BIO152H5 Chapter Notes - Chapter 17: Tata Box, Dna Replication, Intron
Document Summary
Genes specify proteins via transcription and translation (pp. 352 358: beadle and tatum"s studies of mutant strains of neurospora led to the one gene one polypeptide hypothesis. Translation is the synthesis of a polypeptide whose amino acid sequence is specified by the nucleotide sequence in mrna: genetic information is encoded as a sequence of nonoverlapping nucleotide triplets, or codons. A codon in messenger rna (mrna) either is translated into an amino acid (61 of the 64 codons) or serves as a stop signal (3 codons). Codons must be read in the correct reading frame. Transcription is the dna-directed synthesis of rna: a closer look(pp. 358 360: rna synthesis is catalyzed by rna polymerase, which links together rna nucleotides complementary to a dna template strand. This process follows the same base-pairing rules as dna replication, except that in rna, uracil substitutes for thymine: the three stages of transcription are initiation, elongation, and termination.
