BIOS-115 Lecture Notes - Lecture 8: 5.8S Ribosomal Rna, 28S Ribosomal Rna, 18S Ribosomal Rna
4 Nov 2018
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50s, 23s rrna, 5s rrna, 31 proteins + 30s, 16s rrna, 21 proteins. 60s, 28s rrna, 5. 8s rrna, 49 proteins + 40s, 18s rrna, 33 proteins trna. Inverted trna aminoacylation cycle clover leaf anticodon loop transfers specificity. Nature of the genetic code: the code is a triplet code. Aaa = lysine, uug = leucine etc: the code is continuous. Doesn"t skip any nucleotides: the code is non overlapping. Read in successive groups of 3 nucleotides: the code is almost universal. Almost all organisms use the same code: the (cid:272)ode is (cid:862)degenerate(cid:863) or (cid:862)redundant(cid:863) More than one codon can code for the same amino acid: the code has start and stop signals. Stop codons= nonsense codons, all other sense codons: wobble occurs in the anticodon. The wobble hypothesis explains why multiple codons can code for a single amino acid. most organisms have fewer than 45 species of trna. This hence explains why more codons exist than there are specific trna molecules.
