Question 1

Marly describes her friend, Gina, as having blonde hair, green eyes, and fair skin with freckles. Marly has described Gina's _____.

Accepted Answer

Marly has described Gina's observable traits, known as her phenotype. Options A, B, and D refer to genetic factors and inheritance, which are not indicated in Marly's description of Gina's physical appearance.

Question 2

Tristan has a genetic disorder that results from an abnormality in the X chromosome, which becomes constricted and often breaks. His doctor told Tristan's mother that he has:

Accepted Answer

Fragile X syndrome is a genetic disorder that results from the abnormality in the X chromosome. It is characterized by a constriction in the X chromosome, which often breaks or becomes fragile, leading to developmental delays, intellectual disability, and other physical and behavioral symptoms. XYY syndrome is a genetic condition where males have an extra Y chromosome, which can result in physical and behavioral differences. Turner syndrome is a genetic disorder that affects females, where one X chromosome is missing or partially missing, leading to physical and developmental differences. Tay-Sach's disease is a genetic disorder that affects the nervous system and results in progressive deterioration of mental and physical abilities. It is caused by the absence or deficiency of an enzyme that breaks down a fatty substance in the brain. It is not related to abnormalities in the X chromosome.

Question 3

Mary and Jim are expecting a child and prenatal diagnostic procedures have confirmed that the fetus has _____, a neural tube disorder that causes brain and spine abnormalities. Their physician has explained that this gene-linked abnormality could be treated with corrective surgery at birth, orthopedic devices, and physical or medical therapy.

Accepted Answer

Spina bifida is a neural tube disorder that can cause brain and spine abnormalities, and can be treated with corrective surgery at birth, orthopedic devices, and physical or medical therapy. Tay-Sachs disease, PKU, and Huntington's disease are not neural tube disorders and do not involve brain and spine abnormalities.

Question 4

Jason was born with _____. The doctor tells his parents that this genetic disorder occurred because he has an extra copy of chromosome 21.

Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21. Fragile X syndrome, Klinefelter disease, and Tay Sach's disease are all caused by different genetic mutations.

Question 5

Which of the following is true of phenylketonuria?

Accepted Answer

Phenylketonuria (PKU) is an inherited disorder caused by a mutation in the gene responsible for making the enzyme phenylalanine hydroxylase. It follows an autosomal recessive inheritance pattern, meaning that an individual needs to inherit the mutated gene from both parents to develop the disorder. PKU is not a chromosomal disorder, nor does it cause death by 5 years of age. Additionally, it is not caused by an accumulation of lipids in the nervous system, but rather by an inability to metabolize the amino acid phenylalanine properly.

Question 6

Which of the following is a gene-linked abnormality?

Accepted Answer

Phenylketonuria (PKU) is caused by a genetic abnormality where the body is unable to break down phenylalanine, an amino acid found in many proteins. This leads to a buildup of phenylalanine in the body, which can cause intellectual disability and other health problems. PKU is an example of a gene-linked abnormality because it is caused by a specific genetic mutation. Down syndrome, Turner syndrome, and Klinefelter syndrome are chromosomal abnormalities, which are different from gene-linked abnormalities.

Question 7

In some cases, one gene of a pair always exerts its effects, overriding the potential influence of the other gene. This is the _____ principle.

Accepted Answer

The dominant-recessive gene principle states that in some cases, one gene of a pair (the dominant gene) always exerts its effects, overriding the potential influence of the other gene (the recessive gene).

Question 8

Carrie's parents both have brown hair. However, Carrie gets genes for blond hair from both parents, and as result she has blonde hair. This indicates that the gene for blonde hair is a(n):

Accepted Answer

If both of Carrie's parents have brown hair, which is a dominant trait, but Carrie has blonde hair, which is a recessive trait, then the gene for blonde hair must be recessive. It is not dominant because it was not expressed in the phenotype of the parents, and it is not a susceptibility or longevity gene as these terms refer to genes related to health and disease, not physical appearance.

Question 9

Mary's mother has blonde hair and her father has brown hair. Mary has a gene for brown hair and a gene for blonde hair. She has brown hair. This indicates that the gene for brown hair is a(n) _____.

Accepted Answer

In this scenario, the gene for brown hair is expressed, while the gene for blonde hair is not. This suggests that the gene for brown hair is dominant over the gene for blonde hair, making it the best answer choice.

Question 10

Which of the following women has the highest probability of giving birth to a child with Down syndrome?

Accepted Answer

The probability of having a child with Down syndrome increases as a woman's age increases, especially after the age of 35. Jane, who is 41 years old, has a higher probability compared to the other women listed.

Question 11

Which of the following is true of Down syndrome?

Accepted Answer

Down syndrome is characterized by a range of physical and mental challenges, including delays in motor skills and cognitive abilities. It is not specific to any race, is not caused by genetic imprinting errors, and involves an extra copy of chromosome 21, not the Y chromosome.

Question 12

Angelique has a chromosomal disorder characterized by a missing X chromosome making her XO instead of XX. Angelique's doctors have diagnosed her with _____.

Accepted Answer

Turner syndrome is a genetic disorder that affects females who are born with only one fully functioning X chromosome, resulting in XO instead of XX. Fragile X syndrome is a genetic condition caused by a mutation in the FMR1 gene, which affects both males and females. The XYY syndrome is a genetic condition that affects males who have an extra Y chromosome, while Klinefelter syndrome affects males who have an extra X chromosome.

Question 13

Turner syndrome occurs exclusively in:

Accepted Answer

Turner syndrome, also known as monosomy X or 45,X, is a genetic condition that affects only females. It occurs when one of the X chromosomes is missing or partially missing, leading to a variety of physical and developmental problems. It is not limited to any specific ethnic or cultural group.

Question 14

Klinefelter syndrome affects:

Accepted Answer

Klinefelter syndrome is a genetic disorder that affects only males. It occurs when a male is born with an extra copy of the X chromosome, resulting in a total of 47 chromosomes instead of the usual 46. This can lead to physical and developmental differences, such as infertility, tall stature, and delayed puberty.

Question 15

A recessive gene exerts its influence only if:

Accepted Answer

A recessive gene only shows its effect when both genes in a pair are recessive. If one dominant gene is present in the pair, it will mask the effect of the recessive gene. The environment does not affect whether a gene is dominant or recessive. The concept of a "stronger" gene is incorrect as genes do not work in isolation and expression depends on the interaction of both genes in a pair.

Question 16

Paul suffers from hemophilia. Suggest an appropriate treatment option for Paul's condition.

Accepted Answer

Hemophilia is a genetic disorder in which the blood does not clot properly, resulting in excessive bleeding and bruising even with minor injuries. Blood transfusions or injections are an appropriate treatment option for hemophilia as they provide the missing clotting factor that is needed for blood to clot properly. Insulin is not a treatment option for hemophilia. Physical therapy may be helpful as a supportive treatment for joint pain and stiffness that can result from repeated bleeding into joints, but it does not address the underlying issue of clotting. Corrective surgery at birth is not relevant to treating hemophilia.

Question 17

Which of the following is an example of chromosomal abnormality that occurs when whole chromosomes do not separate properly during meiosis?

Accepted Answer

Down syndrome is an example of a chromosomal abnormality that occurs when whole chromosomes do not separate properly during meiosis. Specifically, individuals with Down syndrome have an extra copy of chromosome 21, resulting in a total of 47 chromosomes instead of the usual 46.

Question 18

Samantha has been diagnosed with _____, which is a glandular dysfunction that interferes with mucus production.

Accepted Answer

Cystic fibrosis is a genetic disorder that affects the production of mucus, sweat, and digestive juices. It is caused by a dysfunction of the exocrine glands, especially those that produce mucus.

Question 19

Clark's genotype contains a dominant gene for brown eye color and recessive gene for blue eye color. According to the dominant-recessive gene principle, which of the following phenotypes is most likely to be observed in Clark?

Accepted Answer

According to the dominant-recessive gene principle, if Clark's genotype contains a dominant gene for brown eye color and a recessive gene for blue eye color, the most likely phenotype to be observed in Clark is brown eyes.

Question 20

Tamera has a genetic disorder where her red blood cells take on a hook shape instead of the normal disk shape. The doctors tell Tamera's parents that she has _____, and that this condition also provides her with a resistance to malaria.

Accepted Answer

Tamera has sickle-cell anemia, which is characterized by the abnormal shape of red blood cells. This condition also provides a degree of resistance to malaria. Tay-Sach's disease, leukemia, and Huntington's disease are genetic disorders that affect different parts of the body and do not involve red blood cells.

Quiz 2: Biological Beginnings