The document summarizes the process of protein synthesis. RNA polymerase in the nucleus unwinds DNA and makes mRNA using the DNA as a template. The mRNA then exits the nucleus through the nuclear pore and enters the cytoplasm. In the cytoplasm, rRNA attaches to ribosomes and the start codon of the mRNA. tRNA then brings amino acids to the ribosome based on the mRNA codons to assemble the protein chain. The ribosome moves along the mRNA, adding more amino acids until protein synthesis is complete.