Biomolecules are organic molecules produced by living organisms, essential for the structure, function, and regulation of cells, tissues, and organs.
They sustain biological processes and can be classified into four major categories: carbohydrates, lipids, proteins, and nucleic acids.
1) Carbohydrates
Structure
Composed of carbon (C), hydrogen (H), and oxygen (O) in a 1:2:1 ratio.
Includes monosaccharides (simple sugars), disaccharides, and polysaccharides (complex carbohydrates).
Function
Primary energy source for cells.
Serve as structural components (e.g., cellulose in plants, chitin in arthropods).
Involved in cell recognition and energy storage (glycogen, starch).
2) Lipids
Structure
Hydrophobic or amphiphilic molecules including fats, oils, phospholipids, and steroids.
Non-polar nature allows them to form cell membranes and store energy efficiently.
Function
Energy storage (more efficient than carbohydrates).
Form cell membranes (phospholipids in the lipid bilayer).
Serve as signaling molecules (steroid hormones like estrogen and testosterone).
Provide insulation and organ protection.
3) Proteins
Structure
Polymers of amino acids linked by peptide bonds.
Fold into complex three-dimensional shapes to perform specific functions.
Function
Catalyze biochemical reactions (enzymes).
Provide structural support (collagen, keratin).
Transport molecules (hemoglobin for oxygen transport).
Facilitate cell signaling (hormones, receptors).
Defend against pathogens (antibodies).
4) Nucleic Acids
Structure
Polymers of nucleotides, each consisting of a nitrogenous base, sugar, and phosphate group.
Two main types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Function
Store and transmit genetic information (DNA).
Regulate gene expression and assist in protein synthesis (RNA).
Some RNA molecules have catalytic functions (ribozymes).
Functions of Biomolecules in Biological Processes
Biomolecules have essential roles across various biological processes, crucial for the survival and functioning of living organisms:
A) Carbohydrates: Provide energy and serve as structural components.
B) Lipids: Store energy, form cell membranes, and act as signaling molecules.
C) Proteins: Catalyze biochemical reactions, provide structural support, transport molecules, facilitate signaling, and defend against pathogens.
D) Nucleic Acids: Store and transmit genetic information, regulate gene expression, and are key to the synthesis of proteins.