Deck 12: Mendel, Genes, and Inheritance

Question 1

Which notation represents a testcross? (A "dash" indicates the allele's identity is unknown.)

A) R-MM x R-mm
B) RRMM x rrmm
C) R-M- x R-M-
D) rrMM x RRmm
E) R-M- x rrmm

Answer 1

E

Question 2

____ occurs within a single plant, while ____ occurs between two plants.

A) A dihybrid cross; a monohybrid cross
B) Epistasis; polygenic inheritance
C) A testcross; cross-pollination
D) Self-pollination; cross-pollination
E) A dihybrid cross; self-pollination

Answer 2

D

Question 3

A testcross is used to ____.

A) determine if a parent with a dominant trait is heterozygous or homozygous
B) determine which allele is dominant
C) determine if the progeny of an experimental cross will have a random assortment of alleles
D) prove an organism is double recessive
E) cross an individual with a dominant phenotype with a homozygous dominant individual to prove the alleles are dominant

Answer 3

A

Question 4

Pairs of alleles are found at a particular ____ on a pair of ____.

A) gene; gametes
B) base; homozygous genes
C) nucleotide; genes
D) locus; homologous chromosomes
E) sister chromatid; homologous chromosomes

Question 5

If purple flower color is dominant in pea plants, a cross between true breeding P generation purple and white plants will result in ____.

A) all white flowers in the F₁generation
B) all purple flowers in the F₁generation
C) all purple flowers in the F₁generation, but a lighter purple than in the parents
D) mostly purple flowers in the F₁generation, with an occasional white flower
E) half of the plants having purple flowers and half having white flowers

Question 6

Which notation represents a dihybrid cross?

A) RrMM x Rrmm
B) RRMM x rrmm
C) RrMm x RrMm
D) rrMM x RRmm
E) RrMm x rrmm

Question 7

What is the probability of obtaining a head and a tail (in either order) when tossing a coin two times?

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

Question 8

What is the main premise of the blending theory of inheritance that predominated before 1900?

A) We inherit traits from only one parent.
B) Traits are inherited via a mixing of parental blood.
C) Parental chromosomes undergo recombination to produce blended chromosomes in their offspring.
D) Traits may skip a generation due to the blending of paternal and maternal phenotypes.
E) Paternal and maternal chromosomes separate independently in meiosis, creating gametes with a blend of paternal and maternal chromosomes.

Question 9

In the case of complete dominance, if a plant has a ____ genotype for a particular trait, its phenotype will be the ____ trait.

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

Question 10

A parent has a genotype of RrYy . What is the probability of this individual producing a gamete with the RY genotype?

A) 1/2
B) 1/4
C) 3/4
D) 1/8
E) 0

Question 11

An F₁individual resulting from a cross between a homozygous dominant parent and a homozygous recessive parent is always ____.

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

Question 12

Mendel studied what he called characters and traits. What is the relationship between these terms?

A) Characters are heritable characteristics; traits are alternative forms of these characters.
B) Traits are heritable characteristics; characters are alternative forms of these traits.
C) Characters are the unknown packages transferred to the next generation; traits result from this transfer.
D) Characters are passed to the next generation; traits are never passed to the next generation.
E) Characters and traits are synonymous in Mendel's writings.

Question 13

Events X and Y are independent of each other. If the probability of event X occurring is 1 in 4, and the probability of event Y occurring is 1 in 5, the probability of both events occurring is ____.

A) (1/4)²+ (1/5)²= (1/16) + (1/25) = (25/400) + (16/400) = 41/400
B) (1/4) + (1/5) = (5/20) + (4/20) = 9/20
C) (1/4)²(1/5)²= (1/16)(1/25) = 1/400
D) (1/4)(1/5) = 1/20
E) (1/4 + 1/5)²= (5/20 + 4/20)²= (9/20)²= 81/400

Question 14

Which notation represents a monohybrid cross?

A) RrMM x Rrmm
B) RRMM x rrmm
C) Rr x Rr
D) rr x RR
E) Rr x rr

Question 15

When an individual has two different alleles for a given gene, they are ____ for that gene.

A) heterozygous
B) homozygous
C) self-fertilized
D) self-pollinated
E) recessive

Question 16

Use the product rule to calculate the probability (P) of two independent events, X and Y, both occurring.

A) P = P(X²) + P(Y²)
B) P = P(X²) x P(Y²)
C) P = P(X) x P(Y)
D) P = P(X) + P(Y)
E) P = (P(X) + P(Y))²

Question 17

How does sickle cell disease cause death?

A) The malformed red blood cells cannot transport oxygen.
B) The malformed red blood cells can block capillaries.
C) The malformed red blood cells have a higher affinity for CO₂than for oxygen.
D) The mutant hemoglobin polypeptide cannot bind O₂due to a change in three amino acids.
E) More cells assume the sickle shape as oxygen concentration in the tissues increases.

Question 18

Mendel crossed true-breeding plants having yellow peas with true-breeding plants having green peas. The resulting plants all had yellow peas. An F₁cross resulted in 3/4 of the plants having yellow peas and 1/4 of the plants having green peas. What does this tell you about the alleles for color?

A) Yellow is usually the dominant color, but sometimes green can be dominant.
B) Green is the dominant color.
C) Yellow is the dominant color.
D) Yellow is the recessive color.
E) Yellow and green are codominant.

Question 19

A ____ individual is always part of a testcross.

A) heterozygous
B) homozygous recessive
C) homozygous dominant
D) self-fertilized
E) dihybrid

Question 20

From his experiments, Mendel concluded that each individual carries two factors, or ____, that govern the inheritance of each trait. Different versions of each factor are known as ____.

A) alleles; gene markers
B) genes; loci
C) alleles; genes
D) genes; alleles
E) gene markers; genes

Question 21

If your mother and father both have cystic fibrosis, which is caused by a recessive allele, the odds of you inheriting only one allele for the disorder are ____.

A) 1/4
B) 1/2
C) 3/4
D) 1
E) 0

Question 22

In pea plants, yellow seed color is dominant to green, and wrinkled seed texture is dominant to smooth. In a dihybrid cross between two heterozygous plants with yellow, round seeds, if the two alleles assort independently, what is/are the predicted phenotypic ratio(s) of the offspring?

A) all are yellow and round
B) 8 yellow and round: 8 green and wrinkled
C) nine green and wrinkled: four yellow and round: three green and round
D) nine green and round: three yellow and round: three yellow and wrinkled: one green and wrinkled
E) nine yellow and round: three green and round: three yellow and wrinkled: one green and wrinkled

Question 23

If your mother and father both are healthy but carry the allele for cystic fibrosis, which is caused by a recessive allele, the odds of you inheriting at least one allele for the disorder are ____.

A) 1/4
B) 1/2
C) 3/4
D) 1
E) 0

Question 24

Your father is heterozygous for the recessive disorder phenylketonuria (PKU). You know your mother has two "good" alleles. You have a ____chance of having the disorder.

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

Question 25

In pea plants, round pea texture is dominant over wrinkled texture. How can you obtain true-breeding pea plants having round peas with the least amount of work?

A) Cross plants having round peas with plants having wrinkled peas. Select round pea plants from the progeny because they are now true-breeding.
B) Cross plants having round peas with other plants having round peas. Do this for multiple generations.
C) Cross plants having round peas with plants having wrinkled peas. Select round pea plants from the progeny and do a testcross to determine which parental plants were homozygous dominant.
D) Cross plants having round peas with plants having wrinkled peas. This will tell you which round pea plants are homozygous dominant and are thus true-breeding.
E) It's not possible. You can only get true-breeding plants that have wrinkled peas.

Question 26

The ability of an individual heterozygous for two different genes to produce the four possible gamete types in equal numbers reflects Mendel's Law(s) of ____.

A) Segregation
B) Independent Assortment
C) Punnett Squares
D) Chromosome Theory
E) Segregation and Independent Assortment

Question 27

Identify the disorder caused by a dominant allele.

A) achondroplasia
B) cystic fibrosis
C) albinism
D) sickle-cell anemia
E) Down syndrome

Question 28

What is the probability of rolling a die twice and getting a 2 and a 6 in no particular order?

A) 1/3
B) 1/4
C) 1/8
D) 1/18
E) 1/36

Question 29

A man and woman are each heterozygous for the autosomal recessive disorder cystic fibrosis. If they want to have three children, what is the probability that only one of the children will have cystic fibrosis?

A) 1/4
B) 3/4
C) 9/16
D) 9/64
E) 27/64

Question 30

Your father is heterozygous for a recessive disorder. You know your mother has two "good" alleles. What is the probability that you will have the disorder?

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

Question 31

R is the dominant allele for round pea texture; r is the recessive allele for wrinkled pea texture. If you cross plants having round peas with plants having wrinkled peas, ____.

A) all progeny will be homozygous for pea texture
B) you are conducting a dihybrid cross
C) you are conducting a reciprocal cross
D) all progeny will have wrinkled peas
E) you will be able to determine if the plant with round peas is homozygous or heterozygous for this trait

Question 32

In pea plants, yellow seed color is dominant to green and wrinkled seed texture is dominant to smooth. In a dihybrid cross between two heterozygous plants with yellow, wrinkled seeds, if the two alleles assort independently, what is the probability that an offspring will have smooth, yellow seeds?

A) 0
B) 9/16
C) 3/16
D) 1/16
E) 1/4

Question 33

According to the chromosome theory of inheritance, ____.

A) genes on chromosomes always assort independently
B) paternal chromosomes determine the offspring's phenotype
C) maternal chromosomes determine the offspring's phenotype
D) genes and their alleles are carried on chromosomes
E) genes are carried on chromosomes and alleles are the product of gene expression

Question 34

If your mother has cystic fibrosis, which is caused by a recessive allele, the odds of you having cystic fibrosis are ____.

A) 1/4
B) 1/2
C) 3/4
D) 1
E) impossible to determine without knowing your father's genotype

Question 35

If your mother and father both have cystic fibrosis, which is caused by a recessive allele, the odds of you having cystic fibrosis are ____.

A) 1/4
B) 1/2
C) 3/4
D) 1
E) 0

Question 36

The site on a chromosome where a gene is located is called its ____.

A) character
B) marker
C) locus
D) trait
E) homologue

Question 37

Your parents are both heterozygous for the recessive disorder phenylketonuria (PKU). What is the probability that you will have the disorder?

A) 25%
B) 50%
C) 75%
D) 100%
E) 25% if your three siblings are healthy; 75% if your siblings also have the disorder

Question 38

A cross is performed between parents with genotypes aaBbCc and aaBbcc . What is the probability that the offspring will have the same genotype as the first parent? Assume that capital letters indicate dominant alleles and lower case letters indicate recessive alleles.

A) 1/8
B) 1/4
C) 3/8
D) 3/16
E) 9/16

Question 39

If your mother is heterozygous for Huntington's disease, which is caused by a dominant allele, the odds that you will inherit the disorder from her are ____.

A) 1/4
B) 1/2
C) 3/4
D) 1
E) 0

Question 40

If your mother and father are both heterozygous for Huntington's disease, which is caused by a dominant allele, the odds of you having the disorder are ____.

A) 1/4
B) 1/2
C) 3/4
D) 1
E) 0

Question 41

A couple are both heterozygous for the dominant allele for polydactyly. They want to have three children. What is the probability that all three children will have polydactyly?

A) 3/4
B) 9/64
C) 1/64
D) 27/64
E) 1/2

Question 42

The different alleles in human blood type are a demonstration of ____.

A) incomplete dominance only
B) codominance only
C) dominance and codominance
D) dominance and incomplete dominance
E) dominance, codominance, and incomplete dominance

Question 43

You have type A blood (genotype I^Ai ). Who can you donate blood to in an emergency?

A) type O only
B) type AB only
C) type A only
D) types A and B, not O
E) types A and AB

Question 44

Your mother has albinism, which is a recessive trait. Your father has cystic fibrosis, which is also a recessive trait. You discover that your new father-in-law has albinism and cystic fibrosis. If neither you nor your spouse has either albinism or cystic fibrosis, what are the odds that your first child will have either albinism or cystic fibrosis, but not both?

A) 1/16
B) 3/8
C) 1/8
D) 1/4
E) 0

Question 45

Mouse pigmentation is subject to epistasis of the B alleles by the d alleles. B (black) is dominant over b (brown), and D is dominant over d . Homozygous d is epistatic to the black and brown genes. Given this information, what will result from a F₁cross between two mice?

A) 9/16 black, 3/16 brown, 4/16 white
B) 9/16 white, 3/16 brown, 4/16 black
C) 9/16 black, 6/16 brown, 1/16 white
D) 9/16 white, 6/16 brown, 1/16 black
E) all black mice

Question 46

In snapdragons, the red allele C^Ris incompletely dominant over the white allele C^W. Which two plants would you cross to produce a true-breeding pink snapdragon?

A) pink with pink
B) pink with red
C) red with white
D) pink with white
E) a true-breeding pink snapdragon cannot be created

Question 47

Your mother has albinism, which is a recessive trait. You learn that your spouse's mother also has albinism. Neither you nor your spouse have albinism. What are the odds that your first child will have albinism?

A) 0
B) 1/4
C) 1/2
D) 3/4
E) 1

Question 48

Your father has type B blood, and your mother has type O blood. You learn that you also have blood type O. What does this tell you?

A) Your father is homozygous for type B blood.
B) Your mother is heterozygous for type O blood.
C) Your father's genotype is I^Bi and your mother's genotype is ii .
D) Your father's genotype is I^BI^Band your mother's genotype is ii .
E) Your father's genotype is I^AI^Band your mother's genotype is ii .

Question 49

If a monohybrid cross results in 1:2:1 genotypic and phenotypic ratios in the offspring, then which type of inheritance might be at work?

A) dominance
B) incomplete dominance
C) epistasis
D) pleiotropy
E) polygenic inheritance

Question 50

If a woman has blood type O and a man has blood type AB, what is the probability that they will have a child with blood type O?

A) 0
B) 1/16
C) 1/4
D) 1/2
E) 3/4

Question 51

In snapdragons, the red allele C^Ris incompletely dominant over the white allele C^W. If you cross a pink snapdragon ( C^RC^W) with a white snapdragon ( C^WC^W), what percentage of the progeny will be red?

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

Question 52

Your mother has albinism, which is a recessive trait. Your father has cystic fibrosis, which is also a recessive trait. You discover that your new father-in-law has albinism and cystic fibrosis. If neither you nor your spouse has either albinism or cystic fibrosis, what are the odds that your first child will have neither albinism nor cystic fibrosis?

A) 1/16
B) 3/8
C) 1/8
D) 9/16
E) 0

Question 53

Your mother has albinism, which is a recessive trait. Your father has cystic fibrosis, which is also a recessive trait. You discover that your new father-in-law has albinism and cystic fibrosis. If neither you nor your spouse has either albinism or cystic fibrosis, what are the odds that your first child will have both albinism and cystic fibrosis?

A) 1/16
B) 1/8
C) 1/4
D) 1/2
E) 0

Question 54

You have type O blood (genotype ii ). Who can you donate blood to in an emergency?

A) type O only
B) type B only
C) type A only
D) type AB only
E) types A, B, AB, and O

Question 55

What is the key difference between incomplete dominance and codominance?

A) In incomplete dominance, the recessive allele cannot be detected; in codominance, the expression of the recessive allele is apparent.
B) In incomplete dominance, it is possible to detect the expression of a recessive allele; in codominance, both alleles contribute equally to the phenotype.
C) In codominance, it is possible to detect the expression of a recessive allele; in incomplete dominance, both alleles contribute equally to the phenotype.
D) In incomplete dominance, it is possible to detect the expression of the dominant allele; in codominance, two different genes contribute to multiple phenotypes.
E) The two terms are synonymous.

Question 56

Mouse pigmentation is subject to epistasis of the B alleles by the d alleles. B (black) is dominant over b (brown), and D is dominant over d . Homozygous d is epistatic to the black and brown genes. Given this information, what genotype(s) result in a white mouse (no pigment)?

A) BBdd only
B) Bbdd only
C) bbDD only
D) bbDd only
E) BBdd and Bbdd

Question 57

A man and woman are each heterozygous for the autosomal recessive gene for albinism. They already have two non-albino children and want to have two more. What is the probability that their next two children will be phenotypically identical to each other with regard to skin color (i.e., either both albino or neither albino)?

A) 1/16
B) 3/16
C) 4/16
D) 9/16
E) 10/16

Question 58

A plant of genotype CCdd is crossed to a plant of genotype ccDD; the F₁offspring are then testcrossed to a ccdd plant. If the genes are on different chromosomes, what percentage of the offspring will be ccdd ?

A) 10
B) 20
C) 25
D) 30
E) 50

Question 59

In ____, genes at one locus mask the effect of genes at another locus.

A) incomplete dominance
B) codominance
C) epistasis
D) polygenic inheritance
E) pleiotropy

Question 60

Two snapdragons heterozygous for alleles that encode red and white flower color are crossed. If the red and white alleles show incomplete dominance, what will be the ratios of phenotypes in the offspring?

A) 100% pink
B) 100% red
C) 50% white, 50% red
D) 25% red, 50% pink, 25% white
E) 25% pink, 50% white, 25% red

Question 61

We now know that some of the seven alleles Mendel studied are on the same chromosome in pea plants. Despite this, the law of independent assortment still applies. How would you explain this?

A) Recombination via the synaptonemal complex might have occurred during mitosis.
B) Recombination via the synaptonemal complex might have occurred during meiosis.
C) The law of independent assortment applies to all alleles regardless of their arrangement on chromosomes.
D) Mendel was a good enough mathematician to design experiments that would result in the predicted ratios.
E) Independent assortment occurred during mitosis.

Question 63

The fact that a person who suffers from sickle-cell anemia has symptoms like pneumonia, heart and kidney failure, fatigue, and paralysis is an example of ____.

A) pleiotropy
B) incomplete dominance
C) codominance
D) the effects of multiple alleles
E) epistasis

Question 65

Human skin color is an example of ____, while sickle-cell anemia is an example of ____.

A) multiple alleles; epistasis
B) incomplete dominance; multiple alleles
C) polygenic inheritance; pleiotropy
D) pleiotropy; polygenic inheritance
E) incomplete dominance; pleiotropy

Question 66

How is Mendel's Principle of Independent Assortment related to meiosis?

Question 67

Would meiosis, when it was discovered, have been understood without Mendel's work? Explain why or why not, using Mendel's three key findings about inheritance.

Question 68

Define epistasis and give an example.

Question 69

Explain the genetic basis of height in humans.

Question 70

A couple wants to start a family, but they are concerned that their child might have cystic fibrosis. After taking a family history, you determine that while neither of them has the disease, the woman had a sister with cystic fibrosis (with unaffected parents), and the man's father also had cystic fibrosis. What do you tell them?

Question 71

If a gene has multiple alleles, ____.

A) only two alleles of the gene exist in the population
B) more than two alleles of the gene are present in any given individual
C) more than two alleles of the gene are present in the population
D) one or more of the alleles is epistatic to the other(s)
E) the alleles must be incompletely dominant

Question 72

A patient presents with the following symptoms: anemia, heart failure, pneumonia, paralysis, and abdominal pain. After learning about their family history, you run a genetic test for which disorder?

A) cystic fibrosis
B) albinism
C) sickle-cell anemia
D) achondroplasia
E) schizophrenia

Question 73

Explain why Mendel's work was groundbreaking.

Question 74

June has type B blood and has a baby, Joey, with type AB blood. Her husband, Jim, has type O blood. June believes that there has been a mix-up at the hospital. She suspects that another couple, Ann and Al, who had a baby the same day, were allowed to take her son home. That baby Arnie has type O blood. Al and Ann both have type A blood. Which of the following is a correct statement about who is Joey's father?

A) Neither Jim nor Al could be Joey's father.
B) Jim could be Joey's father, but Al could not.
C) Either Jim or Al could be Joey's father.
D) Al could be Joey's father, but Jim could not.
E) Al is definitely Joey's father, but Jim could also.

Question 75

Rice plants may be tolerant or intolerant to flooding. A true-breeding tolerant plant was crossed with a true-breeding intolerant plant, creating an F₁generation. When plants from the F₁generation are crossed to each other, approximately 75% of the resultant F₂generation was tolerant to flooding. What does this most likely suggest about the flood-tolerant and flood-intolerant alleles?

A) Multiple alleles control flood-tolerance.
B) The alleles for flood-tolerance and flood-intolerance are codominant.
C) The allele for flood-tolerance is incompletely dominant.
D) The allele for flood-intolerance is dominant, while the allele for flood-tolerance is recessive.
E) The allele for flood-tolerance is dominant, while the allele for flood-intolerance is recessive.

Question 76

An individual heterozygous for sickle-cell disease produces both normal and abnormal polypeptides. This is an example of ____.

A) epistasis
B) incomplete dominance
C) polygenic inheritance
D) multiple alleles
E) pleiotropy

Question 77

Polygenic inheritance is often modified by ____.

A) the environment
B) gene blending
C) epistasis
D) dihybrid crosses
E) pleiotropy

Question 78

What is the difference between polygenic inheritance and pleiotropy?

Question 79

Characters that have a continuous distribution, such as height, weight, and skin color, are called ____, and the individual genes that control them are known as ____.

A) quantitative phenotypes; quantitative trait markers
B) quantitative genotypes; quantitative trait loci
C) quantitative traits; quantitative trait markers
D) quantitative traits; quantitative trait loci
E) quantitative markers; quantitative trait markers