Oxygen is a gas that is needed for respiration by most living organisms. It is also involved in many metabolic and biochemical reactions, such as oxidation and cellular energy production.
Carbon is the basis of all organic compounds, which are the building blocks of life. Carbon can form four covalent bonds with other atoms, allowing for a great diversity of molecular structures and functions.
Nitrogen is a component of amino acids, which are the monomers of proteins. Proteins are essential for many biological processes, such as metabolism, catalysis, signaling, and regulation. Nitrogen is also part of nucleic acids, which store and transmit genetic information.
Phosphorus is a component of nucleic acids, as well as adenosine triphosphate (ATP), which is the main energy carrier in cells. Phosphorus is also involved in the formation of phospholipids, which make up the cell membranes, and in the regulation of cellular signaling and metabolism.
Sulfur is a component of some amino acids, such as cysteine and methionine, which are involved in the formation of disulfide bonds that stabilize the structure of proteins. Sulfur is also part of coenzyme A, which is involved in the synthesis and breakdown of fatty acids and other metabolic pathways.