BIOL 3090 : Exam 4 Study Guide
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16) what"s the main pathway for mrna degradation in the cytoplasm? (fig. 8-26 and especially the left half of fig. 8-25): micro-rna: actually encoded by genes in our genome and many by rna poly ii so they have a 7mg caps. Endonucleases drosha and pasha cleave the mirna to 70 nts (still in hairpin) and then mirna is exported from the nucleus to the cytoplasm. The pre-mirna hairpin is processed by dicer and risc once in the cytoplasm. Dicer chops pre-mirna into smaller ss fragments and passes them onto risc which takes them around the cell looking for the fragments compliment. Utrs of mrna and forms an imperfect complementary helix that contains bubbles. And how do they become active for translation (fig. Cytoplasmic versions of polyadenylation factors then extend polya tail. Pabi then binds the polya tail and stabilizes translations factors: what are iron response elements, and how do they regulate translation of the transferrin receptor mrna (fig.
