Deck 6: Matters of Sex

Question 1

The Y chromosome was challenging to sequence because

A)it is very small.
B)the sequence has many sites of high symmetry called palindromes.
C)it is very similar to the X chromosome.
D)not enough men volunteered to have their Y chromosomes sequenceD.

Answer 1

B

Question 2

The two interesting types of people who led researchers to discovery of the SRY gene were

A)physicists and chemists.
B)XX males and XY females.
C)XY males and XX females.
D)XXX females and XYY males.

Answer 2

B

Question 3

The male-specific region of the Y chromosome

A)lies between the two pseudoautosomal regions.
B)is completely identical to its counterparts on the X chromosome.
C)has an abundance of protein-encoding genes.
D)has regions called amplicons that include few palindromic sequences.

Answer 3

A

Question 4

Femaleness or maleness is genetically set at

A)conception.
B)fertilization.
C)the embryonic period.
D)the fetal perioD.

Question 5

Renfrew is a male boa constrictor.He has two copies of a sex chromosome called Z chromosome.Renfrew is a member of the _____ sex.

A)homozygous
B)homogametic
C)hemizygous
D)heterozygous

Question 6

A male with a missing SRY gene would be phenotypically a

A)female.
B)male.
C)a female until age 12,and then a male.
D)a male until age 12,and then a female.

Question 7

Unspecialized structures in embryos that develop into female sex organs are the

A)Mullerian ducts.
B)Wolffian ducts.
C)oocytes.
D)Barr bodies.

Question 8

A daughter can inherit an X-linked recessive disorder when her father is affected and her mother is a carrier.

Question 9

Indifferent gonads develop

A)during the first two weeks of prenatal development.
B)during the fifth week of prenatal development.
C)during the ninth week of prenatal development.
D)when the embryo becomes a fetus.

Question 10

The idea that femaleness is simply what happens when an embryo does not develop as a male is no longer supported by evidence because of the discovery of

A)the SRY gene in females.
B)genes whose expression is necessary for female structures to develop.
C)gene that suppress all of the genes on a female's Y chromosome.
D)hormones that suppress expression of SRY genes in females.

Question 11

A gene on the Y chromosome that determines maleness is

A)ABO.
B)XIST.
C)SRY.
D)
E)BOY.

Question 12

The pseudoautosomal regions of the Y chromosome correspond to

A)male-specific regions of the Y chromosome.
B)female-specific regions of the Y chromosome.
C)counterparts on the X chromosome with which they can cross over.
D)places on the interior of the nuclear membrane where the Y chromosome attaches during cell division.

Question 13

In humans,if the SRY gene is not expressed,the unspecialized gonads develop into

A)testes.
B)ovaries.
C)a tumorous mass.
D)gametes.

Question 14

Human females are the _____ sex.

A)homozygous
B)homogametic
C)hemizygous
D)heterozygous

Question 15

Sex ratio at birth is called the _____ sex ratio.rev: 10_25_2013_QC_38233

A)primary
B)secondary
C)tertiary
D)quaternary

Question 16

A boy developed signs of sexual maturity at age 3.A possible diagnosis is

A)XY female syndrome.
B)XX male syndrome.
C)congenital adrenal hyperplasia due to 21-hydroxylase deficiency.
D)pseudohermaphroditism due to 5-alpha reductase deficiency.

Question 17

The calculation for determining sex ratio is

A)averaging the percentage of students who are female in many large school populations.
B)the number of males divided by the number of females multiplied by 1,000 for people of a particular age.
C)1,000 minus the number of whichever sex is in excess.
D)the number of Y chromosomes in a population divided by one-third the number of X chromosomes.

Question 18

Homosexuality

A)is seen only in humans.
B)reflects the input of a number of genes and environmental factors.
C)is inherited from a mutation on the X chromosome.
D)is only the result of environmental influences.

Question 19

Human males are the _____ sex.

A)homozygous
B)homogametic
C)heterogametic
D)heterozygous

Question 20

Indifferent gonads are

A)the gonads of people who have no interest in having sex.
B)paired structures in the embryo that can develop as either testes or ovaries.
C)paired structures in the embryo that follow a male developmental program and a female pathway in the same person at the same time.
D)the gonads that develop when a person uses birth control.

Question 21

Number of eggs laid per week and milk yield are traits that are

A)sex-linked.
B)sex-limited.
C)sex-influenced.
D)sex-driven.

Question 22

X-linked genes have different patterns of expression in females and males because

A)they are suppressed in males.
B)they are expressed in females only.
C)males have only one copy of these genes.
D)they determine maleness or femaleness.

Question 23

The probability that a boy whose mother is heterozygous for an X-linked trait inherits the recessive allele is

A)1/16.
B)1/8.
C)1/4.
D)1/2.

Question 24

A daughter can inherit an X-linked recessive disorder if

A)her mother is a carrier and her father has the disorder.
B)her mother is affected with the disorder.
C)her father is hemizygous for the disorder and her mother is wild type.
D)her father is a carrier of the disorder.

Question 25

Sean has congenital generalized hypertrichosis,an X-linked dominant condition that produces dense hair on the face and upper body.He can pass this trait

A)definitely to a daughter and definitely not to a son.
B)definitely to a son and definitely not to a daughter.
C)with equal probability to a son or daughter.
D)with a probability of 1/2 to a son and 1/4 to a daughter.

Question 26

X-linked dominant traits are typically expressed

A)much more severely in females because they have two X chromosomes.
B)much more severely in males because they have two Y chromosomes.
C)much more severely in males because they have only one X chromosome.
D)only if X-linked recessive conditions with similar symptoms are also inheriteD.

Question 27

Cliff has colorblindness and icthyosis,which causes scaly skin.Both traits are X-linked recessive.The probability that he transmits both traits to his sons is

A)0
B)1/4
C)1/2
D)3/4

Question 28

Microphthalmia is a condition that causes chickens to have very small eyes,but it only appears in hens.The condition is autosomal recessive.Microphthalmia is sex-influenced and not sex-limited because

A)only females express the trait.
B)only males express the trait.
C)it is not transmitted on a sex chromosome.
D)both sexes have eyeballs.

Question 29

In males,genes on the X chromosome are

A)expressed.
B)disease-causing.
C)mutant.
D)autosomal.

Question 30

An allele that is dominant in one sex but recessive in the other is

A)X-linked.
B)sex-limited.
C)sex-influenced.
D)Y-linkeD.

Question 31

Sixteen-year-old Rhapsody has just learned that her younger brother Clyde is colorblind.Although she knows she has color vision because her cat,Juice,is clearly orange,and she reads that nearly all people with colorblindness are boys,she is concerned about her own sons one day.If she is a carrier for colorblindness,then the risk that a son of hers is colorblind is

A)dependent on the genes the child's father contributes.
B)1/8.
C)1/4.
D)1/2.

Question 32

A human male inherits

A)an X chromosome from both parents.
B)an X chromosome from his mother and a Y chromosome from his father.
C)both X and Y chromosomes from his father.
D)his father's Y chromosome and an X chromosome from either his father or mother.

Question 33

Chloe has the scaly skin condition icthyosis,which is X-linked recessive.Which of the following is most likely true?

A)Her mother and father were both unaffected carriers.
B)Her mother was affected and her father was unaffected.
C)Her father was a carrier.
D)Her mother was a carrier and her father was affecteD.

Question 34

A gene that determines the heaviness of a man's beard is

A)X-linked.
B)sex-limited.
C)sex-influenced.
D)Y-linkeD.

Question 35

In cattle,mahogany spots are dominant in males and recessive in females.This trait is

A)sex-linked.
B)sex-limited.
C)sex-influenced.
D)sexually determineD.

Question 36

Human males and females are genetically equivalent because

A)one of a female's two X chromosomes is inactivated.
B)males only have one X chromosome.
C)one X chromosome is inactive in male cells.
D)males are hemizygous.

Question 37

The probability that the daughter of a woman with a dominant disease-causing allele on the X chromosome and a normal male will be affected with the disorder is

A)2/3.
B)1/2.
C)3/16.
D)1/3.

Question 38

Amed has scaly skin due to the X-linked recessive condition icthyosis.He is _____ for the trait.

A)autosomal dominant
B)heterozygous
C)homozygous
D)hemizygous

Question 39

Plumage in chickens is of two varieties,a "hen" pattern and a "cock" pattern.They differ because the trait is sex-limited;males have different feather arrangements than females.The autosomal gene H controls the trait in this manner: $$\begin{array} { l l } \underline {\text { Genotvpe } }& \underline {\text { Phenotype }} \\ H H & \text { hen pattern in both sexes } \\H h & \text { hen pattern in both sexes } \\h h & \text { hen pattern in females and cock pattern in males }\end{array}$$
Henrietta is one of a flock of hens who has chicks with Boris,the lone rooster.He has tantalizingly beautiful plumage in the cock pattern.If Henrietta is genotype Hh,the probability that a male chick will have his father's gorgeous plumage is

A)1/8.
B)1/4.
C)1/2.
D)1/3.

Question 40

A healthy man and a healthy woman have a son with Lesch-Nyhan syndrome,an X-linked recessive trait.What are the chances that a daughter of this couple will inherit Lesch-Nyhan syndrome?

A)0
B)1/4
C)1/2
D)3/4

Question 41

Prader-Willi and Angelman syndromes both arise from the same area of chromosome 15,illustrating

A)epistasis.
B)X inactivation.
C)genomic imprinting.
D)behavior modification.

Question 42

X inactivation is controlled by

A)the SRY gene.
B)the XIST gene.
C)the XTASY gene.
D)the location of the spindle in mitosis.

Question 43

In genomic imprinting,the expression of a genetic disorder depends on

A)the age of the mother when she became pregnant.
B)whether the trait is X-linked or autosomal.
C)which parent transmits the disease-causing allele.
D)the number of pseudoautosomal genes transmitteD.

Question 44

Imprinting disorders illustrate

A)epistasis.
B)epigenetics.
C)epidermics.
D)apogenetics.

Question 45

Tamryn has a son who has Duchenne muscular dystrophy,which is inherited as an X-linked recessive trait.At a molecular level,the disease is due to lack of the protein dystrophin.Tamryn participates in a study that looks at dystrophin levels in various muscles.The study samples cells from 10 different muscles.The study finds that some cells make dystrophin and some do not.An explanation for this finding is that

A)the mutation is only in some muscle cells.
B)Tamryn is making less dystrophin as she gets older.The study should be repeated at different ages.
C)the X chromosome that bears the mutation is turned on in some cells but off in others.
D)Tamryn does not have a Y chromosome.

Question 46

In female mammals,

A)the maternally inherited X chromosome is shut off in every cell.
B)the paternally inherited X chromosome is shut off in some cells.
C)one X chromosome is shut off in a germline cell.
D)both SRY genes are activateD.

Question 47

A human cell with two Barr bodies and no Y chromosome is from

A)a male with two X chromosomes.
B)a female with three X chromosomes.
C)a chromosomally normal female.
D)a chromosomally normal male.

Question 48

Imprinting affects the phenotype when

A)both alleles of a gene are imprinted.
B)both alleles of a gene are inactivated or deleted.
C)one allele is imprinted and the other is inactivated or deleted.
D)an embryo arises from two female genomes or two male genomes.

Question 49

Marbles is a calico cat with a Manx tail.She wants to have kittens with a male calico,but can't find one.Male calicos are rare;the only ones have the sex chromosome constitution XXY.Male calicos are therefore rare because

A)all male cats have a dominant gene on the Y chromosome that masks the calico gene on the X chromosome.
B)most male cats only have one Y chromosome,so it cannot be shut off.
C)most male cats have only one X chromosome,so it cannot be shut off.
D)male calico cats lack sex chromosomes.

Question 50

A carrier of an X-linked recessive trait who expresses the phenotype is called a(n)

A)manifesting homozygote.
B)manifesting mutant.
C)manifesting heterozygote.
D)imprinting heterozygote.