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Transcription BI 314 - Recitation 2

June 27th, 2012

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Central Dogma of Biology

Important Vocabulary

• Gene: A segment of DNA that codes for a polypeptide or

RNA that is utilized by the organism.

• Transcription: The process of transferring the

information found in a gene (DNA) to mRNA.

• Coding Region: The segment(s) of a gene that codes for

proteins.

Review from last time

Types of RNA

• mRNA: Made directly from the DNA. It specifies the amino acid

sequence of a protein, translated into protein by ribosomes.

• tRNA: The adapter molecule between mRNA and amino acids.

‘Anticodon’ that is complementary to mRNA codon.

• rRNA: Forms part of the structure of the ribosome.

Transcription in Prokaryotes

Initiation/termination in

Prokaryotes

coding strand

Initiation in Eukaryotes

• Much more complex than in prokaryotes.

• Three different types of RNA polymerase:

• 1&3 transcribe genes coding for tRNA, rRNA, etc.

• 2 transcribes genes coding for proteins

• Eukaryotic RNA polymerase requires general

transcription factors to function.

• Much more highly regulated

• Must work around tight packing of DNA

Eukaryotes: Post-

Translational Modifications

Eukaryotes: Post-

Translational Modifications

From DNA to mRNA to Protein

Codon Table

Common Misconceptions

• Not all RNAs encode proteins.

• Protein coding mRNAs do not start at the start codon and

end at the stop codon.

• Only the template strand of double stranded DNA is

used to make mRNA.