Biochemistry is the science dealing with the chemical nature of the bodily processes that occur in all living things. It is the study of how plants, animals, and microbes function at the level of molecules.
Biochemists study the structure and properties of chemical compounds in the cells of living organisms and their role in regulating the chemical processes (collectively called metabolism) that are necessary to life. These chemical processes include transforming simple substances from food into more complex compounds for use by the body, or breaking down complex compounds in food to produce energy. For example, amino acids obtained from food combine to form protein molecules, which are used for cell growth and tissue repair. One very important type of protein are enzymes, which cause chemical reactions in the body to proceed at a faster rate.
Complex compounds in food, such as proteins, fats, and carbohydrates, are broken down into smaller molecules in the body to produce energy. Energy that is not needed immediately is stored for later use.
DNA (deoxyribonucleic acid): A nucleic acid molecule (an organic molecule made of alternating sugar and phosphate groups connected to nitrogen-rich bases) containing genetic information and located in the nucleus of cells.
Gene: A section of a DNA molecule that carries instructions for the formation, functioning, and transmission of specific traits from one generation to another.
Metabolism: The sum of all the chemical processes that take place in the cells of a living organism.
Proteins: Large molecules that are essential to the structure and functioning of all living cells.
Biochemistry also involves the study of the chemical means by which genes influence heredity. (A gene is a molecule of DNA, or deoxyribonucleic acid, which is found in the nucleus of cells. Genes are responsible for carrying physical characteristics from parents to offspring.) A gene can be seen as a sequence of DNA that is coded for a specific protein molecule. These proteins determine specific physical traits (such as hair color, body shape, and height), body chemistry (such as blood type and metabolic functions), and some aspects of behavior and intelligence. Biochemists study the molecular basis of how genes are activated to make specific protein molecules.