Concept explainers
(a)
Interpretation:
The role of acetyl-CoA in the reactions of Ketogenesis should be determined.
Concept introduction:
Ketogenesis is a process by which acetyl CoA is converted into
Ketone bodies are
Acetoacetate, acetone and
(b)
Interpretation:
The number of acetyl-CoA molecules which are used in the production of ketone bodies should be determined.
Concept introduction:
Ketogenesis is a process by which acetyl CoA is converted into ketone bodies.
Ketone bodies are metabolic products that are produced in excess during excessive breakdown of fatty acids. They are water soluble and energy yielding. In a normal man, concentration of ketone bodies in the blood is usually less than
Acetoacetate, acetone and
(c)
Interpretation:
The essential role of ketone bodies during prolonged starvation should be determined.
Concept introduction:
Ketogenesis is a process by which acetyl CoA is converted into ketone bodies.
Ketone bodies are metabolic products that are produced in excess during excessive breakdown of fatty acids. They are water soluble and energy yielding. In a normal man, concentration of ketone bodies in the blood is usually less than
Acetoacetate, acetone and
Gluconeogenesis is the process of formation of glucose from non-carbohydrate sources. The process occurs only in liver and kidney, partially occurs in cytoplasm and in mitochondria
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FUND.OF GEN CHEM CHAP 1-13 W/ACCESS
- For each of the steps below, choose (A) if the step pertains to b-oxidation, (B) if the step pertains to fatty acid synthesis, or (C) if the step is common to both processes. ______ Acetyl CoA is produced as a product.______ Activation (the committed step of the process) requires ATP hydrolysis. ______ Accumulated acetyl CoA serves as a substrate.______ The length of fatty acid carbon chain is modified in the mitochondria. ______ ACP acts as the acyl carrier.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_forwardIn the complete b-oxidation of stearic acid (18:0), a)how many moles of acetyl CoA are produced? ________ b)how many times would the fatty acid pass through the fatty acid spiral for complete oxidation? ________ c)what is the total ATP produced in the citric acid cycle? ________ d)how many moles of NADH are produced? ________ e)how many moles of FADH2 are produced? ________ f)how many moles of ATP are produced after all NADH are reoxidized in the respiratory chain? ________ g)how many moles of ATP are produced after all FADH2 are…arrow_forward
- (8) B-ketothiolase is a multifunctional enzyme in lipid catabolism. Which of the following is NOT one of its functions? (A) It catalyzes the release of (2) acetyl CoA from acetoacetyl CoA during ketolysis. (B) It removes an acetyl CoA from the fatty acyl chain during B-oxidation. (C) It forms acetoacetate by removing acetyl CoA from HMG CoA during ketogenesis. (D) It condenses (2) acetyl CoA molecules to form acetoacetyl CoA during ketogenesis. (9) What is HMG-COA, in the context of fatty acid catabolism? (A) a product of fatty acid oxidation (B) a ketone body made in liver cells (C) a 6-carbon precursor to the acetoacetate ketone body (D) a 4-carbon precursor to the acetoacetate ketone body (E) a product formed when the B-hydroxybutyrate ketone body is oxidized in brain cells (10) Which of the following symptoms might you expect to see in a patient with defective acyl CoA dehydrogenase under fasting conditions? (A) slowed gluconeogenesis in liver (B) hypoglycemia (C) elevated glycogen…arrow_forwardWhat is the reason that amino acid degradation spikes approximately 24 hours after starting a fast? (A) The brain adapts to using ketone bodies, and amino acids serve as the primary precursors for ketone bodies.(B) Red blood cells begin using amino acids to drive their citric acid cycle.(C) Amino acids are broken down and used to replenish glycogen. (D) The liver needs to make glucose for brain and RBCs, and amino acids provide the carbon skeleton for gluconeogenesis.(E) The ammonia released from amino acid breakdown is a substrate for b-oxidation, which increases during prolonged fasting.arrow_forwardHow many acetyl CoA molecules are produced in one cycle of beta oxidation? How many cycles would it take to catabolize a stearic acid molecule (a fatty acid, [18:0]) into acetyl Co A units? a)How many acetyl CoA molecules would be produced? b) How many reduced nucleotides would be produced? c) If a molecule of glucose produces a net 32 ATP when completely catabolized, which do you think will produce more energy, one molecule of glucose or one molecule of stearic acid? Justify your answer.arrow_forward
- In the complete b-oxidation of stearic acid (18:0), a) how many moles of acetyl CoA are produced? b) how many times would the fatty acid pass through the fatty acid spiral for complete oxidation? c) what is the total ATP produced in the citric acid cycle? d) how many moles of NADH are produced? e) how many moles of FADH2 are produced? f) how many moles of ATP are produced after all NADH are reoxidized in the respiratory chain? g) how many moles of ATP are produced after all FADH2 are reoxidized in the respiratory chain? h) how many moles of ATP are produced from the complete oxidation of stearic acid?arrow_forwardHow many acetyl CoA molecules can be produced during the complete β-oxidation of this fatty acid?arrow_forwardWhere does the carbon come from that is used to synthesize ketone bodies? a) Acetyl-CoA generated by decarboxylation of pyruvate b) Acetyl-CoA generated by deamination of amino acids c) Acetyl-CoA generated by beta-oxidation of fatty acids.arrow_forward
- Which of the following statements is/are TRUE about fatty acid activation before β-oxidation? I. The process consumes energy equivalent to two moles of ATP. II. The fatty acid is activated by ATP to give a fatty acyl-CoA.arrow_forwardHow is the production of ketone bodies related to ketoacidosis?arrow_forwardIf we label the two carbons composing the acetyl group of acetyl-CoA with 14C, a radioactive isotope of carbon, and this labeled acetyl-CoA enters the TCA cycle, then which CO2 released by one turn of the TCA cycle will be labeled? 1) Both. 2) Only the CO2 released by the oxidation of alpha-ketoglutarate. 3) Only the CO2 released by the oxidation of isocitrate. 4) Neither.arrow_forward
- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning