Fat soluble vitamins & fatty acids

Retinol

A form of vitamin A that comes from animal sources and is essential for vision, reproduction, growth, epithelial tissue, and immune functions.

Beta-carotene

A provitamin A found in plants that is inefficiently converted to retinal, a form of vitamin A.

Vision

Dependent on retinal, the aldehyde derivative of retinol, which is essential for the isomerization process in the visual cycle.

Retinoic acid

A hormone derived from retinal that plays a crucial role in epithelium regeneration by activating gene transcription.

Vitamin D

Synthesized through exposure to sunlight, it is converted to the active form 1,25-dihydroxycholecalciferol, essential for calcium homeostasis.

Antioxidant

Tocopherols act as antioxidants in lipids by binding to free radicals and preventing the formation of peroxides.

Vitamin K

Essential for blood coagulation and bone formation, existing in various forms like phylloquinone (K1) from plants and menaquinones (K2) from intestinal bacteria.

Fatty acids

Long chain carboxylic acids released from fats after hydrolysis, essential for energy production through beta-oxidation.

Beta-oxidation

The process of breaking down fatty acids into acetyl-CoA molecules for energy production, involving several enzymatic steps.

Ketone bodies

Produced from excess acetyl-CoA during fatty acid oxidation, they serve as an alternative energy source, especially during starvation or prolonged fasting.

Essential Fatty Acids

Unsaturated fatty acids containing double bonds beyond carbon atom number 10, such as linoleic (omega-6) and α-linolenic acids (omega-3), which must be included in the human diet.

Fatty Acid Synthesis

The process occurring in the smooth ER of hepatocytes involving a multienzyme complex (FA synthase) to construct fatty acid chains by adding two-carbon atoms from acetyl-CoA, with NADPH from the pentose phosphate pathway.

Acetyl-CoA Carboxylase

Central regulatory enzyme in fatty acid synthesis that produces malonyl-CoA, inhibiting CPTI and thus fatty acid oxidation, regulated by citrate, palmitic acid, and hormones acting through cAMP.

Palmitic Acid Synthesis

Process in the FA synthase complex involving steps like acetyl-CoA donation, malonyl-unit binding, condensation, reduction, dehydration, and release of palmitic acid, with the overall reaction equation provided.

Eicosanoids

Compounds synthesized from arachidonic and other polyunsaturated fatty acids, regulating various tissue functions like inflammation, pain, blood clotting, and smooth muscle contraction.

Desaturases

Enzymes in the smooth ER catalyzing the synthesis of unsaturated fatty acids by introducing double bonds using NADH as an electron source, with specificity for certain carbon atoms and oxygen consumption during the process.