Deck 19: Introduction to Genetics

Question 1

Which of the following genotypes is homozygous?

A) AaBB
B) aABB
C) aaBB
D) aaBb
E) AaBb

Answer 1

C

Question 2

If two parent organisms have different alleles for a gene that an experimenter wants to test, he or she will perform a

A) dihybrid cross.
B) monohybrid cross.
C) multiple allele cross.
D) trihybrid cross.
E) polyploid cross.

Answer 2

B

Question 3

When an allele's effect on a trait masks that of an allele paired with it, the first allele is referred to as

A) dominant.
B) recessive.
C) codominant.
D) incompletely dominant.
E) hybrid.

Answer 3

A

Question 4

Gene A occurs on chromosome 5, gene B is on chromosome 21. Therefore, these two parts of the chromosomes CANNOT be

A) genes.
B) dominant.
C) loci.
D) alleles.
E) recessive.

Question 5

Skin color comes from the pigment

A) melatonin.
B) melanin.
C) anthocyanin.
D) giberellin.
E) fucoxanthin.

Question 6

The alleles an individual inherits are the

A) phenotype
B) allelotype.
C) homotype.
D) heterotype.
E) genotype.

Question 7

The genotype AA is referred to as

A) heterozygous.
B) hybrid.
C) homozygous recessive.
D) homozygous dominant.
E) codominant.

Question 8

The most accurate description of an organism with genotype AaBb is

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

Question 9

The genotype aa is referred to as

A) heterozygous.
B) hybrid.
C) homozygous recessive.
D) homozygous dominant.
E) codominant.

Question 10

Each version of a gene is called a(n)

A) allele.
B) chromosome.
C) histone.
D) centromere.
E) artifact.

Question 11

Approximately how many genes do humans possess?

A) 100,000
B) 50,000
C) 40,000
D) 25,500
E) 21,500

Question 12

If short hair (L) is dominant to long hair (l) , animals LL and Ll have the same

A) parents.
B) genotypes.
C) phenotypes.
D) alleles.
E) genes.

Question 13

Various forms of a gene at a given locus are called

A) chiasmata.
B) alleles.
C) autosomes.
D) loci.
E) chromatids.

Question 14

Observable functional or physical traits are the

A) phenotype.
B) allelotype.
C) homotype.
D) heterotype.
E) genotype.

Question 15

Skin pigment is made by

A) erythrocytes.
B) phagocytes.
C) melanocytes.
D) dendritic cells.
E) fibroblasts.

Question 16

A locus is

A) a recessive gene.
B) an unmatched allele.
C) a sex chromosome.
D) the location of a specific gene on a chromosome.
E) a dominant gene.

Question 17

The genotype Aa is referred to as

A) heterozygous.
B) incompletely dominant.
C) homozygous recessive.
D) homozygous dominant.
E) codominant.

Question 18

If two copies of a gene are identical alleles, the condition is referred to as

A) homozygous.
B) heterozygous.
C) hybrid.
D) dominant.
E) codominant.

Question 19

When an allele's effect on a trait is masked by that of an allele paired with it, the second allele is referred to as

A) dominant.
B) recessive.
C) codominant.
D) incompletely dominant.
E) hybrid.

Question 20

If two copies of a gene are different alleles, the condition is referred to as

A) homozygous.
B) heterozygous.
C) hybrid.
D) dominant.
E) codominant.

Question 21

A testcross consists of

A) a cross of two pure-breeding forms to find out which form of a gene is dominant.
B) a cross between two unknown forms to determine their genotypes.
C) a cross between an offspring and its parent.
D) a cross of an F ₁ hybrid to an individual that is homozygous recessive.
E) a cross of two F ₂ individuals to produce an F ₃ generation.

Question 22

A graphic tool used to determine the probable outcome of genetic crosses is the

A) Mendelian box.
B) Archimedian triangle.
C) Euclid box.
D) Hardy-Weinberg graph.
E) Punnett square.

Question 23

When an individual with an unknown genotype is crossed with an individual that is homozygous recessive for the trait being studied, the procedure is called a

A) backcross.
B) dihybrid cross.
C) testcross.
D) linked cross.
E) modified cross.

Question 24

A testcross involves

A) two F ₁ hybrids.
B) an F ₁ hybrid and an F ₂ offspring.
C) two parental organisms.
D) an F ₁ hybrid and the homozygous dominant parent.
E) an F ₁ hybrid and an organism that is homozygous recessive for that trait.

Question 25

The principle of segregation applies most specifically to events occurring in preparation of

A) offspring.
B) zygotes.
C) homologous chromosomes.
D) gametes.
E) loci.

Question 26

If tall (D) is dominant to dwarf (d) , and two homozygous varieties DD and dd are crossed, then what kind of offspring will be produced?

A) all intermediate forms
B) all tall
C) all dwarf
D) 1/2 tall, 1/2 dwarf
E) 3/4 tall, 1/4 dwarf

Question 27

In the cross Cc x Cc , gametes have a ____ chance of receiving either allele.

A) 25 - 75
B) 50 - 50
C) 75 - 25
D) 60 - 40
E) 90 - 10

Question 28

The F ₂ phenotypic ratio of a monohybrid cross is

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

Question 29

The theory of segregation

A) deals with the alleles governing two different traits.
B) applies only to linked genes.
C) applies only to sex-linked genes.
D) explains the behavior of a pair of alleles during meiosis.
E) applies only to autosomes.

Question 30

In a monohybrid cross, what kind of genes "disappear" in the F ₁ generation?

A) sex-linked
B) dominant
C) recessive
D) codominant
E) lethal

Question 31

The results of a testcross reveal that all offspring resemble the parent being tested. That parent necessarily is

A) heterozygous.
B) polygenic.
C) homozygous.
D) recessive.
E) pleiotropic.

Question 32

When homologues separate into different gametes after meiosis II, the genes of each pair separate as well. This is the principle of

A) segregation.
B) separation.
C) colonization.
D) variation.
E) independent assortment.

Question 33

If R is dominant to r , the offspring of the cross of RR with rr will

A) be homozygous.
B) display the same phenotype as the RR parent.
C) display the same phenotype as the rr parent.
D) have the same genotype as the RR parent.
E) have the same genotype as the rr parent.

Question 34

In a Punnett square, the letters within the little boxes represent

A) offspring genotypes.
B) parental genotypes.
C) gametes.
D) offspring phenotypes.
E) parental phenotypes.

Question 35

When the first generation parents are homozygous for different alleles, a 3:1 phenotype ratio will most likely appear in which generation of offspring?

A) P ₁
B) H ₁
C) A ₁
D) F ₁
E) F ₂

Question 36

If short hair (L) is dominant to long hair (l) , then what fraction of the offspring produced by a cross of Ll x ll will be homozygous dominant?

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

Question 37

If all offspring of a cross have the genotype Aa , the parents of the crosses would most likely be

A) AA x aa .
B) Aa x Aa .
C) Aa x aa .
D) AA x Aa .
E) none of these.

Question 38

A parent with the genotype CC will produce which gametes?

A) C and c
B) c and c
C) C and C
D) it will vary with the condition of the parent
E) it cannot be determined without more information

Question 39

If short hair (L) is dominant to long hair (l) , then to determine the genotype of a short-haired animal it should be crossed with

A) LL .
B) Ll .
C) ll .
D) all of these.
E) none of these.

Question 40

Geneticists study _______ to determine the possible outcomes of single-gene traits.

A) probability
B) segregation
C) dominance
D) independent assortment
E) phenotype

Question 41

If all the offspring of a cross had the genotype Aa Bb , the parents of the cross would most likely be

A) AA BB x aa bb .
B) AA bb x aa BB .
C) Aa Bb x Aa Bb .
D) Aa bb x aa Bb .
E) both AA BB x aa bb and AA bb x aa BB .

Question 42

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring of genotype aa bb cc ?

A) 1/64
B) 1/32
C) 3/64
D) 1/16
E) 9/64

Question 43

What fraction of the time will a cross of Aa BB cc with Aa Bb CC produce an offspring of genotype Aa Bb CC ?

A) 1/32
B) 1/16
C) 3/32
D) 1/8
E) 0

Question 44

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring that expresses the dominant traits A and B and cc ( A _  B _ cc )?

A) 1/32
B) 3/64
C) 1/16
D) 9/64
E) 27/64

Question 45

Some dogs have erect ears; others have drooping ears. Some dogs bark when following scent; others are silent. Erect ears and barking are due to dominant alleles located on different chromosomes. If two dihybrids are crossed,

A) the most common phenotype is drooping ears and barking.
B) all droopy-eared, silent dogs are pure-breeding.
C) the least common phenotype is drooping ears and barking.
D) there will be no phenotypes or genotypes that resemble the original parents.
E) there will be no offspring that resemble the F ₁ generation.

Question 46

For monohybrid experiments, a testcross could result in which of the following ratios?

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

Question 47

What fraction of the time will a cross of Aa Bb Cc with Aa BB cc produce an offspring of genotype Aa Bb Cc ?

A) 1/32
B) 1/16
C) 3/32
D) 1/8
E) none (no chance of this offspring)

Question 48

Independent assortment occurs during

A) meiosis.
B) mitosis.
C) morphogenesis.
D) segregation.
E) cell fission.

Question 49

The chance of producing an offspring of genotype Aa Bb cc from a cross of Aa BB Cc with Aa BB Cc is

A) 1/32.
B) 1/16.
C) 3/32.
D) 1/8.
E) none (no chance of this offspring)

Question 50

If all the offspring of a testcross are alike and resemble the organism being tested, then that parent is

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

Question 51

The principle of independent assortment states that

A) one allele is always dominant to another.
B) hereditary units from the male and female parents are blended in the offspring.
C) the two hereditary units that influence a certain trait segregate during gamete formation.
D) each hereditary unit on one chromosome is inherited separately from hereditary units on other chromosomes.
E) genes on the same chromosome travel separately.

Question 52

When considering non-related traits, the fact that they may be inherited individually without any effect on one another is known as

A) segregation.
B) independent assortment.
C) synapsis.
D) independent segregation.
E) non-disjunction.

Question 53

The chance of producing an offspring of genotype Aa BB cc from a cross of Aa Bb Cc with Aa Bb Cc is

A) 1/64.
B) 1/32.
C) 3/64.
D) 1/16.
E) 3/32.

Question 54

Some dogs have erect ears; others have drooping ears. Some dogs bark when following a scent; others are silent. Erect ears and barking are due to dominant alleles located on different chromosomes. A dog homozygous for both dominant traits is mated to a droopy-eared, silent follower. The phenotypic ratio expected in the F ₁ is

A) 9:3:3:1.
B) 100 percent of one phenotype.
C) 1:1.
D) 1:2:1.
E) 3:1.

Question 55

Assume short hair (L) is dominant to long hair (l) , and black hair (B) is dominant to brown (b) . If you found a black, short-haired animal, you could determine its genotype by crossing it to an animal with a genotype of

A) LL BB .
B) ll BB .
C) ll Bb .
D) ll bb .
E) LL bb .

Question 56

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring that expresses the phenotype represented by the dominant gene C ( aa bb C_) ?

A) 1/32
B) 3/64
C) 1/16
D) 9/64
E) 27/64

Question 57

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring of genotype Aa bb CC ?

A) 1/64
B) 1/32
C) 3/64
D) 1/16
E) 9/64

Question 58

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring that is pure-breeding?

A) 3/64
B) 1/16
C) 1/8
D) 9/64
E) 27/64

Question 59

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring that expresses all three dominant genes?

A) 3/64
B) 1/16
C) 1/8
D) 9/64
E) 27/64

Question 60

A given chromosome and its genes may end up in any of ____ gametes.

A) 2
B) 4
C) 6
D) 8
E) 10

Question 61

The ABO blood types have ____ different genotypes.

A) 4
B) 6
C) 8
D) 12
E) 16

Question 62

If a child has blood type AB, he or she could NOT have been produced by which set of parents?

A) Type A mother and type B father
B) Type AB mother and type O father
C) Type O mother and type O father
D) Type O mother and type AB father
E) Type B mother and type AB father

Question 63

Individuals with the genotype Gg Hh Ii Jj will produce how many different kinds of gametes?

A) 2
B) 4
C) 6
D) 8
E) 16

Question 64

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . In the F ₂ generation of a cross between BB ss with bb SS , what fraction of the offspring would be expected to be black and spotted?

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

Question 65

The wide-ranging effect of a single gene is called

A) heterozogosity.
B) homozygosity.
C) segregation.
D) pleiotropy.
E) co-dominance.

Question 66

An individual with a genotype of Aa Bb CC is able to produce how many different kinds of gametes?

A) 2
B) 3
C) 4
D) 7
E) 8

Question 67

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . If a red, spotted male was crossed with a black, solid female and all the offspring from several crosses expressed only the dominant traits, the genotype of the female would be

A) BB SS .
B) Bb SS .
C) Bb Ss .
D) BB Ss .
E) none of these.

Question 68

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . If Bb Ss were crossed with Bb ss , the chance that a black, solid individual would be produced is

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

Question 69

ABO blood types are controlled by

A) single genes.
B) multiple alleles.
C) incomplete dominance.
D) codominance.
E) both multiple alleles and codominance.

Question 70

Susan, a mother with type B blood, has a child with type O blood. She claims that Craig, who has type A blood, is the father. He claims that he cannot possibly be the father. Further blood tests ordered by the judge reveal that Craig is AA. The judge rules that

A) Susan is right and Craig must pay child support.
B) Craig is right and doesn't have to pay child support.
C) Susan cannot be the real mother of the child; there must have been an error made at the hospital.
D) it is impossible to reach a decision based on the limited data available.
E) none of these

Question 71

If a child has blood type AB, the parents

A) must both have different blood types.
B) must have blood types A and B, but not blood type AB.
C) must both have blood type AB.
D) can have any blood type.
E) can have different blood types, but neither can have blood type O.

Question 72

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . If two black, solid dogs were crossed several times and the total offspring were eighteen black, solid and five black, spotted puppies, the genotypes of the parents would most likely be

A) Bb Ss x Bb Ss .
B) Bb Ss x Bb SS .
C) BB Ss x Bb ss .
D) BB Ss x Bb Ss .
E) Bb ss x Bb SS .

Question 73

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . If two dihybrids (Bb Ss) were crossed, which would be produced?

A) black and spotted pure-breeding forms
B) black and solid pure-breeding forms
C) red and solid pure-breeding forms
D) red and spotted pure-breeding forms
E) all of these

Question 74

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . A cross of Bb Ss with bb ss would produce the phenotypic ratio

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

Question 75

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . If a red male was crossed with a black female to produce a red, spotted puppy, the genotypes of the parents (with male genotype first) would be

A) Bb Ss x Bb Ss .
B) bb Ss x Bb Ss .
C) bb ss x Bb Ss .
D) bb Ss x Bb ss .
E) Bb ss x Bb ss .

Question 76

The usual F ₂ phenotypic ratio of a dihybrid cross is

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

Question 77

The theory of independent assortment

A) cannot be demonstrated in a monohybrid cross.
B) is illustrated by the behavior of linked genes.
C) indicates that the expression of one gene is independent of the action of another gene.
D) states that alleles for the same characteristic separate during meiosis.
E) is negated by epistasis.

Question 78

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . If two dihybrids (Bb Ss) were crossed, the most common phenotype would be

A) black and solid.
B) black and spotted.
C) red and solid.
D) red and spotted.
E) none of these.

Question 79

Blood types (A, B, and O) are controlled by

A) sex-linked genes.
B) linked genes.
C) multiple genes.
D) multiple alleles.
E) single alleles.

Question 80

In cocker spaniels, black coat color (B) is dominant over red (b) , and solid color (S) is dominant over spotted (s) . If two dihybrids (Bb Ss) were crossed, what fraction of the black, solid offspring would be homozygous?

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