Lipid Metabolism: TAGs and Fatty Acids

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

The creation of fatty acids from acetyl-CoA and other precursors.

A type of lipid made of three fatty acids bonded to a glycerol molecule; the main form of fat storage in the body.

Release of fatty acids from adipose tissue into the bloodstream.

The process of breaking down fatty acids into acetyl-CoA molecules.

Fatty acids are linked to coenzyme A (CoA) in the cytosol to transfer them to the mitochondrial matrix.

Epinephrine and glucagon stimulate fatty acid mobilization from adipose tissue and fatty acid oxidation for energy production.

Storing energy as triacylglycerols in adipose tissue.

The metabolic breakdown of fatty acids in the inner mitochondrial membrane, where fatty acids are oxidized two carbons at a time, producing Acetyl CoA.

The membrane within mitochondria where beta-oxidation occurs.

A crucial molecule produced in the breakdown of fatty acids, entering the citric acid cycle, and a precursor to ketone bodies.

Completes the breakdown of Acetyl CoA, delivering energy in the form of ATP, NADH, and FADH2.

Breaking down fatty acids into smaller molecules, like Acetyl CoA.

Alternative energy sources produced when glucose is scarce, derived from acetyl CoA, used by brain, heart, muscles.

Fatty acids with an odd number of carbon atoms requiring Vitamin B12 for their degradation

Essential for metabolizing odd-number carbon fatty acids preventing methylmalonic acidemia and nerve damage.

A saturated fatty acid with 16 carbon atoms, whose complete oxidation yields 106 ATP.

Adenosine Triphosphate - the primary energy currency of the cell; produced during metabolic processes.

Fatty acid synthesis occurs in the cytosol of the cell.

Fatty acid degradation takes place in the mitochondrial matrix.

Fatty acid synthetase is a dimer that contains all the necessary enzymes for synthesis in one chain.

Fatty acid degradation is catalyzed by several separate proteins on the inner mitochondrial membrane.

Malonyl-CoA is the activated 2-carbon unit donor in fatty acid synthesis.

Acetyl-CoA is the two-carbon molecule released in fatty acid degradation.

NADPH provides reducing power needed for fatty acid synthesis.

The oxidation of fatty acids yields NADH + FADH during degradation.

Citrate activates Acetyl-CoA Carboxylase, a key enzyme in FA synthesis.

Palmitoyl-CoA inhibits Acetyl-CoA Carboxylase, the rate-limiting enzyme in fatty acid synthesis.

Acetyl-CoA Carboxylase is regulated by phosphorylation and dephosphorylation in response to hormones like glucagon or insulin.

Citrate shuttles acetyl-CoA from the mitochondria to the cytosol for fatty acid synthesis.

One NADPH molecule is produced during transport of acetyl-CoA across inner mitochondrial membrane to the cytosol.

The synthesis of palmitate (a 16-carbon saturated fatty acid) requires 8 acetyl-CoA, 7 malonyl-CoA, 14 NADPH, and 7 ATP. The products are palmitate, 14 NADP+, 7 CoASH, 7 ADP, 7 Pi, and 7 CO2.

Provides NADPH for fatty acid synthesis.

Adds carbon units to a fatty acid, starting from C16; happens in the ER.

Introduction of double bonds up to C9 in the fatty acid chain in the endoplasmic reticulum.

High levels of malonyl CoA block fatty acid transport into mitochondria.

High cytoplasmic citrate levels activate acetyl-CoA carboxylase, increasing fatty acid synthesis.

Primarily occurs in the liver, but storage mainly in adipose tissue.

Adipose tissue releases fatty acids for liver oxidation during starvation.

Oxidized acetyl-CoA is used to produce ketone bodies during starvation, serving as an alternative energy source for the brain, heart, and kidney.

Stimulate fatty acid mobilization by activating adipose tissue lipase.

Stimulates fatty acid synthesis by activating protein phosphatases which in turn increase acetyl-CoA production.

Separation of fatty acid synthesis and oxidation in different cellular compartments (cytoplasm and mitochondria) prevents conflict.

Stored as triacylglycerols (TAGs) in adipose tissue, offering the most efficient energy storage compared to carbohydrates and proteins.

The release of fatty acids from adipose tissue into the bloodstream, triggered by hormones like glucagon and catecholamines.

Fatty acids are broken down in the mitochondria, via beta-oxidation, into acetyl-CoA.

The metabolic pathway where fatty acids are broken down in the mitochondrial matrix into 2-carbon units (acetyl-CoA).

The process of creating fatty acids from acetyl-CoA in the cytoplasm, using malonyl-CoA.

A key intermediate in both fatty acid degradation and synthesis, also used in the citric acid cycle.

Alternative fuel sources produced from excess acetyl-CoA during periods of prolonged fasting.

Fatty acids with an odd number of carbon atoms, metabolized via conversion to succinyl-CoA.

Essential for the metabolism of odd-chain fatty acids.

The major storage form of fatty acids, composed of three fatty acids attached to a glycerol molecule