Learning Objectives: By the end of today’s class you should be able to: 1.Describe transcription. 2.Compare and contrast eukaryotic + prokaryotic transcription. 3.Explain mRNA processing in eukaryotes. 4.Describe the general structure of a tRNA molecule. 5.Discuss the three stages of translation.
Fig. 17-9 Transcription Termination in Eukaryotes: Transcribes the sequence AAUAAA Signals for the RNA transcript to be cleaved.
Transcription Termination Sequences In Prokaryotes, transcription stops by way of as transcribed terminator. This is part of the transcription sequence that signals RNA polymerase to detach. (Hairpin theory) In Eukaryotes, transcription stops when a polyadenylation signal AAUAAA occurs. Proteins then cleave the RNA transcript off.
Transfer RNA (tRNA) bridges RNA language and amino acid language
Transfer RNA (tRNA) Single-stranded RNAs of about 74 - 95 nucleotides – On one “end”, they hold an amino acid – On the other “end”, they bind to mRNA There are about 45 different tRNAs in eukaryotic cells