Biology Test Bank 10

Front 1

​A ________ trait is one that can be passed from one generation to another.

Back 1

Heritable

Front 2

​A ________ is a portion of DNA that resides at a particular locus or site on a chromosome and encodes a particular function.

Back 2

Gene

Front 3

​To determine the overall probability of independent events, ________ the probabilities of the individual events.

Back 3

Multiply

Front 4

​One particular allele of a gene may be defined as ________ or standard, because it is present in most individuals and gives rise to an expected trait, or phenotype.

Back 4

Multiply

Front 5

​Geneticists make use of ________ frequencies to map chromosomes, that is, to locate genetic loci on the chromosome.

Back 5

Recombinant

Front 6

A cross between two parents that differs by a single trait is a ________ cross.

Back 6

Monohybrid

Front 7

The physical appearance of a character is the ________, while the genetic constitution is the ________.

Back 7

Phenotype.

Genotype

Front 8

A cross between two parents that differs by two independent traits is a ________ cross.

Back 8

Dihybrid

Front 9

For genes that fail to independently assort, phenotypes that appear in combinations that are not present in either parent are ________.

Back 9

Recombinant

Front 10

Incomplete dominance occurs when

Back 10

​heterozygotes synthesize a reduced amount of an enzyme, producing an intermediate phenotype.

Front 11

Although the law of independent assortment is generally applicable, when two loci are on the same chromosome the phenotypes of the progeny sometimes do not fit the phenotypes predicted. This is due to

Back 11

Linkage

Front 12

When a given trait is the result of multigene action, one of the genes may mask the expression of one or all other genes. This phenomenon is termed

Back 12

Epistasis

Front 13

​Which of the following is not a characteristic that makes an organism suitable for genetic studies?

​A)​A small number of chromosomes

​B)​A short generation time

​C)​Ease of cultivation

​D)​The ability to control crosses

​E)​The availability of a variation for traits

Back 13

A)​A small number of chromosomes

Front 14

A key factor that allowed Mendel to interpret his breeding experiments was that

Back 14

​the varieties of peas he started with were "true-breeding."

pollination could be controlled.

Front 15

Crossing spherical-seeded pea plants with wrinkled-seeded pea plants resulted in progeny that all had spherical seeds. This indicates that the wrinkled-seed trait is?

Back 15

Recessive

Front 16

Which statement about the inheritance of color in schmoos is most likely to be correct?

​A)​Brown is dominant to white.

​B)​White is dominant to brown.

​C)​White and brown are codominant.

​D)​a and c

​E)​You cannot reach any conclusions.

Back 16

A). Brown is dominant to white

Front 17

Which statement about the inheritance of footedness in schmoos is most likely to be correct?

​A)​Big is dominant to small.

​B)​Small is dominant to big.

​C)​Big and small are codominant.

​D)​a and c

​E)​You cannot reach any conclusions.

Back 17

E) You cannot reach any conclusions.

Front 18

If big feet (B) in schmoos is dominant to small feet (b), what is the genotype of the big-footed white parent schmoo with respect to the foot gene?

Back 18

Big B little b (Bb)

Front 19

When reciprocal crosses produce identical results, the trait is

Back 19

Not sex linked

Front 20

The region of the chromosome occupied by a gene is called a ________.

Back 20

Locus

Front 21

The physical appearance of a characteristic is called?

Back 21

The phenotype

Front 22

Different forms of a gene are called

Back 22

Alleles

Front 23

When genes for two different characters degrade in a cross, what type of a cross is it?

Back 23

Dihybrid

Front 24

In Mendel's experiments, if the allele for tall (T) plants was incompletely dominant over the allele for short (t) plants, what would be the result of crossing two Tt plants?

Back 24

1/4 would be tall; 1/2 intermediate height; 1/4 short.

Front 25

The region of the chromosome occupied by a gene is called an?

Back 25

Locus

Front 26

In Mendel's experiments, the spherical seed character (SS) is completely dominant over the wrinkled seed character (ss). If the characters for height were incompletely dominant, such that TT are tall, Tt are intermediate, and tt are short, what would be the result of crossing a spherical-seeded, short (SStt) plant to a wrinkled-seeded, tall (ssTT) plant?

Back 26

All the progeny would be smooth-seeded and intermediate light.

Front 27

If Mendel's crosses between spherical-seeded tall plants and wrinkled-seeded short plants had produced many more than 1/16 wrinkled-seeded short plants in the F2 generation, he might have concluded that

Back 27

The spherical seed and talk traits are linked

Front 28

At a certain locus of the human genome, it is found that 200 different alleles exist in the population. Each person would have at the most __________ alleles.

Back 28

2

Front 29

​An organism that produces either male gametes or female gametes, but not both, is called

Back 29

Dioecious

Front 30

Why would you predict that half of the human babies born will be males and half will be females?

Back 30

Because of the segregation of the X and Y chromosomes during male meiosis

Front 31

When a cross is made and a trait disappears in the F1 generation, only to reappear in the F2, the trait is probably ________.

Back 31

Recessive

Front 32

​A human male carrying an allele for a trait on the X chromosome is

Back 32

Hemizygous

Front 33

Cleft chin is a sex-linked dominant trait. A man with a cleft chin marries a woman with a round chin. What proportion of their female progeny will show the trait?

Back 33

100%

Front 34

​What proportion of their male progeny will show the trait?

Back 34

50%

Front 35

A linkage group corresponds to?

Back 35

The group of genes on the same chromosome

Front 36

It would have been very difficult for Mendel to draw conclusions about the patterns of inheritance if he had used cattle instead of peas. Why?

Back 36

Cattle have small numbers of offspring.

Front 37

Epistasis refers to?

Back 37

The expression of one gene masking the expression of another

Front 38

An agouti mouse that is heterozygous at the agouti and albino loci (AaBb) is mated to an albino mouse that is heterozygous at the agouti locus (aaBb). (Non-albino mice without the dominant agouti allele are black.)

What proportion of the progeny do you expect to be albino?

Back 38

37.5%

Front 39

What proportion of the progeny do you expect to be agouti?

Back 39

50%

Front 40

​What proportion of the progeny do you expect to be black? Black is the alternate phenotype to agouti.

Back 40

12.5%

Front 41

The complete phenotype of an organism is dependent on

​A)​genotype.

​B)​penetrance.

​C)​expressivity.

​D)​polygenes.

​E)​All of the above

Back 41

E) All of the above

Front 42

​A female who is heterozygous for a recessive, sex-linked character is a ________.

Back 42

Carrier

Front 43

​When a dihybrid black, straight-winged fly is crossed to a double-recessive brown, curly-winged fly, the frequency at which black curly-winged and brown straight-winged flies are seen in the progeny is called the

Back 43

Recombinant frequency

Front 44

When the expression of one gene depends on the expression of another gene, the genes demonstrate ________.

Back 44

Epistasis

Front 45

​When many genes contribute to the phenotype, variation is said to be ________.

Back 45

Continuous

Front 46

A ________ is a feature, such as flower color; a ________ is a particular form of a character, such as a white flower.

Back 46

Character.

Trait

Front 47

Gregor Mendel presented his genetics project orally in

Back 47

1865

Front 48

​Mendel concluded that each pea has two units for each character, and each gamete contains one unit. Mendel's "unit" is now referred to as a(n)

Back 48

Gene

Front 49

A particular genetic cross in which the individual in question is crossed with an individual known to be homozygous for a recessive trait is referred to as a

Back 49

Test cross

Front 50

For genes that fail to independently assort, phenotypes that appear in combinations that are not present in either parent are ________.

Back 50

Recombinant

Front 51

Incomplete dominance occurs when

Back 51

​heterozygotes synthesize a reduced amount of an enzyme, producing an intermediate phenotype.

Front 52

Although the law of independent assortment is generally applicable, when two loci are on the same chromosome the phenotypes of the progeny sometimes do not fit the phenotypes predicted. This is due to

Back 52

Linkage

Front 53

When a given trait is the result of multigene action, one of the genes may mask the expression of one or all other genes. This phenomenon is termed

Back 53

Epistasis

Front 54

​Which of the following is not a characteristic that makes an organism suitable for genetic studies?

​A)​A small number of chromosomes

​B)​A short generation time

​C)​Ease of cultivation

​D)​The ability to control crosses

​E)​The availability of a variation for traits

Back 54

A)​A small number of chromosomes

Front 55

A key factor that allowed Mendel to interpret his breeding experiments was that

Back 55

​the varieties of peas he started with were "true-breeding."

pollination could be controlled.

Front 56

Crossing spherical-seeded pea plants with wrinkled-seeded pea plants resulted in progeny that all had spherical seeds. This indicates that the wrinkled-seed trait is?

Back 56

Recessive

Front 57

Which statement about the inheritance of color in schmoos is most likely to be correct?

​A)​Brown is dominant to white.

​B)​White is dominant to brown.

​C)​White and brown are codominant.

​D)​a and c

​E)​You cannot reach any conclusions.

Back 57

A). Brown is dominant to white

Front 58

Which statement about the inheritance of footedness in schmoos is most likely to be correct?

​A)​Big is dominant to small.

​B)​Small is dominant to big.

​C)​Big and small are codominant.

​D)​a and c

​E)​You cannot reach any conclusions.

Back 58

E) You cannot reach any conclusions.

Front 59

If big feet (B) in schmoos is dominant to small feet (b), what is the genotype of the big-footed white parent schmoo with respect to the foot gene?

Back 59

Big B little b (Bb)

Front 60

When reciprocal crosses produce identical results, the trait is

Back 60

Not sex linked

Front 61

The region of the chromosome occupied by a gene is called a ________.

Back 61

Locus

Front 62

The physical appearance of a characteristic is called?

Back 62

The phenotype

Front 63

Different forms of a gene are called

Back 63

Alleles

Front 64

When genes for two different characters degrade in a cross, what type of a cross is it?

Back 64

Dihybrid

Front 65

In Mendel's experiments, if the allele for tall (T) plants was incompletely dominant over the allele for short (t) plants, what would be the result of crossing two Tt plants?

Back 65

1/4 would be tall; 1/2 intermediate height; 1/4 short.

Front 66

The region of the chromosome occupied by a gene is called an?

Back 66

Locus

Front 67

In Mendel's experiments, the spherical seed character (SS) is completely dominant over the wrinkled seed character (ss). If the characters for height were incompletely dominant, such that TT are tall, Tt are intermediate, and tt are short, what would be the result of crossing a spherical-seeded, short (SStt) plant to a wrinkled-seeded, tall (ssTT) plant?

Back 67

All the progeny would be smooth-seeded and intermediate light.

Front 68

If Mendel's crosses between spherical-seeded tall plants and wrinkled-seeded short plants had produced many more than 1/16 wrinkled-seeded short plants in the F2 generation, he might have concluded that

Back 68

The spherical seed and talk traits are linked

Front 69

At a certain locus of the human genome, it is found that 200 different alleles exist in the population. Each person would have at the most __________ alleles.

Back 69

2

Front 70

​An organism that produces either male gametes or female gametes, but not both, is called

Back 70

Dioecious

Front 71

Why would you predict that half of the human babies born will be males and half will be females?

Back 71

Because of the segregation of the X and Y chromosomes during male meiosis

Front 72

When a cross is made and a trait disappears in the F1 generation, only to reappear in the F2, the trait is probably ________.

Back 72

Recessive

Front 73

​A human male carrying an allele for a trait on the X chromosome is

Back 73

Hemizygous

Front 74

Cleft chin is a sex-linked dominant trait. A man with a cleft chin marries a woman with a round chin. What proportion of their female progeny will show the trait?

Back 74

100%

Front 75

​What proportion of their male progeny will show the trait?

Back 75

50%

Front 76

A linkage group corresponds to?

Back 76

The group of genes on the same chromosome

Front 77

It would have been very difficult for Mendel to draw conclusions about the patterns of inheritance if he had used cattle instead of peas. Why?

Back 77

Cattle have small numbers of offspring.

Front 78

Epistasis refers to?

Back 78

The expression of one gene masking the expression of another

Front 79

An agouti mouse that is heterozygous at the agouti and albino loci (AaBb) is mated to an albino mouse that is heterozygous at the agouti locus (aaBb). (Non-albino mice without the dominant agouti allele are black.)

What proportion of the progeny do you expect to be albino?

Back 79

37.5%

Front 80

What proportion of the progeny do you expect to be agouti?

Back 80

50%

Front 81

​What proportion of the progeny do you expect to be black? Black is the alternate phenotype to agouti.

Back 81

12.5%

Front 82

The complete phenotype of an organism is dependent on

​A)​genotype.

​B)​penetrance.

​C)​expressivity.

​D)​polygenes.

​E)​All of the above

Back 82

E) All of the above

Front 83

​A female who is heterozygous for a recessive, sex-linked character is a ________.

Back 83

Carrier

Front 84

​When a dihybrid black, straight-winged fly is crossed to a double-recessive brown, curly-winged fly, the frequency at which black curly-winged and brown straight-winged flies are seen in the progeny is called the

Back 84

Recombinant frequency

Front 85

Alleles for genes located on mitochondrial DNA are said to be maternally inherited. What is the reason for this pattern of inheritance?

Back 85

The egg contributions virtually all of the cytoplasmic organelles to the zygote.

Front 86

When the expression of one gene depends on the expression of another gene, the genes demonstrate ________.

Back 86

Epistasis

Front 87

​When many genes contribute to the phenotype, variation is said to be ________.

Back 87

Continuous

Front 88

A ________ is a feature, such as flower color; a ________ is a particular form of a character, such as a white flower.

Back 88

Character.

Trait

Front 89

Gregor Mendel presented his genetics project orally in

Back 89

1865

Front 90

​Mendel concluded that each pea has two units for each character, and each gamete contains one unit. Mendel's "unit" is now referred to as a(n)

Back 90

Gene

Front 91

A particular genetic cross in which the individual in question is crossed with an individual known to be homozygous for a recessive trait is referred to as a

Back 91

Test cross

Front 92

​52.​Which of the following methods was not used by Mendel in his study of the genetics of the garden pea?

Back 92

Microscopy

Front 93

​In Kˆlreuter's studies, reciprocal crosses

Back 93

Always have identical results

Front 94

​Which of the following statements about Mendelian genetics is false?

​A)​Alternate forms of genes are called alleles.

​B)​A locus is a gene's location on its chromosome.

​C)​Only two alleles can exist for a given gene.

​D)​A genotype is a description of the alleles that represent an individual's genes.

​E)​Individuals with the same phenotype can have different genotypes.

Back 94

​C)​Only two alleles can exist for a given gene.

Front 95

Segregation of alleles occurs

Back 95

During gamete formation

Front 96

A pea plant with red flowers is test crossed, and one half of the resulting progeny have red flowers, while the other half have white flowers. You know that the genotype of the test-crossed parent was

Back 96

Big R little r (Rr)

Front 97

​61.​Which of the following phenomena cannot be observed using only dihybrid crosses?

​A)​Crossing over

​B)​Segregation of alleles

​C)​Independent assortment of alleles

​D)​Recessive lethal alleles

​E)​None of the above

Back 97

E) None of the above

Front 98

​62.​Separation of the alleles of a single gene into different gametes is called

Back 98

Segregation

Front 99

​63.​In mice, short hair is dominant to long hair. If a short-hair individual is crossed with a long-hair individual and both long- and short-hair offspring result, you can conclude that

Back 99

The short-hair individual was heterozygous.