HTHSCI 1LL3 Lecture Notes - Lecture 10: Coding Strand, Start Codon, Operon

• School: McMaster University
• Department: Health Sciences
• Course: HTHSCI 1LL3
• Professor: Teresa Mccurdy

Document Summary

Rna synthesis from a dna template is called transcription . This can be made into protein or can stay in the rna form. This process uses a polymerase that joins the nucleotides to form a single strand. The difference between the sequence in the rna strand and the dna coding strand is that uracil (u) takes the place of thymine (t) in rna. The nucleotide strand is synthesized similar to dna, in the 5" 3" direction (copied from the template strand in the 3" 5" direction). At the 5" carbon is where the phosphate is, which is where the phosphodiester bond is. The big difference between rna and dna polymerases is the ability of rna polymerase to initiate synthesis. A primer is not needed by rna polymerase; another difference is the lack of a separate proofreading exonuclease. If a mistake is made in the rna it is not as detrimental and they can be sent off for degradation.