central dogma of biology - oregon state...
TRANSCRIPT
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.