When the replication machinery encounters a single-strand break, the replication fork collapses resulting in a double-strand break. Which of the following would be the fourth step in repairing this damage?
A. The 3' single-strand overhang invades the intact portion of the chromosome, pairs with its complementary strand, and displaces the other.
B. Once the strand invasion is complete, branched migration occurs.
C. The broken ends are processed, with the 5' ending strand selectively degraded to create 3' overhangs.
D. Branch migration creates Holliday intermediates that are resolved by the enzyme resolvase.
E. Resolution of the Holliday intermediate is followed by ligation and replication is restarted.
Chromatin is composed of:
A. DNA.
B. protein.
C. DNA and RNA.
D. DNA and protein.
E. RNA and protein.
Which of the following alternate forms of nucleic acids are not known to be biologically important?
A. G tetraplex structures can form and act as recognition sites for enzymes that cleave
DNA.
B. Inverted repeats can form hairpins that are important for slowing or preventing protein synthesis.
C. Palindromic sequences can act as recognition sites for enzymes that cleave DNA.
D. Sequence-induced bending of the DNA can act as a binding site for transcription factors.
E. Cruciform structures are formed during recombination.
Which of the following statements is consistent with the observation that the genetic code is nearly universal for all currently known life?
A. All organisms can reproduce with any other organism.
B. All organisms have a common ancestor.
C. All organisms have the same evolutionary genes.
D. All organisms arose at the same time in the history of the earth.
Which of the following is not an activity of viral reverse transcriptase?
A. RNA degradation activity
B. RNA-dependent DNA synthesis
C. DNA-dependent RNA synthesis
D. DNA-dependent DNA synthesis
E. All of the choices given are activities of reverse transcriptase.
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