you should be able to label these pictures label the following: –rna polymerase –dna –mrna...

Focus Question:Focus Question:

How does transcription How does transcription work in prokaryotes and work in prokaryotes and eukaryotes?eukaryotes?

IB Topic 7.3 TranscriptionIB Topic 7.3 Transcription

The “Players”The “Players”

DNADNA RNA polymeraseRNA polymerase mRNAmRNA RibosomeRibosome tRNAtRNA Amino acidsAmino acids

DefinitionDefinition

Transcription-Transcription- the the reading and reading and recording of DNA recording of DNA code. code.

Location: NucleusLocation: Nucleus

Direction of TranscriptionDirection of Transcription

Occurs in the 5’Occurs in the 5’3’ 3’ direction (with direction (with reference to the reference to the mRNA)mRNA)

IB Terms: IB Terms: Sense vs. Antisense strandsSense vs. Antisense strands

Sense strand-Sense strand- the the “other” strand, not “other” strand, not transcribed.transcribed.

Antisense strand-Antisense strand- the the one mRNA attaches to, one mRNA attaches to, and is complimentary and is complimentary to.to.

mRNA is similar to the mRNA is similar to the sense strand, except sense strand, except TTU.U.

New…the “Middle” StepNew…the “Middle” Step

Transcription- beginningTranscription- beginning Middle = mRNA processingMiddle = mRNA processing Translation- endTranslation- end

RNA processingRNA processing Post-transcriptionalPost-transcriptional

Introns-Introns- non-coding non-coding sequences are sequences are removedremoved

Exons-Exons- coding coding sequences are spliced sequences are spliced togethertogether

New Players: Prokaryotic New Players: Prokaryotic TranscriptionTranscription

Promoter-Promoter- place on gene where RNA place on gene where RNA polymerase initially attaches.polymerase initially attaches.

Terminator-Terminator- place on gene where place on gene where transcription ends.transcription ends.

RNA Nucleotides = Ribonucleoside RNA Nucleotides = Ribonucleoside TriphosphatesTriphosphates

Similar to Similar to deoxynucleoside deoxynucleoside triphosphates. triphosphates. Serve as the Serve as the building blocks for building blocks for mRNA.mRNA.

Can work from 5’ to Can work from 5’ to 3’ OR 3’ to 5’3’ OR 3’ to 5’