Concept explainers
(a)
Interpretation:
Whether or not cholesterol produced from acetyl CoA (1) can be produced in a one-step process, (2) can be produced in a multistep process, or (3) cannot be produced from acetyl CoA has to be indicated.
Concept introduction:
Fatty acids are molecules that are long hydrocarbon chain of carboxylic acid. They are building blocks of fat in humans and animals.
The fatty acids are broken down to provide energy. The breakdown of fatty acids is a three parts process. In the first part, the fatty acid is activated. In the second part, the transportation of fatty acid into the mitochondrial matrix is facilitated by a shuttle mechanism. In the third part, the fatty acid is readily oxidized, cycling through a series of four reactions. In these series of reactions, acyl CoA is degraded to acetyl CoA. This pathway is termed as the β-oxidation pathway. Acetyl CoA, FADH2, and NADH are produced in this reaction.
Cholesterol is an important component of cell membranes. It is used as the precursor for sex hormones, bile salts, and adrenal hormones. The biosynthesis of cholesterol occurs in the liver. It is a C27 molecule. The structure of cholesterol is as follows:
(b)
Interpretation:
Whether or not acetoacetyl CoA produced from acetyl CoA (1) can be produced in a one-step process, (2) can be produced in a multistep process, or (3) cannot be produced from acetyl CoA has to be indicated.
Concept introduction:
Fatty acids are molecules that are long hydrocarbon chain of carboxylic acid. They are building blocks of fat in humans and animals.
The fatty acids are broken down to provide energy. The breakdown of fatty acids is a three parts process. In the first part, the fatty acid is activated. In the second part, the transportation of fatty acid into the mitochondrial matrix is facilitated by a shuttle mechanism. In the third part, the fatty acid is readily oxidized, cycling through a series of four reactions. In these series of reactions, acyl CoA is degraded to acetyl CoA. This pathway is termed as the β-oxidation pathway. Acetyl CoA, FADH2, and NADH are produced in this reaction.
Ketogenesis is a
cleavage and hydrogenation to produce ketone bodies.
(c)
Interpretation:
Whether or not malonyl CoA produced from acetyl CoA (1) can be produced in a one-step process, (2) can be produced in a multistep process, or (3) cannot be produced from acetyl CoA has to be indicated.
Concept introduction:
Fatty acids are molecules that are long hydrocarbon chain of carboxylic acid. They are building blocks of fat in humans and animals.
The fatty acids are broken down to provide energy. The breakdown of fatty acids is a three parts process. In the first part, the fatty acid is activated. In the second part, the transportation of fatty acid into the mitochondrial matrix is facilitated by a shuttle mechanism. In the third part, the fatty acid is readily oxidized, cycling through a series of four reactions. In these series of reactions, acyl CoA is degraded to acetyl CoA. This pathway is termed as theβ-oxidation pathway. Acetyl CoA, FADH2, and NADH are produced in this reaction.
Lipogenesis is the process employed for the synthesis of fatty acid. The starting precursor for the synthesis is acetyl CoA. The enzyme employed for the process is fatty acid synthase. It is a multienzyme complex that ties the reaction responsible for the synthesis of fatty acid.
A cyclic process occurs in the enzyme fatty acid synthase. One turn of this cyclic process
constitutes four reactions. The various intermediates formed in the process are associated
with a carrier protein known as ACP.
(d)
Interpretation:
Whether or not pyruvate produced from acetyl CoA (1) can be produced in a one-step process, (2) can be produced in a multistep process, or (3) cannot be produced from acetyl CoA has to be indicated.
Concept introduction:
Fatty acids are molecules that are long hydrocarbon chain of carboxylic acid. They are building blocks of fat in humans and animals.
The fatty acids are broken down to provide energy. The breakdown of fatty acids is a three parts process. In the first part, the fatty acid is activated. In the second part, the transportation of fatty acid into the mitochondrial matrix is facilitated by a shuttle mechanism. In the third part, the fatty acid is readily oxidized, cycling through a series of four reactions. In these series of reactions, acyl CoA is degraded to acetyl CoA. This pathway is termed as the β-oxidation pathway. Acetyl CoA, FADH2, and NADH are produced in this reaction.
Pyruvate is the end product in the glycolysis. In the presence of oxygen, pyruvate is converted to acetyl CoA by the involvement of pyruvate dehydrogenase complex enzymes in the human body.
Want to see the full answer?
Check out a sample textbook solutionChapter 14 Solutions
Organic And Biological Chemistry
- 17. In the urea cycle, ions are converted to urea. Da. pynuvate Ob. sodium Oc, ammonium Od. glutamate 18. Amino acids that are degraded into are termed ketogenic. Oa. a-ketoglutarate b. oxaloacetate Oc. fumarate Od. acetyl CoA 19. When 100 mg of a substance are required daily by the body, the substance would be classified as a a. micronutrient Ob. macronutrient C. nonessential nutrient d. more than one choice is correct 20. What role do most of the water-soluble vitamins have in the body? ca. catalysis b. hormone precursors Oc. components of cell membranes d. coenzymesarrow_forwardWhat metabolic intermediate is formed from the carbon skeleton of each amino acid? a. phenylalaninec. asparagine b. glutamic acidd. glycinearrow_forwardBased on the names of the enzymes participating in glycolysis, what would be the name of the enzyme catalyzing the activation of glycerol? A. Glycerol kinase B. Glycerol dehydrogenase C. Glycerol hydratase D. Glycerasearrow_forward
- 17. In the urea cycle, ions are converted to urea. a. рpyruvate b. sodium C. ammonium O d. glutamatearrow_forwardWhat is the key chemical reaction that is found in the first stage of metabolism?arrow_forward1. What is glycolysis? 2. Discuss the steps involved in glycolysis. 3. What are the enzymes used in each step? 4. Identify the chemical reactions in each step. 5. In which steps are coenzymes used? 6. In which steps are ATP used to activate the process? 7. In which steps are ATP produced? 8. How many ATPs are produced in the glycolysis of glucose molecule? Show the computations. 9. Show how the ATP is computed in the glycolysis process.arrow_forward
- During exercise, oxygen is used up rapidly which slows down the rate of the common catabolic pathway. which causes Excess pyruvate ends up as painful muscle contrations. A. Acetaldehyde B. Ethanol C. Lactate D. Acetyl COAarrow_forwardGlycolysis, A. is the breakdown of glucose to two pyruvic acid molecules. B. requires the input of two ATP molecules. C. produces two NADH molecules. D. does not require oxygen. E. all of the above.arrow_forward
- Organic And Biological ChemistryChemistryISBN:9781305081079Author:STOKER, H. Stephen (howard Stephen)Publisher:Cengage Learning,General, Organic, and Biological ChemistryChemistryISBN:9781285853918Author:H. Stephen StokerPublisher:Cengage LearningChemistry for Today: General, Organic, and Bioche...ChemistryISBN:9781305960060Author:Spencer L. Seager, Michael R. Slabaugh, Maren S. HansenPublisher:Cengage Learning