Biochemistry 2280A Study Guide - Quiz Guide: Small Nuclear Rna, Lac Operon, Biomolecular Structure
4 Jun 2020
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10 x more rna than dna per cell. Ribose sugar -> instead of deoxyribose sugar. Uracil nitrogen base -> instead of thymine. Base-pairs with itself -> complex folding structures. Small nuclear rna (snrna) -> involved -> splicing introns -> pre- messenger rna. Natural & artificially created ribozymes: rna content of cell: 10-15% low molecular weight species -> trnas, snrnas etc. 1-5% mrnas: regulation / usage -> rna: Rapid switching of transcription on & off. Secondary structure -> rna regulates transferrin receptor mrna degradation. Iron in blood -> binds -> transferrin. > rna degraded -> receptor not synthesised: secondary rna structure: Modification -> 5" end of mrna -> addition of nucleotide. Guanosine-triphosphate (gtp) binds -> 5" end of mrna. >> 5"-5" phosphate linkage. ( not normal 3" -oh linkage / 3" -5" nucleotide linkage ) 2" site -> 1st two nucleotides -> mrna molecule. Guanine nitrogen base -> added gtp nucleotide. > nuclear export & translation initiation: 3" cleavage & polyadenylation:
