bio 1500 exam 5 UPDATED ACTUAL Exam
Questions and CORRECT Answers
In his work with pneumonia-causing bacteria and mice, Griffith found that __________. -
CORRECT ANSWER - some substance from pathogenic cells was transferred to
nonpathogenic cells, making them pathogenic
What is the basis for the difference in how the leading and lagging strands of DNA molecules are
synthesized? - CORRECT ANSWER - dna polymerase can join new nucleotides only to
the 3' end of a growing strand
In analyzing the number of different bases in a DNA sample, which result would be consistent
with the base-pairing rules? - CORRECT ANSWER -A+ G = C +T
The elongation of the leading strand during DNA synthesis __________. - CORRECT
ANSWER - depends on the action of DNA polymerase
In a nucleosome, the DNA is wrapped around __________. - CORRECT ANSWER -
histones
Which of the following sequences in double-stranded DNA is most likely to be recognized as a
cutting site for a restriction enzyme?
1. acca and tggt
2. aaaa and tttt
3. ggcc and ccgg
4. aagg and ttcc
5. agtc and tcag - CORRECT ANSWER - ggcc
ccgg
(restriction sites are typically palindromic)
, E. coli 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? -
CORRECT ANSWER - 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? - CORRECT ANSWER -
DNA ligase
The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an
uncommon base, opposite thymine. What combination of proteins could repair such damage? -
CORRECT ANSWER - nuclease, DNA polymerase, DNA ligase
During Griffith's experiments with Streptococcus pneumoniae in mice, material from _____
bacteria transformed _____ bacteria. - CORRECT ANSWER - heat-killed virulent ...
living nonvirulent
Avery and his colleagues' 1944 experiment showed that DNA _____. - CORRECT
ANSWER - was the substance that transformed the bacteria in Griffith's experiment
A scientist assembles a bacteriophage with the protein coat of phage T2 and the DNA of phage
T4. If this composite phage were allowed to infect a bacterium, the phages produced in the host
cell would have _____. - CORRECT ANSWER - the protein and DNA of T4
In an important experiment, a radioactively labeled bacteriophage was allowed to infect bacteria.
In a first trial, the phage contained radioactive DNA, and radioactivity was detected inside the
bacteria. Next, phage containing radioactive protein was used, and the radioactivity was not
detected inside the bacteria. These experiments led to the conclusion that _____. - CORRECT
ANSWER - the genetic material of the phage is DNA
Monomers for the synthesis of DNA are called _____. - CORRECT ANSWER -
nucleotides
Questions and CORRECT Answers
In his work with pneumonia-causing bacteria and mice, Griffith found that __________. -
CORRECT ANSWER - some substance from pathogenic cells was transferred to
nonpathogenic cells, making them pathogenic
What is the basis for the difference in how the leading and lagging strands of DNA molecules are
synthesized? - CORRECT ANSWER - dna polymerase can join new nucleotides only to
the 3' end of a growing strand
In analyzing the number of different bases in a DNA sample, which result would be consistent
with the base-pairing rules? - CORRECT ANSWER -A+ G = C +T
The elongation of the leading strand during DNA synthesis __________. - CORRECT
ANSWER - depends on the action of DNA polymerase
In a nucleosome, the DNA is wrapped around __________. - CORRECT ANSWER -
histones
Which of the following sequences in double-stranded DNA is most likely to be recognized as a
cutting site for a restriction enzyme?
1. acca and tggt
2. aaaa and tttt
3. ggcc and ccgg
4. aagg and ttcc
5. agtc and tcag - CORRECT ANSWER - ggcc
ccgg
(restriction sites are typically palindromic)
, E. coli 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? -
CORRECT ANSWER - 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? - CORRECT ANSWER -
DNA ligase
The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an
uncommon base, opposite thymine. What combination of proteins could repair such damage? -
CORRECT ANSWER - nuclease, DNA polymerase, DNA ligase
During Griffith's experiments with Streptococcus pneumoniae in mice, material from _____
bacteria transformed _____ bacteria. - CORRECT ANSWER - heat-killed virulent ...
living nonvirulent
Avery and his colleagues' 1944 experiment showed that DNA _____. - CORRECT
ANSWER - was the substance that transformed the bacteria in Griffith's experiment
A scientist assembles a bacteriophage with the protein coat of phage T2 and the DNA of phage
T4. If this composite phage were allowed to infect a bacterium, the phages produced in the host
cell would have _____. - CORRECT ANSWER - the protein and DNA of T4
In an important experiment, a radioactively labeled bacteriophage was allowed to infect bacteria.
In a first trial, the phage contained radioactive DNA, and radioactivity was detected inside the
bacteria. Next, phage containing radioactive protein was used, and the radioactivity was not
detected inside the bacteria. These experiments led to the conclusion that _____. - CORRECT
ANSWER - the genetic material of the phage is DNA
Monomers for the synthesis of DNA are called _____. - CORRECT ANSWER -
nucleotides
