BIOTECHNOLOGY DEPARTMENT

APS BAREILLY

What is Biotechnology ?

Biotechnology has been used in a rudimentary form since ancient brewers began using yeast cultures to make beer. The breakthrough that laid the groundwork for modern biotechnology came when the structure of DNA was discovered in the early 1950s. To understand how this insight eventually led to biotech therapies, its helpful to have a basic understanding of DNAs central role in health and disease.

What does DNA do?

DNA is a very long and coiled molecule found in the nucleus or command centre, of a cell. It provides the full blueprint for the construction and operation of a life-form, be it a microbe, a bird, or a human. The information in DNA is stored as a code made up of four basic building blocks, called nucleotides. The order in which the nucleotides appear is akin to the order of the letters that spell words and form sentences and stories. In the case of DNA, the order of nucleotides forms different genes. Each gene contains the instructions for a specific protein. With a few exceptions, every cell in an organism holds a complete copy of that organisms DNA. The genes in the DNA of a particular cell can be either active (turned on) or inactive (turned off) depending on the cells function and needs. Once a gene is activated, the information it holds is used for making or expressing, the protein for which it codes. Many diseases result from genes that are improperly turned on or off.

What functions do proteins control?

The amino acids that form a protein interact with each other, and those complex interactions give each protein its own specific, three-dimensional structure. That structure in turn determines how a protein functions and what other molecules it impacts. Common types of proteins are:.

  • Enzymes, which put molecules together or break them apart
  • Signalling proteins, which relay messages between cells, and receptors, which receive signals sent via proteins from other cells
  • Immune system proteins, such as antibodies, which defend against disease and external threats
  • Structural proteins, which give shape to cells and organs
  • Given the tremendous variety of functions that proteins perform, they are sometimes referred to as the workhorse molecules of life. However, when key proteins are malfunctioning or missing, the result is often disease of one type or another.

    Genetic engineering tools: To manipulate cells and DNA, scientists use tools that are borrowed from nature, including: Restriction enzymes (enzyme that cut DNA at specific location). These naturally occurring enzymes are used as a defence by bacteria to cut up DNA from viruses. DNA ligase is used in nature to repair broken DNA. It can also be used to paste new genes into DNA. Plasmids are circular units of DNA. They can be engineered to carry genes of interest. Bacteriophages (also known as phage's). These are viruses that infect bacteria. Bacteriophages can be engineered to carry recombinant DNA. ,

    How does genetic engineering work?

    Genetic engineering is the cornerstone of modern biotechnology. It is based on scientific tools, developed in recent decades, that enable researchers to: .

  • Identify the gene that produces the protein of interest
  • Cut the DNA sequence that contains the gene from a sample of DNA
  • Place the gene into a vector, such as a plasmid or bacteriophage
  • Use the vector to carry the gene into the DNA of the host cells, such as Escherichia coli  or mammalian cells grown in culture
  • Induce the cells to activate the gene and produce the desired protein
  • Extract and purify the protein for therapeutic use
  • When segments of DNA are cut and pasted together to form new sequences, the result is known as recombinant DNA. When recombinant DNA is inserted into cells, the cells use this modified blueprint and their own cellular machinery to make the protein encoded by the recombinant DNA. Cells that have recombinant DNA are known as genetically modified or transgenic cells.

  • Genetic engineering allows scientists to manufacture molecules that are too complex to make with chemistry. This has resulted in important new types of therapies, such as therapeutic proteins. Therapeutic proteins include those described below as well as ones that are used to replace or augment a patient’s naturally occurring proteins, especially when levels of the natural protein are low or absent due to disease. They can be used for treating such diseases as cancer, blood disorders, rheumatoid arthritis, metabolic diseases, and diseases of the immune system.