UNIT STUDY: Transcription

• RNA is single stranded, DNA is double stranded • RNA has uracil, DNA has tymine

• rRNA - Part of ribsome, ribosomal protien laced with rRNA, the rest of the organelle is protein • mRNA (transcription) - messanger RNA • tRNA (translation) - transfer RNA

• All the jobs of helicase, primase, DNA polymerase, and ligase • It can wind and unwind DNA and bind it to the DNA strand without a primer

• First step of protien synthesis • Begins at promoter region • Promoter region has TATA box (lots of adenine and thymine)

• mRNA strand is being built (5’ to 3’) except for T being switched with U • Takes place on the template, not coding strand • Takes place in the nucleas only

• RNA synthesis ends once RNA polymerase reconises a termination sequence (e.g. AAAA… → UUUU…) • Adenine sequeence doesnt code for anything and there is no need to continue the transcription process • Nuclear protiens reconize poly uracil (on mRNA) to stop translation • mRNA strand is relased and RNA polymerase starts once again somethwere else

• Must be modified to be protected outside of the nucleas • Poly-A-tail: 50 to 250 adenine added to 3’ end by poly-A-polymerase • 5’ cap: 7 guanine added to 5’ end as the starting point for translation

• Introns are non coding regions that may interact with protien synetheis • Introns are only found in eukaryotes • Introns must be removed by splicomeres • Exomns are coding regions resonsible for gene expressiol

• Made of small ribonucleoprotiens (snRNP) • Bind to introns through complimenty bass pairing • Intron renouvial is precise

• Intron nucleotides are removed or converted to ATP once they are removed.