BIOL 2520 Lecture Notes - Lecture 10: Methionine, Polysome, Dipeptide
8 Dec 2017
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Read: chapter 7: from dna to protein: how cells read the genome trna molecules 242-244. The mrna message is decoded by ribosomes 244-252 trnas serve as adaptors. Structure of trna: short rna strand made of 73 to 93 nucleotides, some internal complementarity results in 3d shape, some nucleotides in trna are chemically modified after transcription. Some uridines converted to dihydrouridine or pseudouridine ( ). Required for correct shape and chemistry: amino acid attachment site is the a of a conserved cca se(cid:395)ue(cid:374)(cid:272)e at the 3" e(cid:374)d. In eukaryotes: triplet added without gene template: anticodon three sequential nucleotides in the middle loop which function in the recognition of the complementary mrna codon. Function of transfer rna: trnaserves 2 matching or adaptorfunctions, 1. amino acid to trna, 2. codon to anticodon, works in concert with the ribosome to make polypeptide chain. The genetic code consists of groups of three nucleotides called codons. Each codon codes for an amino acid.
