Genetic Engineering
Genetic engineering (GE) is the laboratory technique that changes the hereditary material of a living cell.
Desirable new genes can be introduced into plants, animals, bacteria or fungi by GE in a precise, controlled and predictable way.
GE also provides a means to detect and cure genetic diseases.
Genes
In order to understand genetic engineering, we need to know what genes are.
All normal cells in our body (except sperm and egg cells) contain 46 chromosomes in their nuclei.
Chromosomes are made of Deoxyribonucleic acid (DNA).
Gene is the basic unit of inheritance and consists of a length of DNA.
The structure of DNA
Deoxyribonucleic acid - DNA
DNA is a long double stranded and spiral molecule, called "Double helix". This double helical DNA was discovered by Watson and Crick in 1953.
The double helical DNA is formed by 2 antiparallel polynucleotide chains (the chains run in opposite directions).
The structure of DNA
DNA consists of 2 chains of nucleotides (polynucleotide chains).
Each nucleotide contains a pentose sugar called deoxyribose, a phosphate group, and one of the four nitrogenous bases: adenine, cytosine, thymine and guanine.
The Structure of Nucleotide
Part of a DNA Molecule
The sugar-phosphate units make up the backbone of the chain.
The nucleotides are held together at their bases by hydrogen bonds. Due to the chemical properties of the bases, A pairs only with T through double hydrogen bonds and C pairs with G through triple hydrogen bonds.
Backbone of DNA
Biological Tasks of DNA
Storage of genetic information
DNA is the cell's blueprint and contains all the information needed to produce and maintain a unique organism.Inheritance
Genetic information is precisely transmitted to all organisms' descendants.
Expression of the genetic message
Information stored in DNA is identified and used to direct the kinds of proteins to be made by a cell.
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