Question 1

A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, 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?

Accepted Answer

A)  DNA polymerase
B)  DNA ligase
C)  nucleotides
D)  Okazaki fragments
E)  primaseF) A) and B)
G) None of the above

Question 2

In an experiment, DNA is allowed to replicate in an environment with all necessary enzymes, dATP, dCTP, dGTP, and radioactively labeled dTTP (³H thymidine) for several minutes and then switched to nonradioactive medium. It is then viewed by electron microscopy and autoradiography. The drawing below represents the results. 
Grains represent radioactive material within the replicating eye.
Figure 16.2
Which is the most likely interpretation?

Accepted Answer

A)  There are two replication forks going in opposite directions.
B)  Thymidine is only being added where the DNA strands are furthest apart.
C)  Thymidine is only added at the very beginning of replication.
D)  Replication proceeds in one direction only.E) B) and C)
F) All of the above

Question 3

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?

Accepted Answer

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 growing strand.
D)  DNA ligase works only in the 3' → 5' direction.
E)  Polymerase can work on only one strand at a time.F) B) and D)
G) A) and C)

Question 4

Why does the DNA double helix have a uniform diameter?

Accepted Answer

A)  Purines pair with pyrimidines.
B)  C nucleotides pair with A nucleotides.
C)  Deoxyribose sugars bind with ribose sugars.
D)  Nucleotides bind with nucleosides.
E)  Nucleotides bind with nucleoside triphosphates.F) A) and B)
G) None of the above

Question 5

Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise?

Accepted Answer

A)  replication followed by mitosis
B)  replication without separation
C)  meiosis followed by mitosis
D)  fertilization by multiple sperm
E)  special association with histone proteinsF) A) and E)
G) A) and B)

Question 6

Use Figure 16.1 to answer the following questions.
  
Figure 16.1
-Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?

Accepted Answer

A)  The evolution of telomerase enzyme
B)  DNA polymerase that cannot replicate the leading strand template to its 5' end
C)  Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which nucleotides can attach
D)  Gaps left at the 3' end of the lagging strand because of the need for a primer
E)  The "no ends" of a circular chromosomeF) B) and C)
G) A) and E)

Question 7

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5'
An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

Accepted Answer

A)  5' G C C T A G G 3'
B)  3' G C C T A G G 5'
C)  5' A C G T T A G G 3'
D)  5' A C G U U A G G 3'
E)  5' G C C U A G G 3'F) A) and C)
G) B) and E)

Question 8

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Accepted Answer

A)  synthesize RNA nucleotides to make a primer
B)  catalyze the lengthening of telomeres
C)  join Okazaki fragments together
D)  unwind the parental double helix
E)  stabilize the unwound parental DNAF) A) and B)
G) A) and C)

Question 9

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells have which impaired ability?

Accepted Answer

A)  They cannot replicate DNA.
B)  They cannot undergo mitosis.
C)  They cannot exchange DNA with other cells.
D)  They cannot repair thymine dimers.
E)  They do not recombine homologous chromosomes during meiosis.F) A) and E)
G) D) and E)

Question 10

Chargaff's analysis of the relative base composition of DNA was significant because he was able to show that

Accepted Answer

A)  the relative proportion of each of the four bases differs within individuals of a species.
B)  the human genome is more complex than that of other species.
C)  the amount of A is always equivalent to T, and C to G.
D)  the amount of ribose is always equivalent to deoxyribose.
E)  transformation causes protein to be brought into the cell.F) A) and B)
G) A) and C)

Question 11

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?

Accepted Answer

A)  sequence of bases
B)  phosphate-sugar backbones
C)  complementary pairing of bases
D)  side groups of nitrogenous bases
E)  different five-carbon sugarsF) B) and D)
G) A) and B)

Question 12

Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?

Accepted Answer

A)  the diameter of the helix
B)  the rate of replication
C)  the sequence of nucleotides
D)  the bond angles of the subunits
E)  the frequency of A vs. T nucleotidesF) B) and D)
G) A) and C)

Question 13

Mendel and Morgan did not know about the structure of DNA; however, which of the following of their contributions was (were) necessary to Watson and Crick?

Accepted Answer

A)  the particulate nature of the hereditary material
B)  dominance vs. recessiveness
C)  sex-linkage
D)  genetic distance and mapping
E)  the usefulness of peas and DrosophilaF) C) and E)
G) A) and E)

Question 14

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

Accepted Answer

A)  DNA contains sulfur, whereas protein does not.
B)  DNA contains phosphorus, but protein does not.
C)  DNA contains nitrogen, whereas protein does not.
D)  DNA contains purines, whereas protein includes pyrimidines.
E)  RNA includes ribose, while DNA includes deoxyribose sugars.F) All of the above
G) C) and D)

Question 15

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?

Accepted Answer

A)  There is no radioactive isotope of nitrogen.
B)  Radioactive nitrogen has a half-life of 100,000 years, and the material would be too dangerous for too long.
C)  Avery et al. have already concluded that this experiment showed inconclusive results.
D)  Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive.
E)  Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.F) A) and B)
G) None of the above

Question 16

In his transformation experiments, what did Griffith observe?

Accepted Answer

A)  Mutant mice were resistant to bacterial infections.
B)  Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
C)  Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic.
D)  Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains.
E)  Mice infected with a pathogenic strain of bacteria can spread the infection to other mice.F) A) and B)
G) B) and D)

Question 17

In prophase I of meiosis in female Drosophila, studies have shown that there is phosphorylation of an amino acid in the tails of histones. A mutation in flies that interferes with this process results in sterility. Which of the following is the most likely hypothesis?

Accepted Answer

A)  These oocytes have no histones.
B)  Any mutation during oogenesis results in sterility.
C)  Phosphorylation of all proteins in the cell must result.
D)  Histone tail phosphorylation prohibits chromosome condensation.
E)  Histone tails must be removed from the rest of the histones.F) A) and B)
G) A) and C)

Question 18

In a nucleosome, the DNA is wrapped around

Accepted Answer

A)  polymerase molecules.
B)  ribosomes.
C)  histones.
D)  a thymine dimer.
E)  satellite DNA.F) A) and D)
G) A) and B)

Question 19

Use Figure 16.1 to answer the following questions.
  
Figure 16.1
-An Okazaki fragment has which of the following arrangements?

Accepted Answer

A)  primase, polymerase, ligase
B)  3' RNA nucleotides, DNA nucleotides 5'
C)  5' RNA nucleotides, DNA nucleotides 3'
D)  DNA polymerase I, DNA polymerase III
E)  5' DNA to 3'F) A) and B)
G) A) and C)

Question 20

A typical bacterial chromosome has ~4.6 million nucleotides. This supports approximately how many genes?

Accepted Answer

A)  4.6 million
B)  4.4 thousand
C)  45 thousand
D)  about 400E) A) and B)
F) A) and C)

Exam 16: The Molecular Basis of Inheritance

Why does the DNA double helix have a uniform diameter?

Correct Answer
verified

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?

Correct Answer
verified

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

Correct Answer
verified

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Correct Answer
verified

Use Figure 16.1 to answer the following questions. Figure 16.1 -Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?

Correct Answer
verified

Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise?

Correct Answer
verified

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, 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
verified

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells have which impaired ability?

Correct Answer
verified

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

Correct Answer
verified

Use Figure 16.1 to answer the following questions. Figure 16.1 -An Okazaki fragment has which of the following arrangements?

Correct Answer
verified

In a nucleosome, the DNA is wrapped around

Correct Answer
verified

Mendel and Morgan did not know about the structure of DNA; however, which of the following of their contributions was (were) necessary to Watson and Crick?

Correct Answer
verified

In his transformation experiments, what did Griffith observe?

Correct Answer
verified

Chargaff's analysis of the relative base composition of DNA was significant because he was able to show that

Correct Answer
verified

In prophase I of meiosis in female Drosophila, studies have shown that there is phosphorylation of an amino acid in the tails of histones. A mutation in flies that interferes with this process results in sterility. Which of the following is the most likely hypothesis?

Correct Answer
verified

A typical bacterial chromosome has ~4.6 million nucleotides. This supports approximately how many genes?

Correct Answer
verified

Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?

Correct Answer
verified

Exam 16: The Molecular Basis of Inheritance

Why does the DNA double helix have a uniform diameter?

Correct AnswerverifiedShow Answer

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?

Correct AnswerverifiedShow Answer

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

Correct AnswerverifiedShow Answer

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Correct AnswerverifiedShow Answer

Use Figure 16.1 to answer the following questions. Figure 16.1 -Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?

Correct AnswerverifiedShow Answer

Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise?

Correct AnswerverifiedShow Answer

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, 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 AnswerverifiedShow Answer

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells have which impaired ability?

Correct AnswerverifiedShow Answer

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

Correct AnswerverifiedShow Answer

Use Figure 16.1 to answer the following questions. Figure 16.1 -An Okazaki fragment has which of the following arrangements?

Correct AnswerverifiedShow Answer

In a nucleosome, the DNA is wrapped around

Correct AnswerverifiedShow Answer

Mendel and Morgan did not know about the structure of DNA; however, which of the following of their contributions was (were) necessary to Watson and Crick?

Correct AnswerverifiedShow Answer

In his transformation experiments, what did Griffith observe?

Correct AnswerverifiedShow Answer

Chargaff's analysis of the relative base composition of DNA was significant because he was able to show that

Correct AnswerverifiedShow Answer

In prophase I of meiosis in female Drosophila, studies have shown that there is phosphorylation of an amino acid in the tails of histones. A mutation in flies that interferes with this process results in sterility. Which of the following is the most likely hypothesis?

Correct AnswerverifiedShow Answer

A typical bacterial chromosome has ~4.6 million nucleotides. This supports approximately how many genes?

Correct AnswerverifiedShow Answer

Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?

Correct AnswerverifiedShow Answer

Correct Answer
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