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Bioscience Topics



Biochemistry is the study of the substances found in living organisms and the chemical reactions underlying life processes. Considered one of the molecular sciences, biochemistry is a branch of both chemistry and biology; the prefix “bio-” comes from bios, the Greek word for “life.” The main goal of biochemistry is to understand the structure and behavior of biomolecules. These are the organic (carbon-containing) compounds that make up the various parts of the living cell and carry out the chemical reactions that enable it to grow, maintain and reproduce itself and to use and store energy.

For centuries, scientists believed the organic compounds only could be formed under the influence of the vital force in the bodies of animals and plants. In 1828, German chemist Friedrich Wöhler disproved this long-held belief by synthesizing urea, an organic compound of carbon, nitrogen, oxygen and hydrogen, in the lab. Five years later, French chemist Anselme Payen discovered the first enzyme, diastase (now called amylase), by developing it in the lab. The field of biochemistry bloomed in the 20th century, with major discoveries about the metabolic pathways in cells and the replication of DNA and RNA and with the development of new techniques such as chromatography, X-ray diffraction, spectroscopy and electron microscopy.

Each of our cells is like a tiny city where the usual municipal activities take place. Each cell produces and uses energy, communicates with other cells in various ways, undertakes building projects and removes the trash. The chemical processes occurring within a living cell or organism that are necessary for the maintenance of life are referred to as metabolism. To perform these assorted metabolic jobs, cells contain a vast array of biomolecules in a state of constant change and adaptation. The majority of these biomolecules fall into one of four categories: nucleic acids, proteins, carbohydrates and lipids.

Nucleic acids are complex, high-molecular weight biochemical macromolecules composed of nucleotides, which are the building blocks of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are found in all living cells and viruses and are responsible for storing and transferring genetic information. They are used as a guide in making proteins by other components of the cell.

Proteins are large molecules composed of small subunits, called amino acids. Using only 20 different amino acids, a cell constructs thousands of different proteins, each of which has a highly specialized role in the cell. The proteins of greatest interest to biochemists are the enzymes, which are the “worker” molecules of the cell. These enzymes serve as promoters, or catalysts, of chemical reactions.

Carbohydrates are the basic fuel molecules of the cell. They contain carbon, hydrogen and oxygen in approximately equal amounts. Green plants and some bacteria use a process known as photosynthesis to make simple carbohydrates (sugars) from carbon dioxide, water and sunlight. Animals, however, obtain their carbohydrates from foods. Once a cell possesses carbohydrates, it may break them down to yield chemical energy or use them as raw material to produce other biomolecules.

Lipids are fatty substances that play a variety of roles in the cell. Some are held in storage for use as high-energy fuel; others serve as essential components of the cell membrane.

Biomolecules of many other types also are found in cells. These compounds perform such diverse duties as transporting energy from one location in the cell to another, harnessing the energy of sunlight to drive chemical reactions and serving as helper molecules (cofactors) for enzyme action. One major aim of biochemistry is to understand metabolism well enough to predict and control changes that occur in cells. Biochemical studies have yielded such benefits as treatments for many metabolic diseases, antibiotics to combat bacteria and methods to boost industrial and agricultural productivity. These advances have been augmented in recent years by the use of genetic engineering techniques.

Related Disciplines

Molecular Biology

The study of processes involving DNA and RNA and their replication.

Cell Biology

The study of all processes that involve cells and their interactions with other cells.


The study of the function and behavior of genes.

Because biochemistry is a broad discipline with a wide range of applications, the subject knowledge and skills acquired from studying biochemistry can lead to many different career paths. Federal and state government agencies have laboratories that employ skilled personnel in basic research programs and in the analysis of samples of food, drugs, air, water, wastes and animal tissue. Drug companies have basic research programs on the causes of disease and applied programs to develop drugs to combat disease. Biotechnology companies, which have interests in the environment, energy, human health care, agriculture and animal health, hire bachelor of science graduates for research, quality control, clinical research, manufacturing/production and information systems. Universities and medical centers always are in need of technicians to work in research labs. Someone with a bachelor#rdquo;s degree in biochemistry can use it to go to medical, dental, veterinary, law or business school. Some use their training as a stepping stone to careers in biotechnology, toxicology, biomedical engineering, clinical chemistry, plant pathology, animal science and other fields.