the steps in protein synthesis are ( 1 ) transport of amino acids into heart cells by a variety of cell-membrane carriers , ( 2 ) atp-dependent activation of the amino acids by specific enzymes , forming aminoacyl-transfer rna molecules , ( 3 ) initiation of protein synthesis on ribosomes to which messenger-rna molecules are bound at the initiation 'code word ' , ( 4 ) elongation of the polypeptide chains by the repetitive operation of a ribosomal enzyme acting on incoming aminoacyl-transfer rnas selected by their ability to bind to the messenger-rna code words in place at any one time , and ( 5 ) completion of chain growth when the appropriate termination code word appears in the messenger rna on the ribosome .
C0597295
protein synthesis
C0035553
ribosome