Concept explainers
(a)
Interpretation:
Whether the carnitine shuttle system is used among (1) the β-oxidation pathway, (2) ketogenesis, or (3) lipogenesis has to be identified.
Concept introduction:
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. The fatty acid is synthesized in two parts. In the first part, there is citrate-malate shuttle system and in the second part, there is a cyclic process to synthesize saturated fatty acid.
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 a β-oxidation pathway.
Ketogenesis is a
(b)
Interpretation:
Whether malonyl ACP is a reactant among (1) the β-oxidation pathway, (2) ketogenesis, or (3) lipogenesis has to be identified.
Concept introduction:
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. The fatty acid is synthesized in two parts. In the first part, there is citrate-malate shuttle system and in the second part, there is a cyclic process to synthesize saturated fatty acid.
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 a β-oxidation pathway.
Ketogenesis is a metabolic process by which ketone bodies are produced by the breakdown of fatty acids and ketogenic amino acids. This metabolic process supplies our organs with needed energy under certain circumstances such as starvation. Fatty acid molecules degrade into acetyl CoA which are utilized as reactants in the process of ketogenesis. These molecules of acetyl CoA undergo the process of condensation twice, followed by chain cleavage and hydrogenation to produce ketone bodies.
(c)
Interpretation:
Whether CO2 is a product among (1) the β-oxidation pathway, (2) ketogenesis, or (3) lipogenesis has to be identified.
Concept introduction:
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. The fatty acid is synthesized in two parts. In the first part, there is citrate-malate shuttle system and in the second part, there is a cyclic process to synthesize saturated fatty acid.
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 a β-oxidation pathway.
Ketogenesis is a metabolic process by which ketone bodies are produced by the breakdown of fatty acids and ketogenic amino acids. This metabolic process supplies our organs with needed energy under certain circumstances such as starvation. Fatty acid molecules degrade into acetyl CoA which are utilized as reactants in the process of ketogenesis. These molecules of acetyl CoA undergo the process of condensation twice, followed by chain cleavage and hydrogenation to produce ketone bodies.
(d)
Interpretation:
Whether molecular O2 is needed among (1) the β-oxidation pathway, (2) ketogenesis, or (3) lipogenesis has to be identified.
Concept introduction:
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. The fatty acid is synthesized in two parts. In the first part, there is citrate-malate shuttle system and in the second part, there is a cyclic process to synthesize saturated fatty acid.
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 a β-oxidation pathway.
Ketogenesis is a metabolic process by which ketone bodies are produced by the breakdown of fatty acids and ketogenic amino acids. This metabolic process supplies our organs with needed energy under certain circumstances such as starvation. Fatty acid molecules degrade into acetyl CoA which are utilized as reactants in the process of ketogenesis. These molecules of acetyl CoA undergo the process of condensation twice, followed by chain cleavage and hydrogenation to produce ketone bodies.
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General, Organic, and Biological Chemistry
- Which of the following statements about the "central role" of TCA is/are correct? a. Some metabolic intermediates of TCA are used as non-carbohydrate sources for gluconeogenesis. b. β-oxidation of lipids produces acetyl-CoA that can enter TCA. c. All metabolic intermediates in TCA are used in the biosynthesis of amino acids. d. Degraded amino acids are converted to metabolic intermediates of TCA, then to ketone bodies.arrow_forwardWhen one acetyl CoA is processed through the citric acid cycle, how many times does each of the following events occur? a. A FAD molecule is a reactant. b. A CoA-SH molecule is produced. c. A dehydrogenase enzyme is needed for the reaction to occur. d. A C5 molecule is produced.arrow_forwardIf your liver cells contained a mutation in ACC2 that rendered it constitutively inactive, what two downstream effects might you see as a result? Choose the TWO correct answers. (A) overproduction of malonyl CoA in the mitochondria (B) increase in ketone body synthesis(C) decreased rates of fatty acid oxidation(D) fewer VLDL particles produced by the liver (E) accumulation of fatty acyl-CoA in the cytoplasmarrow_forward
- If two molecules of palmitoyl acid enters the beta-oxidation, how many acetyl-CoA and NADH molecules are formed?arrow_forwardPlace the following list of reactions or relevant locations in the β oxidation of fatty acids in the proper order. (a) Reaction with carnitine (b) Fatty acid in the cytoplasm (c) Activation of fatty acid by joining to CoA (d) Hydration (e) NAD+ -linked oxidation (f) Thiolysis (g) Acyl CoA in mitochondrion (h) FAD-linked oxidation.arrow_forwardExplain the difference of carbohydrate (glycolysis) from lipid (β-oxidation) metabolism in terms of producing an acetyl-coA that will enter the Kreb cycle?arrow_forward
- Identify the Krebs cycle enzyme that consumes a six-carbon substrate molecule, producing a six-carbon product molecule, but neither consumes nor produces NADH? A. a-ketoglutarate dehydrogenase B. isocitrate dehydrogenase C. succinyl CoA synthetase D. malate dehydrogenase E. aconitasearrow_forwardNot all of the acetyl-CoA from the mitochondria is carboxylated to malonyl-CoA because some are used in the? a.ß-oxidation cycles b.production of ATP c.priming step of the fatty acid biosynthesis d.conversion to pyruvatearrow_forwarda) What is the reason for the non-oxidative phase of the pentose phosphate pathway?b) Which compound is converted into which compound in the step where sequential dehydration and hydration reactions occur in the citric acid cycle?c) Why is ammonia released in some tissues carried by binding to other molecules in the blood? Where is it transmitted in the body for its destruction? What molecule is it transferred onto there? So what molecule does it make?arrow_forward
- Statin drugs are used to treat hypercholesterolemia because they a. prevent cholesterol from inserting in plasma membranes b. prevent cholesterol ester formation c. inhibit HMG-CoA reductase d. stimulate HMG-CoA synthasearrow_forwardThe rate-limiting step in fatty acid synthesis is: a. The reduction of the acetoacetyl group to a ?-hydroxybutyryl group b. Formation of malonyl-CoA from malonate and coenzyme A. c. Condensation of acetyl-CoA and malonyl-CoA. d. The reaction catalyzed by acetyl-CoA carboxylase.arrow_forwardThe pathway that converts glucose to acetyl-CoA is often referred to as an “aerobic oxidation pathway.” (a) Is molecular boxygen involved in any of the steps of glycolysis? (b) Thinking back to Chapter 20, where does molecular oxygen enter the picture?arrow_forward
- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning