PROTEIN SYNTHESIS - TRANSCRIPTIONDNA, and in some cases RNA, is the primary source of heritable information.

Protein SynthesisThe process by which information stored in DNA is used to produce proteins.

Roles of RNAmRNA: RNA sequence of a DNA segment that specifies a polypeptides amino acid sequence.

tRNA: Molecules that bring specific amino acids to the ribosome, as dictated by the mRNA sequence.

rRNA: Structural components of ribosome subunits.

Regulatory RNA: Control gene expression.

TranscriptionConverts DNA sequence information into RNA sequence information.

RNA Polymerase: Enzyme that catalyzes the 5’ → 3’ synthesis of an RNA strand from a single DNA strand.

InitiationRNA polymerase attaches to a "promoter" region in front ("upstream") of a gene• prokaryotes: RNA polymerase binds

directly to the promoter.• eukaryotes: RNA polymerase requires an

assemblage of "Transcription factor" proteins" to be able to bind to the promoter.

Promoters have characteristic DNA sequences (ex "TATA Box" in eukaryotes)

ElongationSimilar to DNA replication, RNA production occurs in a 5' to 3' direction.The "template strand" of DNA is the one that the RNA transcript is being produced off of (its sequence is opposite to the transcript)The "nontemplate strand" or "coding strand" of the DNA will have the same sequence as the RNA transcript (with thymines replaced by uracils in the transcript)

TerminationTranscript production continues until the end of the transcription unit is reached. There are multiple mechanisms of termination.