Oxidation of Fatty Acids Flashcards

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Questions and Answers

What is beta oxidation?

Beta oxidation is the catabolic process by which fatty acid molecules are broken down in the mitochondria in eukaryotes to generate acetyl-CoA, NADH, and FADH2.

What is the product of beta oxidation?

Acetyl-CoA, NADH, and FADH2.

Where does beta oxidation occur?

In the mitochondria.

What occurs during beta oxidation?

Cleavage of fatty acids to form acetyl-CoA. Signup and view all the answers

What are the steps involved in beta oxidation?

<ol> <li>FA Activation by esterification with CoA-Sh; 2. Membrane transport of FA acyl CoA esters; 3. Carbon backbone reaction sequence.</li> </ol> Signup and view all the answers

What are the steps in fatty acid activation?

<ol> <li>FA + ATP → FA-AMP; 2. FA-AMP + CoASH → FA-CoA.</li> </ol> Signup and view all the answers

What enzyme is involved in the activation of fatty acids?

Acyl CoA synthetase. Signup and view all the answers

Where does fatty acid activation occur and what type of linkage is formed?

In the cytoplasm; thioester linkage. Signup and view all the answers

What happens during the mitochondrial uptake of fatty acids?

Fatty acyl-CoA exchanges CoA for carnitine, enters the matrix, and then recharges to form fatty acyl-CoA. Signup and view all the answers

Why is CoA important for transport into the mitochondrial membrane?

Because it is a reactive group required for the transport process. Signup and view all the answers

How many acetyl CoA's are generated from 7 repetitions of beta oxidation starting with palmitoyl CoA?

8 acetyl CoA. Signup and view all the answers

What is the reaction sequence during beta oxidation?

Dehydrogenation, Hydration, Dehydrogenation, Carbon-Carbon Cleavage (Thiolase Reaction). Signup and view all the answers

How does beta oxidation of unsaturated fatty acids differ?

It involves an isomerase reaction to rearrange the double bond before continuing beta oxidation. Signup and view all the answers

How does beta oxidation of polyunsaturated fatty acids occur?

Similar to unsaturated, with multiple isomerization reactions occurring at each double bond. Signup and view all the answers

What happens during the beta oxidation of odd carbon fatty acids?

They are converted to succinyl CoA after an epimerase and mutase reaction. Signup and view all the answers

What is peroxisomal oxidation of fatty acids?

Initial oxidation of long fatty acid chains in peroxisomes until they are short enough to be transported to mitochondria. Signup and view all the answers

What happens to NADH and FADH generated in peroxisomes?

They form hydrogen peroxide instead of going through oxidative phosphorylation. Signup and view all the answers

What happens to hydrogen peroxide generated in peroxisomes?

It is turned into water and oxygen by an enzyme. Signup and view all the answers

Study Notes

Beta Oxidation Overview

Beta oxidation is a catabolic process that breaks down fatty acids into acetyl-CoA, NADH, and FADH2 in the mitochondria.
Acetyl-CoA enters the citric acid cycle, while NADH and FADH2 are utilized in the electron transport chain.
The process occurs mainly in the mitochondrial matrix.

Products and Importance

Products of beta oxidation include acetyl-CoA and the coenzymes NADH and FADH2, crucial for energy metabolism.
Each palmitoyl CoA molecule undergoes seven cycles of beta oxidation, yielding 8 acetyl-CoA molecules.

Steps in Beta Oxidation

FA activation involves esterification with CoA in the cytoplasm, forming fatty acyl-CoA via acyl CoA synthetase.
Mitochondrial uptake requires a transport mechanism facilitated by carnitine, with CPT1 and CPTII enzymes facilitating the exchange of CoA and carnitine.
The overall reaction sequence includes dehydrogenation, hydration, more dehydrogenation, and carbon-carbon cleavage.

Special Cases in Fatty Acid Oxidation

Unsaturated fatty acids undergo normal beta oxidation until a double bond is encountered, requiring isomerization to continue.
Polyunsaturated fatty acids similarly require multiple isomerizations to complete the oxidation process.
Odd carbon fatty acids produce succinyl-CoA after normal beta oxidation cycles, allowing entry into the TCA cycle.

Peroxisomal Oxidation

Very long-chain fatty acids are oxidized in peroxisomes until they are short enough (8 carbons) to be transported into mitochondria.
NADH and FADH2 generated in peroxisomes do not participate in oxidative phosphorylation but instead produce hydrogen peroxide.
Hydrogen peroxide is subsequently converted into water and oxygen through enzymatic action.

Enzymes Involved

Key enzymes include acyl CoA synthetase for activation, CPT1 for mitochondrial uptake, and dehydrogenases for various steps within beta oxidation.
Isomerases and mutases are crucial for modifying unsaturated and odd carbon fatty acids.

Energy Yield from Beta Oxidation

Each cycle of beta oxidation generates 5 ATP (2 from FADH2 and 3 from NADH) through oxidative phosphorylation.
The metabolic efficiency of β-oxidation contributes significantly to ATP production, supporting various cellular functions.

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Description

Explore the process of beta-oxidation and its significance in fatty acid metabolism through these informative flashcards. Learn about key products such as acetyl-CoA, NADH, and FADH2, and their roles in cellular respiration. Enhance your understanding of biochemical pathways essential for energy production.