If every protein is composed of a specific sequence of amino acids, how is it that the protein myoglobin in?

Question

humans has a different sequence than the protein myoglobin in horses?

Answer 1

Some AAs are more 'critical' than others in a protein sequence, whether for structural or functional purposes. It's quite possible for proteins that serve the same function in animals that are only distantly related to have some differences in 'non-critical' AAs. Sometimes AA changes in a protein will (non-lethally) change the function of that protein, potentially leading to morphological changes in the organism. Unless these changes are harmful, they're likely to persist.

Answer 2

the dna, once transcribed to mRNA serves as the instructions for proteins, or at least sequences of amino acids. The ribosome assists in the production of proteins by providing a docking site for the mRNA. a type of transfer RNA(tRNA) has one end that is specific for an amino acid that it carries to the ribosome. on the other end, it has a site that is specific for a particular mRNA sequence(made up of 3 nucleotides mentioned earlier == codon). This tRNA's "anti-codon" does some base pairing with the sequence its specific for and then delivers the amino acid to the growing peptide chain. Now the ribosome in itself is a little more structured than this where the actually addition of the amino acids takes place, but i dont think you have to worry too much about it for now.