Protein Synthesis

Nuclear envelope DNA TRANSCRIPTION Pre-mRNA mRNA TRANSLATION Ribosome Fig. 17-3b-3 (pg 329) Nuclear envelope DNA TRANSCRIPTION Pre-mRNA RNA PROCESSING mRNA Figure 17.3 Overview: the roles of transcription and translation in the flow of genetic information TRANSLATION Ribosome Polypeptide (b) Eukaryotic cell

Gene 2 Gene 1 Gene 3 DNA template strand mRNA Codon TRANSLATION Fig. 17-4 pg 329 Gene 2 DNA molecule Gene 1 Gene 3 DNA template strand TRANSCRIPTION Figure 17.4 The triplet code mRNA Codon TRANSLATION Protein Amino acid

Reading DNA CODE DNA CODE TAC AGA GTT TCA ATT What is the mRNA code? What are the amino acids coded?

First mRNA base (5 end of codon) Third mRNA base (3 end of codon) Fig. 17-5 pg 330 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon) Figure 17.5 The dictionary of the genetic code

Completed RNA transcript Fig. 17-7 pg 332 Promoter Transcription unit 5 3 3 5 DNA Start point RNA polymerase 1 Initiation Elongation Nontemplate strand of DNA RNA nucleotides 5 3 RNA polymerase 3 5 RNA transcript Template strand of DNA Unwound DNA 3 2 Elongation 3 end Rewound DNA 5 5 3 3 3 5 5 Figure 17.7 The stages of transcription: initiation, elongation, and termination 5 Direction of transcription (“downstream”) RNA transcript Template strand of DNA 3 Termination Newly made RNA 5 3 3 5 5 3 Completed RNA transcript

Translation initiation complex Fig. 17-17 p 340 Large ribosomal subunit 3 U C 5 A P site Met 5 A Met U G 3 Initiator tRNA GTP GDP E A mRNA 5 5 3 3 Start codon Figure 17.17 The initiation of translation Small ribosomal subunit mRNA binding site Translation initiation complex

GDP GDP Amino end of polypeptide E 3 mRNA Ribosome ready for Fig. 17-18-4 pg 341 Amino end of polypeptide E 3 mRNA Ribosome ready for next aminoacyl tRNA P site A site 5 GTP GDP E E P A P A Figure 17.18 The elongation cycle of translation GDP GTP E P A

Release factor Free polypeptide 5 3 3 3 2 5 5 Stop codon Fig. 17-19-3 pg 342 Release factor Free polypeptide 5 3 3 3 2 5 5 GTP Stop codon (UAG, UAA, or UGA) 2 GDP Figure 17.19 The termination of translation

Fig. 17-25 pg 348 DNA TRANSCRIPTION 3 Poly-A RNA polymerase 5 RNA transcript RNA PROCESSING Exon RNA transcript (pre-mRNA) Intron Aminoacyl-tRNA synthetase Poly-A NUCLEUS Amino acid AMINO ACID ACTIVATION CYTOPLASM tRNA mRNA Growing polypeptide Cap 3 A Activated amino acid Poly-A P Ribosomal subunits Figure 17.25 A summary of transcription and translation in a eukaryotic cell E Cap 5 TRANSLATION E A Anticodon Codon Ribosome