Water-Soluble Compounds in Living Organisms:

Inorganic:

* Salts: Sodium chloride (NaCl), Potassium chloride (KCl), Calcium chloride (CaCl2)

* Acids: Hydrochloric acid (HCl), Phosphoric acid (H3PO4), Sulfuric acid (H2SO4)

* Bases: Sodium hydroxide (NaOH), Potassium hydroxide (KOH)

Organic:

* Carbohydrates: Glucose, fructose, sucrose, starch, cellulose

* Proteins: Enzymes, hormones, antibodies

* Amino Acids: Building blocks of proteins

* Nucleic Acids: DNA, RNA

* Vitamins: B vitamins (B1, B2, B3, B5, B6, B7, B9, B12), Vitamin C

* Some hormones: Insulin, glucagon, adrenaline

Lipid-Soluble Compounds in Living Organisms:

Fats and Oils:

* Triglycerides: Composed of glycerol and three fatty acid chains

* Phospholipids: Structural component of cell membranes

* Cholesterol: Precursor for steroid hormones and a component of cell membranes

* Waxes: Protective coatings on leaves and animal fur

Steroid Hormones:

* Estrogen: Female sex hormone

* Testosterone: Male sex hormone

* Cortisol: Stress hormone

* Aldosterone: Regulates blood pressure

Other Lipid-Soluble Compounds:

* Vitamins: Vitamins A, D, E, K

* Fatty Acids: Essential fatty acids like omega-3 and omega-6

* Pigments: Carotenoids, chlorophyll

Key Distinction:

The key difference between water-soluble and lipid-soluble compounds is their solubility in water.

* Water-soluble compounds: Have polar groups that interact with water molecules and dissolve easily.

* Lipid-soluble compounds: Have non-polar groups that are repelled by water and dissolve in fats and oils.

This difference affects their transport, absorption, and function in the body.