Why does the presence of telomeres protect the ends of linear chromosomes?
A. Telomere DNA is resistant to nuclease activity.
B. The telomeres represent large buffer zones of DNA sequence that do not code for biomolecules. Loss of these sequences is easily tolerated.
C. Every time somatic cells replicate, telomerase extends the ends of the chromosomes.
D. Specialized telomere-binding proteins prevent loss of DNA during replication.
E. None of these choices is correct.
Which of the following mechanisms is used by retrotransposons?
A. cut-and-paste transposition
B. replicative transposition
C. bacterial transduction
D. transposition via an mRNA intermediate
E. lysogeny
An intermediate in the creation of DNA nucleotides is ribose 5-phosphate, shown here. What enzymatic activity is needed to ready ribose 5-phosphate for use in DNA nucleotide synthesis?
A. DNase
B. reductase
C. oxygenase
D. RNase
E. RNA polymerase
Which one of the following sets of homopolymeric peptides is generated in vitro with the synthetic RNA polymer consisting of the repeating trinucleotide (GUC)n?
A. Poly(Val), Poly(Ala), and Poly(Leu)
B. Poly(Ser), Poly(Gly), and Poly(Arg)
C. Poly(Arg), Poly(Ser), and Poly(Val)
D. Poly(Val), Poly(His), and Poly(Asn)
Insertion sequences:
A. contain one or more genes (such as antibiotic resistance genes) in addition to those needed for transposition.
B. are simple transposons that contain only the sequences required for transposition.
C. are simple transposons that contain only the sequences required for transposition and the gene encoding the transposon.
D. contain auxiliary genes that activate the transposase.
E. None of the choices given describes insertion sequences.
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