ACGT

ACGT stands for the four nucleic-acid bases that make up DNA. The A stands for Adenine and pairs with the T, which stands for Thymine. The C stands for Cytosine and pairs with the G, Guanine. These four nucleic acids make up your genetic code, or DNA.

ACGU stands for the four amino acids that make up RNA. RNA pairs up the same as DNA, except that Thymine is replaced with Uracil.