Biological Molecules

Carbohydrates

• Biological molecules essential for living organisms.

• Elements: Composed of carbon, hydrogen, and oxygen.

• Types:

  • Monosaccharides: Single sugars (e.g., glucose, fructose).

  • Disaccharides: Two sugars (e.g., maltose, sucrose).

  • Complex Carbohydrates: Many sugars (e.g., starch, cellulose, glycogen).

• Functions:

  • Immediate energy source.

  • Form supporting structures (e.g., cell walls).

  • Can be converted to fats and amino acids.

• Testing:

  • Starch Test (Iodine): Brown to blue-black if starch is present.

  • Reducing Sugars Test (Benedict's): Color changes indicate presence of reducing sugars.

Fats

• Definition: Biological molecules classified as lipids, essential for organisms.

• Elements: Composed of carbon, hydrogen, and oxygen.

• Structure: Made of glycerol and fatty acids.

• Types:

  • Saturated Fats: No double bonds, solid at room temperature.

  • Monounsaturated Fats: One double bond, liquid at room temperature.

  • Polyunsaturated Fats: Multiple double bonds, liquid at room temperature.

  • Trans Fats: Artificially hydrogenated, associated with health risks.

• Functions:

  • Energy storage.

  • Insulation.

  • Solvent for vitamins.

  • Structural component of cell membranes.

• Testing:

  • Ethanol Test: Cloudy white emulsion indicates presence of fats.

Proteins

• Definition: Complex biological molecules comprising amino acids.

• Elements: Composed of carbon, hydrogen, oxygen, and nitrogen.

• Structure: Made of amino acids linked by peptide bonds.

• Functions:

  • Growth and repair of tissues.

  • Enzyme and hormone production.

  • Immune function (antibodies).

• Testing:

  • Biuret Test: Violet coloration indicates presence of proteins.

Nutrient Testing Summary

• Reducing Sugars: Benedict's solution, color change indicates amounts.

• Starch: Iodine solution, colors indicate presence.

• Fats: Ethanol emulsion test for white cloudiness.

• Proteins: Biuret test for violet color if proteins are present.