Genetics Unit Test
1. Who is considered the father of genetics?
a. T. A. Knight
b. Hans Krebs
Version A
c. Gregor Mendel
d. Louis Pasteur
2. Which of the following statements is false?
a. if a trait is dominant that means it is more common than the recessive
b. dominant traits can mask or hide recessive traits
c. fraternal twins are not more genetically alike then other separate birth siblings
d. genetic diseases can be cured
3. Which of the following designation did Mendel use for the individuals resulting from a cross between the 2
original pure strains of plants?
a. P
b. P1
c. F1
d. F2
4. The offspring receives traits from its parents, this is called?
a. genetics
b. heredity
c. development
d. maturation
5. The inheritance of 1 trait having no effect on the inheritance of another is known as the?
a. law of dominance
c. law of separate convenience
b. law of universal inheritance
d. law of independent assortment
6. Which of the following is true about the law of segregation?
a. alleles separate from one another during formation of gametes
b. each trait is independent of each other
c. each gene of an organism ends up in a different gamete
d. each trait can be masked or hidden by another trait
7. The phenotype of an organism
a. represents its genetic composition
b. reflects all the traits that are actually expressed
c. occurs only in dominant pure organisms
d. cannot be seen
8. Purple flowers are dominant over white flowers in pea plants. Which of the following represents the genotype of a
pea plant that is heterozygous for flower color?
a. Pp
b. pp
c. PP
d. P
9. In guinea pigs, brown fur is dominant over white fur. Consider the following cross between two guinea pigs. If a
BB male and a bb female guinea pig had babies, what would the probability be that their offspring would have
white fur?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
10. In humans, having a widow’s peak is dominant over not having one. If a Ww male and a Ww female have
offspring, what would the probability be for that child having a widow’s peak?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
11. In humans, having a widow’s peak is dominant over not having one. If a Ww male and a Ww female have
offspring, what would the probability be for that child to have the genotype Ww?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
12. If an individual inherits 2 of the same alleles for a single gene it is called?
a. hereditary
c. homozygous
b. heterozygous
d. mutation
13. Which of the following statements between a monohybrid cross and a dihybrid cross is correct?
a. monohybrid crosses involve traits for which only 1 allele exists, while dihybrid traits involve 2
b. monohybrid crosses involve self-pollination, while dihybrid crosses involve cross-pollination
c. dihybrid crosses require two Punnett squares; monohybrid crosses need only one
d. monohybrid crosses involve one trait; dihybrid crosses involve two traits
14. In humans, the X and Y chromosomes are called the
a. extra chromosomes
b. autosomes
c. sex chromosomes
d. All of the above
15. Male : XY :: (This question is read; A male is to XY as ______ is to _________)
a. male : gametes
c. female : YY
b. male : sperm
d. female : XX
16. When a piece of chromosome attaches itself to a non-homologous chromosome, the resulting mutation is called
a. translocation
c. inversion
b. deletion
d. duplication
17. A change in a gene due to damage or incorrect copying is called
a. evolution
b. mutation
c. segregation
d. meiosis
18. The effects of a mutation can be
a. helpful
b. harmful
c. neutral
d. All of the above
19. The occurrences of certain genetic characteristics in a family over several generations are shown in a__________.
a. Punnett square
c. pedigree
b. monohybrid cross
d. family karyotype
20. Which of the following traits is controlled by multiple alleles in humans?
a. sickle cell anemia
c. hemophilia
b. blood type
d. pattern baldness
21. What would be the blood type of a person who inherited a B allele from one parent and an O allele from the
other?
a. type BO
c. type B
b. type AB
d. type O
22. PKU is a recessive genetic disorder. If both parents are carriers of the disorder, what is the chance that their child
will develop the disease?
a. 25%
c. 50%
b. 33%
d. 100%
23. If a characteristic is sex-linked, it
a. occurs most commonly in males
b. occurs only in females
c. can never occur in females
d. is always fatal
24. Which of the statements below is true of alleles that are found on the X chromosome?
a. cannot be inherited
c. occurs only in adults
b. is sex-linked
d. is dominant
25. Who determines what the sex of an offspring will be?
a. the mother
b. the father
c. both parents
d. the offspring
26. What happens if a cell goes through non-disjunction?
a. there will be too many gametes produced
b. no gametes will be produced
c. a gamete will receive too many or too few copies of a chromosome
d. mitosis cannot take place
27. Consider a cross between a homozygous white-eyed female Drosophila and a red-eyed male Drosophila. Eye
color is a sex-linked gene in flies and red eyes are dominant to white eyes. What percent of the female offspring
would be expected to be white-eyed?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
28. When two members of the F1 generation are allowed to breed with each other, the offspring are referred to as the
____________________ generation.
a. P
b. F2
c. F1
d. D
29. What are different forms of a particular gene called?
a. alleles
b. chromosomes
c. phenotypes
d. none of these
30. What is cellular process where the segregation of alleles occurs?
a. meiosis
b. mitosis
c. replication
d. transcription
31. The portion of a DNA molecule containing the coded instructions that result in a particular characteristic of an
organism is called ____________________.
a. alleles
c. gene
b. chromosomes
d. mutation
32. An organism’s ____________________ refers to the set of alleles it has inherited.
a. genotype
c. karyotype
b. phenotype
d. chromosome map
33. A situation in which both alleles for a trait are expressed independently in a heterozygous offspring is called?
a. codominance
c. dominance
b. incomplete dominance
d. homozygous
34. A pattern of heredity in which a heterozygous individual has a phenotype that is intermediate between the
phenotypes of its two homozygous parents is called _________________________.
a. codominance
c. dominance
b. incomplete dominance
d. homozygous
35. Linked genes can be separated from each other in meiosis if ____________________ occurs.
a. dominance
c. recessivity
b. independent assortment
d. crossing over
36. A____________________ trait is one in which males and females can show different phenotypes even when they
have the same genotype
a. dominant
c. sex-linked
b. sex-influenced
d. recessive
37. A person who is heterozygous for a recessive disorder is called?
a. carrier
b. dominant
c. hemophiliac
d. recessive
38. By studying ____________________, genetic counselors can see how many chromosomes are in the body cells
of an individual.
a. pedigree
c. Punnett square
b. chromosome map
d. karyotype
39. In pea plants, tallness is dominant over shortness. Which of the following genotypes would be homozygous
dominant?
a. TT
b. tt
c. T
d. Tt
40. In pea plants, green seeds are dominant over yellow seeds. In a cross between a Gg and a gg plant, what is the
probability the offspring would have yellow seeds?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
41. In a F1 generation cross of a typical Mendel experiment, what is the probability that the offspring (F2) will receive
the 2 different alleles possible?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
42. The pedigree below traces the inheritance of attached earlobes, which is a dominant trait. Shaded means attached
earlobes, while un-shaded means free ear lobes. What is the genotype of individual 2 in line I (top of pedigree)?
a. Ee
b. EE
c. ee
d. none of the above
43. Use the pedigree above to answer this question. What is the genotype of individual 3 in line III (bottom) of
pedigree?
a. Ee
c. ee
b. EE
d. none of the above
44. Hemophilia is a recessive sex-linked disorder on the X chromosome. If a normal male and a carrier female
reproduce, how likely are the daughters to have hemophilia?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
45. Hemophilia is a recessive sex-linked disorder on the X chromosome. If a normal male and a carrier female
reproduce, how likely are the sons to have hemophilia?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
46. If a person with AB blood type reproduces with a person with heterozygous B blood type, which of the following
could NOT be a genotype of their offspring?
a. AB
b. AA
c. AO
d. BO
47. In dogs, black fur is dominant over brown fur and long tails are dominant over short tails. If 2 dogs that are
hybrids for both traits reproduce, what is the PHENOTYPIC RATIO?
a. 3:1
d. 1:2:1
b. 9:3:3:1
e. 1:1
c. 4:0
48. In pea plants, round seeds are dominant over wrinkled seeds. If a true breeding round and a true breeding
wrinkled reproduce, what is the GENOTYPIC RATIO?
a. 3:1:0
d. 1:2:1
b. 9:3:3:1
e. 1:1
c. 0:4:0
49. In tomatoes, green stems are dominant over purple stems. If a Gg tomato plant and a Gg tomato plant reproduced,
what is the PHENOTYPIC RATIO?
a. 3:1
d. 1:2:1
b. 9:3:3:1
e. 1:1
c. 4:0
50. In human hair texture, curly hair is incompletely dominant over straight hair. The intermediate phenotype is wavy
hair. What is the probability of having a child with curly hair if a person with wavy and a person with curly hair
have kids?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
51. In human hair texture, curly hair is incompletely dominant over straight hair. The intermediate phenotype is wavy
hair. What is the probability of having a child with straight hair if two wavy haired people have kids?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
52. Due to an unfortunate mix up at the hospital, the nurses were not sure which of three babies belonged to Mr. and
Mrs. Mattox. The nurses tested the blood types of all the babies and the Mattox’s. Mr. Mattox was AB, while
Mrs. Mattox was O. Baby 1 had blood type O, baby 2 had blood type AB, and baby 3 had blood type B. Which
baby belonged to the Mattox’s?
a. Baby 1
c. Baby 3
b. Baby 2
d. None of the above
53. In cats, the allele for black fur is dominant to the allele for brown fur, and the allele for short hair is dominant to
the allele for long hair. What would the genotype be for a brown furred, homozygous short hair cat?
a. bbHH
d. BbHh
b. BBhh
e. BbHh
c. BBHH
ab. bbhh
54. In cats, the allele for black fur is dominant to the allele for brown fur, and the allele for short hair is dominant to
the allele for long hair. Which of the following phenotypes is NOT possible in a cross between a heterozygous
black, long haired cat and a brown haired, homozygous short haired cat?
a. black, short
c. brown, short
b. black, long
d. all of these are possible
55. In a certain type of flower, when a red flower is crossed with a white flower, a white and red speckled flower is
produced. What is the probability of getting a white flower if two speckled flowers are crossed?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
56. In a certain type of flower, when a red flower is crossed with a white flower, a white and red speckled flower is
produced. What is the probability of getting a speckled flower if a white and a red flower are crossed?
a. 100%
d. 25%
b. 75%
e. 0%
c. 50%
57. This is a type of mutation where a piece of the chromosome is reversed?
a. translocation
c. inversion
b. deletion
d. duplication
58. Which of the following is true of an individual with Down Syndrome?
a. trisomy of the 21st chromosome
b. somatic cells contain 47 total chromosomes
c. caused by non-disjunction
d. all of these are true
59. Skin color, eye color, and height are examples of ______ type of traits?
a. dominant & recessive
c. polygenic
b. sex-influenced
d. multiple allele
60. In order to compare DNA among individuals in paternity tests and crime investigations scientists perform?
a. Pedigree analysis
b. Non-disjunction comparisons
c. Gel electrophoresis
d. Both A and B
Essay: Complete the following question on a separate sheet of paper in complete sentences.
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Background information:
o You are a llama racer. In order to maintain your prestigious ranking of #1 world wide llama racer
you are constantly looking for a new type of llama to give you the competitive edge. While
wandering the grass filled hills of Argentina you capture the fastest llama of a herd of 1,000 llamas.
Another thing to keep in mind is that you are only allowed to race llamas that have purple hair by the
rules of the International Llama Racing Association (ILRA). Luckily the llama you captured has
purple hair.
a) Fast speed is completely dominant to slow speed
b) Purple hair is completely dominant to brown hair
The Problem:
o You want to breed your newly captured llama, but you do not know its genotype. For full credit you
need to do both of the following:
a) Describe in words how you will be able to tell what the genotype is for both traits (hair and
speed) of your llama in 1 generation.
b) Illustrate the cross (Punnett square) you would do in part if your captured llama is truebreeding for both traits.
 Give the phenotype and genotype probability for the offspring.