p.13
Enzymatic Activities in Fatty Acid Synthesis
What enzyme is responsible for desaturation in fatty acid synthesis?
Stearoyl-CoA desaturase (Δ9 desaturase).
p.10
Fatty Acid Synthesis Overview
What is the overall process of fatty acid synthesis?
The conversion of acetyl-CoA and malonyl-CoA into long-chain fatty acids.
p.10
Role of Acetyl-CoA in Fatty Acid Synthesis
What are the key substrates involved in fatty acid synthesis?
Acetyl-CoA and malonyl-CoA.
p.17
Arachidonic Acid and Eicosanoid Production
What role does arachidonic acid play in the body?
It is an important precursor to eicosanoids.
p.17
Essential Fatty Acids and Human Nutrition
What is arachidonic acid an example of?
An important PUFA derived from an essential fatty acid by elongation and desaturation.
p.7
Enzymatic Activities in Fatty Acid Synthesis
What is the first step in the reverse process of fatty acid oxidation?
Reduction of the β-keto group to a hydroxyl group using NADPH.
p.1
Enzymatic Activities in Fatty Acid Synthesis
What are the key enzymes involved in fatty acid synthesis?
Acetyl-CoA carboxylase and fatty acid synthase (which has 7 enzymatic activities).
p.16
Essential Fatty Acids and Human Nutrition
What type of fatty acid is linoleic acid?
An essential fatty acid, ω-6.
p.12
Fatty Acid Elongation and Desaturation
Where does fatty acid elongation primarily occur?
In the endoplasmic reticulum.
p.11
Fate of Palmitate in Metabolism
What are the possible fates of palmitoyl-CoA?
Esterification to triacylglycerols, elongation, desaturation, and esterification to cholesteryl ester.
p.6
Conversion of Acetyl-CoA to Malonyl-CoA
What happens to Malonyl-CoA in the fatty acid synthesis process?
Malonyl-CoA is attached to P-SH.
p.11
Fate of Palmitate in Metabolism
What is palmitoyl-CoA used for?
It is used for esterification to triacylglycerols, elongation, desaturation, and esterification to cholesteryl ester.
p.16
Essential Fatty Acids and Human Nutrition
What type of fatty acid is α-linolenic acid?
An essential fatty acid, ω-3.
p.17
Arachidonic Acid and Eicosanoid Production
What are the important eicosanoids derived from arachidonic acid?
Prostaglandins, thromboxanes, and leukotrienes.
p.14
Essential Fatty Acids and Human Nutrition
What is one function of polyunsaturated fatty acids?
Increase membrane fluidity.
p.6
Role of Acetyl-CoA in Fatty Acid Synthesis
What is the first step in fatty acid synthesis involving Acetyl-CoA?
Acetyl-CoA is attached to P-SH and then shuffled to cysteine-SH.
p.15
Essential Fatty Acids and Human Nutrition
Why must ω-6 and ω-3 fatty acids be supplied in the diet for humans?
Because humans cannot add double bonds beyond C9.
p.4
Regulation of Acetyl-CoA Carboxylase
How does glucagon affect Acetyl-CoA carboxylase?
It stimulates AMP-dependent kinase, which phosphorylates and inactivates the enzyme.
p.8
Fatty Acid Elongation and Desaturation
What is the first step in the fatty acid synthesis process?
Acyl chain is transferred to cys - SH.
p.13
Enzymatic Activities in Fatty Acid Synthesis
What are the requirements for the stearoyl-CoA desaturase to function?
NAD(P)H, O2, and cytochrome b5.
p.9
Fatty Acid Synthesis Overview
What is the overall equation for palmitate synthesis?
From acetyl-CoA to palmitate, including ATP used by acetyl-CoA carboxylase.
p.15
Essential Fatty Acids and Human Nutrition
What characterizes an ω-9 unsaturated fatty acid?
It has a double bond 9 carbons from the terminal carbon.
p.9
Conversion of Acetyl-CoA to Malonyl-CoA
What is the role of malonyl-CoA in palmitate synthesis?
If malonyl-CoA already exists, it is utilized in the synthesis process.
p.4
Regulation of Acetyl-CoA Carboxylase
What effect does phosphorylation have on Acetyl-CoA carboxylase?
It inactivates the enzyme.
p.7
Enzymatic Activities in Fatty Acid Synthesis
What occurs during the dehydration step in fatty acid synthesis?
The β-hydroxyl is dehydrated to form an α-β double bond with the loss of H2O.
p.14
Arachidonic Acid and Eicosanoid Production
What compounds are formed from polyunsaturated fatty acids?
Bio-active compounds such as eicosanoids.
p.6
Enzymatic Activities in Fatty Acid Synthesis
What occurs during the condensation of the Malonyl group with the Acetyl group?
The process involves decarboxylation, releasing CO2 and forming a 4-carbon 3-ketoacyl-CoA.
p.2
Role of Acetyl-CoA in Fatty Acid Synthesis
Why is citrate formed in the mitochondria?
Because acetyl-CoA cannot cross the mitochondrial membrane.
p.7
Enzymatic Activities in Fatty Acid Synthesis
What is the final step in the reduction of the β-ketoacyl group?
Reduction of the double bond to form a saturated hydrocarbon chain.
p.2
Conversion of Acetyl-CoA to Malonyl-CoA
What is produced when citrate is broken down via citrate lyase?
Cytosolic acetyl-CoA and OAA.
p.3
Regulation of Acetyl-CoA Carboxylase
Why is the conversion of Acetyl-CoA to Malonyl-CoA significant in fatty acid synthesis?
It is the rate-limiting step and a major site of regulation.
p.1
Role of Acetyl-CoA in Fatty Acid Synthesis
What are the primary carbon sources for fatty acid synthesis?
Malonyl-CoA (from CO2 and acetyl-CoA) and acetyl-CoA (mainly derived from glucose).
