1. Carbohydrates:
* Monosaccharides: Simple sugars like glucose, fructose, and galactose.
* Disaccharides: Two monosaccharides joined together, such as sucrose (table sugar) and lactose (milk sugar).
* Polysaccharides: Long chains of monosaccharides, including starch, glycogen, and cellulose.
Functions:
* Energy source: Glucose is the primary fuel for cellular processes.
* Structural support: Cellulose provides rigidity to plant cell walls.
* Storage: Glycogen stores energy in animals, and starch stores energy in plants.
2. Lipids:
* Fats and oils: Triglycerides, composed of glycerol and three fatty acids.
* Phospholipids: Form cell membranes.
* Steroids: Cholesterol, hormones, and other signaling molecules.
Functions:
* Energy storage: Fats store a lot of energy.
* Insulation: Fats help maintain body temperature.
* Structure: Phospholipids form the structural basis of cell membranes.
* Hormonal signaling: Steroids act as chemical messengers.
3. Proteins:
* Amino acids: Building blocks of proteins, joined by peptide bonds.
* Polypeptides: Chains of amino acids.
* Proteins: Complex structures of one or more polypeptides, with specific functions.
Functions:
* Enzymes: Catalyze biological reactions.
* Structural support: Collagen and keratin provide structural support in tissues.
* Transport: Hemoglobin carries oxygen in the blood.
* Hormones: Insulin and growth hormone regulate bodily functions.
4. Nucleic acids:
* Nucleotides: Monomers composed of a sugar, a phosphate group, and a nitrogenous base.
* DNA (Deoxyribonucleic acid): Genetic material, containing instructions for protein synthesis.
* RNA (Ribonucleic acid): Involved in protein synthesis.
Functions:
* Genetic information: DNA carries the genetic code.
* Protein synthesis: RNA plays a crucial role in translating the genetic code into proteins.
In addition to these four major classes, cells also contain a variety of other organic molecules, including:
* Vitamins: Essential organic compounds required in small amounts for various biological functions.
* Coenzymes: Organic molecules that assist enzymes in their catalytic activities.
* Pigments: Molecules that absorb and reflect light, contributing to color.
All these organic molecules work together to maintain the structure, function, and regulation of living cells.
