Unit 7 Exam - Genetics

Two heterozygous tall plants (Tt) are crossed. What are the expected genotypes and percentages of this cross?

• TT 50%; Tt 50%

• TT 25%; tt 75%

• Tt 25%; TT 50%; tt 25%

• TT 25%; Tt 50%; tt 25%

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NGSS.HS-LS3-1

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student is predicting whether the seeds of pea plants produced by the cross shown in the Punnett square will be wrinkled or round. Round (R) seeds are dominant, and wrinkled (r) seeds are recessive.

This cross will produce what percentage of offspring?

• 100% round, 0% wrinkled

• 75% round, 25% wrinkled

• 50% round, 50% wrinkled

• 25% round, 75% wrinkled

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NGSS.HS-LS3-1

A dog that is homozygous recessive for a dwarf allele (dd) is mated with a dog that is homozygous dominant (DD-normal size). What will be the phenotype of the offspring?

• 50% dominant and 50% recessive

• 75% dominant and 25% recessive

• 100% recessive

• 100% dominant

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which genotypes are possible from two heterozygous parents?

• 100% heterozygous

• 100% homozygous dominant

• 50% homozygous dominant, 50% homozygous recessive

• 25% homozygous dominant, 50% heterozygous, 25% homozygous

  recessive

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Which genotype is best matched to its description?

• tt — recessive hybrid

• tT — homozygous

• Tt — heterozygous

• TT — dominant hybrid

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Which best explains why a trait visible in one generation skips the next generation and reappears in the third generation?

• The trait is caused by a dominant allele.

• The trait is caused by a recessive allele.

• A mutation occurs in the third generation.

• A mutation occurs in the second generation.

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Which best describes a Punnett square that is used to make predictions about one trait?

• dihybrid

• monohybrid

• pedigree chart

• independent assortment

Which is a homozygous genotype?

• T

• t

• TT

• Tt

Which is a heterozygous genotype?

• B

• b

• BB

• Bb

When crossing a tan mouse with a white mouse; tan is a dominant fur color. Which genotype is heterozygous?

• tt

• Tt

• TT

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NGSS.HS-LS3-1

NGSS.HS-LS3-2