Biomolecules

 Biomolecules, also known as biological molecules, are organic compounds produced by living organisms that are essential for one or more biological processes. They are the building blocks of life and play a crucial role in all cellular functions, from providing energy and structural support to storing genetic information and regulating metabolic processes.

Most biomolecules are organic compounds, primarily composed of carbon, hydrogen, oxygen, and nitrogen, with smaller amounts of other elements like phosphorus and sulfur. Many are large, complex molecules called macromolecules, formed by the linking together of smaller, repeating units called monomers.

There are four major classes of biomolecules:

 * Carbohydrates:

   * Definition: Chemically defined as polyhydroxy aldehydes or ketones, or compounds that produce them on hydrolysis. They are often called sugars.

   * Monomer: Monosaccharides (simple sugars like glucose, fructose).

   * Examples: Starch, cellulose, glycogen, sucrose, lactose.

   * Functions: Primary source of energy for living organisms, structural components (e.g., cellulose in plant cell walls), and cell recognition.

 * Proteins:

   * Definition: Large, complex macromolecules that are polymers of amino acids.

   * Monomer: Amino acids. There are 20 common types of amino acids.

   * Examples: Enzymes (catalyze biochemical reactions), antibodies (immune defense), hormones (signaling molecules), structural proteins (collagen, keratin), transport proteins (hemoglobin).

   * Functions: Extremely diverse, including structural support, catalyzing metabolic reactions, transporting substances, providing immunity, and regulating cell processes. Their specific three-dimensional structure is crucial for their function.

 * Lipids:

   * Definition: A diverse group of organic molecules that are generally insoluble in water but soluble in organic solvents. They do not typically form large polymers from repeating monomer units in the same way as carbohydrates, proteins, or nucleic acids, though some are assembled from smaller building blocks.

   * Building blocks: Fatty acids and glycerol (for fats and oils).

   * Examples: Fats, oils, waxes, phospholipids, steroids (e.g., cholesterol, hormones like testosterone and estrogen).

   * Functions: Long-term energy storage, insulation, forming cell membranes (phospholipids), and acting as chemical messengers.

 * Nucleic Acids:

   * Definition: Complex macromolecules essential for the storage, transmission, and expression of genetic information.

   * Monomer: Nucleotides (composed of a sugar, a phosphate group, and a nitrogenous base).

   * Examples: Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA).

   * Functions: DNA stores the genetic code, while RNA helps in the expression of this genetic information to synthesize proteins.

These four types of biomolecules interact with each other and are fundamental to the existence and functioning of all living systems.