Organic compounds are compounds that contain carbon atoms covalently bonded to other atoms, usually hydrogen, oxygen, nitrogen, sulfur, or halogens. They are the basis of life on Earth and form the building blocks of many biological molecules, including carbohydrates, proteins, lipids, and nucleic acids.

Organic compounds can be classified into different categories based on their functional groups. For example, alcohols have a hydroxyl (-OH) functional group, while aldehydes and ketones have a carbonyl (C=O) functional group. Amino acids, which are the building blocks of proteins, have an amino (-NH2) and a carboxyl (-COOH) functional group.

Organic compounds can be found in nature, such as in plants, animals, and microorganisms. They are also synthesized by chemical reactions in laboratories and industries, and have a wide range of applications in different fields, including medicine, agriculture, energy, and materials science.

Organic compounds can have different physical and chemical properties depending on their functional groups and molecular structure. For example, some organic compounds are flammable, while others are not. Some are soluble in water, while others are not. Understanding the properties and reactivity of organic compounds is important for their use and manipulation in various applications.