Question 1

If you incubate 14C-CO2 with liver extracts capable of performing gluconeogenesis, where does the radioactive label end up?

Accepted Answer

The input question seems to be referring

Question 2

_____ is a product of pyruvate in erythrocytes.

Accepted Answer

A)  CO2 + H2O 
B)  Ethanol + CO2 
C)  Glucose 
D)  Erythrose-4-phosphate 
E)  Lactate 
A)  CO2 + H2O 
B)  Ethanol + CO2 
C)  Glucose 
D)  Erythrose-4-phosphate 
E)  Lactate

Question 3

Describe the glycolytic pathway from glucose to glyceraldehyde 3-phosphate. Show structures of intermediates, enzyme names, and indicate where any cofactors participate.

Accepted Answer

The glycolytic pathway is a series of en

Question 4

The yeast used in brewing the alcoholic beverage beer can break down glucose either aerobically or anaerobically using alcoholic fermentation. Explain why beer is brewed under anaerobic conditions.

Accepted Answer

Beer is brewed under anaerobic condition

Question 5

Which statement is TRUE for glycolysis?

Accepted Answer

A)  Pyruvate kinase phosphorylates pyruvate during glycolysis. 
B)  Hexokinase catalyzes an unregulated step in glycolysis. 
C)  A dehydration reaction generates a high-energy molecule. 
D)  Hexokinase catalyzes an unregulated step in glycolysis, and a dehydration reaction generates a high-energy molecule . 
E)  None of the statements is true. 
A)  Pyruvate kinase phosphorylates pyruvate during glycolysis. 
B)  Hexokinase catalyzes an unregulated step in glycolysis. 
C)  A dehydration reaction generates a high-energy molecule. 
D)  Hexokinase catalyzes an unregulated step in glycolysis, and a dehydration reaction generates a high-energy molecule . 
E)  None of the statements is true.

Question 6

Which enzyme that is involved in the flow of carbon from glucose to lactate (glycolysis) is NOT also involved in the reversal of this flow (gluconeogenesis)?

Accepted Answer

A)  3-phosphoglycerate kinase 
B)  aldolase 
C)  enolase 
D)  phosphofructokinase-1 
E)  phosphoglucoisomerase 
A)  3-phosphoglycerate kinase 
B)  aldolase 
C)  enolase 
D)  phosphofructokinase-1 
E)  phosphoglucoisomerase

Question 7

Describe the glycolytic pathway from glyceraldehyde 3-phosphate to pyruvate, showing structures of intermediates and names of enzymes. Indicate where any cofactors participate.

Accepted Answer

The glycolytic pathway is a series of en

Question 8

In humans, gluconeogenesis:

Accepted Answer

A)  can result in the conversion of protein into blood glucose. 
B)  helps to reduce blood glucose after a carbohydrate-rich meal. 
C)  is activated by the hormone insulin 
D)  is essential in the conversion of fatty acids to glucose. 
E)  requires the enzyme hexokinase. 
A)  can result in the conversion of protein into blood glucose. 
B)  helps to reduce blood glucose after a carbohydrate-rich meal. 
C)  is activated by the hormone insulin 
D)  is essential in the conversion of fatty acids to glucose. 
E)  requires the enzyme hexokinase.

Question 9

Which reaction in glycolysis utilizes a covalent enzyme intermediate?

Accepted Answer

A)  phosphofructokinase-1 
B)  hexokinase 
C)  phosphohexose isomerase 
D)  aldolase 
E)  triose phosphate isomerase 
A)  phosphofructokinase-1 
B)  hexokinase 
C)  phosphohexose isomerase 
D)  aldolase 
E)  triose phosphate isomerase

Question 10

In the conversion of glucose to pyruvate via glycolysis, all of the following enzymes participate. Indicate the order in which they function by numbering them.
___ hexokinase
___ triose phosphate isomerase
___ phosphohexose isomerase
___ enolase
___ glyceraldehyde 3-phosphate dehydrogenase
___ pyruvate kinase
___ phosphofructokinase-1
Which of the enzymes represents a major regulation point in glycolysis?
Which catalyzes a reaction in which ATP is produced?
Which catalyzes a reaction in which NADH is produced?

Accepted Answer

In the conversion of glucose to pyruvate

Question 11

Which statement is FALSE concerning glycolysis?

Accepted Answer

A)  It is activated by high [AMP]. 
B)  It results in a net synthesis of ATP. 
C)  It results in the synthesis of NAD+. 
D)  Its rate is slowed by a high [NADH]/ [NAD+] ratio. 
E)  None of the 11 intermediates in the glycolytic pathway are phosphorylated. 
A)  It is activated by high [AMP]. 
B)  It results in a net synthesis of ATP. 
C)  It results in the synthesis of NAD+. 
D)  Its rate is slowed by a high [NADH]/ [NAD+] ratio. 
E)  None of the 11 intermediates in the glycolytic pathway are phosphorylated.

Question 12

Which statement regarding glycolysis is TRUE?

Accepted Answer

A)  Both substrate-level phosphorylation reactions in glycolysis are irreversible. 
B)  The oxidation reaction in glycolysis produces two high-energy molecules. 
C)  There are four isomerization reactions in glycolysis. 
D)  One inorganic phosphate is consumed as a substrate for each glucose molecule metabolized via glycolysis. 
E)  All of the statements are true. 
A)  Both substrate-level phosphorylation reactions in glycolysis are irreversible. 
B)  The oxidation reaction in glycolysis produces two high-energy molecules. 
C)  There are four isomerization reactions in glycolysis. 
D)  One inorganic phosphate is consumed as a substrate for each glucose molecule metabolized via glycolysis. 
E)  All of the statements are true.

Question 13

Which process does NOT occur in the steps of glycolysis between glyceraldehyde-3-phosphate and phosphoenolpyruvate?

Accepted Answer

A)  ATP synthesis. 
B)  an isomerization. 
C)  a hydration reaction. 
D)  phosphoryl transfer. 
E)  oxidation. 
A)  ATP synthesis. 
B)  an isomerization. 
C)  a hydration reaction. 
D)  phosphoryl transfer. 
E)  oxidation.

Question 14

When a muscle is stimulated to contract aerobically, less lactic acid is formed than when it contracts anaerobically because:

Accepted Answer

A)  glycolysis does not occur to significant extent under aerobic conditions. 
B)  muscle is metabolically less active under aerobic than anaerobic conditions. 
C)  the lactic acid generated is rapidly incorporated into lipids under aerobic conditions. 
D)  under aerobic conditions in muscle, the major energy-yielding pathway is the pentose phosphate pathway, which does not produce lactate. 
E)  under aerobic conditions most of the pyruvate generated as a result of glycolysis is oxidized by the citric acid cycle rather than reduced to lactate. 
A)  glycolysis does not occur to significant extent under aerobic conditions. 
B)  muscle is metabolically less active under aerobic than anaerobic conditions. 
C)  the lactic acid generated is rapidly incorporated into lipids under aerobic conditions. 
D)  under aerobic conditions in muscle, the major energy-yielding pathway is the pentose phosphate pathway, which does not produce lactate. 
E)  under aerobic conditions most of the pyruvate generated as a result of glycolysis is oxidized by the citric acid cycle rather than reduced to lactate.

Question 15

Two reactions, extra to the ten reactions of glycolysis, are involved in ethanol fermentation by yeast under anaerobic conditions. What is the purpose served by these two reactions in the metabolism of yeast cells?

Accepted Answer

A)  They are required to re-oxidize limited amounts of NADH. 
B)  They are required to ensure a net oxidation of glucose. 
C)  They are required to sustain glycolysis, ensuring ATP production. 
D)  They are required to both ensure a net oxidation of glucose and sustain glycolysis, ensuring ATP production 
E)  They are required to both re-oxidize limited amounts of NADH and sustain glycolysis, ensuring ATP production 
A)  They are required to re-oxidize limited amounts of NADH. 
B)  They are required to ensure a net oxidation of glucose. 
C)  They are required to sustain glycolysis, ensuring ATP production. 
D)  They are required to both ensure a net oxidation of glucose and sustain glycolysis, ensuring ATP production 
E)  They are required to both re-oxidize limited amounts of NADH and sustain glycolysis, ensuring ATP production

Question 16

Inorganic fluoride inhibits enolase. In an anaerobic system that is metabolizing glucose as a substrate, which compound would you expect to increase in concentration following the addition of fluoride?

Accepted Answer

A)  2-phosphoglycerate 
B)  glucose 
C)  glyoxylate 
D)  phosphoenolpyruvate 
E)  pyruvate 
A)  2-phosphoglycerate 
B)  glucose 
C)  glyoxylate 
D)  phosphoenolpyruvate 
E)  pyruvate

Question 17

The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate do NOT involve:

Accepted Answer

A)  ATP synthesis. 
B)  catalysis by phosphoglycerate kinase. 
C)  oxidation of NADH to NAD+. 
D)  the formation of 1,3-bisphosphoglycerate. 
E)  utilization of Pi. 
A)  ATP synthesis. 
B)  catalysis by phosphoglycerate kinase. 
C)  oxidation of NADH to NAD+. 
D)  the formation of 1,3-bisphosphoglycerate. 
E)  utilization of Pi.

Question 18

In glycolysis, fructose 1,6-bisphosphate is converted to two products with a standard free-energy change ($\Delta$G'°) of 23.8 kJ/mol. Under what conditions (encountered in a normal cell) will the free-energy change ($\Delta$G) be negative, enabling the reaction to proceed to the right?

Accepted Answer

A)  If the concentrations of the two products are high relative to that of fructose 1,6-bisphosphate. 
B)  The reaction will not go to the right spontaneously under any conditions because the $\Delta$G'° is positive. 
C)  Under standard conditions, enough energy is released to drive the reaction to the right. 
D)  When there is a high concentration of fructose 1,6-bisphosphate relative to the concentration of products. 
E)  When there is a high concentration of products relative to the concentration of fructose 1,6-bisphosphate. 
A)  If the concentrations of the two products are high relative to that of fructose 1,6-bisphosphate. 
B)  The reaction will not go to the right spontaneously under any conditions because the $\Delta$G'° is positive. 
C)  Under standard conditions, enough energy is released to drive the reaction to the right. 
D)  When there is a high concentration of fructose 1,6-bisphosphate relative to the concentration of products. 
E)  When there is a high concentration of products relative to the concentration of fructose 1,6-bisphosphate.

Question 19

Rat liver is able to metabolize glucose by both the glycolytic and the pentose phosphate pathways. Indicate in the blanks if the following are properties of glycolytic (G), pentose phosphate (P), both (G + P), or neither (0):
_____ NAD+ is involved.
_____ CO2 is liberated.
_____ Phosphate esters are intermediates.
_____ Glyceraldehyde 3-phosphate is an intermediate.
_____ Fructose 6-phosphate is an intermediate.

Accepted Answer

The question asks to identify whether th

Question 20

The compound [18F]2-fluoro-2-deoxyglucose is a(n):

Accepted Answer

A)  intermediate in glycolysis 
B)  positive regulator of glycolysis 
C)  potent anti-cancer agent 
D)  antibiotic 
E)  imaging agent used to detect tumors 
A)  intermediate in glycolysis 
B)  positive regulator of glycolysis 
C)  potent anti-cancer agent 
D)  antibiotic 
E)  imaging agent used to detect tumors

Exam 14: Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

If you incubate 14C-CO2 with liver extracts capable of performing gluconeogenesis, where does the radioactive label end up?

_____ is a product of pyruvate in erythrocytes.

Describe the glycolytic pathway from glucose to glyceraldehyde 3-phosphate. Show structures of intermediates, enzyme names, and indicate where any cofactors participate.

The yeast used in brewing the alcoholic beverage beer can break down glucose either aerobically or anaerobically using alcoholic fermentation. Explain why beer is brewed under anaerobic conditions.

Which statement is TRUE for glycolysis?

Which enzyme that is involved in the flow of carbon from glucose to lactate (glycolysis) is NOT also involved in the reversal of this flow (gluconeogenesis)?

Describe the glycolytic pathway from glyceraldehyde 3-phosphate to pyruvate, showing structures of intermediates and names of enzymes. Indicate where any cofactors participate.

In humans, gluconeogenesis:

Which reaction in glycolysis utilizes a covalent enzyme intermediate?

Which statement is FALSE concerning glycolysis?

Which statement regarding glycolysis is TRUE?

Which process does NOT occur in the steps of glycolysis between glyceraldehyde-3-phosphate and phosphoenolpyruvate?

When a muscle is stimulated to contract aerobically, less lactic acid is formed than when it contracts anaerobically because:

Two reactions, extra to the ten reactions of glycolysis, are involved in ethanol fermentation by yeast under anaerobic conditions. What is the purpose served by these two reactions in the metabolism of yeast cells?

Inorganic fluoride inhibits enolase. In an anaerobic system that is metabolizing glucose as a substrate, which compound would you expect to increase in concentration following the addition of fluoride?

The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate do NOT involve:

In glycolysis, fructose 1,6-bisphosphate is converted to two products with a standard free-energy change ( Δ\DeltaΔ G'°) of 23.8 kJ/mol. Under what conditions (encountered in a normal cell) will the free-energy change ( Δ\DeltaΔ G) be negative, enabling the reaction to proceed to the right?

The compound [18F]2-fluoro-2-deoxyglucose is a(n):

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

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If you incubate ¹⁴C-CO₂ with liver extracts capable of performing gluconeogenesis, where does the radioactive label end up?

In glycolysis, fructose 1,6-bisphosphate is converted to two products with a standard free-energy change ( $\Delta$ G'°) of 23.8 kJ/mol. Under what conditions (encountered in a normal cell) will the free-energy change ( $\Delta$ G) be negative, enabling the reaction to proceed to the right?

The compound [¹⁸F]2-fluoro-2-deoxyglucose is a(n):