Lesson 2: The Structure of DNA
The information in DNA is stored as a code made of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). This system of encoding information is very similar to the way a sequence of letters encodes a meaningful sentence.
A single strand of DNA is made of the bases (or
letters) A, C, G, and T:
ATGCTCGAATAAATGTGAATTTGA
The letters make a code for the building blocks of proteins. You can think of these as words:
ATG CTC GAA TAA ATG TGA ATT TGA
The words combine in a long string to make the code for complete proteins. You can think of these as sentences:
<ATG CTC GAA TAA GCC CAT CCC TGA> <ATG TGA AAA TGT GGG ATT TGA>
These "sentences" are protein-coding DNA sequences called genes. Genes are the blueprint for cellular production of proteins. Proteins are required for the structure, function, and regulation of the body's cells, tissues, and organs.
