Genetics MCAS Review

Last updated almost 2 years ago

15 questions

1

Library

Genetics MCAS Review

Last updated almost 2 years ago

15 questions

1

Use the information below to answer #5 to 6

When exposed to bright sunlight, some people involuntarily sneeze. This reaction is known as a photic response. It is controlled by a single gene with two alleles, H and h. A man and a woman who sneeze when exposed to bright sunlight are both heterozygous for the photic response trait.ygo

1

Use the information below to answer #7 and 8

Corn kernels can be high in starch (starchy) or high in sugar (sweet). The allele for starchy kernels (H) is dominant to the allele for sweet kernels (h). Each kernel on an ear of corn represents an individual offspring. A particular ear of corn has 92 starchy kernels and 88 sweet kernels.

1

In cattle, the allele for no horns (P) is dominant to the allele for horns (p). The allele for cloven hooves (C) is dominant to the allele for mule feet (c). Cattle that are heterozygous for these traits are crossed. The Punnett square for this cross is shown below.

1

In fruit flies, the gene for eye color is on the X chromosome. The allele for red eyes is dominant to the allele for white eyes. A researcher crosses a heterozygous red-eyed female fly (XRXr) with a red-eyed male fly (XRY).Which of the following statements describes the expected outcome of the cross?

All the female and male offspring will have red eyes.

All the female and male offspring will have white eyes.

All the female offspring and half the male offspring will have red eyes

Half the female offspring and all the male offspring will have white eyes.

The feather color of Andalusian chickens is controlled by a single gene with two alleles. A cross between a true-breeding, white-feathered Andalusian hen and a true-breeding, black-feathered Andalusian rooster results in 100% blue-feathered Andalusian offspring. Which of the following describes the inheritance pattern for feather color in these chickens?

It is a polygenic pattern because more than two phenotypes are possible

It is a dominant-recessive pattern because both parents are true breeding.

It is a sex-linked pattern because the hen and the rooster have different feather colors.

It is a codominant pattern because the heterozygous offspring have a different phenotype than either parent.

Scientists studying human diseases often use animal models. For example, fruit flies have been used to study Alzheimer’s disease. Scientists insert certain human genes found in patients with Alzheimer’s disease into fruit flies and observe how these genes affect the fruit flies.Where must the human gene be inserted for a fruit fly to produce offspring with this gene?

in the sex cells of the fly

on several proteins in a fly cell

in the nervous system of the fly

on several chromosomes in a fly cell

Mice with the same parents can have different traits. Which of the following best explains how most of these differences occur?

Gametes join by binary fission.

Cells divide by asexual reproduction.

Genes assort independently during meiosis.

Spontaneous mutations occur during mitosis.

Use the information below to answer #5 to 6

When exposed to bright sunlight, some people involuntarily sneeze. This reaction is known as a photic response. It is controlled by a single gene with two alleles, H and h. A man and a woman who sneeze when exposed to bright sunlight are both heterozygous for the photic response trait.ygo

Use the information below to answer #7 and 8

Corn kernels can be high in starch (starchy) or high in sugar (sweet). The allele for starchy kernels (H) is dominant to the allele for sweet kernels (h). Each kernel on an ear of corn represents an individual offspring. A particular ear of corn has 92 starchy kernels and 88 sweet kernels.

1

Identify the genotypes for two corn plants that, when crossed, will produce plants with 100% starchy kernels.

In flowers, white petals (H) are dominant to yellow (h). A heterozygous white flower and a yellow flower are crossed. What percent of the offspring will be yellow?

In four o’clock plants, the allele for red flower color is incompletely dominant to the allele for white flower color. As a result, plants that are heterozygous for flower color have pink flowers. If two plants with pink flowers are crossed, what are the expected percentages of phenotypes in the offspring?

0% red, 100% pink, 0% white

25% red, 50% pink, 25% white

50% red, 0% pink, 50% white

50% red, 50% pink, 0% white

Fur color in some cats is partially determined by the TYR gene, which has four alleles (C, cb, cs, c). Expression trends for the TYR alleles are summarized in the table below.

A male cat with albino fur color is crossed with a female cat with Siamese fur color. Considering only the effect of the TYR gene, which of the following is expected to be observed in the offspring?

All of the offspring will be albino.

At least some of the offspring will be Siamese.

At least half of the offspring will be the typical color.

Half of the offspring will be Burmese and half will be albino.

In cattle, the allele for no horns (P) is dominant to the allele for horns (p). The allele for cloven hooves (C) is dominant to the allele for mule feet (c). Cattle that are heterozygous for these traits are crossed. The Punnett square for this cross is shown below.

1

Cattle normally have two separate toes on each foot. In a condition called mulefoot, a recessive allele causes the toes to fuse, resembling the foot of a mule.Two cattle, each with normal, separate toes, have a calf with mulefoot. What is the probability that the next calf born to these parent cattle will also have mulefoot?

0%

25%

75%

100%

In betta fish, alleles for color are incompletely dominant. Green fish have genotype GG, dark blue fish have genotype gg, and royal blue fish have genotype Gg.Two royal blue betta fish are crossed. What percentage of the offspring is expected to be green?

0%

25%

50%

75%

For a new liver cell to form, DNA replication is necessary because it ensures that the newly formed cell has which of the following?

two copies of the original cell’s DNA

an identical copy of the original cell’s DNA

a rearranged copy of the original cell’s DNA

only the best parts of the original cell’s DNA

In fruit flies, the gene for eye color is on the X chromosome. The allele for red eyes is dominant to the allele for white eyes. A researcher crosses a heterozygous red-eyed female fly (XRXr) with a red-eyed male fly (XRY).Which of the following statements describes the expected outcome of the cross?

All the female and male offspring will have red eyes.

All the female and male offspring will have white eyes.

All the female offspring and half the male offspring will have red eyes

Half the female offspring and all the male offspring will have white eyes.

The feather color of Andalusian chickens is controlled by a single gene with two alleles. A cross between a true-breeding, white-feathered Andalusian hen and a true-breeding, black-feathered Andalusian rooster results in 100% blue-feathered Andalusian offspring. Which of the following describes the inheritance pattern for feather color in these chickens?

It is a polygenic pattern because more than two phenotypes are possible

It is a dominant-recessive pattern because both parents are true breeding.

It is a sex-linked pattern because the hen and the rooster have different feather colors.

It is a codominant pattern because the heterozygous offspring have a different phenotype than either parent.

Scientists studying human diseases often use animal models. For example, fruit flies have been used to study Alzheimer’s disease. Scientists insert certain human genes found in patients with Alzheimer’s disease into fruit flies and observe how these genes affect the fruit flies.Where must the human gene be inserted for a fruit fly to produce offspring with this gene?

in the sex cells of the fly

on several proteins in a fly cell

in the nervous system of the fly

on several chromosomes in a fly cell

Mice with the same parents can have different traits. Which of the following best explains how most of these differences occur?

Gametes join by binary fission.

Cells divide by asexual reproduction.

Genes assort independently during meiosis.

Spontaneous mutations occur during mitosis.

Identify the most likely inheritance pattern for this trait

A. dominant-recessive

B. codominant

C. sex linked

D. polygenic

Draw a Punnett square using the allele symbols H and h to show the expected genotypes of the man and woman’s biological children. Identify all possible phenotypes of the offspring and their expected percentages.

A. 100% will involuntarily sneeze

B. 75% will involuntarily sneeze, 25% will not

C. 50% will involuntarily sneeze, 50% will not

D. 25% will involuntarily sneeze, 75% will not

E. 100% will not sneeze

What are the most likely genotypes of the parent corn plants that produced this particular ear of corn?

Identify the genotypes for two corn plants that, when crossed, will produce plants with 100% starchy kernels.

In flowers, white petals (H) are dominant to yellow (h). A heterozygous white flower and a yellow flower are crossed. What percent of the offspring will be yellow?

100%

75%

50%

25%

0%

In four o’clock plants, the allele for red flower color is incompletely dominant to the allele for white flower color. As a result, plants that are heterozygous for flower color have pink flowers. If two plants with pink flowers are crossed, what are the expected percentages of phenotypes in the offspring?

0% red, 100% pink, 0% white

25% red, 50% pink, 25% white

50% red, 0% pink, 50% white

50% red, 50% pink, 0% white

Fur color in some cats is partially determined by the TYR gene, which has four alleles (C, cb, cs, c). Expression trends for the TYR alleles are summarized in the table below.

A male cat with albino fur color is crossed with a female cat with Siamese fur color. Considering only the effect of the TYR gene, which of the following is expected to be observed in the offspring?

All of the offspring will be albino.

At least some of the offspring will be Siamese.

At least half of the offspring will be the typical color.

Half of the offspring will be Burmese and half will be albino.

What is the probability that an offspring will have the same phenotype as the parents?

A. 3/16

B. 9/16

C. 11/16

D. 13/16

Cattle normally have two separate toes on each foot. In a condition called mulefoot, a recessive allele causes the toes to fuse, resembling the foot of a mule.Two cattle, each with normal, separate toes, have a calf with mulefoot. What is the probability that the next calf born to these parent cattle will also have mulefoot?

0%

25%

75%

100%

In betta fish, alleles for color are incompletely dominant. Green fish have genotype GG, dark blue fish have genotype gg, and royal blue fish have genotype Gg.Two royal blue betta fish are crossed. What percentage of the offspring is expected to be green?

0%

25%

50%

75%

For a new liver cell to form, DNA replication is necessary because it ensures that the newly formed cell has which of the following?

two copies of the original cell’s DNA

an identical copy of the original cell’s DNA

a rearranged copy of the original cell’s DNA

only the best parts of the original cell’s DNA

Identify the most likely inheritance pattern for this trait 

A. dominant-recessive

B. codominant

C. sex linked

D. polygenic

Draw a Punnett square using the allele symbols H and h to show the expected genotypes of the man and woman’s biological children. Identify all possible phenotypes of the offspring and their expected percentages.

A. 100% will involuntarily sneeze

B. 75% will involuntarily sneeze, 25% will not

C. 50% will involuntarily sneeze, 50% will not

D. 25% will involuntarily sneeze, 75% will not

E. 100% will not sneeze

What are the most likely genotypes of the parent corn plants that produced this particular ear of corn?

A. HH x HH

B. HH x hh

C. Hh x Hh

D. Hh x hh

E. hh x hh

What is the probability that an offspring will have the same phenotype as the parents?

A. 3/16

B. 9/16

C. 11/16

D. 13/16