Question 1

In a certain species of flowering plant, the allele for purple flowers

P

is completely dominant over the allele for white flowers

p

. If a heterozygous plant is crossed with a homozygous recessive plant, what is the predicted ratio of phenotypes in the

F_1

generation?

Accepted Answer

1 purple : 1 white

Answer

1 purple : 3 white

Answer

3 purple : 1 white

Answer

All purple

Question 2

In humans, the ability to roll the tongue is an autosomal dominant trait

P

, while the inability to roll the tongue is recessive

p

. Two individuals who are both heterozygous for tongue rolling have a child. What is the probability that their child will be a non-roller?

Accepted Answer

25%

Answer

50%

Answer

0%

Answer

75%

Question 3

In pea plants, tall stems

P

are dominant to short stems

p

. If a researcher crosses two plants and observes that approximately 50% of the offspring are tall and 50% are short, what are the most likely genotypes of the parent plants?

Accepted Answer

Answer

Answer

Answer

Question 4

In a cross between a pea plant that is true-breeding for round seeds

P

and a pea plant that is true-breeding for wrinkled seeds

p

, the

F_1

generation is allowed to self-pollinate. What percentage of the

F_2

generation is expected to be homozygous for the round seed trait?

Accepted Answer

25%

Answer

50%

Answer

100%

Answer

75%

Question 5

In a specific breed of guinea pig, black coat color

P

is dominant to white coat color

p

. A breeder crosses a black guinea pig of unknown genotype with a white guinea pig and observes that all 8 offspring in the first litter are black. What is the most likely genotype of the black parent, and what would be the result of crossing two of these

F_1

offspring?

Accepted Answer

Parent is

P

;

p

will be 75% black and 25% white

Answer

Parent is

P

;

p

will be 50% black and 50% white

Answer

Parent is

P

;

p

will be 75% black and 25% white

Answer

Parent is

P

;

p

will be 100% black

Question 6

In a species of fruit fly, the allele for long wings

P

is dominant over the allele for vestigial wings

p

. If a scientist performs a cross between two heterozygous fruit flies and produces 200 offspring, approximately how many offspring are expected to exhibit the dominant phenotype according to Mendelian inheritance?

Accepted Answer

150

Answer

50

Answer

100

Answer

200

Question 7

In a monohybrid cross between a homozygous dominant yellow-seeded pea plant

P

and a homozygous recessive green-seeded pea plant

p

, the

F_1

generation consists entirely of yellow-seeded plants. If one of these

F_2

plants is crossed with a green-seeded plant, what genotypic ratio is expected in the offspring?

Accepted Answer

1 Yy : 1 yy

Answer

3 Yy : 1 yy

Answer

1 YY : 2 Yy : 1 yy

Answer

All Yy

Question 8

In a monohybrid cross, a breeder observes that a cross between two individuals with the dominant phenotype produces some offspring with the recessive phenotype. If the total number of offspring is 120, what is the expected number of offspring that will be homozygous dominant for this trait?

Accepted Answer

30

Answer

40

Answer

90

Answer

60

Question 9

In a monohybrid cross, a scientist crosses a true-breeding plant with axial flowers

P

and a true-breeding plant with terminal flowers

p

. If two individuals from the

F_1

generation are crossed, what is the probability that an offspring will be heterozygous for the trait?

Accepted Answer

50%

Answer

25%

Answer

100%

Answer

75%

Question 10

In a monohybrid cross, a breeder crosses two corn plants that both have the dominant phenotype of purple kernels

P

. If the resulting offspring consist of 758 purple-kerneled plants and 242 white-kerneled plants

p

, which of the following best describes the genotypes of the parent plants?

Accepted Answer

Both parents are

P

Answer

Both parents are

P

Answer

One parent is

P

and the other is

p

Answer

One parent is

P

and the other is

p

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