Deck 8: Chromosomes and Human Genetics

Question 1

What information is NOT visible in a karyotype?

A) the individual's sex
B) the number of autosomes
C) genetic mutations
D) chromosomal deletions

Answer 1

C

Question 2

In humans,X-linked genetic diseases

A) are associated with autosomes.
B) tend to be expressed more in females than males.
C) only affect males.
D) tend to be expressed more in males than in females.

Answer 2

D

Question 3

A karyotype shows a chromosomal abnormality that does not change the length of any of the chromosomes.Which abnormality is indicated?

A) inversion
B) deletion
C) translocation
D) duplication

Answer 3

A

Question 4

The sex of a human child is determined by the

A) loci.
B) egg.
C) presence or absence of specific autosomes.
D) presence or absence of the Y chromosome.

Question 5

A ________ is a chart that shows genetic relationships within a family over several generations.

A) karyotype
B) pedigree
C) Punnett square
D) single-gene disorder map

Question 6

During cell division a piece of a chromosome breaks off and reattaches to the same chromosome,but the piece is now in reverse order.How would this abnormality affect the chromosome?

A) An extra copy of the chromosome will be made to ensure normal function.
B) The inverted section will be deleted to prevent problems.
C) The chromosome will take on a circular configuration.
D) Genes in the section that was inverted could lose normal function.

Question 7

On chromosomes within an individual,there are ________ alleles for a given gene found on ________ chromosomes.

A) two; homologous
B) four; maternal
C) four; paternal
D) two; Y

Question 8

Humans have ________ pairs of homologous chromosomes.

A) 46
B) 23
C) 22
D) 44

Question 9

A karyotype of an individual with mild mental retardation shows three copies of the X chromosome.If this individual decides to have children,how is her chromosomal abnormality likely to affect her offspring?

A) All of her children will inherit an extra copy of the X chromosome.
B) Any female children have a 75 percent chance of inheriting an extra copy of an X chromosome.
C) She will be unable to produce male children.
D) Half of her eggs will contain an extra copy of the X chromosome.

Question 10

Which of the following genetic changes would NOT be passed from parent to child?

A) a mutation in a skin cell
B) the loss of a chromosome in a sperm cell
C) the addition of a chromosome in an egg cell
D) a translocation in a gamete

Question 11

Chromosomes that are NOT involved in determining gender are known as

A) autosomes.
B) sex chromosomes.
C) homologues.
D) linked.

Question 12

Which of the following statements about homologous chromosomes is true?

A) There are 46 pairs in humans.
B) They contain the same genes in the same locations.
C) They contain identical alleles in the same locations.
D) They are also known as sex chromosomes.

Question 13

A karyotype from an adult male indicates a chromosomal abnormality,which does not affect his health.Which of the following abnormalities is MOST likely seen?

A) three copies of the X chromosome
B) no copies of chromosome 2
C) a translocation between chromosome 14 and chromosome 15
D) a deletion on chromosome 5

Question 14

One chromosomal abnormality that is usually fatal is

A) a mutation in a gene.
B) an exchange of material between homologous chromosomes.
C) extra copies of sex chromosomes.
D) the addition of an extra autosomal chromosome.

Question 15

The karyotype shown below is from a(n)

A) male.
B) female.
C) individual of undetermined sex.
D) individual with a genetic disorder.

Question 16

In a karyotype of a male,which of the following would indicate an abnormality?

A) one X chromosome and one Y chromosome
B) three copies of chromosome 22
C) 22 pairs of autosomes
D) a total of 46 chromosomes

Question 17

Two copies of the same gene on a single chromosome would indicate a(n)________ had occurred.

A) deletion
B) duplication
C) inversion
D) translocation

Question 18

Which of the following would explain two chromosomes in an individual cell that contain some,but not all,of the same genes at the same loci?

A) Both of the chromosomes are paternal.
B) Both of the chromosomes are maternal.
C) The chromosomes are from a common ancestor.
D) A chromosomal alteration has occurred.

Question 19

In the pedigree shown below the individual indicated represents a(n)

A) healthy male.
B) healthy female.
C) affected male.
D) affected female.

Question 20

Which of the following must be true for a woman who is heterozygous for a given gene?

A) She must be heterozygous for all genes.
B) All of her eggs will contain both of the alleles for that gene.
C) All of her eggs will contain one allele or the other but not both alleles.
D) She carries a rare mutation.

Question 21

A person is genetically XX and develops as a male.How can this be explained?

A) In humans, males are XX.
B) An error in karyotyping this individual must have occurred, because XX individuals cannot develop into males.
C) A piece of a Y chromosome has become attached to one of the X chromosomes.
D) The SRY gene was deleted in this individual.

Question 22

The X chromosome in humans is

A) found as a pair in females.
B) the only human sex chromosome.
C) present only in females.
D) always found in single copy.

Question 23

A female carrier of the X-linked recessive gene for red-green color blindness will display a phenotype of

A) normal color vision.
B) XCXc.
C) red-green color blindness.
D) XCXC.

Question 24

Autosomal dominant diseases are exhibited by anyone who carries at least one dominant allele for that gene.How is it that dominant lethal genes,such as the one that causes Huntington disease,can persist in a population?

A) The disease-causing allele can "hide" in the heterozygous condition.
B) The disease develops only under the influence of other genes.
C) These diseases usually take effect later in life after people have had children.
D) The environment plays a large role in determining whether the gene is expressed.

Question 25

Which of the following statements would indicate a pedigree that shows the inheritance pattern of a recessive X-linked disease?

A) Most affected individuals are females.
B) Most affected individuals are males.
C) Males and females are affected equally.
D) The disease is seen in every generation.

Question 26

Why are X-linked recessive genetic disorders more commonly seen in males?

A) For an X-linked disorder to occur, an individual must receive one allele only found on the X chromosome and a second allele found only on the Y chromosome, which females do not have.
B) Females must receive two copies of the recessive allele to exhibit the disorder, but males need only one copy.
C) The alleles of sex-linked genes are carried only on the Y chromosome, which females do not have.
D) Females only have X chromosomes and genes on the X chromosome are not expressed.

Question 27

An X-linked carrier is a female individual with a ________ genotype,on her X chromosomes,who does not express the recessive trait but can pass it along to offspring.

A) homozygous
B) heterozygous
C) recessive
D) dominant

Question 28

Most inherited human genetic disorders are inherited as ________ alleles.

A) dominant
B) recessive
C) homologous
D) sex-linked

Question 29

Which of the following genotypes represents a human male?

A) XY
B) YY
C) XX
D) XO

Question 30

If a father is affected by an X-linked recessive condition and the mother is a carrier,what is the probability of their children being affected?

A) All sons will be affected.
B) Half of the sons will be affected.
C) All daughters will be affected.
D) Half of the sons will be carriers.

Question 31

In humans,the "master sex switch" that determines whether an embryo will become a male is the

A) X chromosome.
B) locus.
C) SRY gene.
D) androgen switch.

Question 32

A female who is a carrier of the sex-linked gene A has the genotype

A) Aa.
B) AA.
C) aa.
D) XAXa.

Question 33

The genotype of a female carrier of the X-linked recessive gene for Duchene muscular dystrophy is represented as

A) XDY.
B) XDXd.
C) Xd Y.
D) XDXD.

Question 34

The pedigree shown below diagrams an X-linked gene.The individual indicated is ________ for the gene.

A) heterozygous
B) homozygous
C) autosomal
D) There is not enough information to determine the answer.

Question 35

An allele that appears more frequently in males is MOST likely

A) dominant.
B) nonhomologous.
C) autosomal.
D) sex-linked.

Question 36

Both members of a couple are carriers for a recessive disease allele.If the couple has four children,which of the following statements must be true?

A) One of the children has the disease.
B) Two of the children have the disease.
C) All of the male children have the disease.
D) Fifty percent of the children could be carriers of the disease.

Question 37

Because an individual with an XX genotype is a female,is an individual with an XO (no second sex chromosome)a male?

A) No, because the X always overrides the Y and makes that embryo female.
B) No, because the Y chromosome contains the gene that makes an embryo male.
C) Yes, because if there is only one X, the embryo cannot become female.
D) Yes, because all embryos start off as males.

Question 38

Which of the following is true of the genetic cross shown in the figure below?

A) All of their daughters will be carriers.
B) Their sons have a 50 percent chance of being carriers.
C) Their sons have a 50 percent chance of having the disorder.
D) Their daughters have a 50 percent chance of having the disorder.

Question 39

In which of the following situations would looking at a pedigree be MOST useful?

A) An adopted boy is admitted to the hospital with recurrent vomiting.
B) A young girl is born with diminished hearing and a cleft palate.
C) Six unrelated individuals with similar symptoms are admitted to the hospital in a one-week period.
D) Three young boys who are first cousins show symptoms of a neurological disorder.

Question 40

The gene for a certain sex-linked trait is found only on the Y chromosome.If the male parent has this gene,the trait will be expressed in

A) 100 percent of the female offspring.
B) 50 percent of the female offspring.
C) 100 percent of the male offspring.
D) 50 percent of the male offspring.

Question 41

Most inherited human disorders are the result of

A) recessive mutations of genes located on autosomes.
B) dominant mutations of genes located on the X chromosome.
C) recessive mutations of genes located on the Y chromosome.
D) simultaneous mutations of the same gene on homologous chromosomes.

Question 42

Except for the sex chromosomes,all the chromosomes shown in a karyotype are numbered and are called ________.

Question 43

If an individual has two alleles at a given locus that are different,the individual is said to be ________ for the gene.

Question 44

Human males have one chromosome that females do not.That chromosome is the ________ chromosome.

Question 45

What information in a pedigree would indicate a condition is likely dominant?

A) Twenty-five percent of the individuals in the pedigree have the condition.
B) Two-thirds of the affected individuals are females.
C) None of the affected individuals have unaffected parents.
D) Most of the affected individuals are males.

Question 46

Ross is a genetic counselor working with a family that has lost a child to an unidentified illness.The family tells him there have been other children in the family history who have died after having the same symptoms.As Ross examines several generations of the family's pedigree,he notices that females are affected as frequently as males and that parents never exhibit the symptoms.This information leads him to think this disorder has a(n)________ mode of inheritance.

Question 47

Among children with parents who are both carriers of Tay-Sachs,an autosomal recessive disorder,chances are that

A) 75 percent will be carriers.
B) 50 percent will die in a few years.
C) 75 percent will not carry the recessive Tay-Sachs's allele.
D) 50 percent will be carriers.

Question 48

Sickle-cell disease is an inherited chronic blood disease caused by an autosomal recessive allele.Suppose a man with sickle-cell disease fathers a child by a woman who is a carrier for sickle-cell disease.What are the chances their children will exhibit the disease?

A) 0 percent
B) 25 percent
C) 50 percent
D) 75 percent

Question 49

Which of the following information is available in a Punnett square showing the inheritance pattern for an autosomal recessive disorder?

A) the percentage of males likely to be affected by the disorder
B) the percentage of females likely to be affected by the disorder
C) the percentage of all children likely to be affected by the disorder
D) the number of children born to the two parents

Question 50

Every gene in a human occupies a specific position or ________ on a chromosome.

Question 51

Phenylketonuria (PKU)is a metabolism disorder that can result in mental retardation if untreated.This recessive disorder is caused by a defective gene located on chromosome twelve.The most reliable source for the functional gene needed for gene therapy would be a(n)

A) female that is heterozygous for the functional gene.
B) male that is heterozygous for the functional gene.
C) individual that is homozygous dominant for the functional gene.
D) individual that does not have PKU.

Question 52

Which of the following best estimates the occurrence of the X-linked recessive disorder Duchenne muscular dystrophy in all births per year as shown in the figure below?

A) 0.03 percent
B) 0.15 percent
C) 0.015 percent
D) 0.5 percent

Question 53

If the male in generation II of the figure below was affected,what would the pattern of inheritance MOST likely be?

A) X-linked recessive
B) X-linked dominant
C) autosomal recessive
D) autosomal dominant

Question 54

The parents in the figure shown below are carriers of a genetic disorder.Based on the Punnett square,the allele that causes the disorder must be

A) autosomal.
B) sex-linked.
C) dominant.
D) incompletely dominant.

Question 55

If a recessive allele causes a fatal disease that kills the affected individual before he or she can reproduce,why doesn't that allele quickly become extinct in the population?

A) Alleles are never lost from a population.
B) The homozygous dominant individuals protect the recessive allele in their genomes.
C) The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease.
D) The homozygous recessive individuals give their alleles to other individuals before they die from the disease.

Question 56

The source of the gene needed for gene therapy treatment of the sex-linked adrenoleukodystrophy (ALD)would be a(n)________ chromosome with a ________ copy of the ALD gene.

A) X; functional
B) Y; functional
C) X; nonfunctional
D) Y; nonfunctional

Question 57

The genetic disorder followed through the pedigree shown below is

A) recessive and X-linked.
B) recessive and autosomal.
C) dominant and X-linked.
D) dominant and autosomal.

Question 58

If two parents are heterozygous for an autosomal recessive disease,

A) they are both considered genetic carriers for the disease.
B) their children have no chance of inheriting the disease.
C) their children have a 50 percent chance of inheriting the disease.
D) all of their children will also be heterozygous.

Question 59

If a female who carries the X-linked recessive gene for hemophilia mates with a male who does not have hemophilia,what is the chance that their daughter will be a carrier of the gene?

A) 0 percent
B) 25 percent
C) 50 percent
D) 75 percent

Question 60

If a genetic disorder is caused by a dominant allele,individuals with which of the following genotypes would be affected by the disorder?

A) AA and aa
B) aa and Aa
C) AA and Aa
D) AA, Aa, and aa

Question 61

A disease caused by an inherited mutation is a ________ disorder.

Question 62

A female who carries on her X chromosomes one copy of a recessive mutated allele and one normal copy is referred to as a genetic ________.

Question 63

As shown in the figure below,the number of males born each year with hemophilia ________ the number of males born with Fragile-X syndrome each year.

Question 64

Zoe's parents were both heterozygous for the recessive cystic fibrosis allele.Zoe had cystic fibrosis.The chance that any of Zoe's future siblings will have cystic fibrosis is ________.

Question 65

X-linked disorders more commonly affect males than females because males have only one ________ chromosome.

Question 66

What factors make it difficult to study human genetic disorders?

Question 67

Explain how two brothers might have different X chromosomes,but they must share identical Y chromosomes.

Question 68

A parent who is a carrier for the recessive autosomal disorder B has the genotype ________.

Question 69

While examining the pedigree of a human female,you discover that she has 44 autosomes and two sex chromosomes,an X and a Y.This may lead you to suspect that there is a mutation within this individual's ________ gene.

Question 70

A man with a translocation in a chromosome that does not affect gene function may not realize he has a translocation until he attempts to have a child.Explain how a translocation that does not affect the individual may become problematic during reproduction.

Question 71

An allele that is not expressed in heterozygous carriers is called a(n)________ allele.

Question 72

Would a karyotype for a human male be considered normal if it shows 45 autosomes and a single pair of sex chromosomes? Explain your reasoning.

Question 73

Karen and Jared produce three healthy children.The first child is a boy (Daniel)and the next two are girls (Leslie and Alice).Daniel grows up,marries Dana,and they have two children.Their first child is a healthy baby boy and the second is a little girl who is diagnosed with phenylketonuria (PKU).Draw this family's pedigree.

Question 74

A karyotype of a human female reveals a total of 45 chromosomes: 44 autosomes and one sex chromosome.Is this karyotype typical of human females? Explain your reasoning.

Question 75

Can a male human be a carrier of an X-linked trait? Explain your answer.

Question 76

Explain how an individual who has both an X and a Y sex chromosome would develop embryologically as a female instead of a male.

Question 77

A horizontal line directly between a square and a circle in a pedigree indicates that those two individuals are a(n)________ pair.

Question 78

An individual who has the genotype XᴺXⁿ for night blindness is considered a ________ for night blindness.

Question 79

The chromosome on the left of the figure below is chromosome number 5 from the father of a newborn child with cri du chat syndrome.The chromosome on the right is paternal chromosome number 5 in the child.What type of chromosomal abnormality has caused this syndrome in the child? Explain your answer.

Question 80

Researchers hope to develop treatments for sex-linked genetic disorders such as Wiskott-Aldrich syndrome (WAS),by using a virus to insert a properly functioning gene into the patient's blood cells.This technique for correcting defective genes is ________,a specific type of genetic engineering.