Deck 23: Patterns of Gene Inheritance

Question 1

In humans, brown eyes (B) are a simple dominant trait over blue eyes (b). What is the genotype of a brown-eyed woman who has a blue-eyed child?

A) bb
B) Bb
C) BB
D) BBB
E) BbBb

Answer 1

B

Question 2

A woman who can roll her tongue is married to a man who cannot. Two of their four children can roll their tongues and two cannot. If T = tongue rolling and t = cannot roll tongue, then what is the genotype of the parents?

A) woman Tt; man Tt
B) woman TT; man tt
C) woman Tt; man TT
D) woman Tt; man tt
E) woman tt; man tt

Answer 2

D

Question 3

A pheasant breeder starts with two birds in the P generation, one of which is AA and the other is aa. If he takes two of the birds from the F₁ generation and breeds them together, what genotypes can he expect in his F₂ offspring?

A) AA and Aa
B) Aa and aa
C) AA, Aa, and aa
D) AA only
E) Aa only

Answer 3

C

Question 4

In a testcross, an organism with a dominant phenotype, but unknown genotype, is crossed with an organism that is

A) homozygous dominant.
B) heterozygous.
C) homozygous recessive.
D) heterozygous dominant.
E) monohybrid dominant.

Question 5

What genotypic ratio would result from a cross between two individuals who are both heterozygous for a trait?

A) 100% homozygous dominant
B) 100% homozygous recessive
C) 50% homozygous dominant, 50% homozygous recessive
D) 25% homozygous dominant, 50% heterozygous, 25% homozygous recessive
E) 50% homozygous dominant, 50% heterozygous

Question 6

In which kind of monohybrid cross would you expect to find a phenotypic ratio of 3:1 among the offspring?

A) heterozygous × heterozygous
B) homozygous recessive × homozygous recessive
C) homozygous dominant × homozygous dominant
D) homozygous recessive × homozygous dominant
E) homozygous dominant × heterozygous

Question 7

In peas, the yellow seed color is dominant (YY or Yy) over the green seed color (yy). You have been given a plant that only produces yellow seeds and need to determine if the plant is YY or Yy. Which of the following crosses would be most effective for determining the genotype of your plant?

A) your plant × a plant that produces only green seeds
B) your plant × another plant with known genotype YY
C) your plant × another plant with known genotype Yy
D) No cross is necessary. You should just plant your yellow seed and see what color flowers it produces.
E) There is no way to determine the genotype of your plant.

Question 8

The genetic makeup of an individual is also known as their

A) phenotype.
B) loci.
C) genotype.
D) factors.

Question 9

When crossing organisms with differing genotypes, you can expect your actual results to match the predicted results 100% of the time.

Question 10

Which of the following is true according to Mendel's law of segregation?

A) Each individual contains two alleles for each trait.
B) Fertilization restores the presence of two alleles.
C) Alleles separate from each other during gamete formation.
D) Each gamete contains one copy of each allele.
E) All of the answer choices are true about Mendel's law of segregation.

Question 11

Due to a recessively inherited trait, some plants fail to produce chlorophyll and therefore are white rather than green. If we locate a pea plant that is heterozygous for this trait, self-pollinate it, harvest the seeds, and then plant the seeds, what are the likely phenotypes of the resulting offspring?

A) 100% green
B) 100% white
C) approximately 1/2 green and 1/2 white
D) approximately 1/4 white and 3/4 green
E) approximately 1/4 green and 3/4 white

Question 12

The ability to roll the edges of the tongue upward in a U-shape is inherited as a dominant allele at a single gene locus. Which of the following genotypes would produce an individual that can roll their tongue?

A) TT only
B) Tt only
C) tt only
D) TT or Tt
E) Tt or tt

Question 13

For Mendel's law of segregation to occur, the alleles must be

A) at different loci on the same chromosome.
B) at the same loci on the same chromosome.
C) on a nonhomologous pair of chromosomes.
D) on a homologous pair of chromosome at the same loci.
E) on different loci on different chromosomes.

Question 14

Tay-Sachs is a recessive genetic disease in humans. If one parent is homozygous normal and the other is a carrier (heterozygous), what are the chances that their child will have this disease?

A) 0%
B) 25%
C) 50%
D) 75%
E) 100%

Question 15

If T = tall and t = short in plants, the genotype of a short plant would be

A) either TT or Tt.
B) either Tt or tt.
C) only TT.
D) only tt.
E) TT, Tt, or tt.

Question 16

In humans, widow's peak (W) is dominant over straight hairline (w). If a heterozygous male marries a female with a straight hairline, what percent of their children can be expected to have widow's peak?

A) 0%
B) 25%
C) 50%
D) 100%
E) The answer cannot be determined by the information given.

Question 17

The alternate forms of a gene for the same trait are known as

A) alleles.
B) phenotypes.
C) genotypes.
D) codominants.
E) incomplete dominants.

Question 18

Mendel carried out most of his research with

A) livestock.
B) pea plants.
C) guinea pigs.
D) fruit flies.
E) bacteria.

Question 19

Mendel's law of segregation implies that the two members of an allele pair

A) are distributed to separate gametes.
B) are distributed to the same gamete.
C) are assorted dependently.
D) are segregated pairwise.
E) must always code for the identical trait or feature.

Question 20

An individual's physical characteristics, or microscopic and metabolic characteristics, are known as their

A) phenotype.
B) genotype.
C) alleles.
D) traits.
E) pedigree.

Question 21

In humans, assume straight hairline is recessive to widow's peak. A woman with a straight hairline is married to a man with a widow's peak whose mother had a straight hairline. What are the chances of the couple having a child with a straight hairline?

A) 0%
B) 25%
C) 50%
D) 75%
E) 100%

Question 22

In guinea pigs, B = black, b = brown, S = short hair, s = long hair. A guinea pig heterozygous for both traits is mated with a brown, short-haired guinea pig whose mother had long hair. What phenotypic ratio is expected in the offspring?

A) 9 black long hair, 3 black short hair, 3 brown long hair, 1 brown short hair.
B) 9 black short hair, 6 black long hair, 3 brown long hair, 1 black short hair.
C) 6 black short hair, 1 black long hair, 6 brown short hair, 2 brown long hair.
D) 6 brown short hair, 6 black long hair, 2 brown long hair, 2 black short hair.
E) 1 black short hair, 1 black long hair, 1 brown short hair, 1 brown long hair.

Question 23

If the probability in any pregnancy of having a boy is 50%, then what is the probability of having 3 boys in a row?

A) 3/4
B) 1/4
C) 1/8
D) 1/2
E) 3/16

Question 24

A blue-eyed, left-handed woman marries a brown-eyed, right-handed man who is heterozygous for both of his traits. If blue eyes and left-handedness are recessive, how many different phenotypes are possible in their children?

A) one
B) two
C) three
D) four
E) five

Question 25

Two parents heterozygous for cystic fibrosis have a child with the disease. The parents are expecting a second child. What is the probability that the second child will also have cystic fibrosis?

A) 100% probability
B) 75% probability
C) 50% probability
D) 25% probability
E) 0% probability

Question 26

When pairs of factors separate independently of other pairs of factors, this is known as

A) the law of segregation.
B) the law of independent assortment.
C) the law of dominance.
D) multiple alleles.
E) codominance.

Question 27

Albinism is inherited as a recessive trait. An albino woman is married to a man with normal coloring and their first child is an albino. What was the genotype of the man?

A) homozygous dominant
B) heterozygous
C) homozygous recessive
D) incompletely dominant
E) sex-linked recessive

Question 28

Both parents are heterozygous for Tay-Sachs disease (an autosomal recessive disorder). Three children in a row were born with Tay-Sachs disease. What is the chance that a fourth child will have Tay-Sachs disease?

A) 0%
B) 25%
C) 50%
D) 75%
E) 100%

Question 29

If the genotype of an organism is YySsTt, then yST would represent

A) the genotype of the offspring.
B) a possible phenotype of the offspring.
C) a gamete of the parent.
D) a possible zygote.
E) the P generation.

Question 30

Which of the following crosses will yield only homozygous recessive offspring?

A) RRYY × RRYY
B) RRYY × rryy
C) RrYy × rryy
D) rryy × rryy
E) RrYy × RrYy

Question 31

Two parents with widow's peak and short fingers have a child with a continuous hairline and long fingers. What are the genotypes of the two parents? (W = widow's peak; S = short fingers)

A) WWSS × wwss
B) wwss × WWSS
C) WWss × WWss
D) WwSs × WwSs
E) WwSs × wwss

Question 32

A cross that involves two traits is called a

A) monohybrid cross.
B) dihybrid cross.
C) Punnett square.
D) testcross.
E) trihybrid cross.

Question 33

In guinea pigs, B = black, b = brown, S = short hair, s = long hair. A black, short-haired animal who is homozygous for both traits, reproduces with a brown, long-haired animal. What is the expected phenotypic ratio of the offspring?

A) 1 black short hair, 1 black long hair, 1 brown short hair, 1 brown long hair
B) 3 black short hair, 1 brown long hair, 3 black long hair, 1 brown short hair
C) 9 black short hair, 3 black long hair, 3 brown long hair, 1 brown short hair
D) 100% black short hair
E) 1 black short hair, 1 brown short hair

Question 34

An individual with a dominant phenotype is crossed with an individual with a recessive phenotype. Five out of nine offspring show the dominant phenotype. What is the genotype of the dominant parent?

A) homozygous dominant
B) heterozygous
C) homozygous recessive
D) either homozyous dominant or heterozygous
E) There is not enough information to determine the genotype of the dominant parent.

Question 35

Unattached earlobes (EE or Ee) are dominant over attached earlobes (ee). A couple has unattached earlobes. Both notice that one of their parents on both sides have attached earlobes (ee). Therefore, they correctly assume that they are carriers for attached earlobes (Ee). If the couple proceeds to have four children, then

A) they can be certain that three will be heterozygous and one homozygous recessive.
B) if the first three are heterozygous, the fourth must be homozygous recessive.
C) the children must repeat the grandparents' genotype (Ee).
D) all children must have unattached earlobes since both parents possess the dominant gene for it.
E) two heterozygous, one homozygous dominant, and one homozygous recessive is a likely outcome, but all genotype ratios are possible.

Question 36

In cattle, consider that the lack of horns is dominant to the presence of horns. A bull without horns is crossed with a horned cow. All eight offspring lack horns. The bull is most likely

A) homozygous dominant.
B) homozygous recessive.
C) heterozygous.
D) sex-lined recessive.
E) heterozygous recessive.

Question 37

Which of the following crosses will yield four phenotypes in a ratio of 9:3:3:1?

A) RRYY × RRYY
B) RRYY × rryy
C) RrYy × RrYy
D) RrYy × rryy
E) rryy × rryy

Question 38

Which of the following crosses will yield four phenotypes in the 1:1:1:1 ratio?

A) RRYY × RRYY
B) RRYY × rryy
C) RrYy × RrYy
D) RrYy × rryy
E) rryy × rryy

Question 39

In 1940, two researchers named Weiner and Landsteiner discovered that about 85% of the human population sampled possessed a blood cell protein called the Rh factor. The presence of Rh factor was labeled Rh positive (Rh⁺) and was found to be dominant over the absence of the blood factor (Rh^-). Rh factor is inherited in a typical Mendelian pattern. Based on this information, one could predict that two Rh⁺ parents could never have an Rh^- child.

Question 40

Which of the following would be considered a heterozygous dihybrid genotype?

A) Ww
B) sS
C) WWSs
D) WWss
E) WwSs

Question 41

In humans, aniridia, a type of blindness, is due to a dominant allele A. Migraine headaches are due to another dominant allele M. If a man who suffers from both conditions (AaMm) marries a woman who suffers from both (AaMm), what are the chances of an offspring expressing both traits?

A) 9/16
B) 3/16
C) 1/2
D) 1/16
E) 4/16

Question 42

Consider skin color is regulated by three genes: A, B, and C. All recessive alleles would be 0 or white on the color scale. All dominant alleles would be 6 or black on the color scale. What color is a person with AAbbCc genotype?

A) 6 or black
B) 5 or dark
C) 3 or medium brown
D) 2 or light
E) 0 or white

Question 43

In which kind of cross could you expect to find ratios of 1:1:1:1 among the offspring?

A) monohybrid cross
B) dihybrid cross
C) one-trait testcross
D) two-trait testcross
E) No cross will yield offspring in 1:1:1:1 ratios.

Question 44

If one parent has type B blood and the other has type AB, what type might the child have?

A) A or O only
B) B or O only
C) A or B only
D) A, B, AB only
E) A, B, O, or AB

Question 45

Hydrangeas are flowering plants with large, showy blooms. When the plant is grown in alkaline soil, the flowers are pink. When the plant is grown in acidic soil, the flowers turn blue. This change is phenotype is an example of

A) codominance.
B) incomplete dominance.
C) environmental influence.
D) polygenic inheritance.
E) epistatic interaction.

Question 46

You have two true-breeding rose bushes, one with red flowers and one with white flowers. A cross between these two roses yields a rose bush with two-color flowers. Each flower is both red and white. This is an example of

A) codominance.
B) incomplete dominance.
C) environmental effects.
D) polygenic inheritance.
E) epistatic interaction.

Question 47

When two or more sets of alleles affect the same trait, it is termed

A) a single-trait cross.
B) a double-trait cross.
C) codominant.
D) incomplete dominance.
E) polygenic inheritance.

Question 48

In four o'clock flowers, R = red, r = white, and Rr = pink. If two hybrids are crossed, what are the chances that an offspring will have pink flowers?

A) 0%
B) 25%
C) 50%
D) 75%
E) 100%

Question 49

The inheritance of blood types in humans can be explained by

A) simple Mendelian genetics (one gene pair).
B) linked genes.
C) simple dominance.
D) multiple alleles.
E) polygenic inheritance.

Question 50

In the determination of eye color, the HERC2 gene overrides the instructions of the OCA2 gene. If individuals are homozygous for a recessive allele of HERC2, they will have blue eyes regardless of the genotype associated with OCA2. This is an example of

A) epistatic interactions.
B) a two-trait cross.
C) incomplete dominance.
D) codominance.
E) homologous chromosomes.

Question 51

A man with blood type O would not be able to father a child with

A) blood type A.
B) blood type B.
C) blood type AB.
D) blood type O.
E) any blood type.

Question 52

Given that curly hair (WW) and straight hair (ww) exhibit incomplete dominance, what are the chances that two individuals with wavy hair will have a curly-haired child?

A) none
B) 25%
C) 50%
D) 75%
E) 100%

Question 53

In horses, black coat (B) is dominant over brown coat (b), and being a trotter (T) is dominant over being a pacer (t). A black horse who is a pacer is crossed with a brown horse who is a trotter. The offspring is a brown pacer. What is the genotype of the brown trotter parent?

A) BBTT
B) BbTt
C) Bbtt
D) bbTt
E) bbtt

Question 54

You have two true-breeding rose bushes, one with red flowers and one with white flowers. A cross between these two roses yields a bush with pink flowers. The pink flower color is an example of

A) codominance.
B) incomplete dominance.
C) environmental effects.
D) polygenic inheritance.
E) epistatic interaction.

Question 55

Which of the following produces an intermediate phenotype?

A) codominance
B) sex-linked inheritance
C) polygenic inheritance
D) simple Mendelian inheritance
E) incomplete dominance

Question 56

Traits that are controlled by several sets or pairs of alleles, such as skin color and height in humans, are the result of what form of inheritance?

A) polygenic
B) incomplete dominance
C) multiple allele systems
D) simple Mendelian inheritance
E) codominance

Question 57

Mr. X has been accused by Miss Z of fathering her child. The child's blood type is AB and Miss Z's blood type is A. Which blood type(s) would eliminate Mr. X as a possible father of the child?

A) only A
B) only B
C) AB
D) only O
E) either A or O

Question 58

A cross is made between two parents with genotypes AaBB and aabb. If there are 32 offspring, how many of them would be expected to exhibit both dominant characteristics?

A) 32
B) 24
C) 16
D) 8
E) 0

Question 59

The leaves of a maple tree vary in size depending on the location of the leaves on the tree. Those growing at the outer region of the tree tend to be smaller than those growing closer to the trunk of the tree. This allows leaves that are growing in the shade to have a larger surface area. This is an example of

A) response to environmental factors.
B) epistatic interactions.
C) codominance.
D) Mendelian inheritance.
E) incomplete dominance.

Question 60

Huntington disease is an autosomal dominant disorder that leads to progressive degeneration of brain cells. There is no effective treatment for the disorder and individuals usually die in their 40s or 50s, 10 to 15 years after the onset of symptoms. Which of these statements about Huntington disease is true?

A) As an autosomal dominant disease, Huntington disease is expressed only if both parents carry the trait.
B) Huntington disease usually skips a generation.
C) Researchers have located the gene for Huntington disease on chromosome 9.
D) Huntington disease usually appears during the teenage years.
E) Huntington disease is caused by a mutated copy of the gene for a protein called huntingtin.

Question 61

What genetic disorder is associated with the lack of an enzyme necessary for the normal metabolism of the amino acid phenylalanine?

A) phenylketonuria (PKU)
B) Marfan syndrome
C) Huntington disease
D) sickle cell disease
E) cystic fibrosis (CF)

Question 62

Which of the following is an autosomal dominant disorder?

A) Marfan syndrome
B) Tay-Sachs
C) sickle cell disease
D) cystic fibrosis (CF)
E) phenylketonuria (PKU)

Question 63

In humans, an individual who has wavy hair is a heterozygote with one curly hair allele and one straight hair allele. Indicate the phenotypic and genotypic ratios expected for the offspring from a straight-haired man and a wavy-haired woman.

Question 64

In the following pedigree, what does the colored circle indicate?

A) an affected father
B) an affected mother
C) an affected daughter
D) an affected son
E) an affected cousin

Question 65

Which allele combination represents a recessive monohybrid trait?

A) aa
B) Aa
C) AA
D) ab
E) Ab

Question 66

In the human population, short fingers are dominant over long fingers. Indicate the genotypic and phenotypic ratios if a heterozygous short-fingered female reproduces with a long-fingered male.

Question 67

How many alleles are required to express a monohybrid trait?

A) 2
B) 1
C) 3
D) 5
E) 4

Question 68

What pattern of inheritance is shown in the following pedigree? What is the probability that the affected son in generation III will pass the trait on to his children?

A) autosomal recessive; 25%
B) autosomal recessive; 50%
C) autosomal dominant; 25%
D) autosomal dominant; 50%
E) autosomal dominant; 100%

Question 69

Which genetic disorder is associated with a defect in the elastic connective tissue protein called fibrillin?

A) Marfan syndrome
B) Huntington disease
C) sickle cell disease
D) phenylketonuria (PKU)
E) cystic fibrosis (CF)

Question 70

Which genetic disorder is associated with an irregular shape of the red blood cells?

A) sickle cell disease
B) Marfan syndrome
C) Huntington disease
D) phenylketonuria (PKU)
E) cystic fibrosis (CF)

Question 71

When investigators try to determine what percentage of various human traits is due to nature (inheritance) and what percentage is due to nurture (the environment), scientists often examine

A) siblings that share only one parent and were separated at birth.
B) non-identical siblings that were separated at birth.
C) identical human twins that were separated at birth.
D) adopted siblings that have been separated due to divorce.
E) unrelated children who have been adopted by the same family and grew up together.

Question 72

Indicate the genotypic and phenotypic ratios that you could expect if an individual who is heterozygous for Huntington disease has children with a normal individual.

Question 73

In the following pedigree, the inherited condition is due to an autosomal dominant allele.