Compounds Essential to Human Function

Nutrients are divided into macronutrients and micronutrients. Macronutrients—carbohydrates, proteins, and fats—are required in large quantities to fuel cellular activities and maintain tissue structure. Micronutrients, including vitamins and minerals, are needed in small amounts but are crucial for physiological functions like healing, growth, and immunity.

Carbohydrates and lipids both serve as fuel and energy reserves for cellular activities. Carbohydrates include monosaccharides like glucose, disaccharides like lactose, and polysaccharides such as glycogen for glucose storage. Lipids are hydrophobic compounds that store reserve energy and form essential cell membrane components, making lipid derived compounds in the human body critical for cellular structure.

Proteins are composed of amino acids joined by peptide bonds and serve multiple critical functions. They catalyze biochemical reactions as enzymes, ensure structural integrity of tissues and organs, and are essential components of all body tissues. The role of proteins in the human body extends to muscle contraction, nutrient transport, and metabolic processes.

Water is vital for multiple physiological functions in the body. It serves as a lubricant, cushion, and heat sink, and is the chief component of body fluids like saliva and plasma. Additionally, water acts as a reactant in hydrolysis reactions and a by-product of dehydration synthesis, making the role of water in human biology fundamental to all cellular processes.

Inorganic compounds include water, salts, acids, and bases—substances without carbon-hydrogen bonds. Salts dissociate into ions other than H+ or OH–, while acids release H+ and bases accept H+. These electrolytes collectively regulate body fluid homeostasis and maintain the physiological balance necessary for proper cellular function.

Nucleic acids, DNA and RNA, are polymers of nucleotides composed of a phosphate group, pentose sugar, and nitrogenous base. DNA stores genetic information that transfers to RNA, which acts as a blueprint for protein synthesis. This process is essential for organism survival and reproduction.

ATP is composed of a ribose sugar, adenine base, and three phosphate groups. The two covalent bonds linking the three phosphates store significant potential energy. When these high-energy bonds break, the released energy fuels critical body activities including muscle contraction, nutrient transport, and metabolic reactions.