|Making Proteins From Genes
|Genes within DNA strands produce proteins, chains of amino acids, that regulate the body's
functions. There are 20 different amino acids which can be combined to create countless proteins. This is done
is through a marvelous transcription and translation process.
First the DNA strand separates and then the base pairs in the "sense strand" are transcibed into messenger
RNA, or mRNA for short. In the transcription, DNA bases are matched up with their corresponding pairs, with the
exception of Adenine, which is matched up with uracil instead of thymine. mRNA is then processed in groups of 3
base pairs. These 3 base pair combinations called "codons." The codons are then translated by ribosomes
to generate specific amino acids.
||All amino acids share common chemical elements and structure. The diagram at the right shows
the general format of an amino acid. The "R" in the diagram represents the unique part of amino acid.
|Each of the amino acids is represented by a one letter abbreviation. The table at the right
lists the single letter abbreviations and the full names of each amino acid. Special sequences called "stops"
indicate the end of each protein. In the applet stops are displayed as blanks.
|Try this applet. Makeup a DNA sequence using the buttons for A (Adenine), C (cytosine), G
(guanine), and T (thymine). For each three bases the program will transcribe a mRNA sequence. Press the "Map
Amino Acids" button and the corresponding amino acid sequence will be displayed. The single letter amino acid
abbreviation matches up with its full name in the table above.
|Copyright (c) 2004 by Sawatch Software, Inc.
Credits: DNA image courtesy of CNN.com
Last updated July 6, 2004