
Concept explainers
(a)
Interpretation: To indicate whether lactate is involved in (1) the pentose phosphate pathway, (2) the Cori cycle, (3) glycolysis, or (4) lactate fermentation.
Concept introduction: The pentose phosphate pathway is defined as the metabolic pathway in which NADPH,
Glucose is converted to pyruvate by glycolysis metabolic pathway; pyruvate is further converted to lactate in the skeletal muscle cells by anaerobic reactions. The lactate is diffused into the bloodstream, by which it is transported to the liver. Lactate is reconverted to pyruvate. Gluconeogenesis metabolic pathway uses this pyruvate to synthesize glucose in the liver cells. Glucose is diffused into the bloodstream and is transported back to the active skeletal muscle cells. This cycle is known as the Cori cycle.
Glycolysis is the metabolic pathway that breaks down a glucose molecule and converts it into two pyruvate molecules along with the production of two ATP molecules and NADH coenzymes.
Fermentation is defined as the biochemical anaerobic process by which NADH is oxidized to
The structure of lactate is as follows:
(a)

Answer to Problem 24.105EP
Lactate is associated with (2) the Cori cycle and (4) the lactate fermentation.
Explanation of Solution
An overview of the Cori cycle is as follows:
Lactate is converted to pyruvate in the liver. Therefore, lactate is associated with the Cori cycle.
Pyruvate is converted to lactate under oxygen-poor conditions by lactate dehydrogenase enzymes in the human body. This anaerobic reduction of pyruvate to form lactate by enzymes is called lactate fermentation. The
Therefore, lactate is associated with the Cori cycle and the lactate fermentation.
(b)
Interpretation: To indicate whether
Concept introduction: The pentose phosphate pathway is defined as the metabolic pathway in which NADPH,
Glucose is converted to pyruvate by glycolysis metabolic pathway; pyruvate is further converted to lactate in the skeletal muscle cells by anaerobic reactions. The lactate is diffused into the bloodstream, by which it is transported to the liver. Lactate is reconverted to pyruvate. Gluconeogenesis metabolic pathway uses this pyruvate to synthesize glucose in the liver cells. Glucose is diffused into the bloodstream and is transported back to the active skeletal muscle cells. This cycle is known as the Cori cycle.
Glycolysis is the metabolic pathway that breaks down a glucose molecule and converts it into two pyruvate molecules along with the production of two ATP molecules and NADH coenzymes.
Pyruvate is converted to lactate under oxygen-poor conditions by lactate dehydrogenase enzymes in the human body. This anaerobic reduction of pyruvate to form lactate by enzymes is called lactate fermentation.
Nicotinamide adenine dinucleotide is associated with the
(b)

Answer to Problem 24.105EP
Explanation of Solution
An overview of the Cori cycle is as follows:
In the Cori cycle,
Pyruvate is converted to lactate under oxygen-poor conditions by lactate dehydrogenase enzymes in the human body. This anaerobic reduction of pyruvate to form lactate by enzymes is called lactate fermentation. The chemical reaction for the formation of lactate is as follows:
In the lactate fermentation, NADH is oxidized to
The net overall equation for the glycolysis process is as follows:
(c)
Interpretation: To indicate whether
Concept introduction: The pentose phosphate pathway is defined as the metabolic pathway in which NADPH,
Glucose is converted to pyruvate by glycolysis metabolic pathway; pyruvate is further converted to lactate in the skeletal muscle cells by anaerobic reactions. The lactate is diffused into the bloodstream, by which it is transported to the liver. Lactate is reconverted to pyruvate. Gluconeogenesis metabolic pathway uses this pyruvate to synthesize glucose in the liver cells. Glucose is diffused into the bloodstream and is transported back to the active skeletal muscle cells. This cycle is known as the Cori cycle.
Glycolysis is the metabolic pathway that breaks down a glucose molecule and converts it into two pyruvate molecules along with the production of two ATP molecules and NADH coenzymes.
Pyruvate is converted to lactate under oxygen-poor conditions by lactate dehydrogenase enzymes in the human body. This anaerobic reduction of pyruvate to form lactate by enzymes is called lactate fermentation.
(c)

Answer to Problem 24.105EP
Explanation of Solution
The first stage of the pentose phosphate pathway is the oxidative stage. In the oxidative stage (involves three steps) of the pentose phosphate pathway,
The general equation for the entire pentose phosphate pathway is as follows:
Therefore,
The net overall equation for the glycolysis process is as follows:
Glucose enters the glycolysis metabolic pathway in the form of
(d)
Interpretation: To indicate whether
Concept introduction: The pentose phosphate pathway is defined as the metabolic pathway in which NADPH,
Glucose is converted to pyruvate by glycolysis metabolic pathway; pyruvate is further converted to lactate in the skeletal muscle cells by anaerobic reactions. The lactate is diffused into the bloodstream, by which it is transported to the liver. Lactate is reconverted to pyruvate. Gluconeogenesis metabolic pathway uses this pyruvate to synthesize glucose in the liver cells. Glucose is diffused into the bloodstream and is transported back to the active skeletal muscle cells. This cycle is known as the Cori cycle.
Glycolysis is the metabolic pathway that breaks down a glucose molecule and converts it into two pyruvate molecules along with the production of two ATP molecules and NADH coenzymes.
Pyruvate is converted to lactate under oxygen-poor conditions by lactate dehydrogenase enzymes in the human body. This anaerobic reduction of pyruvate to form lactate by enzymes is called lactate fermentation.
(d)

Answer to Problem 24.105EP
Explanation of Solution
The first stage of the pentose phosphate pathway is the oxidative stage. In the oxidative stage (involves three steps) of the pentose phosphate pathway,
The first step of the second stage i.e. the non-oxidative stage of the pentose phosphate pathway is the isomerization of
Want to see more full solutions like this?
Chapter 24 Solutions
Study Guide with Selected Solutions for Stoker's General, Organic, and Biological Chemistry, 7th
- Determine if the following salt is neutral, acidic or basic. If acidic or basic, write the appropriate equilibrium equation for the acid or base that exists when the salt is dissolved in aqueous solution. If neutral, simply write only NR. Be sure to include the proper phases for all species within the reaction LiNO3arrow_forwardAn unknown weak acid with a concentration of 0.410 M has a pH of 5.600. What is the Ka of the weak acid?arrow_forward(racemic) 19.84 Using your reaction roadmaps as a guide, show how to convert 2-oxepanone and ethanol into 1-cyclopentenecarbaldehyde. You must use 2-oxepanone as the source of all carbon atoms in the target molecule. Show all reagents and all molecules synthesized along the way. & + EtOH H 2-Oxepanone 1-Cyclopentenecarbaldehydearrow_forward
- R₂ R₁ R₁ a R Rg Nu R₂ Rg R₁ R R₁₂ R3 R R Nu enolate forming R₁ R B-Alkylated carbonyl species or amines Cyclic B-Ketoester R₁₁ HOB R R₁B R R₁₂ B-Hydroxy carbonyl R diester R2 R3 R₁ RB OR R₂ 0 aB-Unsaturated carbonyl NaOR Aldol HOR reaction 1) LDA 2) R-X 3) H₂O/H₂O ketone, aldehyde 1) 2°-amine 2) acid chloride 3) H₂O'/H₂O 0 O R₁ R₁ R R₁ R₁₂ Alkylated a-carbon R₁ H.C R₁ H.C Alkylated methyl ketone acetoacetic ester B-Ketoester ester R₁ HO R₂ R B-Dicarbonyl HO Alkylated carboxylic acid malonic ester Write the reagents required to bring about each reaction next to the arrows shown. Next, record any regiochemistry or stereochemistry considerations relevant to the reaction. You should also record any key aspects of the mechanism, such as forma- tion of an important intermediate, as a helpful reminder. You may want to keep track of all reactions that make carbon-carbon bonds, because these help you build large molecules from smaller fragments. This especially applies to the reactions in…arrow_forwardProvide the reasonable steps to achieve the following synthesis.arrow_forwardIdentify which compound is more acidic. Justify your choice.arrow_forward
- Provide the reasonable steps to achieve the following synthesis.arrow_forwardWhen anisole is treated with excess bromine, the reaction gives a product which shows two singlets in 1H NMR. Draw the product.arrow_forward(ii) Draw a reasonable mechanism for the following reaction: CI NaOH heat OH (hint: SNAr Reaction) :arrow_forward
- Chemistry for Today: General, Organic, and Bioche...ChemistryISBN:9781305960060Author:Spencer L. Seager, Michael R. Slabaugh, Maren S. HansenPublisher:Cengage LearningGeneral, Organic, and Biological ChemistryChemistryISBN:9781285853918Author:H. Stephen StokerPublisher:Cengage LearningOrganic And Biological ChemistryChemistryISBN:9781305081079Author:STOKER, H. Stephen (howard Stephen)Publisher:Cengage Learning,
- Chemistry In FocusChemistryISBN:9781305084476Author:Tro, Nivaldo J., Neu, Don.Publisher:Cengage LearningChemistry: Matter and ChangeChemistryISBN:9780078746376Author:Dinah Zike, Laurel Dingrando, Nicholas Hainen, Cheryl WistromPublisher:Glencoe/McGraw-Hill School Pub CoIntroduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning




