Eukaryotic Protein Synthesis

Transcription

The creation of complementary mRNA from DNA in the nucleus

Introns

Spliced out segments of DNA that are not translated

Exons

Coding segments of eukaryotic DNA

Regulatory genes

Control activity of other genes and often code for depressor proteins which bind to promoter region and prevent transcription

Alternative splicing

Once introns are removed exon sections of DNA are joined to produce final mRNA transcript which can be spliced in different ways to produce different proteins

Triplet

Sequence of three DNA bases

Codon

Sequence of three mRNA bases

Anticodon

Complementary sequence of three tRNA bases

Degenerate (redundant)

One amino acid can be coded for by more than one DNA triplet

Why is DNA universal?

One DNA triplet codes for the same amino acid in all organisms

Promoter regions

Regulates the activity of the gene and enzymes bind here to start transcription

Gene expression

Occurs when a protein is produced from a gene (transcription and translation)

Gene

A section of DNA that codes for a protein

mRNA

Takes genetic code transcribed from DNA to the ribosome

tRNA

Carries specific amino acids to the ribosome to build proteins (a specific amino acid attaches at one of be and the anti-codon is at the other end)

rRNA

Ribosomal RNA

Translation

The building of a polypeptide chain from amino acids guided by the sequence of codons in mRNA

Transcription factors

Bind to promoter region to initiate transcription and a transcription complex is formed that enables RNA polymerase to bind to it

Structural genes

Code for proteins involved in structure and function

order of gene expression

gene, transcription and translation, proteins, characteristics

products of -stages of gene expression

RNA, translation pre mRNA, final RNA, transcription polypeptide chain

start codon

AUG, introduces met amino acid

stop codon

UAA, UAG, UGA

where does mRNA travel to after transcription

ribosome

where does RNA travel after translation

Rough ER

RNA polymerase binds to promoter region and the DNA unwinds

RNA polymerase moves along template strand creating a complimentary strand

single stranded pre mRNA is formed

introns are spliced out

methyll cap and poly a tail is added

single stranded final mRNA is formed

stages of transcription