The molecule that stores the information about the order of amino acids in a protein is messenger RNA (mRNA).

Here's how it works:

1. DNA contains the genetic code: The blueprint for a protein is stored in the DNA within a gene.

2. Transcription: The DNA sequence of a gene is copied into mRNA. This process is called transcription.

3. Translation: The mRNA travels out of the nucleus to the ribosomes, where it is "read" to assemble the protein. The sequence of codons (three-nucleotide units) in the mRNA dictates the order of amino acids in the protein.

So, while DNA contains the original genetic code, mRNA is the molecule that directly carries the instructions for protein synthesis.