Question 1

Which of the following conditions is a sex-linked abnormality that can occur in both males and females?
A) Fragile X syndrome
B) Klinefelter's syndrome
C) Turner's syndrome
D) Down syndrome

Accepted Answer

Klinefelter's syndrome occurs only in males and Turner's syndrome occurs only in females. Down syndrome can occur in both males and females, but results from a variation on the 21st chromosome pair rather than on the 23rd chromosome pair (i.e., sex chromosomes).

Question 2

Which of the following sex-linked disorders occurs most frequently?
A) Klinefelter's syndrome
B) Turner's syndrome
C) hemophilia
D) color blindness

Accepted Answer

Color blindness is the most common sex-linked disorder, affecting approximately 1 in 12 men and 1 in 200 women. Klinefelter's syndrome and Turner's syndrome are chromosomal abnormalities, not specifically sex-linked disorders, and hemophilia is a rare bleeding disorder that is sex-linked but less common than color blindness.

Question 3

Andre is a hemophiliac, which means that he has problems with:
A) blood clotting
B) exocrine glands
C) amino acid metabolism
D) muscle control

Accepted Answer

Hemophilia A and B are disorders that interfere with normal blood clotting and occur at different loci on the X chromosome. Hemophilia A is usually accompanied by color blindness.

Question 4

At birth, Debbie was given a mandatory screening test and tested positive for a disorder that required her to be placed immediately on a restricted diet to control her symptoms. Which of the following is mostly likely the condition for which she is being treated?
A) sickle-cell anemia
B) Huntington's disease
C) cystic fibrosis
D) phenylketonuria

Accepted Answer

Phenylketonuria (PKU) is a disorder in which the body cannot break down an amino acid called phenylalanine. Without treatment, it can cause intellectual disability, seizures, and behavioral problems. Treatment involves a restricted diet low in phenylalanine. Screening for PKU is mandatory in the United States and many other countries.

Question 5

Melissa has a single X chromosome and no Y chromosome, an immature female appearance, and lacks internal reproductive organs. What is the most appropriate diagnosis of her condition?
A) Down syndrome
B) Turner's syndrome
C) Fragile X syndrome
D) Klinefelter's syndrome

Accepted Answer

Turner syndrome occurs in about 1 of 10,000 females. One of the X chromosomes is either missing or inactive. The characteristics of Turner syndrome match Melissa's: Individuals with Turner syndrome usually have an immature female appearance-they do not develop secondary sex characteristics. They also lack internal reproductive organs. These females may be abnormally short, and some are mentally retarded. The disorder is usually discovered at puberty, and hormone replacement therapy can help with a more normal appearance.

Question 6

Olaf has been diagnosed with Klinefelter's syndrome. What is his chromosomal pattern?
A) XO
B) XY
C) XXY
D) XYY

Accepted Answer

Klinefelter's syndrome can result from any of the following chromosomal patterns: XXY,XXXY,XXXXY

Question 7

The primary reason that sex-linked traits are observed more frequently in men than in women is that:
A) mutations are much more common in male offspring
B) male babies are weaker so are more likely to be spontaneously aborted if any developmental process is compromised
C) the Y chromosome is much smaller and has fewer genes than the X chromosome
D) women generally do not talk about sex-related behavior as much as do men

Accepted Answer

Sex-linked traits are, by definition, those that are determined by genes on the 23rd chromosome pair (the sex chromosomes). If a normally recessive allele appears on the male's X chromosome, there often is no allele on the Y chromosome to offset it, and the recessive trait will be expressed as the individual's phenotype. In contrast, in females, the recessive trait will be expressed only if it occurs on both X chromosomes. Because a trait will be expressed in males when two recessive alleles are inherited or when a recessive allele is inherited from the mother and no allele appears on the Y chromosome to offset it, sex-linked traits are more frequently observed in men than in women.

Question 8

Which of the following syndromes occurs only in females?
A) Down syndrome
B) Turner's syndrome
C) Klinefelter's syndrome
D) Fragile X syndrome

Accepted Answer

Both Down syndrome and Fragile X occur in both males and females. Klinefelter's syndrome appears in only males. Turner's syndrome appears in only females and occurs when one of the X chromosomes is missing or inactive.

Question 9

If Margaret (a woman) is becoming bald as the result of a genetic trait called pattern baldness, we would know that she inherited a _______ allele for this trait from her mother and a ___________ allele from her father:
A) dominant; recessive
B) recessive; dominant
C) dominant; dominant
D) recessive; recessive

Accepted Answer

Pattern baldness, which can include a receding hairline, loss of hair on the top of the head, or overall hair thinning, is a common example of a sex-linked disorder. Many men inherit the recessive allele and some display pattern baldness as early as in their teens. Many women carry the recessive allele as well, but a dominant allele on the other X chromosome prevents pattern baldness from being displayed. Unless a woman inherits a recessive allele from both parents, she is unlikely to display this genetic trait.

Question 10

What percent of babies born today in the United States are healthy and normal?
A) 60%
B) 73%
C) 87%
D) 97%

Accepted Answer

According to the Centers for Disease Control and Prevention (CDC), at least 97% of babies born in the United States are considered healthy and without any major complications. While there may be smaller health concerns or issues that need extra attention, the vast majority of newborns are born healthy and continue to grow and develop normally.

Question 11

If we know that a disease results from a sex-linked recessive trait, we would expect that it would:
A) be more common among men than women
B) be more common among women than men
C) develop earlier in life for boys than girls
D) develop earlier in life for girls than boys

Accepted Answer

Traits that are controlled by the sex chromosomes (X and Y) are called sex-linked traits. Because the males' Y chromosome is smaller than the females' second X, men are more likely to display recessive sex-linked traits in their phenotype.

Question 12

Which of the following is NOT a sex-linked disorder?
A) Down syndrome
B) hemophilia
C) Fragile X syndrome
D) color blindness

Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21 and is not related to the sex chromosomes, so it is not a sex-linked disorder. Hemophilia, Fragile X syndrome, and color blindness are all caused by mutations on genes located on the X chromosome and are therefore sex-linked disorders.

Question 13

Which of the following inherited disorders results in problems with blood clotting?
A) Klinefelter's syndrome
B) Turner's syndrome
C) hemophilia
D) color blindness

Accepted Answer

Hemophilia is an inherited disorder that affects blood clotting. Those with hemophilia have a deficiency in one of the clotting factors, leading to prolonged bleeding and difficulty stopping bleeding after an injury. Klinefelter's syndrome and Turner's syndrome are genetic disorders that affect sex chromosomes, while color blindness is a genetic disorder affecting vision.

Question 14

Which recessive genetic disorder occurs primarily among people of European Ashkenazi Jewish ancestry, resulting in early death in those children afflicted with it?
A) cystic fibrosis
B) Tay-Sachs disease
C) phenylketonuria
D) sickle-cell anemia

Accepted Answer

Tay-Sachs disease is a recessive genetic disorder that occurs primarily among people of European Ashkenazi Jewish ancestry. It results in early death in those children afflicted with it.

Question 15

Individuals with this syndrome have a functional X chromosome, but either a missing or inactive second X chromosome.
A) Klinefelter's syndrome
B) Fragile X syndrome
C) Down syndrome
D) Turner's syndrome

Accepted Answer

Turner's syndrome is caused by the absence or inactivation of one of the two X chromosomes in a female. Individuals with Turner's syndrome usually have short stature, ovarian failure, and other physical features.

Question 16

Todd is mentally retarded, sterile, and has small external genitalia, undescended testicles, and breast enlargement. His chromosome pattern is XXY. Since puberty, he has received hormone replacement therapy in order to maintain his secondary-sex characteristics. What sex-linked abnormality does Todd most likely have?
A) Klinefelter's syndrome
B) Down syndrome
C) Turner's syndrome
D) Fragile X syndrome

Accepted Answer

Klinefelter's syndrome occurs in about 1 of 1,000 males and involves the characteristics described: sterility, small external genitalia, undescended testicles, and breast enlargement.

Question 17

The part of the DNA molecule that does not function as genes, but that can influence how genes work is referred to as
A) polygenetic forces
B) recombinant processes
C) epigenetic forces
D) meta-genetic forces

Accepted Answer

The part of DNA that can influence how genes work is referred to as epigenetic forces. Epigenetic modifications, such as methylation or histone modification, can change the way genes are expressed without changing the DNA sequence itself. These modifications can be influenced by environmental factors and can have lasting effects on gene expression. Polygenetic forces, recombinant processes, and meta-genetic forces are not accurate descriptions of the non-coding regions of DNA.

Question 18

Andre explains that early malnutrition - an environmental condition - actually may change the way that genes express themselves. In other words, starvation turns some genes "off" and others "on," thereby influencing genetic processes. The central argument that Andre is making emphasizes the basic idea of:
A) epigenetics
B) polygenic inheritance
C) incomplete dominance
D) recombinant processes

Accepted Answer

Epigenetics refers to the idea that nongenetic factors can change the way that genes are expressed. Here, malnutrition is an environmental condition that influences these epigenetic processes, which in turn influence how genes behave.

Question 19

Having an African-American ancestry puts individuals at higher risk for developing which of the following genetic disorders?
A) sickle-cell trait and sickle-cell anemia
B) cystic fibrosis
C) Tay-Sachs disease
D) Down syndrome

Accepted Answer

Sickle-cell trait occurs in about 1 of 12 U.S. African Americans; sickle-cell anemia occurs in about 1 of 500. Other groups whose ancestors lived in low-lying malarial wetlands show high rates as well.

Question 20

Anne mentions that her cousin has a congenital anomaly. You would know that this is sometimes also referred to as:
A) a sex-linked trait
B) a birth defect
C) an autosomal disorder
D) a heterozygous trait

Accepted Answer

The answer of Anne mentions that her cousin has a...

Quiz 2: Heredity and Environment

Which of the following conditions is a sex-linked abnormality that can occur in both males and females?

Which of the following sex-linked disorders occurs most frequently?

Andre is a hemophiliac, which means that he has problems with:

At birth, Debbie was given a mandatory screening test and tested positive for a disorder that required her to be placed immediately on a restricted diet to control her symptoms. Which of the following is mostly likely the condition for which she is being treated?

Melissa has a single X chromosome and no Y chromosome, an immature female appearance, and lacks internal reproductive organs. What is the most appropriate diagnosis of her condition?

Olaf has been diagnosed with Klinefelter's syndrome. What is his chromosomal pattern?

The primary reason that sex-linked traits are observed more frequently in men than in women is that:

Which of the following syndromes occurs only in females?

If Margaret (a woman) is becoming bald as the result of a genetic trait called pattern baldness, we would know that she inherited a _ allele for this trait from her mother and a _____ allele from her father:

What percent of babies born today in the United States are healthy and normal?

If we know that a disease results from a sex-linked recessive trait, we would expect that it would:

Which of the following is NOT a sex-linked disorder?

Which of the following inherited disorders results in problems with blood clotting?

Which recessive genetic disorder occurs primarily among people of European Ashkenazi Jewish ancestry, resulting in early death in those children afflicted with it?

Individuals with this syndrome have a functional X chromosome, but either a missing or inactive second X chromosome.

The part of the DNA molecule that does not function as genes, but that can influence how genes work is referred to as

Having an African-American ancestry puts individuals at higher risk for developing which of the following genetic disorders?

Anne mentions that her cousin has a congenital anomaly. You would know that this is sometimes also referred to as: