FIGURE 1-9 The information encoded in DNA is converted into the amino acid sequences of proteins by a multistep process. Step 1: Transcription factors and other proteins bind to the regulatory regions of the specific genes they control to activate those genes. Step 2: RNA polymerase begins transcription of an activated gene at a specific location, the start site. The polymerase moves along the DNA, linking nucleotides into a single-stranded pre-mRNA transcript using one of the DNA strands as a template. Step 3: The transcript is processed to remove noncoding sequences. Step 4: In a eukaryotic cell, the mature mRNA moves to the cytoplasm, where it is bound by ribosomes that read its sequence and assemble a protein by chemically linking amino acids into a linear chain.