Biotechnology: Principles and Processes

Notes

Introduction

What is Biotechnology?

Biotechnology is the branch of science that uses living organisms, cells, enzymes, or biological systems to develop useful products and processes for human welfare.

Definition (NCERT)

Biotechnology is the technological application that uses biological systems, living organisms or their derivatives to make or modify products or processes for specific use.

Principles of Biotechnology

Modern biotechnology is based on two core techniques:

1. Genetic Engineering

It involves the direct manipulation of DNA (genes) to alter the genetic makeup of an organism.

2. Bioprocess Engineering

It involves growing genetically modified organisms (GMOs) under controlled conditions to produce useful products on a large scale.

Essential Tools of Recombinant DNA Technology (rDNA)

The following tools are essential for genetic engineering:

Restriction Enzymes

DNA Ligase

Cloning Vectors

Competent Host Cells

1. Restriction Enzymes (Restriction Endonucleases)

Definition

Restriction enzymes are molecular scissors that cut DNA at specific recognition sites.

Discovery

Werner Arber

Hamilton Smith

Daniel Nathans

(Nobel Prize in 1978)

Example

EcoRI

Recognition sequence:

5' — GAATTC — 3'

Cuts between G and A.

Produces sticky ends.

Sticky Ends

Sticky ends are single-stranded overhanging ends produced after DNA is cut.

Advantages:

Easy joining of DNA fragments

Efficient recombinant DNA formation

Blunt Ends

DNA fragments having no overhangs.

Less efficient for joining.

Naming of Restriction Enzymes

Example: EcoRI

E → Escherichia

co → coli

R → Strain RY13

I → First enzyme isolated

2. DNA Ligase

Function

DNA ligase joins DNA fragments by forming phosphodiester bonds.

Known as molecular glue.

3. Cloning Vectors

Definition

DNA molecules used to carry foreign DNA into host cells.

Features of Good Vector

Origin of replication (Ori)

Selectable marker

Restriction sites

Small size

High copy number

Plasmid

Circular DNA present in bacteria.

Common Vector:

pBR322

Features:

Ori

ampR (Ampicillin resistance)

tetR (Tetracycline resistance)

Bacteriophage

Virus infecting bacteria.

Example:

Lambda (λ) phage

Used as cloning vector.

4. Competent Host Cells

Host cells are treated chemically or electrically to…