DNA contains the genetic code to manufacture necessary proteins that the cells needs to function. Transcription is the process where the genetic code contained in the DNA double helix is copied by another nucleic acid known as messenger RNA(mRNA). The DNA remains in the nucleus however, the mRNA can bring the transcript to the cytoplasm and attach to a ribosome, where translation occurs. The process of translation refers to the production of a polypeptide, according to the codons on the mRNA transcript. Every three bases in messenger RNA is called a codon or triplet. It is the instructions for a particular amino acid. As each codon is "read" on the mRNA transcript, another type of RNA called transfer RNA(tRNA) carries the appropriate amino acid to the ribosome. The first codon is a "start" codon, for the amino acid methionine. This initiates translation. As each amino acid is added and connected by peptide bonds, a long chain of amino acids called a polypeptide, forms. When a stop codon is reached, the polypeptide detaches and folds into a functional protein.
Transcription is from DNA to RNA, and translation is from RNA to a protien. In transcription, the DNA strand is 'unzipped' by the enzyme helicase. This allows one of the DNA strands to be decoded. Then, the mRNA nucleotides find their complement on the DNA strand, and bond together. Once the mRNA strand copies the DNA strand, it detatches itself, and leaves the nucleus to go to the ribosomes for protien synthesis. The DNA 'zips' up after the mRNA leaves. In translation, the mRNA attatches itself to a ribosome. Then, the tRNA carries an animo acid (which has anti-codons), and pairs it with its corresponding mRNA codon. When both amino acids are in place, the rRNA connects them by forming a peptide bond. This process continues until a stop codon is reached. The tRNA is 'recycled' so it can be used over and over again. In the final step, the proteins are transported to parts of the body that need them.