Problem 27
Describe the role of the stop signals in protein synthesis.
Problem 28
RECALL Does mRNA bind to one or to both ribosomal subunits in the course of protein synthesis?
Problem 29
RECALL What is the Shine-Dalgarno sequence? What role does it play in protein synthesis?
Problem 38
REFLECT AND APPLY Suggest a possible conclusion from the fact that peptidyl transferase is one of the most conserved sequences in all of biology.
Problem 39
REFLECT AND APPLY In the early days of research on protein synthesis, some scientists observed that their most highly purified ribosome preparations, containing almost exclusively single ribosomes, were less active than preparations that were less highly purified. Suggest an explanation for this observation.
Problem 44
RECALL Why is selenocysteine called the 21 st amino acid when there are many more amino acids found than the 20 basic ones coded for by the genetic code?
Problem 48
RECALL What are two major similarities between protein synthesis in bacteria and in eukaryotes? What are two major differences?
Problem 49
REFLECT AND APPLY Why do amino acids other than methionine occur in the N-terminal position of proteins from eukaryotes?
Problem 52
REFLECT AND APPLY Why is it advantageous to have a mechanism to override the effect of stop codons in protein synthesis?
Problem 57
REFLECT AND APPLY The amino acid hydroxyproline is found in collagen. There is no codon for hydroxyproline. Explain the occurrence of this amino acid in a common protein.
