1. Carbon (C): The backbone of all organic molecules, including carbohydrates, lipids, proteins, and nucleic acids. Carbon's ability to form four bonds with other atoms allows for the creation of complex, diverse molecules essential for life.
2. Hydrogen (H): Found in water (H2O), which is crucial for all living organisms. Also present in carbohydrates, lipids, proteins, and nucleic acids. Hydrogen bonds between water molecules are essential for many biological processes.
3. Oxygen (O): Component of water and essential for respiration, the process by which organisms extract energy from food. Oxygen is also found in carbohydrates, lipids, proteins, and nucleic acids.
4. Nitrogen (N): A major component of proteins and nucleic acids (DNA and RNA). Nitrogen is also found in amino acids, the building blocks of proteins, and in the nitrogenous bases of DNA and RNA.
These four elements make up the vast majority of the mass of living organisms, and they are essential for the functioning of all biological processes.
