Protein Synthesis

Protein Synthesis

process by which a cell makes proteins from DNA, using RNA

Gene expression

production of protein from specific gene; includes two processes: transcription and translation

Transcription

gene for specific protein is copied; creates messenger RNA (mRNA); exits through nuclear pore

Translation

occurs in cytosol; mRNA binds with ribosome, initiating synthesis of polypeptide (Specific sequence of amino acids)

gene

long chain of DNA bases, read as triplets

codon

triplets that specify for an mRNA

anti-codon

carries an amino acid, which makes up a functioning polypeptide

genetic code

list of which amino acid is specified by each RNA codon

mRNA

messenger RNA, carries instructions for building a polypeptide, from gene in DNA to ribosomes in cytoplasm

rRNA

ribosomal RNA, structural component of ribosomes that, along with tRNA, helps translate message from mRNA

tRNA

transfer RNA, binds to amino acids, and pairs with bases of codons of mRNA at ribosome to begin process of protein synthesis

sequence of events in transcription

initiation, elongation, termination

initiation

RNA polymerase and transcription factors bind to promoter region near gene on template strand of DNA- unzips and unwinds DNA double helix with aid of enzyme helicase

elongation

RNA polymerase covalently bonds complementary nucleotides to growing mRNA molecule

Termination

signal of gene is reached, and newly formed pre-mRNA molecule is ready for modification

Splicing

introns are removed and exons are joined together to form the final mRNA transcript

introns

sequences that do not specify an amino acid

exons

sequences that specify an amino acid

Sequence of Events in Translation

Initiation, elongation, termination