Final answer:
A large molecule containing triplet codes that form genes is DNA. Each triplet corresponds to a specific amino acid, similar to a three-letter code representing a word.
Step-by-step explanation:
A large molecule containing triplet codes, such as ATT and TCG, that together form genes is DNA.
Genes are composed of multiple triplets in a unique sequence, which provide the code to build an entire protein. Each triplet, or codon, corresponds to a specific amino acid, similar to how the three-letter code 'd-o-g' signals the image of a dog.
The DNA code is translated into an amino acid sequence through a two-step process involving an RNA molecule as an intermediate.