How is Information Stored

How is Information Stored - codon codes for one amino acid...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
How is Information Stored? The diagram below shows that one strand of the DNA double-helix serves as a template for the construction of mRNA. The sequence of nucleotides in this DNA strand is complimentary (opposite) the sequence in mRNA. The diagram also shows that the sequence of nucleotides in mRNA determines the amino acids in the protein. For example GUG in mRNA (or CAC in DNA) codes for valine (see below). The strand of DNA that contains the genetic code is called the anti-sense strand. It is often referred to as the template strand. The other strand (the sense strand) is not used. Notice that the sense strand has the same base sequence as mRNA except that mRNA has U instead of T. The codes in DNA are copied to produce mRNA. Each three-letter code in mRNA (called a
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: codon ) codes for one amino acid. The sequence of amino acids in proteins is therefore most directly determined by the sequence of bases in mRNA, which in turn, are determined by the sequence of bases in DNA. There are four letters in the genetic alphabet (A, T, G, and C) and each codon contains three letters. It is therefore possible to have 64 different codons. Because there are only 20 different amino acids and 64 possible codons, some amino acids have several different codons. Terminators are codes that indicate the end of a genetic message (gene). An initiator codon (usually AUG) indicates where the genetic information begins....
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online