Figure 17.2 Overview: the roles of transcription and translation in the flow of genetic information (Layer 5)

Figure 17.3 The triplet code

Figure 17.4 The dictionary of the genetic code

Figure 17.6 The stages of transcription: initiation, elongation, and termination (Layer 4)

Figure 17.7 The initiation of transcription at a eukaryotic promoter

Figure 17.8 RNA processing; addition of the 5 cap and poly(A) tail

The function of the cap is: –prevent mRNA degradation by hydrolytic enzymes –helps attach to the ribosome Function of the 3’ tail: –same functions as the 5’cap –also helps facilitate export of mRNA from nucleus

Figure The roles of snRNPs and spliceosomes in mRNA splicing

RNA Splicing Removes noncoding regions called introns snRNPs (small nuclear ribonucleoproteins) recognize the splicing signals that are at the ends of introns The RNA in the snRNP is called snRNA (small nuclear RNA) spliceosomes are the larger protein assemblies formed by the joining of snRNPs

Figure Correspondence between exons and protein domains

Figure 17.13a The structure of transfer RNA (tRNA)

Figure 17.13b The structure of transfer RNA (tRNA)

Figure Translation: the basic concept

Termination

Figure An aminoacyl-tRNA synthetase joins a specific amino acid to a tRNA

Figure The anatomy of a functioning ribosome

Figure The initiation of translation

Figure The elongation cycle of translation

Figure The termination of translation

Peptide Bonds Join Amino Acids

Figure Polyribosomes

Figure The signal mechanism for targeting proteins to the ER

The polypeptides of proteins destined for the endomembrane system are marked by a signal peptide, which targets the protein to the ER. A signal recognition particle (SRP) functions as an adaptor that brings the ribosome to a receptor protein built into the ER membrane.

Figure Coupled transcription and translation in bacteria

Figure The molecular basis of sickle-cell disease: a point mutation

Figure Categories and consequences of point mutations: Base-pair substitution

Figure Categories and consequences of point mutations: Base-pair insertion or deletion

Figure A summary of transcription and translation in a eukaryotic cell