Unit 4 EOC Prep Test

The Punnett square shows the possible allele combinations that result from a two-factor cross between pea plants. Both pea plants are heterozygous for seed shape (round, R, and wrinkled, r) and pod color (green, Y, and yellow, y).

Which of the following conclusions can be reached about the offspring of this cross?

• Half of the offspring will produce round seeds and half will produce wrinkled seeds, and half of the offspring will have green pods and half will have yellow pods because of random assortment of alleles.

• All of the plants will produce round seeds with green pods, because these are the dominant traits.

• For a large number of offspring, there should be a ratio close to 9:3:3:1 of round-seed plants with green pods, wrinkled-seed plants with green pods, round-seed plants with yellow pods, wrinkled-seed plants with yellow pods, because this is the expected ratio with independent assortment of dominant and recessive alleles.

• The offspring will consist of 9 round-seed plants with green pods, 3 wrinkled-seed plants with green pods, 3 round-seed plants with yellow pods, and 1 wrinkled-seed plant with yellow pods, because this is the expected result with independent assortment of dominant and recessive alleles.

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NGSS.HS-LS3-1

A pea plant that has only dominant alleles for two traits, AB, is crossed with a pea plant that has only the recessive alleles, ab, for the same traits. Which outcome of the F₂ cross shows that the traits A and B sort independently?

• All 4 possible genotypes are produced in a ratio of approximately 9:3:3:1.

• Both of 2 possible genotypes are produced in a ratio of approximately 3:1.

• All 4 possible genotypes are produced in a ratio of approximately 1:1:1:1.

• Both of 2 possible genotypes are produced in a ratio of approximately 1:1.

When crossing pea plants with contrasting traits, Mendel found that some characteristics that seemed to disappear in the F₁ generation reappeared in the F₂ generation. What did Mendel conclude from this result?

• Different characteristics arise and disappear spontaneously from mutations during gamete formation.

• The characteristics show incomplete dominance.

• The forms of a trait, or alleles, segregate during the reproductive process.

• The alleles for the trait must be on different chromosomes.

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NGSS.HS-LS3-1

Mendel established several principles of heredity from his experiments and observations. What did he conclude regarding the inheritance of genes from parents?

• Offspring inherit two copies of each gene from the dominant parent.

• Offspring inherit one copy of each gene, and some genes are inherited from one parent and some from the other parent.

• Offspring inherit two copies of each gene, one from each parent.

• Offspring inherit one copy of each different allele that exists for a gene.

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NGSS.HS-LS3-1

A red-flowered plant is crossed with a white-flowered plant, and the resulting offspring have pink flowers. What is the best explanation for this pattern of inheritance?

• This is incomplete dominance, where every other flower cell expresses the white allele and the remaining flower cells express the red allele, which gives the appearance of a pink plant.

• This is incomplete dominance, where both alleles are expressed at the same time, giving an intermediate phenotype.

• This is codominance, where every other flower cell expresses the white allele and the remaining flower cells express the red allele, which gives the appearance of a pink plant.

• This is codominance, where both alleles are expressed at the same time, giving an intermediate phenotype.

Leaf color in a morning glory is always the same as the maternal parent plant. What mechanism of inheritance does this pattern represent?

• maternal inheritance through asexual reproduction

• simple dominance, as the maternal plants always pass on the dominant allele for leaf color

• maternal inheritance of chloroplast genes for leaf color

• genetic imprinting of the gene for leaf color

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NGSS.HS-LS3-1

During prophase I of meiosis, the homologous chromosomes pair up to form tetrads. What are two outcomes of this pairing that increase genetic variation?

• The homologous chromosomes exchange genetic material in a process called crossing-over, and the DNA is replicated, introducing new mutations.

• The homologous chromosomes exchange genetic material in a process called gene linkage, and the DNA is replicated, introducing new mutations.

• The homologous chromosomes exchange genetic material in a process called gene linkage, and the homologous chromosomes are separated into the daughter cells, forming new combinations of chromosomes.

• The homologous chromosomes exchange genetic material in a process called crossing-over, and the homologous chromosomes are assorted into the daughter cells, forming new combinations of chromosomes.

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NGSS.HS-LS3-2

The gene map shows some of the genes on chromosome 2 of the fruit fly Drosophila melanogaster.

Which pair of traits is most likely to assort independently?

• Curved wing and bent wing, as wings cannot be both curved and bent.

• Purple eye and light eye, as they are closest together and crossovers between them will be rare.

• Dachs (short legs) and brown eye, as they affect different parts of the body and so crossovers between them are more likely.

• Aristaless and speck body, as they are furthest apart and crossovers between them are more likely.

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In an experiment, viruses were marked with radioactive DNA labeled with phosphorus-32, as shown on the left, or with radioactive protein, which was labeled with sulfur-35, shown on the right. After the viruses infected bacteria, radiation was found inside only the bacteria that had been infected by the virus that had radioactive DNA.

What is the experiment called, and what is its significance?

• The Hershey-Chase experiment showed that the radioactive DNA is found inside the infected bacteria; therefore, DNA is the molecule that carries genetic information.

• The Hershey-Chase experiment showed that viruses with either radioactive DNA or radioactive protein can infect bacteria; therefore, both types of molecules can carry genetic information.

• The Franklin X-ray experiment showed that radioactive DNA forms a helical structure inside the infected bacteria; therefore, DNA is the molecule that carries genetic information.

• The Franklin X-ray experiment showed that either radioactive DNA or radioactive protein can form a helical structure inside the infected bacteria; therefore, both types of molecules can carry genetic information.

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What question was addressed by the experiments of Oswald Avery, which used heat-killed bacteria and bacterial extracts treated with enzymes?

• Is heat-killing or enzyme treatment more effective at preventing bacterial infections?

• Is heat-killing or enzyme treatment more effective at causing genetic mutations?

• Are proteins, lipids, carbohydrates, RNA, or DNA useful for preventing bacterial transformation?

• Are proteins, lipids, carbohydrates, RNA, or DNA responsible for causing bacterial transformation?

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NGSS.HS-LS1-1