BASIC BIOCHEMISTRYMLAB - 242

Introduction

INTRODUCTION TO BASIC BIOCHEMISTRY

Biochemistry can be defined as the science concerned with the chemical basis of life.BIO = LIFE (Greek)

The cell is the structural unit of living systems. Thus, biochemistry can also be described as: The science concerned with the chemical constituents of living cells and with the reactions they undergo.

What is Biochemistry?• Biochemistry is the application of chemistry to

the study of biological processes at the cellular and molecular level.

• It emerged as a distinct discipline around the beginning of the 20th century when scientists combined chemistry, physiology and biology to

investigate the chemistry of living systems by:

A. Studying the structure and behavior of the complex molecules found in biological material.

B. The ways these molecules interact to form cells, tissues and whole organism.

Principles of Biochemistry • Cells (basic structural units of living organisms) are highly

organized and constant source of energy is required to maintain the ordered state.

• Living processes contain thousands of chemical reactions. Precise regulation and integration of these reactions are required to maintain life

• All organisms use the same type of molecules: carbohydrates, proteins, lipids & nucleic acids.

Cells• Basic building blocks of life

• Smallest living unit of an organism

• Grow, reproduce, use energy, adapt, respond to their environment

• Many cannot be seen with the naked eye

• A cell may be an entire organism or it may be one of billions of cells that make up the organism

• Basis Types of Cells: Prokaryotic and eukaryotic

Biomolecules:The four main classes of molecules in biochemistry are: carbohydrates, lipids, proteins, and nucleic acids.

Monomers are relatively small molecules that are linked together to create large macromolecules, which are known as Polymers. 

Biomolecules:

Carbohydrates are made from monomers called monosaccharides.

Examples of these monosaccharide include glucose (C6H12O6), fructose (C6H12O6)

Sugars

• Carbohydrates most abundant organic molecule found in nature.

• Initially synthesized in plants from a complex series of reactions involving photosynthesis.

• Basic unit is monosaccharaides.

• Monosaccharaides can form larger molecules e.g. glycogen, plant starch or cellulose.

Functions• Store energy in the form of starch (photosynthesis

in plants) or glycogen (in animals and humans).

• Provide energy through metabolism pathways and cycles.

• Supply carbon for synthesis of other compounds.

• Form structural components in cells and tissues.

Lipids are usually made from one molecule of glycerol combined with other molecules.

For example in triglycerides, the main group of bulk lipids, there is one molecule of glycerol and three fatty acids.

Fatty acids

• Are monocarboxylic acid contains even number C atoms

• Two types: saturated (C-C sb) and unsaturated (C-C db)

• Fatty acids are components of several lipid molecules.

• E,g. of lipids are triacylglycerol, streiods (cholestrol, sex hormones), fat soluble vitamins.

Functions• Storage of energy in the form of fat• Membrane structures• Insulation (thermal blanket)• Synthesis of hormones

Proteins are very large molecules made from monomers called amino acids.

There are 20 standard amino acids.When amino acids combine, they form a special bond called a peptide bond and become a polypeptide, or protein.

Amino Acids

• Building blocks of proteins.

• 20 commonly occurring.

• Contains amino group and carboxyl group function groups (behavioral properties)

• R Group (side chains) determines the chemical properties of each amino acids.

• Also determines how the protein folds and its biological function.

• Individual amino acids in protein connected by peptide bond.

• Functions as transport proteins,

structural proteins, enzymes, antibodies, cell receptors.

Nucleic acids are the molecules that make up DNA, (to store their genetic information).

The most common nucleic acids are Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA).

THE AIM OF BIOCHEMISTRY

To describe & explain, in molecular terms, all chemical processes of living cells.

The major objective of biochemistry is the understanding of all of the chemical processes associated with living cells.

Knowledge of biochemistry is essential to all life sciences

Genetics :The biochemistry of the nucleic acids lies at the heart of genetics.Physiology : The study of body function, overlaps with biochemistry almost completely.Immunology employs numerous biochemical techniques.

Pharmacology and pharmacy rest on a sound knowledge of biochemistry and physiology; in particular, most drugs are metabolized by enzyme-catalyzed reactions. Toxicology : Poisons act on biochemical reactions or processes.Pathology (the study of disease) : Biochemical approaches are being used increasingly to study basic aspects of such as inflammation, cell injury, and cancer.

Relationship between biochemistry & medicine

The interrelationship of biochemistry and medicine is a wide, two-way street. Biochemical studies have illuminated many aspects of health and disease, and conversely, the study of various aspects of health and disease has opened up new areas of biochemistry.

Most & perhaps all disease has a biochemical basis

Most, if not all diseases are manifestations of abnormalities of molecules, chemical reactions, or biochemical processes.

Biochemistry has become the foundation for understanding all biological processes. It has provided explanations for the causes of many diseases in humans, animals and plants.