1. Name Period Date
Chapter 12 DNA Test
Multiple Choice
Write the letter that best answers the question or completes the statement on the line provided.
1. What did Avery conclude caused transformation?
a. DNA was the transforming factor.
b. A protein was the transforming factor.
c. A carbohydrate was the transforming factor.
d. A lipid was the transforming factor.
_____ 2. What is inside a bacteriophage?
a. protein. c. lipid
b. nucleic acid. d. carbohydrate
______3. What happens when a piece of DNA is missing?
a. Genetic information is stored.
b. Genetic information is copied.
c. Genetic information is lost.
d. Genetic information is transmitted.
_____ 4. In what way is DNA like a book?
a. DNA has information organized with an kind of index.
b. DNA has stored information, that can be copied and passed on.
c. DNA has information wrapped in an identifying cover.
d. DNA has information that is periodically updated.
_____ 5. Which of the following could make up one nucleotide found in DNA?
a. adenine + phosphate group + thymine
b. cytosine + phosphate group + guanine
c. deoxyribose + phosphate group + polymerase
d. deoxyribose + phosphate group + cytosine
_____ 6. Because of base pairing in DNA, the percentage of
a. adenine in DNA is about equal to the percentage of guanine.
b. thymine in DNA is about equal to the percentage of adenine.
c. adenine in DNA is much greater than the percentage of thymine.
d. cytosine in DNA is much greater than the percentage of guanine.
Percentages of Bases in Five Organisms
Source of DNA A T G C
Human 19.9 29.4
Chicken 28.8 21.5
Bacterium (S.
13.4
lutea)
Figure 12–1

2. _____ 7. Figure 12–1 shows the results of measuring the percentages of the four bases in the
DNA of three organisms. Some of the values are missing. Based on Chargaff’s rule, the
percentages of guanine bases in chicken DNA should be around
a. 28.8% c. 21.5%
b. 19.9% d. 13.4%
_____ 8. Avery’s experiment worked because bacteriophages and bacteria share which
component?
a. proteins c. DNA
b. carbohydrates d. lipids
_____ 9. What did Rosalind Franklin contribute to the effort to identify the structure of DNA?
a. models made of cardboard and wire showing the shape of DNA
b. the ratios of the two sets of nucleotide pairs in DNA
c. radioactive evidence that DNA carried the genetic code
d. x-ray diffraction photos of the DNA molecule
_____ 10. During DNA replication, a DNA strand that has the bases CTAGGT produces a strand
with the bases
a. TCGAAC. c. AGCTTG.
b. GATCCA. d. GAUCCA.
_____ 11. What did Griffith observe when he injected a mixture of heat-killed, disease-causing
bacteria and live harmless bacteria into mice?
a. The disease-causing bacteria dies.
b. The mice developed pneumonia.
c . The harmless bacteria died.
d. The mice were unaffected.
12. What do bacteriophages infect?
a. mice. c. viruses.
b. humans. d. bacteria.
13. Which part of the bacteriophage in Figure 12–1 contains
genetic material?
a. A b. B
c. C d. D
14. In which cells is the accurate transmission of information
Figure 12–1
most important?
a. nerve cells c. sex cells
b. skin cells d. bone cells
15. Because of base pairing in DNA, the percentage of
a. adenine molecules in DNA is about equal to the percentage of guanine molecules.
b. thymine molecules in DNA is about equal to the percentage of adenine molecules
c. adenine molecules in DNA is much greater than the percentage of thymine molecules.
d. cytosine molecules in DNA is much greater than the percentage of guanine molecules
16. What structural problem prevents adenine from pairing with guanine?
a. The bases are both short. c. They lack the deoxyribose group.
b. They lack phosphate groups. d. The bases are both long.

3. 32 35
17. What would Hershey and Chase have concluded if both radioactive P and S were
found in the bacteria in their experiment?
a. The virus’s protein coat was not injected into the bacteria.
b. The virus’s DNA was not injected into the bacteria.
c. Genes are made of protein and carbohydrates.
d. Both the virus’s protein coat and its DNA were injected into the bacteria.
18. Which scientist made x-ray diffraction photos of DNA?
a. Franklin c. Watson
b. Chargaff d. Avery
19. DNA replication results in two DNA molecules,
a. each with two new strands.
b. one with two new strands and the other with two original strands.
c. each with one new strand and one original strand.
d. each with two original strands.
20. Which of the following include all the others?
a. DNA molecules c. chromosomes
b. histones d. nucleosomes
Figure 12–2
21. In Figure 12–2, what is adding base pairs to the strand?
a. histones c. DNA polymerase
b. nucleosomes d. chromatin
22. In eukaryotes, DNA
a. is located in the nucleus. c. is located in the ribosomes.
b. floats freely in the cytoplasm. d. is circular.
23. What binds to the prokaryotic chromosome to start DNA replication?
a. replication forks c. chromatids
b. regulatory proteins d. telomeres
24. Why did Hershey and Chase label the viral DNA with radioactive phosphorous and not
radioactive sulfur?
a. DNA contains phosphorus and no sulfur.
b. Proteins contain phosphorus and no sulfur.
c. DNA contains sulfur and little phosphorous.
d. Proteins acids contain sulfur and little phosphorous.

4. Modified True/False
Indicate whether the statement is true or false. If false, change the underlined word or phrase to make
the statement true.
_____25. A bacteriophage is larger than a bacterium. ____________________
_____26. The three parts of a DNA nucleotide are the phosphate group, deoxyribose, and the
base. ____________________
_____27. In eukaryotes, DNA replication proceeds in one direction along the DNA
molecule.__________________
Completion
Complete each statement on the line provided.
28. The structure labeled X in Figure 12–2 is a(n) .
29. The Watson and Crick model of DNA is a(n) , in
which two strands are wound around each other.
Figure 12–2
30. The matching strand to the one in Figure 12–3, reading from the bottom up,
would be _________________________.
31. _________________________ are weak bonds that hold the two strands of
DNA together, but also allow the DNA to separate and replicate.
32. Chromatin contains proteins called ______________________.
33. The tips of chromosomes are known as _________________________.
Figure 12–3
Short Answer
In complete sentences, write the answers to the questions on the lines
provided.
34. Identify the three main components in the nucleotides shown in
Figure 12–4.
Figure 12–4
35. How did Avery build on Griffith’s work?

5. 36. How did Hershey and Chase know that it was the DNA that had infected the bacterial cells in their
experiment?
37. Identify one difference between prokaryotic and eukaryotic DNA replication.
38. Identify and explain the role of the molecule, represented by the spheres in Figure
12–4.
Figure 12–4
Using Science Skills
Use the diagram below to answer the following questions on the lines provided.
Griffith’s Experiments
Figure 12–5
39. Interpret Visuals What process did Griffith identify in the series of experiments in Figure 12–5?
40. Compare and Contrast In which experiments in Figure 12–5 do the mice live?
41. Explain What happened to the bacteria and the mice in Experiment 4, in Figure 12–5?
42. Predict What would happen if Griffith took some of the bacteria from Experiment 4 in Figure 12–
5, grew them on culture plates, killed them with heat, and mixed them with harmless bacteria?
How could he test this hypothesis?

6. Essay
Write the answer to each question in the space provided.
43. How did Griffith arrive at the conclusion that a gene from one kind of bacteria transformed another
kind of bacteria?
44. How is DNA like a book? Explain your answer.
45. Figure 12–6 shows a short segment of DNA. Explain how the
chemical components of a nucleotide give DNA a structure that
allows DNA to hold itself together and yet come apart for
replication.
Figure 12–6
46. Describe how two chromosomes separate after replication in a prokaryotic cell versus a eukaryotic
cell?