key term - Fatty Acid Synthesis

Definition

Fatty acid synthesis is the metabolic pathway that converts acetyl-CoA into long-chain fatty acids, which are essential components of cell membranes, energy storage, and various biological processes. This term is particularly relevant in the context of understanding the chemistry of thioesters and acyl phosphates, as well as some biological carbonyl condensation reactions.

5 Must Know Facts For Your Next Test

1. Fatty acid synthesis primarily occurs in the cytoplasm of cells, whereas fatty acid oxidation (breakdown) takes place in the mitochondria.
2. The process of fatty acid synthesis involves the repeated addition of two-carbon units from malonyl-CoA to the growing fatty acid chain, catalyzed by the fatty acid synthase complex.
3. Acetyl-CoA, the starting substrate for fatty acid synthesis, is derived from the breakdown of carbohydrates, fats, and proteins through various metabolic pathways.
4. Malonyl-CoA, the two-carbon donor for chain elongation, is produced by the carboxylation of acetyl-CoA, catalyzed by the enzyme acetyl-CoA carboxylase.
5. The fatty acid synthase complex contains multiple catalytic domains that perform the necessary reactions, including condensation, reduction, dehydration, and enoyl reduction, to produce the final fatty acid product.

Review Questions

• Explain the role of acetyl-CoA and malonyl-CoA in the fatty acid synthesis pathway.
  • Acetyl-CoA serves as the initial substrate for fatty acid synthesis, providing the starting two-carbon unit. Malonyl-CoA, produced by the carboxylation of acetyl-CoA, then acts as the two-carbon donor that is repeatedly added to the growing fatty acid chain. The interplay between these two key metabolic intermediates is essential for the stepwise elongation of fatty acids during the synthetic process.
• Describe the function of the fatty acid synthase complex and its role in the overall fatty acid synthesis pathway.
  • The fatty acid synthase complex is a multi-enzyme system that catalyzes the various reactions required for the synthesis of fatty acids. It contains domains that perform the necessary condensation, reduction, dehydration, and enoyl reduction steps to convert the initial acetyl-CoA and malonyl-CoA substrates into the final long-chain fatty acid product. The coordinated action of the different catalytic domains within the fatty acid synthase complex is crucial for the efficient and regulated production of fatty acids in the cell.
• Analyze the significance of fatty acid synthesis in the context of the chemistry of thioesters and acyl phosphates, as well as biological carbonyl condensation reactions.
  • Fatty acid synthesis is closely linked to the chemistry of thioesters and acyl phosphates, as these high-energy intermediates are involved in the various steps of the synthetic pathway. The thioester bond in acetyl-CoA and malonyl-CoA, for example, provides the driving force for the condensation reactions catalyzed by the fatty acid synthase complex. Additionally, the carbonyl condensation reactions that occur during fatty acid synthesis, such as the Claisen-like condensation between the growing fatty acid chain and malonyl-CoA, are important examples of the types of biological carbonyl condensation reactions discussed in the context of these topics. Understanding the chemistry underlying fatty acid synthesis is crucial for comprehending the broader biochemical processes involved in energy metabolism and lipid biosynthesis.

Related terms

Acetyl-CoA:

The central metabolic intermediate that serves as the primary substrate for fatty acid synthesis, formed from the oxidation of carbohydrates, fats, and proteins.

Malonyl-CoA: An important intermediate in fatty acid synthesis, produced by the carboxylation of acetyl-CoA, which provides the two-carbon units for chain elongation.

Fatty Acid Synthase:

A multi-enzyme complex that catalyzes the stepwise addition of two-carbon units from malonyl-CoA to the growing fatty acid chain.