The genetic code of "ATTGCA" is a sequence of DNA nucleotides, which are the building blocks of DNA. In this sequence, "ATTGCA," each letter (A, T, G, and C) represents a different nucleotide. A nucleotide is composed of a sugar molecule, a phosphate group, and a nitrogen base. In "ATTGCA," the specific nitrogen bases are adenine (A), thymine (T), guanine (G), and cytosine (C), respectively. Therefore, the genetic code of "ATTGCA" represents a specific sequence of nucleotides in DNA.