All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
Example Questions
Example Question #14 : Dna Replication And Repair
Upon a double-stranded DNA break, a cell can repair the DNA by resecting damaged DNA by nucleases and resynthesis of DNA by DNA polymerase. Next, DNA ligase binds the resynthesized fragment to the original DNA strand. What best describes this process?
Selective autophagy
Non-homologous end joining repair
Homology-directed repair
V(D)J recombination
Homologous recombination
Non-homologous end joining repair
The correct answer is non-homologous end joining repair. This type of DNA repair is more common than homology-directed repair which repairs damaged DNA by using a homologous template. Homologous recombination is a specific type of homology-directed repair. V(D)J recombination is a form of genetic recombination that occurs in developing lymphocytes to give rise to diverse antibodies. Selective autophagy is the selective removal of damaged proteins from the cell following a stress event such as heat exposure.
Example Question #15 : Dna Replication And Repair
DNA ligase IV has been studied for its role in what process specifically?
Homology directed DNA repair
None of the other answers
Non-homologous end joining DNA repair
Homologous recombination
DNA replication of lagging strand
Non-homologous end joining DNA repair
The correct answer is non-homologous end joining DNA repair. This specific DNA ligase joins the double stranded phosphodiester bond break in DNA by consumption of ATP, however, this repair mechanism often times is error prone and results in indels (insertion/deletion mutations). Homology directed DNA repair and homologous recombination are very similar processes that rely on template sequences to "swap" DNA sequences with other parts of the genome, however, they do not rely on this ligase. DNA ligase IV does not have a role in DNA replication.
Example Question #11 : Dna Replication And Repair
Primase is an enzyme that synthesize small primers for DNA polymerase to bind to so it can initiate DNA replication. What are these primers made of?
DNA
RNA
Carbohydrates
Lipids
Protein
RNA
Primase synthesizes RNA primers for DNA polymerase to bind to and initiate DNA replication.
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All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
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