Chapter 24 Quiz

Genes on the same chromosome are more likely to assort independently if they

are located far apart.

The location of a gene on a chromosome is called a

locus.

If a chromosomal segment is turned around 180°, the chromosomal mutation is termed a(n)

inversion.

A mother is a carrier for blue eyes (autosomal recessive) and for hemophilia (X-linked recessive). Which of these is a correct statement?

The father's genotype can determine whether a son has blue eyes but will not determine whether a son will be a hemophiliac.

A person with an XO genotype is classified as having

Turner syndrome.

An XXX female would most likely result from nondisjunction in

the mother during egg formation.

In which way would males and females differ in terms of chromosomes?

the types of sex chromosomes

Which of the following refers to the movement of a piece of one chromosome to another nonhomologous chromosome?

translocation

The most common autosomal abnormality seen among humans is

trisomy 21.

Color-blindness is inherited as an X-linked recessive trait. A male who is color-blind has children with a heterozygous woman. What percent of their total children will be color-blind?

50%

Hemophilia (h) is a sex-linked recessive trait. If a male with hemophilia has children with a female who is a carrier,

50% of their daughters will be hemophiliac.

If a woman is a carrier for the color-blind recessive allele and a man has normal vision, what are their chances that their son will have color-blindness?

50%, since the mother is only a carrier

Which of the following is true about a karyotype? A. sex chromosomes are identified separately from autosomes B. banding patterns are used in pairing chromosomes C. chromosome pairs are assorted by both size and shape D. a red blood cell is generally the source of the chromosomes E. homologous chromosomes are arranged in pairs

A, B, C, E

A karyotype would be effective in detecting all of the following genetic diseases except?

Duchenne muscular dystrophy

n the following question, the distance between alleles on a chromosome is visualized. Which of the following pairs of alleles would be most likely to cross over?

A..........B

Which statement about Down syndrome is correct? Check all that apply. A. Down syndrome generally results from eggs being fertilized with sperm that are carrying an extra chromosome. B. Characteristics of Down syndrome include stubby fingers and a palm crease. C. Individuals with Down syndrome may experience varying degrees of intellectual disability. D. Down syndrome is caused by a third copy of chromosome 21. E. Down syndrome is usually associated with chromosomal nondisjunction in meiosis.

B, C, D, E

Which statement is true regarding a Barr body?

Barr bodies are found in the nuclei of female cells.

Which of the following sex-linked diseases is characterized by a waddling gait, toe walking, frequent falls, and difficulty in rising, and may appear as soon as the child starts to walk?

Duchenne muscular dystrophy

Karyotyping can be used to diagnose which of the following genetic disorders?

Down syndrome

Characteristics such as short stature, a fold in the eyelids, a fissured tongue, and intellectual disability are associated with

Down syndrome.

If an individual has a XYY genotype, they are classified as having

Jacobs syndrome.

An individual who has an XXY combination of sex chromosomes is said to have

Klinefelter syndrome.

Which of the following conditions is due to a change in chromosome structure?

Williams syndrome

A female with two Barr bodies in her cells would have what combination of sex chromosomes?

XXX

Genes on which chromosome determine if the sex of a child will be male or female?

Y

All of the genes on a single chromosome form a

a linkage group.

A woman with color-blindness (recessive trait) will pass the allele to

all her children.

Down syndrome

can occur if the sperm has an extra copy of chromosome 21.

During meiosis, what process can sometimes "unlink" genes?

crossing over

Genes that are linked

do not sort independently.

Which refers to the addition of a repeat segment of a chromosome?

duplication

If a person inherits two X chromosomes, this individual will be

female.

Which one of the following x-linked disorders is caused by an abnormal number of repeat sequences in the genome and is the most common cause of inherited mental impairment?

fragile X syndrome

Which of the following sex-linked disorders was common among the royal families of Europe, and all of the affected males could trace their ancestry to Queen Victoria of England?

hemophilia

Considering that males can have Klinefelter (XXY) syndrome, XYY, and normal XY chromosomal combinations, and females can have Turner (XO) syndrome, poly-X (XXX, XXXX), and normal XX combinations, it is obvious that

male characteristics result from the minimal presence of one Y chromosome.

A baby born with 48 chromosomes and an xxxy genotype would be

male with Klinefelter syndrome.

Which disorder is characterized by a lack of the protein dystrophin?

muscular dystrophy

When homologous chromosomes fail to separate during meiosis, this is termed

nondisjunction.

In fruit flies, bar eye is inherited by a dominant X-linked allele (B for bar). If a heterozygous bar-eyed female is mated to a non-bar-eyed male, what will be the expected ratio of phenotype given four offspring?

one bar-eyed and one non-bar-eyed female, one bar-eyed and one non-bar-eyed male

Generally, it is not possible to determine whether nondisjunction failed to occur in oogenesis or spermatogenesis. However, it is possible to assert that XYY results from nondisjunction during

spermatogenesis.