Summative Quiz for Chapter 13
Based on what you have learned about the experiments conducted by Griffith and Avery and colleagues with bacteria, which of the following would result in transformation of living R cells?
Cell-free extracts from S cells
In addition to identifying the genetic material, the experiments of Avery, MacLeod, and McCarty with different strains of Streptococcus pneumoniae demonstrated that
DNA may be taken up by bacterial cells and be active.
The nucleoside analogue acyclovir, which is used to treat herpes simplex virus (HSV) infections, lacks a 3′ hydroxyl group (-OH). Predict what will happen if the host cell DNA polymerase incorporates a molecule of acyclovir into an elongating strand of HSV DNA.
DNA polymerase will not be able to link a successive nucleotide.
Which of the following does not demonstrate the stability of the DNA double helix?
DNA synthesis requires energy.
What structural aspect of the DNA facilitates dissociation of the two DNA strands for replication?
Hydrogen bonding between paired bases
Which statement about DNA replication is false?
Okazaki fragments are synthesized as parts of the leading strand.
What effect would a primase inhibitor have on DNA replication?
Primase would not be able to provide primers for DNA polymerases.
A-T base pairs in a DNA double helix
are chemically distinct from G-C base pairs.
If the Meselson-Stahl density gradient experiment had resulted in two bands of DNA molecules after only one round of replication, one containing only 15N and the second only 14N, this result would have indicated that replication was
conservative
In order to show that DNA in cell extracts is responsible for genetic transformation in Streptococcus pneumoniae, important corroborating evidence should indicate that _______ also destroy transforming activity.
enzymes that hydrolyze DNA
To replicate their DNA in a timely manner, most eukaryotic chromosomes
have multiple origins of replication.
In many eukaryotes, there are repetitive sequences called telomeres at the ends of chromosomes. After successive rounds of DNA replication, the _______ strand becomes shorter. In some cells, an enzyme called _______ repairs the shortened strand.
lagging; telomerase
The uniform diameter of the DNA structure provides evidence for
purine-pyrimidine pairing.
If 23 percent of the bases in a sample of double-stranded DNA are adenine, what percentage of the bases are uracil?
0
Choose the correct order of the following four events in the excision repair of DNA:
2, 4, 1, 3
If a sequence of one strand of DNA is 5′-TGACTATC-3′, what is the complementary strand?
3′-ACTGATAG-5′
If DNA polymerase III introduces an incorrect nucleotide, what is the first corrective action made by the DNA repair system?
The replication complex excises the incorrect nucleotide.
A researcher studies normal human fibroblast cells. They can be maintained in culture but die off after about 30 cell generations. Unexpectedly, a colony of cells continues to survive and divide past 30 generations. Which scenario is most likely true for these cells?
The telomerase gene is being expressed.