After studying this chapter, you should be able to:
- Explain what biochemistry is about and appreciate its central role in the life sciences.
- Understand the relationship of biochemistry to health and disease and to medicine.
- Appreciate how the Human Genome Project has given rise to, or stimulated interest in numerous disciplines that are already illuminating many aspects of biology and medicine.
Biochemistry can be defined as the science of the chemical basis of life (Gk bios “life”). The cell is the structural unit of living systems. Thus, biochemistry can also be described as the study of the chemical constituents of living cells and of the reactions and processes they undergo. By this definition, biochemistry encompasses large areas of cell biology, molecular biology, and molecular genetics.
The Aim of Biochemistry Is to Describe and Explain, in Molecular Terms, All Chemical Processes of Living Cells
The major objective of biochemistry is the complete understanding, at the molecular level, of all of the chemical processes associated with living cells. To achieve this objective, biochemists have sought to isolate the numerous molecules found in cells, determine their structures, and analyze how they function. Many techniques have been used for these purposes; some of them are summarized in Table 1–1.
Table 1–1 The Principal Methods and Preparations Used in Biochemical Laboratories |Favorite Table|Download (.pdf)
Table 1–1 The Principal Methods and Preparations Used in Biochemical Laboratories
|Methods for Separating and Purifying Biomolecules1|
|Salt fractionation (eg, precipitation of proteins with ammonium sulfate)|
|Chromatography: Paper, ion exchange, affinity, thin-layer, gas–liquid, high-pressure liquid, gel filtration|
|Electrophoresis: Paper, high-voltage, agarose, cellulose acetate, starch gel, polyacrylamide gel, SDS-polyacrylamide gel|
|Methods for Determining Biomolecular Structures|
|UV, visible, infrared, and NMR spectroscopy|
|Use of acid or alkaline hydrolysis to degrade the biomolecule under study into its basic constituents|
|Use of a battery of enzymes of known specificity to degrade the biomolecule under study (eg, proteases, nucleases, glycosidases)|
|Specific sequencing methods (eg, for proteins and nucleic acids)|
|Preparations for Studying Biochemical Processes|
|Whole animal (includes transgenic animals and animals with gene knockouts)|
|Isolated perfused organ|
|Isolated cell organelles|
|Subfractionation of organelles|
|Purified metabolites and enzymes|
|Isolated genes (including polymerase chain reaction and site-directed mutagenesis)|
Other objectives of biochemistry include helping to understand the origins of life on Earth and to integrate biochemical knowledge into efforts to maintain health and to understand diseases and treat them effectively.
A Knowledge of Biochemistry Is Essential to All Life Sciences