Protein Synthesis

DNA in the Cell The Central Dogma DNA  RNA  Protein

RNA Ribonucleic Acid Like DNA it is composed of nucleotides Unlike DNA it is single stranded, has a different sugar (Ribose), and contains Uracil instead of Thymine There are three main types of RNA involved in protein synthesis, messenger RNA, ribosomal RNA, and transfer RNA.

Step I: Transcription Occurs in the nucleus. Transcription is the process of converting the permanent instruction of DNA into the temporary instruction in mRNA.

Gene A gene is a segment of DNA that codes the instructions for one protein.

Transcription DNA Helicase unzips the DNA RNA Polymerase adds complimentary RNA nucleotides to the DNA of the gene. DNAmRNA Adenine =Uracil Cytosine = Guanine Guanine = Cytosine Thymine = Adenine

Step II: Translation mRNA travels to a ribosome where it is translated into proteins. The ribosome is composed of rRNA and associated proteins.

Translation A mRNA codon (three base sequence) enters a ribosome.

At the ribosome, the mRNA codon bonds to the anticodon of a tRNA (Transfer RNA) that is transferring one amino acid.

The Genetic Code

The mRNA continues moving through the ribosome, and as each new amino acids is brought it bonds to the previous amino acid creating a chain of amino acids (a Protein)

The Cytomembrane System The completed Protein may now travel in a Vesicle to the Golgi Body (where modified), and then in a Vesicle to the membrane or somewhere within the Cell