DNA, RNA, and Protein Synthesis
The information encoded in genetic material is responsible for establishing and maintaining the cellular and biochemical functions of an organism.
In most organisms, the genetic material is a long double stranded DNA polymer.
The sequence of units (deoxy ribo nucleotides) of
one DNA strand is complementary to the deoxy ribo nucleotides of the other strand.
This complementarity enables new DNA molecules to be synthesized with the same linear order of deoxyribonucleotides in each strand as an original DNA molecule.
The process of DNA synthesis is called replication.
A specific order of deoxyribonucleotides determines the information content of an individual genetic element (gene).
Some genes encode proteins, and others encode only ribonucleic acid (RNA) molecules.
The protein- coding genes (structural genes) are decoded by two successive major cellular processes: RNA synthesis (transcription) and protein synthesis (translation).
First, a messenger RNA (mRNA) molecule is synthesized
from a structural gene using one of the two DNA strands as a template.
Second, an individual mRNA molecule interacts with other components, including ribosomes, transfer RNAs (tRNAs), and enzymes, to produce a protein molecule.
A protein consists of a precise sequence of amino acids,
which is essential for its activity.
Although the deoxyribonucleotide sequences are different in genes encoding different functions, and for genes encoding similar functions in different organisms, the chemical compositions are the same.
This enables molecular biotechnologists to transfer genes among a variety of organisms to create beneficial products.
To understand how this is accomplished, it is helpful to know about the structure of DNA, replication, transcription, and translation.