Changes

'''Genetic code''' is the instructions in a gene that tell the [[cell]] how to make a specific protein. A, T, G, and C are the "letters" of the [[DNA]] code; they stand for the chemicals [[adenine]], [[thymine]], [[guanine]], and [[cytosine]], respectively, that make up the nucleotide bases of DNA. Each gene's code combines the four chemicals in various ways to spell out 3-letter "words" that specify which amino acid is needed at every step in making a protein.

'''Genetic code''' is the instructions in a [[gene]] that tell the [[cell]] how to make a specific protein. A, T, G, and C are the "letters" of the [[DNA]] code; they stand for the chemicals [[adenine]], [[thymine]], [[guanine]], and [[cytosine]], respectively, that make up the nucleotide bases of DNA. Each gene's code combines the four chemicals in various ways to spell out 3-letter "words" that specify which amino acid is needed at every step in making a protein.

All living things use the same genetic code system, however, there exist some viruses that contain only RNA, which has the nucleotide base of [[uracil]] ("U") instead of thymine ("T").

All living things use the same genetic code system, however, there exist some viruses that contain only RNA, which has the nucleotide base of [[uracil]] ("U") instead of thymine ("T").