Genetics: A Conceptual Approach

Benjamin Pierce

Chapter 10 DNA: The Chemical Nature of the Gene - all with Video Answers

Educators

Chapter Questions

04:20

Problem 1

What four general characteristics must the genetic material possess?

Sidharth Anand

Numerade Educator

04:55

Problem 2

Briefly outline the history of our knowledge of the structure of DNA until the time of Watson and Crick. Which do you think were the principal contributions and developments?

Wade Corn

Numerade Educator

03:01

Problem 3

What experiments demonstrated that DNA is the genetic material?

Wade Corn

Numerade Educator

06:44

Problem 4

What is transformation? How did Avery and his colleagues demonstrate that the transforming principle is DNA?

Sidharth Anand

Numerade Educator

02:34

Problem 5

How did Hershey and Chase show that DNA is passed to new phages in phage reproduction?

Wade Corn

Numerade Educator

01:25

Problem 6

Why was the discovery of DNA structure so important?

Wade Corn

Numerade Educator

03:26

Problem 7

Draw and identify the three parts of a DNA nucleotide.

Wade Corn

Numerade Educator

01:54

Problem 8

How does an RNA nucleotide differ from a DNA nucleotide?

Wade Corn

Numerade Educator

02:58

Problem 9

How does a purine differ from a pyrimidine? What purines and pyrimidines are found in DNA and RNA?

Wade Corn

Numerade Educator

04:11

Problem 10

Draw a short segment of a single polynucleotide strand, including at least three nucleotides. Indicate the polarity of the strand by identifying the $5^{\prime}$ end and the $3^{\prime}$ end.

Wade Corn

Numerade Educator

01:17

Problem 11

Which bases are capable of forming hydrogen bonds with each other?

Wade Corn

Numerade Educator

03:08

Problem 12

What different types of chemical bonds are found in DNA and where are they found?

Wade Corn

Numerade Educator

03:27

Problem 13

What are some of the important genetic implications of the DNA structure?

Wade Corn

Numerade Educator

02:29

Problem 14

What are the three major pathways of information flow within the cell?

Wade Corn

Numerade Educator

03:10

Problem 15

What are hairpins and how do they form?

Wade Corn

Numerade Educator

01:17

Problem 16

What is DNA methylation?

Wade Corn

Numerade Educator

04:30

The introduction to this chapter, which describes the sequencing of 4000-year-old DNA, emphasizes DNA's extreme stability. What aspects of DNA's structure contribute to the stability of the molecule? Why is RNA less stable than DNA?

Wade Corn

Numerade Educator

04:26

Problem 18

Match the researchers (a-j) with the discoveries listed. a. Kossel
b. Fraenkel-Conrat
c. Watson and Crick
d. Levene
e. Miescher
f. Hershey and Chase
g. Avery, MacLeod, and McCarty
h. Griffith
i. Franklin and Wilkins
¡. Chargaff
______.Took X-ray diffraction pictures used in constructing the structure of DNA.
-________.Determined that DNA contains nitrogenous bases.
_____Identified DNA as the genetic material in bacteriophages. Discovered regularity in the ratios of different bases in DNA.
_______ Determined that DNA is responsible for transformation in bacteria.
________Worked out the helical structure of DNA by building models. Discovered that DNA consists of repeating nucleotides. Determined that DNA is acidic and high in phosphorus. Conducted experiments showing that RNA can serve as the genetic material in some viruses. _________Demonstrated that heat-killed material from bacteria can genetically transform live bacteria.

Wade Corn

Numerade Educator

03:02

Problem 19

A student mixes some heat-killed type IIS Streptococcus pneumoniae bacteria with live type IIR bacteria and injects the mixture into a mouse. The mouse develops pneumonia and dies. The student recovers some type IIS bacteria from the dead mouse. If this is the only experiment conducted by the student, has the student demonstrated that transformation has taken place? What other explanations might explain the presence of the type IIS bacteria in the dead mouse?

Wade Corn

Numerade Educator

02:12

Problem 20

Predict what would happen if Griffith had mixed some heat-killed type IIIS bacteria and some heat-killed type IIR bacteria and injected these into a mouse. Would the mouse have contracted pneumonia and died? Explain why or why not.

Wade Corn

Numerade Educator

02:04

Problem 21

Explain how heat-killed type IIIS bacteria in Griffith's experiment genetically altered the live type IIR bacteria. (Hint: See the discussion of transformation in Chapter 9.)

Wade Corn

Numerade Educator

01:33

Problem 22

What results would you expect if the bacteriophage that Hershey and Chase used in their experiment had contained RNA instead of DNA?

Wade Corn

Numerade Educator

03:10

Problem 23

Which of the processes of information transfer illustrated in Figure 10.17 are required for the T2 phage reproduction illustrated in Figure $10.5 ?$

Wade Corn

Numerade Educator

02:01

Problem 24

Imagine that you are a student in Alfred Hershey and Martha Chase's lab in the late 1940 s. You are given five test tubes containing $E .$ coli bacteria infected with T2 bacteriophages that have been labeled with either $^{32} \mathrm{P}$ or $^{35} \mathrm{S}$. Unfortunately, you forget to mark the tubes and are now uncertain about which were labeled with $^{32} \mathrm{P}$ and which with $^{35} \mathrm{S}$. You place the contents of each tube in a blender and turn it on for a few seconds to shear off the phage protein coats. You then centrifuge the contents to separate the protein coats and the cells. You check for the presence of radioactivity and obtain the following results. Which tubes contained $E .$ coli infected with $^{32}$ P-labeled phage? Explain your answer.
(TABLE CAN'T COPY)

Wade Corn

Numerade Educator

01:57

Problem 25

Figure 10.9 illustrates Fraenkel-Conrat and Singer's experiment on the genetic material of TMV. What results would you expect in this experiment if protein carried the genetic information of TMV instead of RNA?

Wade Corn

Numerade Educator

00:59

Problem 26

DNA molecules of different sizes are often separated with the use of a technique called electrophoresis (see Chapter 19). With this technique, DNA molecules are placed in a gel, an electrical current is applied to the gel, and the DNA molecules migrate toward the positive $(+)$ pole of the current. What aspect of its structure causes a DNA molecule to migrate toward the positive pole?

Wade Corn

Numerade Educator

02:15

Problem 27

Each nucleotide pair of a DNA double helix weighs about $1 \times 10^{-21} \mathrm{g}$. The human body contains approximately 0.5 g of DNA. How many nucleotide pairs of DNA are in the human body? If you assume that all the DNA in human cells is in the B-DNA form, how far would the DNA reach if stretched end to end?

Wade Corn

Numerade Educator

01:18

Problem 28

One nucleotide strand of a DNA molecule has the base sequence illustrated below. 5' -ATTGCTACGG-3' Give the base sequence and label the $5^{\prime}$ and $3^{\prime}$ ends of the complementary DNA nucleotide strand.

Wade Corn

Numerade Educator

02:41

Problem 29

Erwin Chargaff collected data on the proportions of nitrogenous bases from the DNA of a variety of different organisms and tissues (E. Chargaff, in The Nucleic Acids: Chemistry and Biology, vol. 1, E. Chargaff and J. N. Davidson, Eds. New York: Academic Press, 1955 ). The following data are from the DNA of several organisms analyzed by Chargaff.
(IMAGE CAN'T COPY)
(TABLE CAN'T COPY)
a. For each organism, compute the ratio of $(\mathrm{A}+\mathrm{G}) /(\mathrm{T}+\mathrm{C})$ and the ratio
of $(\mathrm{A}+\mathrm{T}) /(\mathrm{C}+\mathrm{G})$
b. Are these ratios constant or do they vary among the organisms? Explain why.
c. Is the $(A+G) /(T+C)$ ratio different for the sperm samples? Would you expect it to be? Why or why not?

Parvati Devi

Numerade Educator

06:21

Problem 30

Boris Magasanik collected data on the amounts of the bases of RNA isolated from a number of sources, expressed relative to a value of 10 for adenine (B. Magasanik, in The Nucleic Acids: Chemistry and Biology, vol. $1,$ E. Chargaff and J. N. Davidson, Eds. New York:
Academic Press, 1955 ).
(TABLE CAN'T COPY)
a. For each organism, compute the ratio of $(\mathrm{A}+\mathrm{G}) /(\mathrm{U}+\mathrm{C})$
b. How do these ratios compare with the $(A+G) /(T+C)$ ratio found in DNA (see Problem 29 )? Explain.

Kyle Ukes

Numerade Educator

02:33

Problem 31

Which of the following relations or ratios would be true for a double stranded DNA molecule?
a. $A+T=G+C$
$\mathbf{b .} A+T=T+C$
c. $A+C=G+T$
d. $A+T C+G=1.0$
$\mathbf{e} . \mathrm{A}+\mathrm{GC}+\mathrm{T}=1.0$
$\mathbf{f} . \mathrm{AC}=\mathrm{GT}$
$\mathbf{g} . \mathrm{AG}=\mathrm{CT}$
h. $A T=G C$

Peter Zanzonco

Numerade Educator

01:21

Problem 32

If a double-stranded DNA molecule is $15 \%$ thymine, what are the percentages of all the other bases?

Wade Corn

Numerade Educator

01:45

Problem 33

Suppose that each of the bases in DNA were capable of pairing with any other base. What effect would this capability have on DNA's capacity to serve as the source of genetic information?

Wade Corn

Numerade Educator

01:50

Problem 34

Heinz Shuster collected the following data on the base composition of ribgrass mosaic virus (H. Shuster, in The Nucleic Acids: Chemistry and Biology, vol. $3,$ E. Chargaff and J. N. Davidson, Eds. New York: Academic Press, 1955 ). On the basis of this information, is the hereditary information of the ribgrass mosaic virus RNA or DNA? Is it likely to be single stranded or double stranded?
(FIGURE CANT COPY)

Wade Corn

Numerade Educator

02:16

Problem 35

The relative amounts of each nitrogenous base are tabulated here for four different viruses. For each virus listed in the following table, indicate whether its genetic material is DNA or RNA and whether it is single stranded or double stranded. Explain your reasoning.
(TABLE CAN'T COPY)

Wade Corn

Numerade Educator

00:47

Problem 36

A B-DNA molecule has 1 million nucleotide pairs. How many complete turns of the helix are there in this molecule?

Wade Corn

Numerade Educator

01:14

Problem 37

For entertainment on a Friday night, a genetics professor proposed that his children diagram a polynucleotide strand of DNA. Having learned about DNA in preschool, his 5 -year-old daughter was able to draw a polynucleotide strand, but she made a few mistakes. The daughter's diagram (represented here) contained at least 10 mistakes.
a. Make a list of all the mistakes in the structure of this DNA polynucleotide strand.
b. Draw the correct structure for the polynucleotide strand.
(EQUATION CAN'T COPY)

Hailey Tomashek

Numerade Educator

01:33

Problem 38

Write a sequence of bases in an RNA molecule that will produce a hairpin structure.

Wade Corn

Numerade Educator

01:28

Problem 39

Suppose that an automated, unmanned probe is sent into deep space to search for extraterrestrial life. After wandering for many light-years among the far reaches of the universe, this probe arrives on a distant planet and detects life. The chemical composition of life on this planet is completely different from that of life on Earth, and its genetic material is not composed of nucleic acids. What predictions can you make about the chemical properties of the genetic material on this planet?

Wade Corn

Numerade Educator

03:27

Problem 40

How might $32 \mathrm{p}$ and $^{35} \mathrm{S}$ be used to demonstrate that the transforming principle is DNA? Briefly outline an experiment that would show that DNA, rather than protein, is the transforming principle.

Wade Corn

Numerade Educator

02:06

Problem 41

Researchers have proposed that early life on Earth used RNA as its source of genetic information and that DNA eventually replaced RNA as the source of genetic information. What aspects of DNA structure might make it better suited than RNA to be the genetic material?

Wade Corn

Numerade Educator

02:47

Problem 42

Scientists have reportedly isolated short fragments of DNA from fossilized dinosaur bones hundreds of millions of years old. The technique used to isolate this DNA is the polymerase chain reaction, which is capable of amplifying very small amounts of DNA a millionfold (see Chapter 19 ). Critics have claimed that the DNA isolated from dinosaur bones is not purely of ancient origin, but instead has been contaminated by DNA from present-day organisms such as bacteria, mold, or humans. What precautions, analyses, and control experiments could be carried out to ensure that DNA recovered from fossils is truly of ancient origin?

Wade Corn

Numerade Educator

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