Accepted Answer

Anaerobic degradation of benzoate proceeds via production of hydroxylated intermediates such as benzoyl-CoA, which are then converted to catechols. Therefore, choice D is incorrect. Choices A, B, C and E are all correct regarding anaerobic degradation of aromatic molecules.

Question 4

The energy yield from fermentation is lower than from respiration because

Accepted Answer

Respiration completely oxidizes glucose to CO2, resulting in greater generation of NADH and thus ATP. Fermentation, on the other hand, does not completely oxidize glucose and therefore generates less ATP.

Question 5

Each of the following was used to elucidate the TCA cycle EXCEPT

Accepted Answer

The use of C14-labeled carbon compounds as a source of carbon under anoxic conditions is not a method commonly used to elucidate the TCA cycle. The other options mentioned are commonly used methods to study the TCA cycle.

Question 6

________ enters the tricarboxylic acid cycle by condensing with oxaloacetate to form ________.

Accepted Answer

Acetyl-S-CoA enters the tricarboxylic acid cycle by condensing with oxaloacetate to form citrate, which is the first intermediate of the cycle.

Question 7

Some bacteria in the human gut microbiota primarily feed on glucose derivatives from mucus secretions. Which of the following is NOT correct with respect to "mucus farming" by bacteria?

Accepted Answer

The glucose derivatives from mucus secretions are not converted to glucose and degraded via the Embden-Meyerhof-Parnas pathway, as stated in choice D. Rather, they are metabolized via the Entner-Doudoroff pathway, as stated in choice B. The other choices (A, B, C, and E) are correct with respect to mucus farming by bacteria.

Question 8

Which of the diagrammed molecules is a global signal of nutritional status?

Accepted Answer

The answer of Which of the diagrammed molecules is a...

Question 9

Which of the following is evidence that the Entner-Doudoroff (ED) route might have evolved earlier than the Embden-Meyerhof-Parnas pathway (EMP)?

Accepted Answer

The Entner-Doudoroff (ED) pathway involves fewer substrate-level phosphorylations and yields less energy and fewer reductants than the Embden-Meyerhof-Parnas (EMP) pathway. This simplicity and lower energy yield suggest it might have evolved earlier, as early metabolic pathways are generally less efficient.

Question 10

How can a technique such as calorimetry be used to measure $$\Delta$$G?

Accepted Answer

The answer of How can a technique such as calorimetry...

Question 11

Ethanolic fermentation is used in making beverages such as beer, wine, and pulque. It is carried out by yeast and

Accepted Answer

Zymomonas is a type of bacteria commonly used for ethanol production in the beverage industry.

Question 12

The greatest amount of reduced coenzyme NADH + H⁺ is produced during which stage of aerobic respiration?

Accepted Answer

The tricarboxylic acid cycle (also known as the citric acid cycle or Krebs cycle) produces the greatest amount of reduced coenzyme NADH + H⁺ per molecule of glucose metabolized, as it generates three NADH molecules per turn of the cycle.

Question 13

All oxidative catabolism of toluene and other benzene derivatives proceeds through

Accepted Answer

The oxidative catabolism of toluene and other benzene derivatives proceeds through catechols. These compounds are formed through the initial attack of a monooxygenase enzyme on the aromatic ring, which introduces a hydroxyl group. Further oxidation leads to the formation of catechols, which are then metabolized through various pathways.

Answer: A
 Benzoyl-S-CoA is an intermediate in the degradation of aromatic compounds like toluene. It is formed through the action of a CoA ligase enzyme, which activates benzoyl acid by attaching it to coenzyme A (CoA). This intermediate can then be further metabolized through the beta-oxidation pathway.

Answer: D
 Cis, cis-muconate is an intermediate in the degradation of aromatic compounds like toluene. It is formed from catechols through the action of a meta-cleavage enzyme. Cis, cis-muconate can then be further metabolized through the beta-oxidation pathway.

Option B and E are incorrect as aniline and D-gluconate are not intermediates in the oxidative catabolism of toluene and other benzene derivatives.

Question 14

Oxidative catabolism of benzoate and other aromatic compounds is catalyzed by

Accepted Answer

The oxidative catabolism of benzoate and other aromatic compounds is primarily catalyzed by specific dioxygenases. These enzymes introduce molecular oxygen into the aromatic ring, leading to the formation of dihydroxyaromatic compounds that can be further metabolized by other enzymes. Other enzymes listed, such as NADPH:ferredoxin oxidoreductase and catechol 2,3, monooxygenase, may play a role in microbial metabolism, but they are not directly involved in the oxidative catabolism of aromatic compounds.

Question 15

Amino acids can be synthesized using which one of the molecules from the diagram below?

Accepted Answer

The answer of Amino acids can be synthesized using which...

Question 16

Clostridium acetobutylicum has been used to produce which solvents?

Accepted Answer

Clostridium acetobutylicum has been used mainly for the production of acetone and butanol.

Question 17

In the pentose phosphate shunt, glucose 6-phosphate is oxidized to 6-phosphogluconate, which is then decarboxylated to ribulose 5-phosphate. What is the main metabolic role of this pathway?

Accepted Answer

The pentose phosphate pathway primarily generates NADPH and ribose-5-phosphate, which are crucial for biosynthetic reactions and nucleotide synthesis, respectively. It also produces various sugars with three to seven carbon atoms for biosynthesis.

Question 18

The dye ________ turns ________ in the presence of acid products and is included in fermentation broth for some diagnostic tests.

Accepted Answer

Phenol red is a pH indicator dye that turns yellow in an acidic environment. It is commonly included in fermentation broth to detect the production of acid by microorganisms. This is useful in diagnostic tests to differentiate between different species or strains of bacteria based on their ability to ferment certain sugars.

Question 19

Define "organotroph" and "heterotroph." Are these terms equivalent?

Accepted Answer

The answer of Define "organotroph" and "heterotroph." Are these terms...

Question 20

What are the differences among DG, DG°, and DG°'?

Accepted Answer

The answer of What are the differences among DG, DG°,...

Quiz 13: Energetics and Catabolism

Pyruvate dehydrogenase complex connects glycolysis to respiration. Which is a correct mechanism for how the activity of this enzyme complex is regulated?

Pathways involving both anabolic and catabolic reactions are referred to as

Species of Pseudomonas and Rhodococcus can degrade benzoate and other aromatic molecules, either aerobically or anaerobically. Which of the following is NOT correct regarding anaerobic degradation of aromatic molecules?

The energy yield from fermentation is lower than from respiration because

Each of the following was used to elucidate the TCA cycle EXCEPT

enters the tricarboxylic acid cycle by condensing with oxaloacetate to form .

Some bacteria in the human gut microbiota primarily feed on glucose derivatives from mucus secretions. Which of the following is NOT correct with respect to "mucus farming" by bacteria?

Which of the diagrammed molecules is a global signal of nutritional status?

Which of the following is evidence that the Entner-Doudoroff (ED) route might have evolved earlier than the Embden-Meyerhof-Parnas pathway (EMP) ?

How can a technique such as calorimetry be used to measure $\Delta$ G?

Ethanolic fermentation is used in making beverages such as beer, wine, and pulque. It is carried out by yeast and

The greatest amount of reduced coenzyme NADH + H⁺ is produced during which stage of aerobic respiration?

All oxidative catabolism of toluene and other benzene derivatives proceeds through

Oxidative catabolism of benzoate and other aromatic compounds is catalyzed by

Amino acids can be synthesized using which one of the molecules from the diagram below?

Clostridium acetobutylicum has been used to produce which solvents?

In the pentose phosphate shunt, glucose 6-phosphate is oxidized to 6-phosphogluconate, which is then decarboxylated to ribulose 5-phosphate. What is the main metabolic role of this pathway?

The dye turns in the presence of acid products and is included in fermentation broth for some diagnostic tests.

Define "organotroph" and "heterotroph." Are these terms equivalent?

What are the differences among DG, DG°, and DG°'?

Quiz 13: Energetics and Catabolism

Pyruvate dehydrogenase complex connects glycolysis to respiration. Which is a correct mechanism for how the activity of this enzyme complex is regulated?

Pathways involving both anabolic and catabolic reactions are referred to as

Species of Pseudomonas and Rhodococcus can degrade benzoate and other aromatic molecules, either aerobically or anaerobically. Which of the following is NOT correct regarding anaerobic degradation of aromatic molecules?

The energy yield from fermentation is lower than from respiration because

Each of the following was used to elucidate the TCA cycle EXCEPT

________ enters the tricarboxylic acid cycle by condensing with oxaloacetate to form ________.

Some bacteria in the human gut microbiota primarily feed on glucose derivatives from mucus secretions. Which of the following is NOT correct with respect to "mucus farming" by bacteria?

Which of the diagrammed molecules is a global signal of nutritional status?

Which of the following is evidence that the Entner-Doudoroff (ED) route might have evolved earlier than the Embden-Meyerhof-Parnas pathway (EMP) ?

How can a technique such as calorimetry be used to measure Δ\DeltaΔ G?

Ethanolic fermentation is used in making beverages such as beer, wine, and pulque. It is carried out by yeast and

The greatest amount of reduced coenzyme NADH + H⁺ is produced during which stage of aerobic respiration?

All oxidative catabolism of toluene and other benzene derivatives proceeds through

Oxidative catabolism of benzoate and other aromatic compounds is catalyzed by

Amino acids can be synthesized using which one of the molecules from the diagram below?

Clostridium acetobutylicum has been used to produce which solvents?

In the pentose phosphate shunt, glucose 6-phosphate is oxidized to 6-phosphogluconate, which is then decarboxylated to ribulose 5-phosphate. What is the main metabolic role of this pathway?

The dye ________ turns ________ in the presence of acid products and is included in fermentation broth for some diagnostic tests.

Define "organotroph" and "heterotroph." Are these terms equivalent?

What are the differences among DG, DG°, and DG°'?

enters the tricarboxylic acid cycle by condensing with oxaloacetate to form .

How can a technique such as calorimetry be used to measure $\Delta$ G?

The dye turns in the presence of acid products and is included in fermentation broth for some diagnostic tests.