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12. Units of Heredity: Chromosomes and Inheritance
This activity contains 39 questions.
a recessive X-linked gene
a chromosomal aberration
a chromosomal inversion
an autosomal recessive trait
a dominant X-linked gene
Hemophilia is a sex-linked disorder. Which is the best prediction of the offspring if the mother is a carrier and the father has hemophilia?
Fifty percent of the sons will have hemophilia, and 50% of the daughters will have hemophilia.
All sons will have hemophilia and all daughters will be normal.
Twenty-five percent of the daughters will have hemophilia, and all the sons will have hemophilia.
All sons and daughters will have hemophilia.
All sons and all daughters will be normal.
A female is born with color blindness. What is the most probable genotype of the parents?
Both her mother and father are carriers of the trait.
Her father is color-blind and her mother is neither color-blind nor a carrier.
Her mother is color-blind and her father is not.
Her mother is color-blind and her father is a carrier of the trait.
Her father is color-blind and her mother is a carrier of the trait.
What is the result from change of the hemoglobin gene in sickle-cell anemia?
hemoglobin S, a form of hemoglobin that coalesces into crystals
an extra X chromosome that leads to the production of too much hemoglobin
complete lack of hemoglobin
A person who is a carrier for a genetic disease has which of the following phenotypes?
They have a full-blown case of the disease.
They have only a mild case of the disease.
They do not have the disease.
They do not have the disease in childhood but will develop the disease later in life.
They will develop the disease after encountering an environmental trigger.
How many pairs of autosomes are present in humans?
Which of the following explanations could account for dominant alleles that cause lethal disorders being less common than recessive alleles that cause lethal disorders?
All dominant alleles cause death before childbearing age.
Carrying one dominant lethal allele causes death; carrying one recessive lethal allele does not.
Recessive lethal alleles must cause sterility.
Dominant alleles that cause lethal disorders are more serious than recessive lethal disorders.
If a disease is caused by a dominant allele, it means that a person with the disease ________.
is more likely to be male
need to have only one copy of the allele that causes the disease to have symptoms of the disease
is more likely to be female
will pass it on to children only if the person's mate also has the disease
will always pass it on to children
Much genetic information can be derived from pedigrees (family genetic histories). This is done primarily for humans because ____________.
other animals have long life spans
humans cannot be crossed experimentally
humans have many chromosomes
we know relatively little about human genetics
A plant biologist develops a seedless fruit. To be seedless, the fruit must be sterile. The sterility is the result of adding an entire set of chromosomes to the genome of the organism. What is this condition called?
sex-linked recessive inheritance
Alterations in a single trait, like white eyes versus red eyes in fruit flies or color blindness versus normal vision in humans, are the result of ______.
Which of the following can result in aneuploidy?
A normal sperm cell fertilizes an egg with a chromosome with an inversion.
A normal sperm cell fertilizes an egg cell with the recessive allele for Down syndrome.
A normal sperm cell fertilizes an egg cell in which nondisjunction of chromosome 21 occurred during anaphase II.
The embryo is exposed to a chemical that causes a deletion of the short arm of chromosome 5.
A normal sperm cell fertilizes an egg cell in which a piece of chromosome 21 is inverted.
Which of the following can result in Down syndrome?
a chromosomal deletion
nondisjunction during meiosis
What is nondisjunction?
failure of cells to divide by cytokinesis after telophase
failure of chromosomes to duplicate before mitosis or meiosis
an extra duplication of all the chromosomes before mitosis or meiosis
failure of homologous chromosomes or sister chromatids to separate
Karyotyping was done for a patient of suspected blood cancer. Chromosomal analysis indicated that there was an extra-long chromosome 9 and a shorter chromosome 22, called the Philadelphia chromosome. It is a diagnosis of chronic myeloid leukemia, a form of blood cancer in which a big portion of chromosome 22 is transferred to chromosome 9 and a small portion of 22 is transferred to chromosome 9. What is this form of chromosomal abnormality called?
The b and c genes on a chromosome are linked. BBCC × bbcc is crossed to produce the F
heterozygotes. Which of the following gametes can an F
BC, Bc, bC, and bc
A fruit fly that is heterozygous for two genes (AaBb) is crossed with a homozygous recessive fruit fly (aabb). If the genes assorted independently, what proportion of the offspring would have the same phenotype as the parents?
25% AaBb and 25% aabb
If a somatic cell from a diploid organism has 32 chromosomes, how many chromosomes would be in a gamete that is the result of nondisjunction involving a single pair of homologous chromosome?
16 or 18
31 or 33
32 or 64
15 or 17
15 or 16
Nondisjunction during meiosis can occur at either the first or second meiotic division. Although neither event is desired, why would a nondisjunction during the second meiotic division be preferred over a nondisjunction in the first meiotic division?
The overall product of meiosis would be that no gametes produced.
The overall products of meiosis would be 50% normal and 50% abnormal gametes.
The overall products of meiosis would be 100% abnormal gametes.
The overall products of meiosis would be 100% normal gametes.
Amniocentesis is a technique __________.
a form of gene therapy that modifies or inhibits gene expression or the function of gene products
of repairing deformities in fetuses
used in prenatal diagnosis to detect chromosomal mutations and metabolic disorders in embryos
used for detection of possible chromosomal abnormalities and metabolic disorders of the mother
What is the application of preimplantation genetic diagnosis (PGD)?
diagnosis of AIDS in embryos
screening for genetic abnormalities in a growing fetus
screening of embryos of in vitro fertilization for genetic defects
detecting pregnancy in women
Which statement about Down syndrome is FALSE?
The frequency increases dramatically in mothers over the age of 40.
Affected individuals have an extra autosome.
Affected individuals have an extra sex chromosome.
The cause is a nondisjunction when chromosomes do not separate during the meiotic division.
The long time lag between onset of meiosis in ovarian tissue (during fetal development) and its completion (at ovulation) is most likely the reason for increased incidence in older mothers.
Klinefelter syndrome (XXY) is an example of chromosomal aneuploidy that can be readily diagnosed by ________.
An X-linked carrier is a ___________.
homozygous recessive female
Which of the following is a transfer of genetic material between nonhomologous chromosomes?
Cri-du-chat syndrome is caused by ________.
Which of the following genetic conditions is seen more often in males than in females?
Duchenne muscular dystrophy
A female is not color-blind, but half her sons are color-blind. Her daughters are not color-blind. Which conclusion is correct?
The father is color-blind.
The woman is heterozygous for the color-blindness gene.
The father is not color-blind but is heterozygous for the color-blindness gene.
Color blindness is dominant.
Color blindness is autosomal.
X-linked conditions are caused by ___________.
inheritance of an extra X chromosome
genes that only females have
genes on the X chromosome
proteins that damage the X chromosome
genes that only males have
A trait is seen with equal frequency in males and females. Two people who do not have the trait might have offspring who do have the trait, at a frequency of approximately 1 in 4. The inheritance of this trait is __________.
recessive and autosomal
recessive and X-linked
caused by polyploidy
dominant and X-linked
Which disease is autosomal and results in misshapen RBCs that clog capillaries?
What is one difference between polyploidy and aneuploidy?
Polyploidy is extra sex chromosomes, whereas aneuploidy is extra autosomes.
Polyploidy is extra sets of chromosomes; aneuploidy does not increase by a full set.
Polyploidy causes diseases and disorders in humans, whereas aneuploidy does not.
Polyploidy is one extra chromosome, whereas aneuploidy is one missing chromosome
Nondisjunction involving the X chromosomes may occur during oogenesis and produce two kinds of eggs. If normal sperm fertilize the two types of eggs, which of the following pairs of genotypes are possible?
XX and XY
XXY and XO
XYY and YO
XYY and XO
Which of the following is correct regarding the sex chromosomes?
The X chromosome carries only gender-related genes.
The Y chromosome carries a greater number of genes than does the X.
The X chromosome carries more genes for nonsexual traits than does the Y chromosome.
X and Y are different in size but carry nearly equal numbers of genes.
The pedigrees of the European royal families show hemophilia was carried by Queen Victoria's daughters, which had important consequences in European history. What are the consequences of hemophilia?
The Factor VIII gene is located on an autosome.
Red blood cells become sickle shaped.
The pedigree shows more female hemophiliacs than male.
The blood does not clot after an injury.
The main advantage of preimplantation genetic diagnosis (PGD) over amniocentesis is that _________________.
PGD can be done later than amniocentesis
PGD can be done three days after fertilization, and amniocentesis is performed many months after conception, when the fetus is more mature
PGD and amniocentesis are techniques that can be done after normal conception
it is the only technique that allows a karyotype to be generated
Which condition or disease can be caused by aneuploidy?
The probability that a man inherited his Y chromosome from his maternal grandfather is______.
A woman whose husband worked as an X-ray technician gives birth to a hemophiliac son. Which of the following statements is true?
Hemophilia is environmentally induced, not genetic.
She should not blame the exposure because she carried the hemophilia allele.
She should blame X-ray exposure because the radiation caused the hemophilia.
Karyotyping should have been done to check the hemophilia gene.
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