Chapter 23
Classical and Modern Genetics:
Why do offspring resemble their parents?
1. Which of the following diseases is not hereditary?
a. sickle-cell anemia
b. cystic fibrosis
c. diabetes
d. arthritis
e. All of the above are hereditary.
Ans: e
Link To: Classical Genetics
Difficulty Level:Easy
2. Which genetic characteristics did Gregor Mendel omit from his studies?
a. hairy toe knuckles
b. pod texture
c. flower color
d. height
e. hybrids
Ans: a
Link To: Classical Genetics
Difficulty Level:Easy
3. What is the cellular function of deoxyribonucleic acid?
a. provides structure to the nucleus
b. governs all chemical functions
c. carries inheritance information
d. serves as an antibiotic for bacteria
e. b and c
Ans: e
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Easy
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4. Transcription of DNA
a. supplies information that runs cell chemistry.
b. divides the cell through mitosis.
c. determines the genetic code.
d. destroys extra nucleotides.
e. all of the above
Ans: a
Link To: The Genetic Code
Difficulty Level: Easy
5. Which statement about viruses is false?
a. Viruses kill the cell.
b. Viruses are RNA segments coated with protein.
c. Viruses can metabolize.
d. Viruses are DNA segments coated with protein.
e. Viruses use the cell’s enzymes.
Ans: c
Link To: The Genetic Code
Difficulty Level:Easy
6. Which of the following does not have to contain a DNA molecule?
a. gene
b. chromosome
c. cell
d. virus
e. zygote
Ans: d
Link To: The Genetic Code
Difficulty Level: Easy
7. Which does not follow from Mendel’s work?
a. All organisms employ the same genetic code.
b. Traits can be either dominant or recessive.
c. Units of inheritance pass traits from parents to offspring.
d. Both parents contribute equally to the traits of the offspring.
e. Tallness is dominant over shortness in pea plants.
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Ans: a
Link To: Classical Genetics
Difficulty Level: Easy
8. The "double helix" of DNA refers to the
a. hydrogen bonding of the nucleotides.
b. twisting of the ladder-like double strands of bases.
c. hexagon shape of the carbon atoms.
d. fact that DNA is at the core of all medical studies.
e. unique chemistry of the RNA bases.
Ans: b
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Easy
9. Which is not part of a nucleotide?
a. recessive gene
b. phosphate group
c. adenine
d. sugar
e. guanine
Ans: a
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Easy
10. Which of the following statements about DNA is false?
a. DNA molecules are made of smaller molecules.
b. Every living cell on earth contains DNA molecules.
c. DNA strands contain alternating sugar and phosphate molecules.
d. RNA is the mirror opposite of DNA.
e. Hydrogen bonds join the two sides of the DNA ladder.
Ans: d
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Easy
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11. What did Mendel's genetic model predict?
a. Parents are equally important in the transfer of genetic information.
b. The male contributes most of the dominant traits.
c. The female contributes most of the dominant traits.
d. Physical traits are expressed in a random proportion.
e. Mental traits are expressed in a ratio of 9:3:3:1.
Ans: a
Link To: Classical Genetics
Difficulty Level: Easy
12. Which of these processes precedes fertilization?
a. oxidation
b. respiration
c. mitosis
d. meiosis
e. mutation
Ans: d
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Easy
13. In a cell, the process of transcription
a. transfers DNA information from the nucleus to the rest of the cell.
b. uses RNA to carry genetic information.
c. relays instructions to regulate the cell chemistry.
d. all of the above
e. only two of the above
Ans: d
Link To: The Genetic Code
Difficulty Level: Easy
14. What is a codon?
a. the genetic code
b. a set of three bases on the mRNA
c. a set of three bases on the tRNA
d. an amino acid string
e. a protein
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Ans: b
Link To: The Genetic Code
Difficulty Level: Easy
15. Where does protein synthesis in a cell actually take place?
a. tRNA
b. mRNA
c. nucleus
d. ribosome
e. codon
Ans: d
Link To: The Genetic Code
Difficulty Level Easy
16. What is a gene?
a. a particular stretch of DNA located on a chromosome
b. several chromosomes that control physical features
c. a combination of tRNA, mRNA, and rRNA
d. the hydrogen bonds of the DNA base pairs
e. an amino acid string
Ans: a
Link To: Classical Genetics
Difficulty Level: Easy
17. Which of the following can cause a mutation?
a. a change in the RNA of the parent
b. damage to the cell membrane of the parent
c. an alternation of DNA in a parent's egg or sperm
d. diseases such as cancer or hypertension
e. infertility in older parents
Ans: c
Link To: The Genetic Code
Difficulty Level: Easy
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18. The “unit of inheritance” is the cell.
Ans: False
Link To: Classical Genetics
Difficulty Level: Easy
19. Three types of RNA are used in protein assembly.
Ans: True
Link To: The Genetic Code
Difficulty Level: Easy
20. Introns are the coding sections of a chromosome.
Ans: False
Link To: The Genetic Code
Difficulty Level:Easy
21. One goal of the Human Genome Project is to understand the genome of the fruit fly.
Ans: True
Link To: The Human Genome
Difficulty Level: Easy
22. Viruses mutate at a rate that is much faster than normal cells.
Ans: True
Link To: The Genetic Code
Difficulty Level: Easy
23. Mendel's statistical analysis of pea plants changed the study of genetics from qualitative to
quantitative.
Ans: True
Link To: Classical Genetics
Difficulty Level: Easy
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24. Deoxyribonucleic acid located throughout the cell in eukaryotes.
Ans: False
Link To: The Human Genome
Difficulty Level: Easy
25. In mRNA the base uracil (U) substitutes for the DNA base thymine (T) to bond with adenine.
Ans: True
Link To: The Genetic Code
Difficulty Level: Easy
26. Most of the DNA in your body may be used to control the actions of the genes, in effect
turning them on or off.
Ans: True
Link To: The Genetic Code
Difficulty Level: Easy
27. Viruses depend upon the host cell mechanisms to reproduce.
Ans: True
Link To: The Genetic Code
Difficulty Level: Easy
28. The main cause of skin cancer is damage to the DNA molecule by unprotected exposure to
ultraviolet radiation.
Ans: True
Link To: The Genetic Code
Difficulty Level: Easy
29. The best way to treat a virus is to stimulate the body to produce its own antibodies to that
virus.
Ans: True
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Link To: The Genetic Code
Difficulty Level: Easy
30. Recessive genes can influence how the dominant gene is expressed in the first generation.
Ans: False
Link To: Classical Genetics
Difficulty Level: Easy
31. The genetic distribution 9:3:3:1 is characteristic of
a. the second generation, one gene trait.
b. the first generation, four gene traits.
c. the third generation, four gene traits.
d. the second generation, two gene traits.
e. none of the above
Ans: d
Link To: Classical Genetics
Difficulty Level:Medium
32. What would make you more susceptible to viral attack?
a. moving to Tokyo
b. a junior year abroad
c. wilderness camping in Kenya
d. all of the above
e. none of the above
Ans: d
Link To: The Genetic Code
Difficulty Level: Medium
33. Which could be an example of DNA sequencing?
a. 0 1 1 1 0 0
b. C A T C A T
c. T U T T A T
d. a b c d e f
e. + - - + + -
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Ans: b
Link To: The Human Genome
Difficulty Level: Medium
34. What is the difference between DNA and tRNA?
a. size
b. shape
c. location
d. sugar
e. all of the above
Ans: e
Link To: The Genetic Code
Difficulty Level: Medium
35. What makes exact DNA replication possible?
a. The acidity of the cell cytoplasm eliminates mistakes.
b. The geometry of individual base pairs allows only one base to form a hydrogen bond with its
complement base.
c. Floating nucleotides can bond with each other in random combinations.
d. Meiosis passes complete genetic information to two identical daughter cells.
e. Mitosis is a powerful process that eclipses all other cell functions.
Ans: b
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Medium
36. Why do children resemble their parents?
a. Parents and children usually share an environment.
b. RNA carries the genes for physical features from parents to children.
c. Children's genes are a combination of the base-pair sequence in the genes of both parents.
d. Family members look alike by chance.
e. A child's physical features are determined in utero.
Ans: c
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Medium
37. The difference between mRNA and tRNA is that
a. mRNA carries the gene sequence and tRNA translates the gene sequence.
b. tRNA models the message and mRNA reads the message.
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c. mRNA is inside the cell and tRNA is outside the cell.
d. tRNA carries a code of bases and mRNA decodes this.
e. mRNA magnifies the gene sequence and tRNA truncates the gene sequence.
Ans: a
Link To: The Genetic Code
Difficulty Level: Medium
38. A genetic disease can be expressed in the offspring when
a. both parents had a recessive gene for that disease.
b. both parents had a dominant gene for that disease.
c. only one parent had a dominant gene for that disease.
d. only one parent had a recessive gene for that disease.
e. a & b & c
Ans: e
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Medium
39. If scientists find a cure for the common cold this year, they will have to find a new cure next
year.
Ans: True
Link To: The Genetic Code
Difficulty Level: Medium
40. All first generation hybrids from purebred parents will all look the same.
Ans: True
Link To: Classical Genetics
Difficulty Level: Medium
41. Elaborate on the central rule of molecular biology, "One gene equals one protein."
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Ans: A particular section of DNA (one gene) will code for one mRNA molecule, which will then
carry this code to one tRNA, which will transfer this code using rRNA, which will synthesize the
sequence of amino acids in one particular protein, which finally, will drive a chemical reaction in
the cell.
Link To: The Genetic Code
Difficulty Level: Medium
42. Review the steps in the replication of DNA.
Ans: Enzymes in the cell break the hydrogen bonds from sections of the DNA double helix. The
bonds were connecting base pairs adenine (A) and thymine (T), cytosine (C) and guanine (G).
Once the double helix is split, the sugar-phosphate sides of the DNA ladder have the single bases
A, T, C, and G exposed, but still in the same sequence. The fluid around the DNA contains
nucleotides with unattached bases that will bind to the specific sites on the DNA ladder as
dictated by base pair geometry (A-T, C-G, T-A, G-C). The end product of this replication is two
double-stranded DNA molecules, each of which is identical to the original.
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Medium
43. How do antibiotics work?
Ans: Antibiotics block particular enzymes in bacteria that have invaded a human body. Without
the enzymes, the bacteria die without harming the body they invaded.
Link To: The Genetic Code
Difficulty Level: Medium
44. How did the bioinformatics revolution accelerate work in the Human Genome Project?
Ans: In the Human Genome Project, scientists were able to map and sequence the 3 billion base
pairs in the 30,000 genes of 23 paired chromosomes in the human genome. The project finished
five years early and under budget, primarily because of an entrepreneur's idea to automate the
process of DNA sequencing. In his plan thousands of short sections of DNA were sequenced by
machines and the overlap of these sections gave the sequence of the whole DNA molecule. This
technique would have been impossible without the computer grinding the numbers.
Link To: The Human Genome
Difficulty Level: Medium
45. What is a mutation and how is it caused?
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Ans: A mutation is the change in the genetic material of a parent that is inherited by the
offspring. Ultraviolet radiation, X-rays, and nuclear radiation can cause mutations, to name a
few.
Link To: The Genetic Code
Difficulty Level: Medium
46. What is the difference between DNA mapping and DNA sequencing?
Ans: DNA mapping is the process of finding the position of every gene on every chromosome.
The DNA map of 30,000 human genes is complete. DNA sequencing is a much more
cumbersome process of determining the exact order of every base pair on every gene of a
particular part of a DNA molecule. DNA sequencing of the human genome was completed in
2000 and published jointly by a private and a public company.
Link To: The Human Genome
Difficulty Level: Medium
47. What are the four possible "rungs" on the DNA ladder? In other words, what are the only
possible bonding pairs of DNA bases? Why can only these bonds occur.
Ans: adenine to thymine; thymine to adenine; cytosine to guanine; guanine to cytosine—because
of geometry.
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Hard
48. In what way does Gregor Mendel represent the quintessential scientist?
Ans: Mendel used the scientific method to plan and conduct plant experiments during the mid
1800s. He first observed nature and asked questions. Next, he set up a series of experiments and
conducted meticulous, although tedious, research to answer these
questions. He kept careful records and analyzed his work. He published his results, which much
later became the foundation for classical genetics.
Link To: Classical Genetics
Difficulty Level: Hard
49. How is the codon related to the genetic code?
Ans: A codon is a set of three bases on the mRNA, which determines which of the 64 possible
tRNA molecules will attach at that point. Each codon can be matched with a single amino acid.
The order of codons determines the sequence of amino acids, in other
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words, the primary structure of the protein. Therefore, the relationship between the codons and
the amino acid sequence created by the codons is the genetic code.
Link To: The Genetic Code
Difficulty Level: Hard
50. Compare the HIV virus that causes AIDS with a typical computer virus.
Ans: Both the HIV virus that causes AIDS and the computer virus contain a set of instructions
that cause them to be taken into the operating network of the host (cell or hard drive). In the case
of the HIV virus, an RNA sequence in the virus is transcribed back into DNA, with enzymes, to
replace a section of the cell’s own DNA. Once in place, the viral contaminated DNA is replicated
instead of the original cell DNA. Once replicated, the HIV virus goes into the blood system and
damages the T-lymphocytes, cells critical to the human immune system. In a similar fashion, the
computer virus takes over the operating system of the hard drive and damages the computer.
Link To: The Genetic Code
Difficulty Level: Hard
51. How does tRNA determine a protein’s primary structure?
Ans: Transfer RNA reads mRNA’s coded message of base pair sequences. If tRNA is a
complement for the mRNA base pair sequence, then tRNA will bond at that particular spot. An
amino acid that matches the codon (three-base set) of the mRNA is attached to the other end of
the tRNA. In time a string of amino acids in a specific sequence is assembled and the primary
structure of the protein determined.
Link To: The Genetic Code
Difficulty Level: Hard
52. How does DNA differ from RNA; how are they alike?
Ans: Both DNA and RNA are molecules made from sugar, phosphate and bases found in living
cells. DNA is longer than RNA; is double-stranded with hydrogen bonds connecting the bases
adenine to thymine and guanine to cytosine. RNA is a short, single strand with bases adenine,
guanine, cytosine and urasil. RNA comes in three types, depending on the function, and can
cross the nuclear membrane. DNA is only found in the nucleus. The RNA sugar is ribose; the
DNA sugar is deoxyribose.
Link To: DNA and the Birth of Molecular Genetics
Difficulty Level: Hard
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53. Using the three basic rules of classical genetics, explain why more people curl their tongue
than those who cannot.
Ans: Rule 1. Physical characteristics or traits are passed from parents to offspring by some
unknown mechanism (we call it a gene).
• Rule 2. Each offspring has two genes for each trait, one gene from each parent.
• Rule 3. Some genes are dominant and some are recessive. When present together, the trait of a
dominant gene will be expressed in preference to the trait of a recessive gene. Therefore, since
tongue-rolling is a dominant trait, there should be three times as many folks who can roll their
tongues as those who cannot.
Link To: Classical Genetics
Difficulty Level: Hard
54. Now that the Human Genome Project has been completed, what are the research goals for
Celera Corporation, J. Craig Venter's bioinformatics company? How are these important to
society?
Ans: Answers will vary, however one goal may be to more quickly and precisely code DNA so
that genetic engineering can take place.
Link To: The Human Genome
Difficulty Level: Hard
55. Set up an experiment to determine gene dominance in pug dogs.
The characteristics of interest are fur texture (smooth and rough) and leg length (long and short).
This is a two trait by two trait cross. Crosses must include smooth + long, smooth + short, rough
+ long and rough + short. Experiment should follow the scientific method.
Link To: Classical Genetics
Difficulty Level: Hard
56.McDonalds has recently decided to buy beef from farms that do not use antibiotics in raising
cattle. What is the scientific basis for this decision?
Ans: Antibiotics have been shown to be passed along to whoever eats the beef. Ingestion/use of
antibiotics can lead to strains of bacteria that are resistant to antibiotics.
Link To: The Genetic Code
Difficulty Level: Hard
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57. If you were living in a time where it was possible to alter the genetic code of your offspring,
what traits would you select? If these same traits were selected by the majority of parents, how
would the global future be changed? List both the positive and the negative changes.
Ans: Answers will vary but should include the breeding in traits that are both positive and
negative. They may also mention an over abundance of male or female children depending on
what is in vogue at the time.
Link To: The Human Genome, Classical Genetics
Difficulty Level: Hard
58. A recent finding is that antibiotics are being prescribed too often. If you are a doctor seeing a
child with a simple ear infection, what biochemical and genetic principles must you consider
before prescribing an antibiotic? How would you explain your decision to the parent of the sick
child?
Ans: Answers will vary but should consider the ability of the child’s body to produce resistance
to the disease as well as the likelihood that the disease will develop a resistance to antibiotics.
Link To: The Genetic Code
Difficulty Level: Hard
59. List and discuss the different paths a bacterium cell and a virus cell would take from the
point of entry in an organism to the eventual death of that
organism.
Ans: Answers will vary but should include the body’s ability to resist the disease and the
disease’s ability to resist antibiotics.
Link To: The Genetic Code
Difficulty Level: Hard
60. Script a likely discussion in the year 2020 between the head of a genetic engineering
company, a medical researcher, and a conservative senator in charge of funding for the National
Institutes of Health.
Ans: Answers will vary but will include something about altering genetic code.
Link To: The Human Genome
Difficulty Level: Hard
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61. A couple who are native Swedes, leave Sweden and move to Tahiti. After 5 years of baking
in the sun, they have a child. Describe this child based on the three laws of Mendelian genetics.
Ans: The child should be a mix of the parents’ genes. There should be no effect from the change
in the child based on environment—other than possible mutation.
Link To: Classical Genetics
Difficulty Level: Hard
62. A child is born with blue eyes to parents who both have brown eyes. Is this possible? Justify
your answer.
Ans: Absolutely. Blue eyes are the result of recessive gene; both parents could be heterozygous
for brown eyes.
Link To: Classical Genetics
Difficulty Level: Hard
63. Knowing that a pair of X chromosomes codes for females, and an X plus a Y chromosome
codes for males, who determines the gender of the child, the father or the mother? Why?
Ans: Females may only provide and X chromosome; males may provide an X or a Y
chromosome, therefore the male determines gender.
Link To: Classical Genetics
Difficulty Level: Hard
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