Deck 9: Patterns of Inheritance

Question 1

Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

A)2:1
B)1:1
C)1:2:1
D)3:1

Answer 1

B

Question 2

What is the specific location of a gene on a chromosome?

A)locus
B)phenotype
C)genotype
D)allele

Answer 2

A

Question 3

Mendel's law of segregation indicates that

A)two alleles segregate into each gamete.
B)more gametes carrying the dominant allele are produced than gametes carrying the recessive allele.
C)gametes have one allele copy for each gene.
D)gametes are diploid.

Answer 3

C

Question 4

A couple has two female children. What is the probability that their next child will be male?

A)25%
B)50%
C)33%
D)67%

Question 5

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds. The seeds of all of the offspring are yellow. Why?

A)The yellow allele is recessive to the green allele.
B)All of the offspring are homozygous yellow.
C)The yellow allele is dominant to the green allele.
D)The alleles are codominant.

Question 6

Mendel crossed purebred purple-flowered plants with purebred white-flowered plants, and all of the resulting offspring produced purple flowers. The offspring are all ________, and the allele for purple flowers is ________.

A)heterozygotes; recessive
B)heterozygotes; dominant
C)homozygotes; recessive
D)homozygotes; dominant

Question 7

The ________ is most commonly found in nature.

A)recessive trait
B)wild-type trait
C)parental type
D)dominant trait

Question 8

In humans, the presence or absence of dimples is a trait controlled by a single gene. What is the genotype of an individual who is heterozygous for dimples?

A)DD
B)Dd
C)dd
D)DI

Question 9

To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who ________.

A)expresses the dominant trait
B)is homozygous recessive for that trait
C)is homozygous dominant for that trait
D)is heterozygous for that trait

Question 10

A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would produce a(n)________.

A)purebred variety
B)hybrid
C)P generation
D)F₂ generation

Question 11

The best definition of a purebred plant is one that ________.

A)cannot be cross-fertilized
B)passes on the next generation only those traits identical to the parent
C)produces sterile offspring when cross-fertilized
D)self-fertilizes to produce hybrid offspring

Question 12

In humans, free earlobes (E)are dominant to attached earlobes (e)and the presence of freckles (F)is dominant to the absence of freckles (f). If an individual heterozygous for both of these traits were to mate with an individual with attached earlobes and no freckles, what is the probability of having a child with attached earlobes and freckles?

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

Question 13

An individual with the genotype AaBb produces four different gametes in equal proportions. This is a demonstration of ________.

A)the chromosomal theory of inheritance
B)Mendel's law of independent assortment
C)linkage
D)Mendel's principle of segregation

Question 14

Alleles are described as ________.

A)homologous chromosomes
B)environmental factors that affect gene expression
C)alternate versions of a gene
D)alternate phenotypes

Question 15

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds. The F₁ plants have yellow seeds. What is the expected phenotypic ratio of seed color of the offspring of an F₁ × F₁ cross?

A)1:2:1
B)2:1
C)3:1
D)9:3:3:1

Question 16

Round seeds (R)are dominant to wrinkled seeds (r), and yellow seeds (Y)are dominant to green seeds (y). What is the expected phenotypic ratio of a cross between an RrYy and an rryy individual?

A)1:2:1
B)9:3:3:1
C)3:1
D)1:1:1:1

Question 17

An individual who is homozygous ________.

A)expresses the dominant trait
B)carries two different alleles for a gene
C)carries two copies of the same allele for a gene
D)expresses the recessive trait

Question 18

Attached earlobes are recessive to free earlobes. What is the probability of having a child with attached earlobes when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

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

Question 19

What would you examine to determine whether a trait is sex linked?

A)karyotype
B)pedigree
C)DNA sequence
D)blood test

Question 20

Which cross will produce only heterozygous offspring?

A)AA × aa
B)AA × Aa
C)Aa × Aa
D)Aa × aa

Question 21

Linked genes are usually ________.

A)found on the X chromosome
B)found on the Y chromosome
C)codominant
D)located close together on a chromosome

Question 22

Which trait is polygenic in humans?

A)cystic fibrosis
B)height
C)blood type
D)sickle-cell disease

Question 23

Achondroplasia is a form of dwarfism caused by a dominant allele. The homozygous dominant genotype causes death, so individuals who have this condition are all heterozygotes. If a person with achondroplasia mates with a person who does not have achondroplasia, what percentage of their children would be expected to have achondroplasia?

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

Question 24

An individual who is heterozygous for cystic fibrosis ________.

A)cannot have children with cystic fibrosis
B)is a carrier
C)will have children who are all carriers of cystic fibrosis
D)has cystic fibrosis

Question 25

An individual with (naturally)curly hair and an individual with (naturally)straight hair mate; all of their offspring have (naturally)wavy hair. What is the relationship between the alleles for hair texture?

A)pleiotropy
B)incomplete dominance
C)wavy hair dominant to both straight and curly hair
D)codominance

Question 26

Genes that violate Mendel's principle of independent assortment are ________.

A)codominant
B)linked
C)recessive
D)pleiotropic

Question 27

Red-green colorblindness is inherited as a sex-linked recessive trait. The gene is found on the X chromosome. Can a man with normal color vision father a daughter who is red-green colorblind?

A)Yes, if the woman with whom he mates is red-green colorblind.
B)Yes, if the man is heterozygous for red-green colorblindness.
C)No, he can't (unless there is a mutation).
D)No, the expression of the trait skips a generation.

Question 28

A BbCc × bbcc cross that produces offspring in a 5:5:1:1 phenotypic ratio is evidence of ________.

A)linked genes
B)polygenic inheritance
C)incomplete dominance
D)codominance

Question 29

Many human traits, such as our performance on intelligence tests or our susceptibility to heart disease, are ________.

A)determined only by our genes
B)influenced by both genes and the environment
C)determined by genes in some people and by the environment in other people
D)determined solely by environmental factors

Question 30

Which outcome could help you identify a trait whose expression is determined by the effects of two or more genes (polygenic inheritance)?

A)A mating between a homozygous and a heterozygous individual produces more than the expected number of offspring expressing the dominant trait.
B)All of the alleles of the gene for that trait are equally expressed.
C)Pleiotropy occurs.
D)The trait varies along a continuum in the population.

Question 31

A dihybrid cross produces 30 recombinant offspring out of a total of 1,000 offspring. What is the recombination frequency of the two gene pairs?

A)6%
B)3%
C)30%
D)1)5%

Question 32

Which technique is used to collect fetal cells during pregnancy for genetic testing?

A)testcross
B)dihybrid cross
C)amniocentesis
D)pedigree analysis

Question 33

What is the key to the recognition of incomplete dominance?

A)The phenotype of the heterozygote falls between the phenotypes of the homozygotes.
B)The trait exhibits a continuous distribution.
C)The alleles affect more than one trait.
D)The heterozygote expresses the phenotype of both homozygotes.

Question 34

Assume that having three nostrils is inherited as a sex-linked trait on the Y chromosome. A man with three nostrils has a daughter who has a son with a man who has only two nostrils. What is the probability that the three-nostril man's grandson has three nostrils?

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

Question 35

Hypophosphatemia (vitamin D-resistant rickets)is inherited as a sex-linked dominant trait. The relevant gene is found on the X chromosome. What is the expected outcome of a cross between a homozygous recessive woman and a man with hypophosphatemia?

A)All of their daughters and none of their sons exhibit hypophosphatemia.
B)Fifty percent of their daughters and fifty percent of their sons exhibit hypophosphatemia.
C)All of their sons and none of their daughters exhibit hypophosphatemia.
D)Twenty-five percent of their offspring exhibit hypophosphatemia.

Question 36

An individual with the blood group genotype L^MLN has the phenotype MN. What is the relationship between the L^M and L^N alleles?

A)codominance
B)pleiotropy
C)L^N is dominant
D)incomplete dominance

Question 37

What is the key to the recognition of codominance?

A)The phenotype of the heterozygote is intermediate between the phenotypes of the homozygotes.
B)The trait exhibits a continuous distribution.
C)The alleles affect more than one trait.
D)The heterozygote expresses the phenotype of both homozygotes.

Question 38

Mendel's laws are based on the behavior of chromosomes during ________.

A)prophase I of meiosis only
B)mitotic anaphase
C)prophase I and prophase II of meiosis
D)metaphase I and anaphase I of meiosis

Question 39

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. Marfan syndrome is an example of ________.

A)codominance
B)homozygous recessive
C)pleiotropy
D)incomplete dominance

Question 40

An individual with (naturally)curly hair and an individual with (naturally)straight hair mate; all of their offspring have (naturally)wavy hair. If an individual with wavy hair mates with an individual with straight hair, what is the probability that their child will have curly hair?

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

Question 41

Scientists have long been interested in differences between dogs and wolves in their social behavior toward humans. Dogs and wolves share a common ancestor. In trying to understand the differences, a researcher analyzed data collected from 18 domesticated dogs and 10 wolves that had been raised by humans. Which data would be most useful to understand the genetic basis of this behavior?

A)The pedigree for the dogs and the geographic location from which the wolves came.
B)The number of chromosomes in wolves and dogs.
C)Differences in DNA sequences between the dogs and the wolves.
D)Examination of DNA from the ancient ancestor of dogs and wolves.

Question 42

Please refer to the following art to answer the following questions.
In the accompanying art, you see a table with the actual number of offspring that resulted from a dihybrid cross. The numbers do not show the 9:3:3:1 ratio predicted. One phenotype occurred more than predicted; another occurred less. The reason could be because ________.

A)of errors in mitosis
B)some of the alleles were linked
C)of polygenic inheritance

Question 43

The parents of a child with unusual disease symptoms take the child to a doctor for help. The doctor suspects that the condition might have a genetic basis. She recommends that the child be taken to a specialty clinic where physicians and staff members are trained to diagnose genetic diseases and counsel parents. Ultimately, the child is diagnosed with a rare recessively inherited disease. The parents are tested for the gene, and both are found to be heterozygous. The parents are expecting another child and ask about a test to determine if this child may carry the disease. All but one of these tests may detect genetic disorders in the unborn child. Choose the EXCEPTION.

A)chorionic villus sampling
B)pedigree analysis
C)blood tests to measure levels of alpha-fetoprotein
D)amniocentesis

Question 44

Please read the following scenario to answer the following questions.
Widow's peak, a pointed hairline on the forehead, is a genetic trait caused by a dominant allele. It can be traced back through a family's history using pedigree analysis.
The pedigree shown here is of three generations of a family. Notice that some individuals (shown in gray)have a widow's peak (W = dominant allele and w = recessive allele).
Mary has the genotype ________.

A)WW
B)ww
C)Ww

Question 45

Scientists have long been interested in differences between dogs and wolves in their social behavior toward humans. Dogs and wolves share a common ancestor. In trying to understand the differences, a researcher analyzed data collected from 18 domesticated dogs and 10 wolves that had been raised by humans. If she discovered that the degree of social relationship a dog exhibited toward humans was positively correlated with a chemical modification of a part of a chromosome rather than what alleles a dog had, this would be an example of ________.

A)pleiotropy
B)incomplete dominance
C)epigenetics
D)polygenic inheritance

Question 46

Scientists have long been interested in differences between dogs and wolves in their social behavior toward humans. Dogs and wolves share a common ancestor. In trying to understand the differences, a researcher analyzed data collected from 18 domesticated dogs and 10 wolves that had been raised by humans. Which data would be most useful to this study?

A)The degree of DNA similarities between dogs and humans.
B)The extent to which the dogs and the wolves sought assistance from humans when presented with a challenge.
C)The extent to which the dogs and the wolves licked and vocalized to their pups.
D)A measurement of the number of times the dogs and the wolves communicated with one another when threatened.

Question 47

Please read the following scenario to answer the following questions.
Widow's peak, a pointed hairline on the forehead, is a genetic trait caused by a dominant allele. It can be traced back through a family's history using pedigree analysis.
The pedigree shown here is of three generations of a family. Notice that some individuals (shown in gray)have a widow's peak (W = dominant allele and w = recessive allele).
Janice's genotype is ________.

A)Ww
B)WW
C)ww
D)WW or Ww

Question 48

To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who is homozygous recessive for that trait. This technique is referred to as a(n)________.

A)dihybrid cross
B)test cross
C)amniocentesis
D)pedigree analysis

Question 49

This hypothetical pedigree for a disease in humans illustrates inheritance that is ________.

A)autosomal recessive
B)autosomal dominant
C)sex-linked dominant
D)carried on the Y chromosome

Question 50

A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would be called a ________.

A)pedigree analysis
B)monohybrid cross
C)test cross
D)dihybrid cross

Question 51

Please read the following scenario to answer the following question.
The parents of a child with unusual disease symptoms take the child to a doctor for help. The doctor suspects that the condition might have a genetic basis. She recommends that the child be taken to a specialty clinic where physicians and staff members are trained to diagnose genetic diseases and counsel parents. Ultimately, the child is diagnosed with a rare recessively inherited disease. The parents are tested for the gene, and both are found to be heterozygous. The parents want to have another child but are afraid this child will also be affected.
What would genetic counselors say is the probability that the second child will have the disease?

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

Question 52

Humans have been applying the principles of genetics for many years without actually knowing about genes. Evidence for this is that humans ________.

A)have rerouted waterways in order to trade with people in distant regions
B)clear forests to plant crops
C)choose to save seeds from plants with the best yield to plant for the next generation
D)and other species are subject to many of the same diseases

Question 53

Recombinant offspring were produced by the mating shown in the accompanying art. What is the recombination frequency of purple-round and red-long offspring?

A)21%
B)381
C)21 + 21
D)11%

Question 54

Experience with dog breeding has taught geneticists that ________.

A)given enough time, any desired trait can be bred into dogs
B)purebred dogs are often sterile due to inbreeding
C)while physical traits can be molded through artificial selection, behavioral traits cannot
D)geographically isolated groups of dogs may be selected for quite different traits, resulting in a different dog breed

Question 55

This pedigree supports the fact that widow's peak is due to a dominant allele, because if it were due to a recessive allele and both parents show the recessive phenotype, then ________.

A)half of the sons would have a widow's peak
B)all of the offspring would have a widow's peak
C)none of the daughters would have a widow's peak
D)all of the daughters and none of the sons would have a widow's peak