Harper's Biochemistry Chapter 22 - Oxidation of Fatty Acids: Ketogenesis
91 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a potential consequence of excessive ketone body production during prolonged diabetes?

  • Diabetic neuropathy
  • Hypoglycemia
  • Ketoacidosis (correct)
  • Fatty liver disease

Which substance is critical as a coenzyme in the process of fatty acid oxidation?

  • Coenzyme A
  • ATP
  • Vitamin D
  • NAD+ (correct)

What happens to fatty acids before they are catabolized in the body?

  • They are converted into carbohydrates.
  • They are activated. (correct)
  • They are sent to the blood for transport.
  • They are broken down into glucose.

What condition can lead to impaired fatty acid oxidation and subsequent hypoglycemia?

<p>Carnitine deficiency (A)</p> Signup and view all the answers

How are long-chain fatty acids transported in plasma?

<p>Bound to albumin (C)</p> Signup and view all the answers

Which type of fatty acids is more water-soluble?

<p>Short-chain fatty acids (C)</p> Signup and view all the answers

Which process is directly dependent on fatty acid oxidation?

<p>Gluconeogenesis (C)</p> Signup and view all the answers

What is the primary role of acetoacetate in extrahepatic tissues?

<p>It is converted back to acetoacetyl-CoA for energy production. (D)</p> Signup and view all the answers

Which compound directly links O-acyl-CoA to acetoacetate for energy utilization?

<p>Succinyl-CoA (C)</p> Signup and view all the answers

In the oxidation of unsaturated fatty acids, which alteration occurs during the β-oxidation cycle?

<p>Conversion of Δ3-cis double bonds to Δ3-trans double bonds. (D)</p> Signup and view all the answers

What is the end product of the reversible reaction involving 3-hydroxybutyrate during its utilization?

<p>Acetoacetate (D)</p> Signup and view all the answers

Which of the following statements correctly describes the production of ketone bodies in the liver?

<p>Results from an active enzymatic mechanism producing acetoacetate from acetoacetyl-CoA. (C)</p> Signup and view all the answers

What two carbon units are formed during beta-oxidation?

<p>Acetyl-CoA (D)</p> Signup and view all the answers

Which enzyme catalyzes the removal of hydrogen atoms during the first step of beta-oxidation?

<p>Acyl-CoA dehydrogenase (D)</p> Signup and view all the answers

What is the role of carnitine in fatty acid oxidation?

<p>It facilitates the transportation of long-chain fatty acids into the mitochondria. (B)</p> Signup and view all the answers

How many acetyl-CoA molecules are generated from palmitoyl-CoA (C16) during beta-oxidation?

<p>8 (B)</p> Signup and view all the answers

What are the reducing equivalents generated during the beta-oxidation pathway?

<p>NADH and FADH2 (A)</p> Signup and view all the answers

What type of reaction occurs at the beta (3) carbon during the beta-oxidation of fatty acids?

<p>Oxidation (B)</p> Signup and view all the answers

Which statement accurately describes the cleavage process in beta-oxidation?

<p>It cleaves fatty acids in a cyclic manner. (A)</p> Signup and view all the answers

What product is directly formed from the oxidation of acyl-CoA in the beta-oxidation pathway?

<p>Acetyl-CoA (D)</p> Signup and view all the answers

What is the significance of FADH2 and NADH produced in the beta-oxidation process?

<p>They are utilized in oxidative phosphorylation for ATP production. (B)</p> Signup and view all the answers

What is the net gain of ATP per mole of palmitate after considering activation?

<p>106 mol (B)</p> Signup and view all the answers

How many moles of FADH2 are produced during the complete oxidation of palmitate?

<p>7 mol (B)</p> Signup and view all the answers

What percentage of the free energy of combustion of palmitic acid is represented by the generated ATP?

<p>33% (B)</p> Signup and view all the answers

Which component of the ATP generation process is involved in the activation step?

<p>ATP (D)</p> Signup and view all the answers

During β-oxidation, how much ATP is produced from NADH per mole of palmitate?

<p>17.5 mol (B)</p> Signup and view all the answers

What is the total ATP used during the complete oxidation of palmitate?

<p>2 mol (B)</p> Signup and view all the answers

How many moles of Acetyl-CoA are produced from the oxidation of one mole of palmitate?

<p>8 mol (C)</p> Signup and view all the answers

What is the total ATP formed through both β-oxidation and the citric acid cycle from palmitate?

<p>108 mol (B)</p> Signup and view all the answers

Which of the following steps does NOT contribute to the generation of ATP when oxidizing palmitate?

<p>Activation step (B)</p> Signup and view all the answers

What is the total ATP formed per mole of palmitate after accounting for the ATP used in activation?

<p>106 mol (C)</p> Signup and view all the answers

Which of the following is a ketone body?

<p>D-3-Hydroxybutyrate (C)</p> Signup and view all the answers

What is the role of NAD+ in the reaction involving D-3-Hydroxybutyrate?

<p>It acts as an oxidizing agent. (D)</p> Signup and view all the answers

Which compound is an intermediate in the conversion to acetone?

<p>Acetoacetate (D)</p> Signup and view all the answers

Which of the following statements about ketone bodies is true?

<p>They are produced primarily during fatty acid oxidation. (A)</p> Signup and view all the answers

In the context of ketogenesis, what happens to NADH?

<p>It is oxidized to form NAD+ and release energy. (D)</p> Signup and view all the answers

Which reaction involves the formation of acetoacetate?

<p>The oxidation of fatty acids. (B)</p> Signup and view all the answers

Which of the following ketone bodies is not a direct product of fatty acid oxidation?

<p>Acetyl-CoA (B)</p> Signup and view all the answers

Which enzyme is responsible for the conversion of acetoacetate to D-3-Hydroxybutyrate?

<p>D-3-Hydroxybutyrate dehydrogenase (C)</p> Signup and view all the answers

What structural feature distinguishes ketone bodies from other metabolic products?

<p>Presence of a carbonyl group. (C)</p> Signup and view all the answers

What is a major fate of D-3-Hydroxybutyrate in the body?

<p>It is converted back to acetyl-CoA for energy production. (C)</p> Signup and view all the answers

Which of the following statements correctly describes the process of fatty acid breakdown in the mitochondria?

<p>Fatty acids are degraded to acetyl-CoA and release energy through a separate process. (C)</p> Signup and view all the answers

During ketogenesis, which of the following conditions favors the synthesis of ketone bodies?

<p>Low insulin levels and high fatty acid availability. (C)</p> Signup and view all the answers

Which compound is NOT one of the three primary ketone bodies produced in liver mitochondria?

<p>Glycerol (D)</p> Signup and view all the answers

What is the primary consequence of excessive ketone body production in the body?

<p>Development of ketoacidosis if prolonged. (A)</p> Signup and view all the answers

Which stage of fatty acid metabolism is known to be regulated in regard to ketogenesis?

<p>Conversion of acetyl-CoA to ketone bodies. (D)</p> Signup and view all the answers

What characterizes the separation of fatty acid oxidation from biosynthesis in the cell?

<p>Fatty acid oxidation occurs in mitochondria while biosynthesis occurs in the cytosol. (C)</p> Signup and view all the answers

Impaired fatty acid oxidation can lead to which of the following conditions?

<p>Hypoglycemia. (D)</p> Signup and view all the answers

What is the primary product formed from the successive cleavage of fatty acids during β-oxidation?

<p>Acetyl-CoA (B)</p> Signup and view all the answers

Which enzyme is responsible for the transfer of acyl groups from CoA to carnitine in the transport of long-chain fatty acids?

<p>Carnitine palmitoyltransferase-I (B)</p> Signup and view all the answers

What type of bond is formed during the first step of β-oxidation at the α and β carbon atoms?

<p>Alkene bond (D)</p> Signup and view all the answers

During β-oxidation, which of the following compounds is generated as a reducing equivalent?

<p>FADH2 (A)</p> Signup and view all the answers

What role do FADH2 and NADH play in relation to ATP production during the β-oxidation cycle?

<p>They are utilized in oxidative phosphorylation to form ATP. (D)</p> Signup and view all the answers

What is necessary for the fatty acyl-CoA to cross the inner mitochondrial membrane?

<p>Carnitine (A)</p> Signup and view all the answers

In the β-oxidation pathway, how many acetyl-CoA molecules will palmitic acid (C16) yield?

<p>8 (C)</p> Signup and view all the answers

Which of the following correctly describes the β-oxidation cycle?

<p>It results in the repetitive cleavage of fatty acids into acetyl-CoA units. (D)</p> Signup and view all the answers

Which statement about the generation of reducing equivalents during β-oxidation is true?

<p>Both NADH and FADH2 are generated during the pathway. (B)</p> Signup and view all the answers

What role does NADPH play in the process described?

<p>It acts as a reducing agent during ketogenesis. (A)</p> Signup and view all the answers

Which step in the process of ketogenesis requires the addition of CoA?

<p>Breakdown of acetoacetyl-CoA by thiolase (B)</p> Signup and view all the answers

How does the concentration of ketone bodies affect oxidative machinery?

<p>It leads to saturation of the oxidative machinery. (B)</p> Signup and view all the answers

What is the possible consequence of extreme ATP yields from NADPH sources in relation to ketone body levels?

<p>Potential inhibition of ketogenesis (C)</p> Signup and view all the answers

What is indicated by a rise in blood levels of ketone bodies to 12 mmol/L?

<p>Saturation of the oxidative machinery (D)</p> Signup and view all the answers

What is the role of HMG-CoA lyase in ketogenesis?

<p>It facilitates the splitting of acetoacetyl-CoA into acetoacetate and acetyl-CoA. (C)</p> Signup and view all the answers

Which of the following is predominantly produced during ketosis?

<p>D-3-Hydroxybutyrate (A)</p> Signup and view all the answers

What is required in the mitochondria for ketogenesis to occur?

<p>Both HMG-CoA synthase and HMG-CoA lyase. (D)</p> Signup and view all the answers

From which molecule is D-3-Hydroxybutyrate formed?

<p>Acetoacetate (D)</p> Signup and view all the answers

Which substrate undergoes β-oxidation to contribute to the formation of ketone bodies?

<p>Fatty acids (A)</p> Signup and view all the answers

What is the result of the condensation reaction catalyzed by HMG-CoA synthase?

<p>Formation of HMG-CoA. (B)</p> Signup and view all the answers

Where in mammals does ketogenesis primarily take place?

<p>In the liver and rumen epithelium. (C)</p> Signup and view all the answers

During β-oxidation, what is the fate of a fatty acid before it can contribute to ketone body formation?

<p>It undergoes dehydrogenation and cleavage to form acetyl-CoA. (B)</p> Signup and view all the answers

Which of the following is NOT a direct step in the production of ketone bodies?

<p>Synthesis of cholesterol from acetyl-CoA. (C)</p> Signup and view all the answers

What is the primary product formed when 3-hydroxyacyl-CoA undergoes dehydrogenation during beta-oxidation?

<p>3-ketoacyl-CoA (C)</p> Signup and view all the answers

During the complete beta-oxidation of a long-chain fatty acid, what is the outcome of each cycle in terms of products created?

<p>1 Acetyl-CoA and 1 FADH2 (B)</p> Signup and view all the answers

What role does thiolase play in the beta-oxidation pathway?

<p>Cleaves 3-ketoacyl-CoA to generate Acetyl-CoA (B)</p> Signup and view all the answers

Which compound remains at the end of fatty acid oxidation for odd-chain fatty acids?

<p>Propionyl-CoA (D)</p> Signup and view all the answers

How many cycles of beta-oxidation are required to completely oxidize palmitate (C16)?

<p>7 (D)</p> Signup and view all the answers

What is the total gross ATP yield from the complete oxidation of palmitate, after considering activation energy?

<p>108 ATP (C)</p> Signup and view all the answers

Which coenzyme is specifically involved in the conversion of 3-hydroxyacyl-CoA to its corresponding 3-keto derivative?

<p>NAD+ (B)</p> Signup and view all the answers

What is the end product of the complete oxidation pathway for a C16 fatty acid in terms of ATP production?

<p>80 ATP (A)</p> Signup and view all the answers

What is the significance of the propionyl residue that remains after the beta-oxidation of odd-chain fatty acids?

<p>It is used to synthesize glucose. (D)</p> Signup and view all the answers

In beta-oxidation, how many moles of NADH are generated from the complete oxidation of palmitate?

<p>7 (A)</p> Signup and view all the answers

Match the ketone bodies with their corresponding properties:

<p>Acetoacetate = Direct product of fatty acid oxidation D-3-Hydroxybutyrate = Used as a fuel by extrahepatic tissues Acetone = Volatile and not used for energy Ketone bodies = Produced during high rates of fatty acid oxidation</p> Signup and view all the answers

Match the stages of fatty acid metabolism with their descriptions:

<p>Activation = Process of preparing fatty acids for transport β-oxidation = Pathway for breaking down fatty acids to acetyl-CoA Ketogenesis = Production of ketone bodies in the liver Fatty acid synthesis = Formation of fatty acids from acetyl-CoA</p> Signup and view all the answers

Match the conditions with their effects on ketone body production:

<p>High fatty acid oxidation = Increased ketone body synthesis Prolonged fasting = Leads to ketosis Diabetes = Causes excessive ketone body production Normal metabolism = Utilization of ketone bodies for energy</p> Signup and view all the answers

Match the terms with their corresponding definitions:

<p>Acetyl-CoA = End product of fatty acid oxidation Ketosis = Excessive accumulation of ketone bodies Ketoacidosis = Pathological condition from prolonged ketosis Mitochondria = Site of fatty acid oxidation</p> Signup and view all the answers

Match the enzymes with their roles in fatty acid metabolism:

<p>Carnitine acyltransferase = Transfers acyl groups from CoA to carnitine Acyl-CoA dehydrogenase = Catalyzes the initial step of β-oxidation β-hydroxyacyl-CoA dehydrogenase = Converts D-3-hydroxybutyrate to acetoacetate Thiolase = Cleaves acyl-CoA to form acetyl-CoA</p> Signup and view all the answers

Match the following enzymes with their functions in the β-oxidation pathway:

<p>Acyl-CoA dehydrogenase = Removes hydrogen atoms and forms FADH2 Carnitine palmitoyltransferase-I = Transfers acyl groups from CoA to carnitine Carnitine palmitoyltransferase-II = Reforms acyl-CoA from acylcarnitine Translocase = Transports acylcarnitine into the mitochondrial matrix</p> Signup and view all the answers

Match the following products to their sources in the β-oxidation pathway:

<p>Acetyl-CoA = Formed from cleavage of fatty acyl-CoA FADH2 = Generated during the oxidation of acyl-CoA NADH = Produced in later steps of fatty acid oxidation Acylcarnitine = Formed during the transfer of acyl groups to carnitine</p> Signup and view all the answers

Match the following statements with their corresponding terms in β-oxidation:

<p>Triglycerides = Storage form of fatty acids Acyl-CoA = Activated fatty acid for oxidation β-Oxidation = Process of breaking down fatty acids Cyclic pathway = Describes the repetitive nature of β-oxidation</p> Signup and view all the answers

Match the following fatty acids with their number of Acetyl-CoA produced during β-oxidation:

<p>Palmitic acid (C16) = 8 Acetyl-CoA Stearic acid (C18) = 9 Acetyl-CoA Oleic acid (C18:1) = 9 Acetyl-CoA Lauric acid (C12) = 6 Acetyl-CoA</p> Signup and view all the answers

Match the following outcomes to their respective processes in β-oxidation:

<p>NADH and FADH2 generation = Result of acyl-CoA oxidation ATP formation = Outcome of oxidative phosphorylation Transport of long-chain fatty acids = Involves carnitine Removal of two carbons = Occurs in each cycle of β-oxidation</p> Signup and view all the answers

Flashcards

Fatty Acid Oxidation

The breakdown of fatty acids to generate energy. It's crucial for producing ATP and is a key component of energy production during starvation and in conditions like diabetes.

Ketone Bodies

Byproducts of fatty acid breakdown. They are acidic and when produced excessively, like in diabetes, can cause ketoacidosis.

Ketoacidosis

A dangerous condition caused by excess ketone bodies in the blood, often associated with diabetes.

Gлуconeogenesis

The process of producing glucose from non-carbohydrate sources, like fatty acids. It's dependent on fatty acid oxidation.

Signup and view all the flashcards

Free Fatty Acids (FFAs)

Unesterified fatty acids in the blood, often bound to albumin for transport.

Signup and view all the flashcards

Carnitine

Essential for transporting long-chain fatty acids into the mitochondria for breakdown.

Signup and view all the flashcards

Carnitine Palmitoyltransferase

An enzyme crucial for the transport of fatty acids into the mitochondria.

Signup and view all the flashcards

Acyl-CoA

A key intermediate in the fatty acid oxidation process.

Signup and view all the flashcards

Inner Mitochondrial Membrane

The membrane within mitochondria where fatty acid breakdown occurs.

Signup and view all the flashcards

β-oxidation of fatty acids

A metabolic pathway that breaks down fatty acids into acetyl-CoA molecules, releasing energy.

Signup and view all the flashcards

acetyl-CoA

A molecule that is an important intermediate in metabolism, and is formed as a product of fatty acid breakdown.

Signup and view all the flashcards

β-oxidation cycle

Cyclic process in the mitochondrial matrix that degrades long-chain fatty acids into acetyl-CoA, generating FADH2 and NADH.

Signup and view all the flashcards

Fatty acid cleavage

The process of breaking a fatty acid chain into smaller molecules, releasing energy in the process.

Signup and view all the flashcards

FADH2 and NADH

Electron carriers produced during β-oxidation that transport electrons to the electron transport chain, contributing to ATP generation.

Signup and view all the flashcards

Acyl-CoA dehydrogenase

Enzyme that removes hydrogen atoms during β-oxidation, forming trans-Δ2-enoyl-CoA and generating FADH2.

Signup and view all the flashcards

Carnitine's role in fatty acid transport

Acyl-CoA molecules are converted to acylcarnitine for transport across the inner mitochondrial membrane; carnitine shuttles the fatty acid into the mitochondrial matrix for breakdown.

Signup and view all the flashcards

Ketone Bodies

Byproducts of fatty acid breakdown, including acetone, acetoacetate, and beta-hydroxybutyrate.

Signup and view all the flashcards

Acetoacetate

A ketone body produced during fatty acid metabolism.

Signup and view all the flashcards

Acetone

A volatile ketone body, often detectable in the breath.

Signup and view all the flashcards

Beta-hydroxybutyrate

Another type of ketone body, derived from fatty acid oxidation.

Signup and view all the flashcards

Palmitate oxidation

The breakdown of a 16-carbon fatty acid (palmitate) to produce ATP.

Signup and view all the flashcards

Activation step (fatty acid)

The initial step in fatty acid oxidation, where the fatty acid is prepared for further processing, consuming 2 ATP.

Signup and view all the flashcards

β-oxidation

A metabolic pathway where fatty acids are broken down into acetyl-CoA molecules, generating FADH2 and NADH.

Signup and view all the flashcards

FADH2 and NADH

Electron carriers produced during β-oxidation, carrying high-energy electrons to the electron transport chain.

Signup and view all the flashcards

Citric acid cycle

A series of reactions where acetyl-CoA is further oxidized, producing ATP and other energy-carrying molecules.

Signup and view all the flashcards

ATP production (palmitate)

The complete oxidation of 1 molecule of palmitate generates 106 molecules of ATP.

Signup and view all the flashcards

ATP used (activation)

2 molecules of ATP are consumed in the activation step of fatty acid oxidation.

Signup and view all the flashcards

Ketone Body Fuel source

Ketone bodies are utilized by extrahepatic tissues as an alternative energy source, particularly during prolonged fasting or in cases of uncontrolled diabetes.

Signup and view all the flashcards

Acetoacetate activation

Acetoacetate, a ketone body, is activated to acetoacetyl-CoA in extrahepatic tissues by the enzyme succinyl-CoA-acetoacetate-CoA transferase.

Signup and view all the flashcards

Fatty Acid Oxidation and Unsaturated Fatty Acids

β-oxidation of unsaturated fatty acids, like linoleic acid, proceeds similarly to saturated fatty acids until isomerization of a cis double bond at position Δ3, enabling more β-oxidation cycles to occur (Δ2-trans-Δ4-cis).

Signup and view all the flashcards

Acetoacetate to Acetoacetyl-CoA

Acetoacetyl-CoA is formed from acetoacetate, initiating further metabolic pathways.

Signup and view all the flashcards

3-Hydroxybutyrate Utilization

3-hydroxybutyrate, another ketone body, is converted back to acetoacetate in extrahepatic tissues, creating NADH in the process.

Signup and view all the flashcards

Fatty Acid Oxidation

The breakdown of fatty acids in mitochondria to produce energy in the form of acetyl-CoA.

Signup and view all the flashcards

Ketone Bodies

Byproducts of fatty acid breakdown, including acetoacetate, beta-hydroxybutyrate, and acetone.

Signup and view all the flashcards

Ketogenesis

The formation of ketone bodies from fatty acids in the liver.

Signup and view all the flashcards

β-oxidation

A metabolic pathway that breaks down fatty acids into acetyl-CoA.

Signup and view all the flashcards

Mitochondria

Cellular organelles where fatty acid oxidation occurs.

Signup and view all the flashcards

Acetyl-CoA

A key intermediate in fatty acid oxidation and the citric acid cycle.

Signup and view all the flashcards

Carnitine

Essential for the transport of long-chain fatty acids into the mitochondria.

Signup and view all the flashcards

Fatty acid cleavage

The process of breaking a fatty acid chain into smaller molecules (acetyl-CoA), releasing energy.

Signup and view all the flashcards

β-oxidation

A metabolic pathway breaking down fatty acids into acetyl-CoA, producing energy.

Signup and view all the flashcards

β-oxidation cycle

A cyclic process in the mitochondria that degrades long-chain fatty acids.

Signup and view all the flashcards

Acetyl-CoA

An important intermediate in metabolism. Produced from fatty acid breakdown.

Signup and view all the flashcards

Acyl-CoA dehydrogenase

Enzyme removing hydrogen atoms in β-oxidation.

Signup and view all the flashcards

FADH2 and NADH

Electron carriers produced in β-oxidation, carrying electrons to the electron transport chain.

Signup and view all the flashcards

Carnitine's role in fatty acid transport

Acyl-CoA is converted to acylcarnitine for transport across inner mitochondrial membrane; carnitine shuttles fatty acid for breakdown.

Signup and view all the flashcards

Fatty acid activation

Initial step preparing fatty acids for breakdown

Signup and view all the flashcards

β-oxidation

A metabolic pathway that breaks down fatty acids into acetyl-CoA, generating energy.

Signup and view all the flashcards

Acetyl-CoA

A key molecule formed from fatty acid breakdown, entering the citric acid cycle.

Signup and view all the flashcards

Fatty Acid Oxidation

Breakdown of fatty acids in mitochondria to produce energy.

Signup and view all the flashcards

Palmitate

A 16-carbon saturated fatty acid.

Signup and view all the flashcards

3-Hydroxyacyl-CoA Dehydrogenase

Enzyme that catalyzes the oxidation of 3-hydroxyacyl-CoA to 3-ketoacyl-CoA.

Signup and view all the flashcards

Δ2-Enoyl-CoA Hydratase

Enzyme that adds water to the 2,3-double bond of a fatty acid in β-oxidation.

Signup and view all the flashcards

Thiolase

Enzyme that cleaves 3-ketoacyl-CoA into acetyl-CoA and a shorter acyl-CoA.

Signup and view all the flashcards

FADH2 and NADH

Electron carriers produced during β-oxidation, carrying high-energy electrons to the electron transport chain.

Signup and view all the flashcards

Odd-Chain Fatty Acids

Fatty acids containing an odd number of carbon atoms.

Signup and view all the flashcards

Propionyl-CoA

Intermediate in the oxidation of odd-chain fatty acids.

Signup and view all the flashcards

Succinyl-CoA

Product of propionyl-CoA metabolism; a citric acid cycle intermediate.

Signup and view all the flashcards

Citric Acid Cycle

Series of reactions where acetyl-CoA is further oxidized, producing ATP and other energy-carrying molecules.

Signup and view all the flashcards

ATP Production (Palmitate)

The complete oxidation of a 16-carbon fatty acid (palmitate) generates a significant amount of ATP.

Signup and view all the flashcards

NADPH source for dienoyl-CoA reductase

Intramitochondrial sources like glutamate dehydrogenase, isocitrate dehydrogenase, and NAD(P)H transhydrogenase provide NADPH for the dienoyl-CoA reductase step in fatty acid oxidation.

Signup and view all the flashcards

Ketone bodies concentration

When ketone body concentration reaches ~12 mmol/L, the oxidative machinery becomes saturated.

Signup and view all the flashcards

Ketone body formation & utilization

Liver produces ketone bodies from fatty acids, which are then used by extrahepatic tissues as an alternative energy source

Signup and view all the flashcards

Acetoacetyl-CoA breakdown

Thiolase breaks down acetoacetyl-CoA to produce two acetyl-CoA molecules, requiring one CoA.

Signup and view all the flashcards

Liver's role in ketogenesis

Liver is the primary site of ketone body production

Signup and view all the flashcards

Ketone bodies in blood

Ketone bodies are released into the blood from the liver

Signup and view all the flashcards

Extrahepatic tissues' role

Extrahepatic tissues utilize ketone bodies for energy production

Signup and view all the flashcards

Acetoacetate activation

The enzyme succinyl-CoA-acetoacetate-CoA transferase converts acetoacetate to acetoacetyl-CoA in extrahepatic tissues.

Signup and view all the flashcards

d-3-Hydroxybutyrate Dehydrogenase

A mitochondrial enzyme that reversibly converts d-3-hydroxybutyrate to acetoacetate.

Signup and view all the flashcards

Ketogenesis

The formation of ketone bodies from fatty acids in the liver.

Signup and view all the flashcards

Acetoacetate

A ketone body produced from the breakdown of fatty acids.

Signup and view all the flashcards

3-Hydroxybutyrate

A prominent ketone body in blood and urine during ketosis.

Signup and view all the flashcards

Ketone bodies

Byproducts of fatty acid breakdown, including acetone, acetoacetate, and beta-hydroxybutyrate.

Signup and view all the flashcards

Mitochondria

Cellular organelles where fatty acid oxidation and ketogenesis occurs.

Signup and view all the flashcards

Fatty Acid Oxidation

The breakdown of fatty acids in mitochondria to produce energy in the form of acetyl-CoA.

Signup and view all the flashcards

Ketogenesis

The formation of ketone bodies from fatty acids in the liver.

Signup and view all the flashcards

Ketone Bodies

Byproducts of fatty acid breakdown, including acetoacetate, beta-hydroxybutyrate, and acetone.

Signup and view all the flashcards

β-oxidation

A metabolic pathway that breaks down fatty acids into acetyl-CoA.

Signup and view all the flashcards

Mitochondria

Cellular organelles where fatty acid oxidation and ketogenesis occur.

Signup and view all the flashcards

Acetyl-CoA

A key intermediate in fatty acid oxidation and the citric acid cycle.

Signup and view all the flashcards

Carnitine

Essential for the transport of long-chain fatty acids into the mitochondria.

Signup and view all the flashcards

Fatty acid activation

Initial step preparing fatty acids for breakdown, costing 2 ATP.

Signup and view all the flashcards

Acetoacetate

A ketone body produced from the breakdown of fatty acids.

Signup and view all the flashcards

3-Hydroxybutyrate

A prominent ketone body in blood and urine during ketosis.

Signup and view all the flashcards

Fatty Acid Oxidation

Breakdown of fatty acids to produce energy in the form of acetyl-CoA.

Signup and view all the flashcards

β-oxidation

Metabolic pathway breaking down fatty acids into acetyl-CoA.

Signup and view all the flashcards

Acetyl-CoA

Key intermediate molecule in fatty acid oxidation and citric acid cycle.

Signup and view all the flashcards

Mitochondria

Cellular organelles where fatty acid oxidation occurs.

Signup and view all the flashcards

Carnitine

Essential for transporting long-chain fatty acids into mitochondria.

Signup and view all the flashcards

β-oxidation cycle

Cyclic process in mitochondria degrading long-chain fatty acids.

Signup and view all the flashcards

Fatty acid cleavage

Breaking a fatty acid chain into smaller molecules (acetyl-CoA), releasing energy.

Signup and view all the flashcards

Acyl-CoA dehydrogenase

Enzyme removing hydrogen atoms in β-oxidation.

Signup and view all the flashcards

FADH2 and NADH

Electron carriers produced in β-oxidation, carrying electrons to the electron transport chain; crucial electron carriers producing ATP.

Signup and view all the flashcards

Ketone Bodies

Byproducts of excessive fatty acid breakdown—acetoacetate, beta-hydroxybutyrate, and acetone.

Signup and view all the flashcards

Ketogenesis

Formation of ketone bodies from fatty acids, mainly in the liver.

Signup and view all the flashcards

Study Notes

Oxidation of Fatty Acids: Ketogenesis

  • Fatty acids are broken down in mitochondria to acetyl-CoA, producing large amounts of energy.
  • When fatty acid oxidation is high, the liver produces ketone bodies (acetoacetate, D-3-hydroxybutyrate, acetone).
  • Ketone bodies are used as fuels by other tissues.
  • Excessive ketone body production leads to ketosis, potentially life-threatening ketoacidosis.
  • Fatty acid oxidation is crucial for gluconeogenesis. Impairments cause hypoglycemia.
  • Fatty acid oxidation occurs in mitochondria, a different compartment from fatty acid synthesis.
  • Fatty acids are transported in the blood as free fatty acids bound to albumin.
  • Fatty acids must be activated (converted to acyl-CoA) before breakdown. This step requires ATP.
  • Acyl-CoA synthetase catalyzes this activation process.
  • Activated fatty acids cannot directly cross the inner mitochondrial membrane.
  • Carnitine shuttles fatty acids across the membrane as acylcarnitine.
  • Carnitine palmitoyltransferase-I transfers acyl groups from CoA to carnitine.
  • Acylcarnitine crosses the inner membrane via a transporter.
  • Carnitine palmitoyltransferase-II transfers acyl groups back to CoA.
  • Beta-oxidation is a process of cleaving two carbons at a time from acyl-CoA.
  • Each cycle of beta-oxidation yields one FADHâ‚‚ and one NADH, supplying ATP through oxidative phosphorylation.
  • Palmitate (C16) yields 8 acetyl-CoA molecules, generating a large quantity of ATP.
  • Peroxisomes modify beta-oxidation, oxidizing very long-chain fatty acids.
  • Unsaturated fatty acids have modified beta-oxidation pathways.
  • Ketogenesis occurs during high rates of fatty acid oxidation.
  • Acetoacetyl-CoA is formed from two acetyl-CoA molecules via HMG-CoA synthase.
  • Acetoacetyl-CoA is split into acetoacetate (converted to acetone) and 3-hydroxybutyrate.
  • Ketone bodies are used as fuel in extrahepatic tissues.
  • Excess ketone bodies are eliminated from the body.
  • Ketogenesis is regulated at 3 steps.
  • Control of free fatty acid mobilization from adipose tissue.
  • CPT-I activity in liver: determining the proportion of fatty acids that undergo oxidation or are esterified.
  • Partition of acetyl-CoA between ketogenesis and the citric acid cycle.
  • Impaired fatty acid oxidation can cause hypoglycemia, organ fat buildup, and hypoketonemia.
  • Ketosis is mild in starvation, but can be severe in diabetes mellitus and some other conditions.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Harper's Biochemistry Chapter 22 - Oxidation of Fatty Acids (Ketogenesis) PDF

Description

Explore the biochemical process of fatty acid oxidation and ketogenesis in this quiz. Learn how fatty acids are broken down to produce acetyl-CoA and the implications of ketone body production. Understand the significance of this process in energy metabolism and its role in conditions like ketosis and hypoglycemia.

More Like This

Ketogenesis
10 questions

Ketogenesis

FeatureRichBrazilNutTree avatar
FeatureRichBrazilNutTree
Biochemistry: Fatty Acid Metabolism
131 questions

Biochemistry: Fatty Acid Metabolism

AmazingEiffelTower avatar
AmazingEiffelTower
Fatty Acid Synthesis and Ketogenesis
22 questions

Fatty Acid Synthesis and Ketogenesis

EnergyEfficientTabla avatar
EnergyEfficientTabla
Use Quizgecko on...
Browser
Open
Browser
Browser