What is Biochemistry? Definition, Branches, & Applications - GeeksforGeeks (2025)

The word “Biochemistry’’ was coined by the German chemist Carl Neuberg in 1930. Biological chemistry, often known as biochemistry, is a laboratory-based branch of Biology that combines biology and chemistry. It explores chemical processes that occur in and around living organisms and gives rise to the complexity of life.

What is Biochemistry?

Biochemistry is the branch of biology which deals with the combine study of biology and chemistry within a living organism.

Biochemists study the structure, composition, and chemical reactions of substances in living systems and, in turn, their functions and ways to control them. It arose as a separate branch of biology when scientists combined biology with organic, inorganic, and physical chemistry. They started researching areas such as How food provides energy to living things, the chemistry of inheritance, what crucial changes take place in diseases, etc.

Branches of Biochemistry

Biochemistry is divided into numerous branches, each having a distinct focus and field of research. A quick rundown of some of the most popular branches is provided below:

1. Structural Biochemistry: It is among one of the main branches of Biochemistry and focuses on understanding the molecular structure of biological macromolecules, particularly proteins and nucleic acids
2. Cellular Biochemistry: This field focuses on how chemicals actually work inside of cells. It includes investigating how cells synthesize energy, how they maintain their structural integrity as well as how they use and store nutrients.
3. Molecular Biochemistry: This area examines the structure and function of biomolecules, such as carbohydrates, proteins and DNA. It involves understanding the interactions and metabolic events that the molecules do.
4. Metabolic Biochemistry: This field focuses on the chemical processes that the body goes through in order to stay alive. It entails researching the metabolism of nutrients, energy production, and detoxification.
5. Biochemical Genetics: This area of study explores how genes function in biological processes. It involves understanding the role of genes in the synthesis of proteins and other macromolecules.
6. Enzymology: This field focuses on biological catalysts or enzymes like certain proteins or catalytic RNA as well as the actions of coenzymes and cofactors such as metals and vitamins.

Molecules of Biochemistry or Biomolecules

Complex biomolecules such as proteins, lipids, carbohydrates, and nucleic acids make up living systems. Carbohydrates and proteins are necessary components of our food. A few basic compounds like vitamins and mineral salts are also crucial for the survival of living organisms.

There are four main classes of molecules in biochemistry. They are carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Another name for carbohydrates is saccharides (Greek: sakcharon, which means sugar). The main source of carbohydrates is the plant kingdom, where they comprise an extensive array of naturally occurring chemical molecules such as glucose, starch, and cane sugar. The majority of them are hydrates of carbon, hence the general formula Cx (H2O) y. Chemically, carbohydrates are substances that, upon hydrolysis, producee optically active polyhydroxy aldehydes or ketones. They are categorised based on their behaviour on hydrolysis:

• Monosaccharides: It is incapable of hydrolyzing further to produce a simpler polyhydroxy aldehyde or ketone unit. Eg: ribose, fructose, and glucose.
• Oligosaccharides: Upon hydrolysis, they produce two to ten monosaccharide units. Depending on how many monosaccharides they produce, they are further divided into disaccharides, trisaccharides, tetrasaccharides, etc.
• Polysaccharides: Upon hydrolysis, they produce a large number of monosaccharide units. Examples: cellulose, starch, and glycogen.

Proteins

The most common biomolecule in a living organism is a protein. The main foods that include proteins are fish, meat, dairy, cheese, legumes, and peanuts. They are found in every part of the body and serve as the foundation for life's structure and functioning. They are also necessary for the body's growth and maintenance. The word protein originates from a Greek word "proteios," meaning fundamental or of utmost importance.

All proteins are comprised of α-amino acids. They consist of amino (–NH2) and carboxyl (–COOH) functional groups and depending on the relative position of amino group with respect to carboxyl group, the amino acids are divided into α,β,γ, δ and so on.

The relative proportions of amino and carboxyl groups in an amino acid's molecule determine whether the amino acid is basic, neutral, or acidic.It is neutral if there are the same number of amino and carboxyl groups; it is basic if there are more amino groups than carboxyl groups, and acidic if there are more carboxyl groups than amino groups. The "nonnessential amino acids" refers to the amino acids that are synthesised within the body. In contrast, essential amino acids are those that the body is unable to synthesise and must receive through diet.

Nucleic acids:

Chromosomes, in the cell nucleus, are responsible for heredity and they are composed of proteins and nucleic acids, another class of biomolecules. These mostly fall into two categories: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Nucleic acids are also known as polynucleotides because they are long chain polymers of nucleotides.

Lipids

They are esters of fatty acids and alcohols. They are fatty, waxy, or oily compounds that are soluble in organic solvents and insoluble in polar solvents such as water. Lipids include fats and oils (triglycerides), Phospholipids, Waxes and Steroids.

Types of Lipids

1. Triglycerides: Fats and oils are triglycerides. These all have the same basic structure. Triglycerides consist of a glycerol molecule bonded to three fatty acids.
2. Waxes: These are lipids that contain two monomers, one fatty acid bonded through an ester linkage to one alcohol (a hydrocarbon containing a hydroxyl group).
3. Steroids: Such lipids contain four connected carbon rings. Though steroids can bond to fatty acids, they do not contain a fatty acid chain, and the monomer of a steroid biomolecule is difficult to define.
4. Phospholipids: They are similar to triglycerides. Fatty acids are linked to the glycerol backbone of phospholipids. The distinction is that, unlike triglycerides, which have three fatty acid chains, phospholipids only have two.

Applications of Biochemistry

Biochemistry has numerous applications in medicine, veterinary medicine and dentistry. Other applications are as follows:

• Food Science: Biochemists ascertain the chemical composition of foods, devise techniques to create cheap, plentiful supply of nutritious food, extract nutrients from waste products, and prolong the shelf life of food items.
• Agriculture: Biochemists study the interaction of plants and pests with herbicides and insecticides. They study the compound’s structure–activity relationships and then assess their ability to inhibit growth, as well as evaluate the toxic consequences on surrounding life.
• Clinical Chemistry, Physiology, Toxicology and Pharmacology: Biochemists study the mechanisms of drug actions; study viruses; perform research related to organ function; and study the diagnosis, treatment, and evaluation of health using biochemistry principles.