Biology: Life on Earth 7e
Student Self Test Questions and Answers
Chapter 10: Gene Expression and Regulation
Self Test
1. Which of the following is an accurate statement concerning the differences between DNA and RNA?
a. RNA is usually double-stranded, but DNA is usually single-stranded.
b. RNA has the sugar deoxyribose, but DNA has the sugar ribose.
c. RNA contains three different nucleotides, but DNA contains four different nucleotides.
d. RNA lacks the base thymine (which is found in DNA) and has uracil instead.
2. The process of RNA synthesis is called __________.
a. transcription
b. translation
c. replication
d. mutation
3. Information in DNA is carried in __________.
a. the sugar-phosphate backbone of one DNA strand
b. the base pairs between nucleotides in the two DNA strands
c. the proteins that bind to the DNA double helix
d. the order of the nucleotide bases in one DNA strand
4. Which of the following statements about the functions of RNA is correct?
a. The information for protein synthesis is carried by tRNA.
b. rRNA is an intermediate in the synthesis of mRNA.
c. rRNA is an important component of ribosomes.
d. Translation requires tRNA and mRNA, but not rRNA.
5. Which of the following correctly lists the items in order of their relative sizes?
a. nucleotide, codon, base pair, promoter, hemoglobin mRNA, hemoglobin gene, ribosome,
chromosome
b. nucleotide, base pair, codon, promoter, hemoglobin gene, hemoglobin mRNA, ribosome,
chromosome
c. nucleotide, base pair, codon, promoter, hemoglobin mRNA, hemoglobin gene, ribosome,
chromosome
d. nucleotide, base pair, codon, promoter, hemoglobin mRNA, hemoglobin gene, chromosome,
ribosome
6. Both transcription and translation occur in three steps. What happens during the elongation step of each process?
a. During the elongation step of transcription, the RNA molecule is synthesized. During the
elongation step of translation, the protein molecule is synthesized.
b. During the elongation step of transcription, the RNA molecule is stretched out to full length.
During the elongation step of translation, the protein molecule is stretched out to full length.
c. During the elongation step of transcription, synthesis of an RNA molecule is started. During the
elongation step of translation, synthesis of a protein molecule is started.
d. During the elongation step of transcription, the mRNA molecule is completed. During the
elongation step of translation, the protein molecule is completed.
7. The flow of genetic information in cells depends on specific base pairing between nucleotides. Which of the
following correctly matches the type of base pairing with the process of translation?
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
a. In translation, RNA base-pairs with DNA.
b. In translation, rRNA base-pairs with mRNA.
c. In translation, tRNA base-pairs with rRNA.
d. In translation, tRNA base-pairs with mRNA.
8. During DNA replication, a mistake was made in which an A was changed to a G. This kind of mutation is called
a(n) __________.
a. point mutation
b. insertion mutation
c. deletion mutation
d. neutral mutation
9. The DNA sequence of a codon in a gene was changed from AAT to AAC. This type of mutation is called a(n)
__________. (Refer to Table 10-3 in your textbook.)
a. point mutation
b. insertion mutation
c. deletion mutation
d. neutral mutation
10. The cells in your skin have a different shape and different function from the cells in your liver because the two
types of cells have different __________.
a. DNA
b. proteins
c. lipids
d. carbohydrates
11. Which genes are expressed in a cell depends on the cell’s __________.
a. environment
b. history
c. function
d. all of the above
e. All except one of the above answers are correct.
12. Which of the following is NOT a step at which gene expression can be regulated in eukaryotic cells?
a. the rate of transcription
b. the rate of translation
c. the rate of DNA replication
d. the types and rates of protein modification
e. the rate of enzyme activity
13. In mammals, males have one X chromosome and one Y chromosome and females have two X chromosomes.
How is the expression of genes on the X chromosome regulated so that there is equal expression of genes on the X
chromosome in males and females?
a. One X chromosome in females is inactivated so that females have only a single X chromosome
capable of transcription.
b. The genes on the X chromosome in males are transcribed twice as fast as in females.
c. All of the X chromosomes are inactivated so that no genes are expressed from the X
chromosome in either males or females.
d. The Y chromosome contains balancing genes that help to raise the levels of mRNA produced by
the X chromosome in males.
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
14. Imagine that a codon in the template strand of a gene has the sequence TAC. What sequence of the anticodon
would decode this codon? Explain your answer.
a. ATG, because the anticodon is complementary to the template strand
b. AUG, because the anticodon is complementary to the template strand
c. UAC, because the anticodon has the same sequence as the template strand (but it has U
instead of T)
d. TAC, because the anticodon has the same sequence as the template strand
15. Certain genes, sometimes called housekeeping genes, are expressed in all cells in your body. Other genes are
expressed only in certain specialized cells. Which of the following genes is likely to be a housekeeping gene?
a. hemoglobin
b. milk proteins
c. ribosomal proteins
d. insulin
16. Imagine that a probe sent to Mars brings back a sample that contains a very primitive life-form that appears
similar to bacteria. Scientists are able to revive it and begin to grow it in culture. Much to their amazement, they
discover that the organism has DNA and that the DNA encodes proteins. However, the DNA of these Martian
microbes contains only two nucleotides, and these nucleotides contain bases that are not present in the DNA of
organisms on Earth. If the Martian microbe uses triplet codons, what is the maximum number of different amino acids
that it can have in its proteins? Explain.
a. 9, because 32 = 3 x 3 = 9
b. 16, because 42 = 4 x 4 = 16
c. 8, because 23 = 2 x 2 x 2 = 8
d. 7, because there are 8 possible codons (2 3 = 2 x 2 x 2 = 8) but at least one of the codons must
be a stop.
17. Some people have eyes of two different colors. What is a possible explanation for this trait?
a. A mutation occurred in the sperm that produced this individual’s embryo.
b. A mutation occurred in the egg that produced this individual’s embryo.
c. A chemical toxin inhibited production of pigment in one eye but not the other.
d. During early stages of development, a mutation occurred in the cell that developed into one of
the eyes, but not other cells in the embryo.
18. How did Beadle and Tatum use genetic mutations in strains of Neurospora as an investigative tool?
a. They tested the hypothesis that a specific region of DNA (genes) could somehow encode a
specific enzyme.
b. They crossed mutant strains that required a specific dietary supplement to survive with normal
Neurospora.
c. They showed that strains with a dietary supplement requirement were defective in one or another
enzyme in the biochemical synthetic pathway for that supplement but never to more than one
enzyme from the same biochemical pathway.
d. all of the above
19. mRNA complementary to DNA is produced via __________.
a. replication
b. transcription
c. translation
d. protein synthesis
information encoded in RNA specifies amino acid sequences. See section 10.1.3 of your text.
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
20. The "genetic code" includes __________.
a. units of three bases, each triplet (or codon) corresponding to a single amino acid
b. specific base sequences in the nucleic acids that indicate where to "begin" and "end" the
synthesis of a polypeptide
c. only two bases per amino acid
d. The first two answers are correct.
21. What is the promoter region?
a. It is a region of RNA that binds to the RNA polymerase and initiates transcription.
b. It is a component of each type of RNA.
c. It is responsible for the selective nature of transcription.
d. It is a region of a parent DNA strand that binds to the RNA polymerase and initiates transcription.
See section 10.2.1 of your text.
22. Which of the following is the first step in translation?
a. bases of the tRNA anticodon bind with the bases of the mRNA codon
b. the formation of a peptide bond between amino acids attached to the adjacent tRNAs on the
ribosome
c. the ribosomal subunits are disassembled
d. stop codons on the mRNA bind to special proteins rather than tRNA molecules
23. Regulation of genetic expression __________.
a. involves a limited number of molecules and steps and has been well understood for some time
b. can be influenced by environmental conditions, including temperature changes
c. can occur at any point during replication, transcription, or translation and involves many, many
different molecules
d. Both the second and third answers above are correct.
24. Cells produce molecules in a series of steps called ____________________ pathways.
25. Since DNA is in the nucleus, and protein synthesis takes place in the cytoplasm, there must be an intermediary
that carries the DNA's message to the cytoplasm. This intermediary is called ____________________.
26. ____________________ consist of three bases. Each of these either initiates or stops translation or specifies a
particular amino acid in DNA translation.
27. Three codons tell protein synthesis to cease. These codons are called ____________________ codons.
28. RNA ____________________ is the molecule that is responsible for synthesizing each form of RNA.
29. ____________________ is the type of RNA molecule that is created in the nucleus and then carries the genetic
information to the cytoplasm.
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
30. There are three different types of RNA, each with different functions. The image below depicts these different
RNA types. Label the types and the portions of each as indicated.
Answer:
Label A:
Label B:
Label C:
31. Transcription and translation have many components. Label those indicated on the image below.
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
Answer:
Label A:
Label B:
Label C:
Label D:
Label E:
32. There are discrete steps in the process of transcription. Label these steps on the image below.
Answer:
Label A:
Label B:
Label C:
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
33. Identify each of the structures in the diagram below as they relate to transcription and translation.
Answer:
Label A:
Label B:
Label C:
Label D:
Label E:
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
34. A typical DNA strand includes many portions that do not code for proteins. Label these structures on the diagram
below. Follow the genetic material as it moves through the processes illustrated in Part b, labeling each step.
Answer:
Label A:
Label B:
Label C:
Label D:
Label E:
35. What does mRNA carry from the nucleus?
a. ribosomes
b. information
c. amino acids
d. tRNA
36. Unripe black walnuts contain a compound, juglone, that inhibits RNA polymerase. With which process would
juglone most likely interfere?
a. mutation rate
b. DNA replication
c. transcription
d. translation
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
37. If you were to create a drug that recognized and bound irreversibly to the promoter region of a specific gene,
thereby blocking it, what effect would you expect that drug to have?
a. There would be no effect on the gene.
b. Only transcription of that gene would halt.
c. Only translation of the gene would halt.
d. Both transcription and, eventually, translation of the gene would halt.
38. What kind of point mutation would have the most dramatic effect on the protein coded for by that gene?
a. a base substitution
b. a base insertion near the beginning of the coding sequence
c. a base insertion near the end of the coding sequence
d. deletion of three bases near the start of the coding sequence
39. The codon that will be recognized by the anticodon GAU is ___________________.
40. ____________ is the specific kind of nucleic acid found in ribosomes.
41. A mutation in which only one nucleotide in the DNA is changed is called a ____________ mutation.
42. One kind of mutation that has a high probability of affecting the final protein is a __________ mutation.
43. In female mammals one X chromosome in each cell is inactivated, and the inactivated X forms a structure called
a _____________.
44. Gene _________ is the production of the protein (or RNA) coded for by a gene.
45. A gene
a. is synonymous with a chromosome
b. is composed of mRNA
c. is a specific segment of nucleotides in DNA
d. contains only those nucleotides required to synthesize a protein
e. specifies the sequence of nutrients required by the body
46. Which of the following is a single-stranded molecule that contains the information for assembly of a specific
protein?
a. transfer RNA
b. messenger RNA
c. exon DNA
d. intron DNA
e. ribosomal RNA
47. Anticodon is the term applied to
a. the list of amino acids that corresponds to the genetic code
b. the concept that multiple codons sometimes code for a single amino acid
c. the part of the tRNA that interacts with the codon
d. the several three-nucleotide stretches that code for "stop"
e. the part of the tRNA that binds to an amino acid
48. DNA
a. takes part directly in protein synthesis by leaving the nucleus and being translated on the
ribosome
b. takes part indirectly in protein synthesis; the DNA itself stays in the nucleus
c. has nothing to do with protein synthesis; it is involved only in cell division
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Biology: Life on Earth 7e
Student Self Test Questions and Answers
d. is involved in protein synthesis within the nucleus
e. codes for mRNA but not for tRNA or rRNA
49. Synthesis of a protein based on the sequence of messenger RNA
a. is catalyzed by DNA polymerase
b. is catalyzed by RNA polymerase
c. is called translation
d. is called transcription
e. occurs in the nucleus
50. A Barr body is
a. a condensed X chromosome
b. an organelle involved in protein synthesis
c. another term for chromosomes as they are seen during cell division
d. visible in cells of both males and females
e. present only in males, because their female chromosomes are inactivated
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