There is always concern that new strains of influenza virus will emerge; lack of resistance to a particularly virulent virus could result in a pandemic. Which statement best describes one mechanism by which a new virus could be created?
A. Viral RNA polymerase creates additional RNA genomic segments.
B. One of the eight RNA segments of the influenza genome is eliminated from viral genome.
C. Viral RNA polymerase creates an inaccurate cDNA copy from which RNA transcripts are synthesized.
D. The RNA genome is inaccurately replicated by the viral RNA polymerase.
E. The viral genome is inaccurately translated by host ribosomes.
Researchers trying to determine the genetic basis of a rare inherited disease have been examining the pedigrees of eight families affected with the disease.
For three of the families the disease is coinherited with markers on chromosome 2, but for the other five families the disease is coinherited with markers from chromosome 10 . Why might this discrepancy occur?
A. The same disease can be caused by defects in two or more genes on the same chromosome.
B. The gene product of chromosome 2 silences the defect on chromosome 10
C. The same disease can be caused by defects in two or more genes on different chromosomes.
D. Since more families showed linkage to chromosome 10, the disease gene is on chromosome 10 . The three families showing linkage to chromosome 2 are likely false positives.
A mutation creates a deletion in the C-terminal region of the bacterial RecA protein of E. coli rendering it Rec-. It would be reasonable to surmise this mutation might:
A. increase autoinhibition of RecA.
B. increase RecA binding to DNA.
C. decrease autoinhibition of RecA.
D. be both A and B.
E. be both B and C.
The function of DNA ligase is to:
A. catalyze the formation of covalent bonds between adjacent nucleotides.
B. unwind the double-stranded DNA prior to replication.
C. keep the single strands of DNA apart during replication.
D. facilitate base pairing between single stranded molecules of DNA.
E. catalyze the formation of hydrogen bonds between adjacent nucleotides.
The characterization of prions demonstrated that:
A. this viruslike structure can cause disease.
B. secondary structure of a prion can cause disease.
C PrPC causes disease.
D. this viruslike structure and secondary structure of a prion can both cause disease.
E. secondary structure of a prion and PrPC both cause disease.
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