Using the Central Dogma of Biology:
DNA transcription RNA translation Protein
protein synthesis can be broken down into two major processes: transcription and translation.
Transcription
In transcription the genetic material of an organism (the DNA) acts as a template on which an mRNA polynucleotides chain is formed. The reaction is necessary for the transfer of information from DNA to protein. It is catalysed by the enzyme RNA polymerase.
RNA polymerase binds to the promoter, a specific DNA sequence that indicates when RNA synthesis should begin. After binding to the promoter, the RNA polymerase unwinds one coil of the DNA helix. This exposes a short section of single-stranded DNA that will act as a template for complimentary base-pairing with the arriving ribonucleotides. Two incoming ribonucleoside triphosphate monomers are joined together to start an RNA chain. The RNA polymerase moves along the DNA template strand and consequently the RNA chain grows. The enzyme will proceed with the reaction until it encounters a “stop signal”, a special sequence in the DNA that terminates the reaction. At this point the copy of the DNA called mRNA is released from the nucleus and attaches to a ribosome in the cytoplasm.
Translation
Transfer RNA molecules are found in the cytoplasm. These agents are central to protein synthesis. There is a minimum of 20 tRNA molecules. Each of these has a distinct triplet of bases (anticodon) at one end and a carboxyl end for an amino acid to attach itself. This means the amino acids are activated to their high-energy forms from which peptide bonds automatically to make polypeptides. This activation process is necessary in protein synthesis, as free amino acids cannot be added directly to the growing polypeptide chain.
The tRNA molecule also controls where the amino acid is added during the making of the proteins. Special enzymes called aminoacyl-tRNA synthetase couple each amino acid to its corresponding tRNA molecule. There are different synthetase enzymes for each amino acid.
The tRNA molecule acts as “adaptors” that change the nucleic-acid sequence information into protein-sequence.
The tRNA molecule attaches itself to its specific amino acid in the cytoplasm and carries it to the mRNA on the ribosome. The anticodon of each tRNA connects to complimentary codon on the mRNA molecule. Only one the many different tRNA molecules can base-pair with each codon.
There are 64 different possible combinations made up of 3 nucleotides, most of them will be made somewhere along the mRNA molecule. Three of the 64 codons, called stop codons, code for a “termination” of the polypeptide chain.
The genetic code is said to be degenerate because there is more than on tRNA molecule for each amino acid or a single tRNA molecule can base-pair with more than one codon.
The latter stage is called translation because that’s when the DNA code is translated into an amino acid sequence.