Biomolecules are fundamental organic molecules produced by living organisms. These complex compounds are present in all living things, performing a wide array of functions essential for growth, maintenance, and reproduction. They are involved in nearly every biological process, from storing energy to transmitting genetic information.
Carbohydrates The Body’s Energy Source
Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen atoms, typically in a 1:2:1 ratio. Their primary role is to act as the body’s main source of energy. When consumed, carbohydrates are broken down into glucose, a simple sugar that cells use as fuel or store for later use.
Carbohydrates are classified based on their structural complexity. Monosaccharides, like glucose and fructose, are simple sugars. Disaccharides, such as sucrose, form when two monosaccharides link. Polysaccharides, or complex carbohydrates, are long chains made of many simple sugar units, including starch, cellulose, and glycogen. Starch provides energy storage in plants, glycogen is the storage form of glucose in animals, and cellulose provides structural support in plant cell walls.
Lipids Essential for Structure and Energy Storage
Lipids are a diverse group of molecules insoluble in water, often due to long hydrocarbon chains. They serve multiple roles, including long-term energy storage, forming structural components of cell membranes, and acting as signaling molecules.
Fats, specifically triglycerides, are a common type of lipid and the primary storage form of metabolic energy. Phospholipids form the lipid bilayer of cell membranes, regulating what enters and exits cells. Steroids, such as cholesterol, are also lipids, playing roles in membrane fluidity and acting as precursors for hormones. Waxes provide protection and sealing functions in the human body, animals, and plants.
Proteins The Versatile Builders
Proteins are complex macromolecules constructed from long chains of smaller units called amino acids. There are 20 different types of amino acids that combine in various sequences to form a wide array of proteins. The specific sequence of these amino acids dictates a protein’s unique three-dimensional structure, which determines its function.
Proteins perform an extensive range of functions. Many act as enzymes, which are biological catalysts that speed up chemical reactions within cells. Other proteins provide structural support; for example, collagen gives strength to connective tissues, skin, and bones, while keratin forms hair and nails. Proteins also function as transport molecules, with hemoglobin carrying oxygen throughout the body. Furthermore, proteins like antibodies are crucial for the immune system, protecting the body by binding to foreign particles.
Nucleic Acids The Information Carriers of Life
Nucleic acids are molecules essential for the storage and expression of genetic information in all living cells. These large biomolecules are composed of repeating units called nucleotides. Each nucleotide consists of a sugar molecule, a phosphate group, and a nitrogen-containing base.
The two main types of nucleic acids are Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA). DNA serves as the genetic material, storing hereditary instructions passed from parents to offspring. RNA plays a central role in carrying out these instructions by translating the genetic code from DNA into proteins.