An investigator studying protein synthesis in human stem cells isolates tRNA molecules bound to mRNA molecules. The isolated tRNA molecules have inosine in the 5' position of the anticodon; of these, some are bound to adenine, some to cytosine, and some to uracil at the 3' position of the mRNA codon. Which of the following properties of the genetic code is best illustrated by this finding?
AUnambiguity
BNon-overlapping
CDegeneracy
DSpecificity of the start codon
ESpecificity of stop codons
A researcher is tracing the fate of C-peptide, a product of preproinsulin cleavage. Which of the following is a true statement regarding the fate of C-peptide?
AC-peptide exits the cells via a protein channel
BC-peptide is further cleaved into insulin
CC-peptide is packaged with insulin in secretory vesicles
DC-peptide is immediately degraded by the proteasome
EC-peptide activates an intracellular signaling cascade
An investigator is studying the genetic profile of an isolated pathogen that proliferates within macrophages. The pathogen contains sulfatide on the surface of its cell wall to prevent fusion of the phagosome and lysosome. She finds that some of the organisms under investigation have mutations in a gene that encodes the enzyme required for synthesis of RNA from a DNA template. The mutations are most likely to reduce the therapeutic effect of which of the following drugs?
APyrazinamide
BEthambutol
CRifampin
DStreptomycin
ELevofloxacin
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