Biochemistry is the branch of science that deals with the study of chemical processes that are
going on in the living body. It forms a bridge between Biology and Chemistry by studying how
complex chemical reactions and chemical structures give rise to life and life's processes.
Biochemistry incorporates everything in between a molecule and a cell and all the interactions
between them.
The history of biochemistry can be said to have started with the ancient Greeks who were
interested in the composition and processes of life, although biochemistry as a specific
scientific discipline has its beginning around the early 19th century.
The name Biochemistry was coined in 1903 by a German chemist named Carl Neuberg.
However, work in this very living, aspect of chemistry had started much earlier. Claude
Bernard is accredited with the Sirehood of Biochemistry.
Carl Alexander Neuberg (29 July 1877 – 30 May 1956) was an early pioneer in biochemistry,
and he is often referred to as the "father of modern biochemistry".
In 1937 Hans Krebs discovered the process of the Citric Acid Cycle (also known as Krebs cycle,
in honor to him).
Biochemistry essentially remains the study of the structure and functions of cellular components
such as Enzymes and cellular organelles and the processes carried out both on and by the
macromolecules – Carbohydrates, Fats and especially the Proteins, Vitamins etc.
Knowledge of biochemistry is also important in diagnosing a disease by estimating the level of
various biomolecules like Enzymes, Hormones, Lipids, and Proteins etc. in the body by which a
Pathologist can easily understand the root of disease and therefore implementing the ideal
treatment strategy for the complete cure of disease.
In the modern era, people rely on taking various supplements like Multivitamins, Minerals, and
Protein shakes etc. for better health in the hectic schedule. All the functions and proper intake of
these supplements can only be described in the biochemistry after analyzing the body
composition of the person and the need of these supplements for them and thereafter prescribing
the ideal supplements to them.
So, Clinical biochemistry plays a vital role in medical science by giving the proper knowledge of
biochemical processes that are going on in normal as well as pathological conditions in a living
body, their diagnostic methods and ideal treatments for the complete cure of pathological
conditions.
Because life processes are performed by organic molecules the discipline of biochemistry relies
heavily on fundamental principles of organic chemistry and other basic sciences. It is of no
surprise that the first "biochemists" actually were organic chemists who specialized in the
chemistry of compounds derived from living organisms.
The chemical basis of life.
The biomolecules such as proteins that are present in living organisms are carbon-based
compounds. Carbon is the third most abundant element in living organisms (relative abundance
H > O > C > N > P > S). The most common ions are Ca+2, K+, Na+, Mg+2, and Cl-. The properties
of biomolecules, such as shape and chemical reactivity, are best described by the discipline of
organic chemistry.
Functional groups.
The chemical reactions of biomolecules are dictated by the functional groups they contain. E.g.
organic compounds and functional groups that will be encountered constantly in the proteins,
carbohydrates, nucleic acids and simple metabolites you will study.
The structure, charge properties, polarity, and basic chemical reactivity of all of these
compounds and functional groups determine the behavior of the biomolecules.
Many biomolecules are polymers.
The principle biomolecules in cells (proteins, polysaccharides, and nucleic acids) are polymer
chains of amino acids, monosaccharides, and nucleotides, respectively. Biopolymers are formed
by condensation reactions in which water is removed from the reacting monomer units. Each
monomer unit of a biopolymer is referred to as a residue.
Proteins.
Most of the chemical reactions of the cell are carried out by proteins. Proteins also are the major
structural components of most cells and tissues. Proteins are often called polypeptides in
reference to the fact that they are composed of amino acids held together by peptide bonds.
Peptide bonds actually are amide bonds which are formed by the condensation of the carboxyl
groups and amino groups of consecutive amino acids in the polymer chain.
The enzymes comprise one subclass of proteins. These proteins carry out chemical reactions with
extraordinary specificity and speed (up to 1017-fold enhancement in reaction rate).
Lipids and membranes
Lipids are a diverse collection of biomolecules that are composed mostly of carbon and
hydrogen, i.e., hydrocarbons. Lipids contain relatively few polar functional groups. They
typically are more soluble in organic solvents than in water. The primary building block of many
lipids is a fatty acid.
Carbohydrates
Most carbohydrates are polysaccharides. Polysaccharides are polymers of simple sugars known
as monosaccharides (e.g., glucose). Different polysaccharides perform either structural
(cellulose) or energy storage (glycogen, starch) functions.
Nucleic acids
Nucleic acids are composed of nucleotide monomer units. Nucleotides themselves are composed
of a monosaccharide, a nitrogenous base, and one or more phosphate groups. The nucleotide
ATP is the major energy currency of the cell which is used to power a huge variety of energy-
requiring reactions
Nucleotides play key roles in information transfer in all organisms (DNA → RNA → protein).
The Energetics of life
Living organisms are highly complicated at the molecular level. A large amount of energy is
invested in maintaining the ordered and complicated state of cells and tissues. In humans and
animals, energy needed for work and biosynthesis of cellular structures is derived
from organic molecules in the diet. Often these come from plant sources, who derived their
energy for synthesis of biomolecules from sunlight. In animals, energy is derived from the
breakdown of fuel molecules by processes referred to as catabolism. In turn, the energy released
from catabolism is used to drive biosynthetic processes collectively referred to as anabolism
Biochemistry and evolution.
Biochemistry has greatly extended our knowledge of phylogeny and evolution that was
acquired originally through the disciplines of comparative anatomy, population genetics and
paleontology. In fact, only through biochemistry have we come to appreciate that all living
organisms are similar at the molecular level. Namely, they share similar means of replication,
cellular structure, and often energy utilization & production. For this reason, much of what we
can learn about simple organisms such as Escherichia coli can be applied to the study of higher
organisms such as us.
The similarity of organisms at a molecular level indicates that all are derived from a common
ancestor
