Genetics Unit Review

In peas, yellow seed color (Y) is dominant to green seed color (y). Which describes an organism that has nonidentical alleles for seed color?

• yy and has green seeds

• Yy and has yellow seeds

• YY and has yellow seeds

• Yy and has green seeds

A purebred plant that has yellow flowers is crossed with a purebred plant that has white flowers. All the offspring have yellow flowers. Which conclusion about yellow flowers is supported by these results?

• Yellow flower color is a dominant trait.

• Yellow flower color is a recessive trait.

• Yellow flower color is a heterozygous trait.

• Yellow flower color is a monohybrid trait.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Round seeds and yellow seed color are dominant to wrinkled seeds and green seed color. What is the probability of having offspring that have wrinkled seeds and yellow seed color for the cross RRYY x RrYy?

• 0%

• 25%

• 50%

• 100%

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NGSS.MS-LS3-2

In peas, yellow seed color (Y) is dominant to green seed color (y). A homozygous green pea plant is crossed with a heterozygous yellow pea plant. What is the predicted phenotypic ratio of the offspring?

• 50 percent yellow, 50 percent green

• 50 percent Yy, 50 percent yy

• 100 percent yellow, 0 percent green

• 100 percent Yy, 0 percent yy

Gregor Mendel used pea plants that were heterozygous for each of two traits—seed color and seed shape—to generate a dihybrid cross. The phenotypic ratio of the resulting offspring was nine with round and yellow seeds, three with round and green seeds, three with wrinkled and yellow seeds, and one with wrinkled and green seeds. From these results, what could Mendel conclude?

• Traits are inherited as pairs, sets, or groups.

• Traits that are dominant mask traits that are recessive.

• Gametes carry one allele for each trait.

• Traits are passed independently of one another.

In a dihybrid cross for round and yellow seeds (RrYy x RrYy), what is the probability of having green and wrinkled seeds?

• 1:16

• 3:16

• 8:16

• 9:16

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NGSS.HS-LS3-2

NGSS.HS-LS3-3

Which of Mendel’s generations was allowed to self-pollinate?

• F₁ generation

• P generation

• F₁ generation and F₂ generation

• P generation and F₂ generation

A scientist is studying fruit fly wings. Straight wings are dominant, and curly wings are recessive. Which statement correctly describes the F₁ generation if a straight-winged parent is crossed with a curly-winged parent and if both parents are true breeding?

• The offspring will have two genes for straight wings.

• The offspring will produce only gametes that have genes for curly wings.

• The offspring will have one allele for straight wings and one allele for curly wings.

• The offspring will have only one kind of allele for the gene that determines wing type.

A pea plant exhibits a recessive trait. Which statement is most likely true about the plant?

• The plant is identical to its parent plant.

• The plant has different alleles for the gene that codes for the trait.

• The plant has two identical alleles for the gene that codes for the trait.

• The plant does not have the same genes for the trait as its parent plant.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

In the F₂ generation of Mendel’s crosses,

• all plants had the dominant trait.

• half of the plants had the dominant allele.

• all plants had both the dominant and recessive alleles.

• one in four plants had two alleles for the recessive trait.