Nature of Biochemical Reactions

Nature of Biochemical Reactions

Biochemical reactions are the complicated form of organic reactions in the living organisms. Living organisms have enzymes that accelerate the rate of these reactions but the basic chemistry is same. Although there are many possible biochemical reactions, they fall into only a few types.

1.      Oxidation-Reduction Reactions

When a biochemical reaction results in the loss of electrons it is called an oxidation reaction. When electrons are gained in a reaction it is a reduction reaction. Oxidations and reductions always go together since electrons are passed from one molecule to another. Such coupled reactions are referred to as redox reactions.

The metabolic processes of the human body like glycolysis, Kreb's Cycle, and Electron Transport Chain involve the transfer of electrons by redox reactions.

2.      Reactions involving movement of functional groups within or between molecules

For example, the transfer of phosphate groups from oxygen atom of one molecule to the oxygen atom of other molecule.

 

Glucose + ATP                                    Glucose 6-Phosphate + ADP

 

3.      Reaction involving the addition and removal of water

For example, hydrolysis of an amide linkage to an amine and a carboxyl group.

 

Asparagines + H₂O                                       Aspartic acid + NH₃

4.      Bond-breaking reactions

For example, carbon-carbon bond breakage. A reaction of glycolysis e.g. breakdown of F1,6-biphosphate to glyceraldehydes-3-phosphate and dihydroxyacetone phosphate.

 

Regulation of biochemical reactions

Biochemical reactions should not go too fast or too slow. These reactions should occur at required state for proper functioning of the cell. That is why there is a very good regulation system for these reactions.

Endergonic and exergonic reactions

Reactions that produce the energy are termed as exergonic reactions and the reactions that require energy to initiate the reaction are known as endergonic reactions.

Macromolecule or Biomolecules

Macromolecule or Biomolecules is organic molecule that is covalently linked to each other. Major complex biomolecules found in human are nucleic acid, proteins, lipids and carbohydrates. These biomolecules are constructed by simple molecules like deoxyribonucleotides & ribonucleotide, amino acid, fatty acid and glucose, respectively.

Supramolecules

Macromolecules that are linked with each other by non-covalent bonds are called supramolecules such as complex of peptides and nucleotides (DNA and Proteins). Supramolecules further assembled into cell organelles.

Elemental composition of human body

More than 99% mass of human body is made up of six nutrients that are carbon, oxygen, hydrogen, nitrogen, calcium and phosphorous.

Normal chemical composition of human body

Chemical composition of normal human body is water 60-70%, proteins 15%, lipids 15%, carbohydrates 2% & minerals 8%.