BIO 101 Exam 4

Gregor Mendel concluded that each pea has two units for each trait, and each gamete contains one unit. Mendel's "units" are now called?

• genes

• chromosomes

• characters

• transcription factors

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

A recessive allele is one

• that produces no effect when present in the homozygous condition

• that is not expressed as strongly as a dominant allele

• that appears only in a heterozygote

• whose effect is masked by a dominant allele

Which of the following statements about genotypes and phenotypes are true?

• Matings between individuals with recessive phenotypes produce offspring with dominant phenotypes.

• Individuals with the same phenotype may have different genotypes.

• Individuals ith the same genotype may have different phenotypes.

• Matings between individuals with dominant phenotypes cannot produce offspring with recessive phenotypes.

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

A pea plant with red flowers is test crossed; half of the resulting progeny have red flowers, whereas the other half have white flowers. The genotype of the test crossed parent was

• rr

• RR

• either RR or Rr

• Rr

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NGSS.HS-LS3-1

All of the following combinations are possible in the gametes of an organism that is AaBb except

• aa

• ab

• AB

• Ab

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NGSS.HS-LS3-2

Imagine that a newly discovered species of fish normally has three eyes (E), but the rare mutation (e) causes "diopthalmic" fish with two eyes to be born. In addition, eye color in these fish is inherited similarly to humans, with black eyes (B) being dominant to blue (b). Assuming these two generes are carried on separate chromosomes, what must the genotypes of two black-eyed parents be if they have a blue-eyed, diopthmalmic son?

• Both eebb

• EEBB and eebb

• Both EeBb

• eeBB and EEbb

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

Suppose you cross a pea plant with yellow, smooth seeds with one that has wrinkled, green seeds. You examine the seeds of 967 offspring and find that some have yellow, smooth seeds and some have yellow, wrinkled seeds, but no green seeds of either type show up. What is the genotype of the yellow-seeded parent?

• YYss

• YYSs

• YYSS

• YySS

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

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

• inversions

• chromosome exchange

• linkage

• chromatid abnormalities

Hemophilia is a sex-linked recessive gene that causes a blood disorder. What are the chances that the daughter of a normal man and a heterozygous woman will have hemophilia?

• 75%

• 0%

• 100%

• 25%

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NGSS.HS-LS3-1

NGSS.HS-LS3-3

Co-dominance occurs when

• expression of two different alleles alternates from one generation to the next

• a heterozygote expresses an intermediate phenotype

• offspring exhibit several different phenotypic expressions of a single trait

• both of the alleles in a heterozygote are expressed phenotypically in an individual