Biology 1002B Lecture Notes - Lecture 14: Nuclear Localization Sequence, Small Nuclear Rna, Signal Peptidase
16 Aug 2017
School
Department
Course
Professor
Document Summary
Guanine nucleotide reversed: 3"-oh group faces the beginning rather than the end of the molecule. Capping enzyme adds 5" cap to the pre-mrna soon after rna polymerase ii begins transcription without need for complementary base pairing. Connected to rest of mrna by 3 phosphate groups. Remains when pre-mrna is processed to mrna. Site where ribosomes attach at the start of translation. Transcription continues past the end of the gene and eventually stops. Proteins bind to the polyadenylation signal and cleaves the transcript downstream of this point: understood as mrna, cleavage = signal for polymerase to stop transcribing. Poly (a) polymerase adds a chain of 50 to 250. Adenines one at a time to the 3" end of the pre- mrna: enables efficient translation and protection from rna-digesting enzymes in the cytoplasm. Introns non-protein coding sequences that interrupt the protein coding sequence. Transcribed but removed from pre-rna during rna processing.
