In his work with pneumonia-causing bacteria and mice, Griffith found
a. the protein coat from pathogenic cells was able to transform
b. heat-killed pathogenic cells caused pneumonia.
c. some substances from pathogenic cells was transferred to
nonpathogenic cells, making them pathogenic
d. the polysaccharide coat of bacteria caused pneumonia.
What is the basis for the differences in how the leading and lagging
strands of DNA molecules are synthesized?
a. The origins of replication occur only at the 5'end.
b. Helicases and single-strand binding proteins work at the 5' end.
c. DNA polymerase can join new nucleotides only to the 3'end of a
d. DNA ligase works only in the 3'->5' direction.
In analyzing the number of differences bases in a DNA sample, which
result would be consistent with the base-pairing rules?
The elongation of the leading strand during DNA synthesis
a. progresses away from the replication fork
b. occurs in the 3'->5 direction
c. does not require a template strand
d. depends on the action of DNA polymerase
In a nucleosome, the DNA is wrapped around
c. polymerase molecules
d. a thymine dimer
E. colie cells grown on 15N medium are transferred to 14N medium and
allowed to grow for two more generations (two rounds of DNA
replication). DNA extracted from these cells is centrifuged. What
density distribution of DNA would you expect in this experiment?
a. one high-density and one low density band
b. one intermediate-density band
c. one high density and one intermediate-density band
d. one low density and one intermediate- density band
A biochemist isolates, purifies, and combines in a test tube a
variety of molecules needed for DNA replication. When she adds some
DNA to the mixture, replication occurs, but each DNA molecule consists
of a normal strand paired with numerous segments of DNA a few hundred
nucleotides long. What has she probably left out of the mixture.
a. DNA polymerase
b. DNA ligase
c. Okazaki fragments
The spontaneous loss of amino groups from adenine and DNA results in
hypoxanthine, an uncommon base, opposite thymine. What combination of
proteins could repair such damage?
a. nuclease, DNA polymerase, DNA ligase
b. telomerase, primase, DNA polymerase
c. telomerase, helicase, single-strand binding protein
d. DNA ligase, replication fork proteins, adenylyl cylase