Types of RNA
mRNA--(messenger) intermediate molecules used for transfer the information from DNA to
rRNA--(ribosomal) functional RNA molecules that are components of the ribosome.
tRNA--(transfer) functional RNA molecules that serve as adapters in translation.
• A region of a DNA molecule containing a sequence of bases that is transcribed into a
• Several regions are responsible for the proper function of a gene.
o Regulatory region (promoter)-sequence of bases that control the initiation of
o Transcribed region – sequence of bases that are read into a functional molecule
(RNA and protein).
o Termination site- sequence of nucleotides that stops transcription.
• Transcription (copying) is the first step in converting genetic information into proteins
• RNA polymerase synthesizes an RNA transcript using one strand of DNA as the
o This strand is the template strand, the other the non-template strand
• RNA polymerase synthesizes the RNA strand in the 5’ -> 3’ direction.
o This RNA is complementary to the DNA template strand.
• Transcription begins nears promoter sites and ends at terminator sites
• Three steps of Transcription
o Termination Initiation: How Does Transcription Begin?
The enzyme RNA polymerase binds to a specific site in DNA (promoter) with the help of
Elongation and Termination
• After the enzyme RNA polymerase binds to the promoter, it catalyzes the pr