TRANSCRIPTION AND TRANSCRIPTION AND TRANSLATIONTRANSLATION

Transcription notesTranscription notes

Point of Transcription – to make an Point of Transcription – to make an accurate small piece of an organisms accurate small piece of an organisms DNADNA

Information from DNA is copied onto a Information from DNA is copied onto a special RNA molecule called special RNA molecule called Messenger RNA (mRNA)Messenger RNA (mRNA)

mRNA is carried from the nucleus mRNA is carried from the nucleus and travels out to the cytoplasm’s and travels out to the cytoplasm’s ribosome for protein synthesis.ribosome for protein synthesis.

TTanscriptionanscription

RNA Polymerase catalyzes the RNA Polymerase catalyzes the synthesis of mRNA from DNAsynthesis of mRNA from DNA

Only one strand of DNA is ever read, Only one strand of DNA is ever read, this strand is the this strand is the Sense (template) Sense (template) StrandStrand

A special sequence of nucleotides on A special sequence of nucleotides on the DNA tells an RNA Polymerase the DNA tells an RNA Polymerase where to bind and where to release.where to bind and where to release.

RNA PolymeraseRNA Polymerase

Like DNA Polymerase – RNA Like DNA Polymerase – RNA Polymerase reads a sense strand in Polymerase reads a sense strand in the 3’ to 5’ directionthe 3’ to 5’ direction

It there for creates a new strand in the It there for creates a new strand in the 5’ to 3’ direction, adding new 5’ to 3’ direction, adding new nucleotides to the 3’ –OH group.nucleotides to the 3’ –OH group.

RNA Polymerase opens up the DNA RNA Polymerase opens up the DNA helix as it reads through the sequence helix as it reads through the sequence creating a complementary strandcreating a complementary strand

Once the mRNA strand is made:Once the mRNA strand is made:- In Prokaryotes the strand is ready for In Prokaryotes the strand is ready for

Translation.Translation.- In Eukaryotes the strand needs In Eukaryotes the strand needs

additional RNA processing before additional RNA processing before leaving the nucleusleaving the nucleus

Before leaving the Nucleus Before leaving the Nucleus mRNA undergoes mRNA undergoes

processingprocessing Tails are added to the 3’ and 5’ endsTails are added to the 3’ and 5’ ends All Introns are removed, so only the All Introns are removed, so only the

exons that contain the information exons that contain the information for the gene are sent out to the for the gene are sent out to the ribosome for translation to begin.ribosome for translation to begin.

TRANSCRIPTIONTRANSCRIPTION

http://www-class.unl.edu/biochem/http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gp2/m_biology/animation/gene/gene_a2.htmlgene_a2.html

TRANSLATIONTRANSLATION

http://www.biostudio.com/http://www.biostudio.com/demo_freeman_protein_synthesis.htdemo_freeman_protein_synthesis.htmm

Both ProcessesBoth Processes

Walk through of translationWalk through of translation Translation overview linkTranslation overview link