8.1 Introduction 8.2 Chaperones may be required for protein folding 8.3 Post-translational membrane insertion depends on leader sequences 8.4 A hierarchy of sequences determines location within organelles 8.5 Signal sequences initiate translocation 8.6 How do proteins enter and leave membranes? 8.7 Anchor signals are needed for membrane residence 8.8 Bacteria use both co-translational and post-translational translocation 8.9 Pores are used for nuclear ingress and egress 8.10 Protein degradation by proteasomes
7.1 Introduction 7.2 Codon-anticodon recognition involves wobbling 7.3 tRNA contains modified bases that influence its pairing properties 7.4 (There are sporadic alterations of the universal code) 7.5 tRNAs are charged with amino acids by synthetases 7.6 Accuracy depends on proofreading 7.7 Suppressor tRNAs have mutated anticodons that read new codons 7.8 The accuracy of translation 7.9 tRNA may influence the reading frame
5.1 Introduction 5.2 Transfer RNA is the adapter 5.3 Messenger RNA is translated by ribosomes 5.4 The life cycle of bacterial messenger RNA 5.5 Translation of eukaryotic mRNA 5.6 The 5 end of eukaryotic mRNA is capped 5.7 The 3 terminus is polyadenylated 5.8 Bacterial mRNA degradation involves multiple enzymes
Gene clusters are formed by duplication and divergence Sequence divergence is the basis for the evolutionary clock Pseudogenes are dead ends of evolution Unequal crossing-over rearranges gene clusters Genes for rRNA form tandem repeats ( The repeated genes for rRNA maintain constant sequence) Crossover fixation could maintain identical repeats Satellite DNAs often lie in heterochromatin Arthropod satellites have very short identical repeats Mammalian satellites consist of hierarchical repeats Minisatellites are useful for genetic mapping
