Campbell Biology

Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson

Chapter 16

The Molecular Basis of Inheritance - all with Video Answers

Educators

Chapter Questions

Problem 1

In his work with pneumonia-causing bacteria and mice, Griffith found that
a. the protein coat from pathogenic cells was able to transform nonpathogenic cells.
b. heat-killed pathogenic cells caused pneumonia.
c. some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic.
d. the polysaccharide coat of bacteria caused pneumonia.

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 2

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?
a. The origins of replication occur only at the $5^{\prime}$ end.
b. Helicases and single-strand binding proteins work at the $5^{\prime}$ end.
c. DNA polymerase can join new nucleotides only to the $3^{\prime}$ end of a pre-existing strand.
d. DNA ligase works only in the $3^{\prime} \rightarrow 5^{\prime}$ direction.

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 3

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?
a. $A=G$
b. $\mathrm{A}+\mathrm{G}=\mathrm{C}+\mathrm{T}$
c. $A+T=G+C$
d. $A=C$

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 4

The elongation of the leading strand during DNA synthesis
a. progresses away from the replication fork.
b. occurs in the $3^{\prime} \rightarrow 5^{\prime}$ direction.
c. does not require a template strand.
d. depends on the action of DNA polymerase.

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 5

In a nucleosome, the DNA is wrapped around
a. histones.
b. ribosomes.
c. polymerase molecules.
d. a thymine dimer.

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 6

E. coli cells grown on $^{15} \mathrm{N}$ medium are transferred to $^{14} \mathrm{N}$ 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

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 7

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
d. primase

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 8

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?
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 cyclase

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 9

Although the proteins that cause the $E .$ coli chromosome to coil are not histones, what property would you expect them to share with histones, given their ability to bind to DNA (see Figure 5.14 )?

Prashant Bana

Numerade Educator

Problem 10

Some bacteria may be able to respond to environmental stress by increasing the rate at which mutations occur during cell division. How might this be accomplished? Might there be an evolutionary advantage of this ability? Explain.

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 11

Model building can be an important part of the scientific process. The illustration shown above is a computergenerated model of a DNA replication complex. The parental and newly synthesized DNA strands are color-coded differently, as are each of the following three proteins: DNA pol III, the sliding clamp, and single-strand binding protein. Use what you've learned in this chapter to clarify this model by labeling each DNA strand and each protein and indicating the overall direction of DNA replication.

Christina Vrettakos

Christina Vrettakos

Numerade Educator

Problem 12

The continuity of life is based on heritable information in the form of DNA, and structure and function are correlated at all levels of biological organization. In a short essay $(100-150$ words), describe how the structure of DNA is correlated with its role as the molecular basis of inheritance.

Rashmi Gondi

Numerade Educator

Problem 13

This image shows DNA interacting with a computer-generated model of a TAL protein, one of a family of proteins found only in a species of the bacterium Xanthomonas. The bacterium uses proteins like this one to find particular gene sequences in cells of the organisms it infects, such as tomatoes, rice, and citrus fruits. Researchers are excited about working with this family of proteins. Their goal is to generate modified versions that can home in on specific gene sequences. Such proteins could then be used in an approach called gene therapy to "fix" mutated genes in individuals with genetic diseases. Given what you know about DNA structure and considering the image above, discuss how the TAL protein's structure suggests that it functions.

James Thierer

Numerade Educator