Deck 6: Matters of Sex

Question 1

A gene on the Y chromosome that determines maleness is

A)ABO.
B)XIST.
C)SRY.
D)a Barr body.
E)E.BOY.

Answer 1

C

Question 2

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) feminism.
E) genes that suppress expression of SRY in females.

Answer 2

B

Question 3

Femaleness or maleness is genetically set at

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

Answer 3

A

Question 4

In an XY embryo,production of anti-Mullerian hormone inhibits development of

A) a uterus, uterine tubes, and upper vagina.
B) the epididymides, ductus deferentia, seminal vesicles, and ejaculatory duct.
C) breasts, nipples, and aereolae.
D) the kidneys and liver.
E) the brain, cervix, and labia.

Question 5

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

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

Question 6

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

A) XY female syndrome.
B) XX male syndrome.
C) SRY deficiency.
D) congenital adrenal hyperplasia due to 21-hydroxylase deficiency.
E) a deletion of the SRY gene.

Question 7

Homosexuality

A) is seen only in humans.
B) has been documented for only a few hundred years in only a few societies.
C) likely reflects the input of several if not many genes and environmental factors.
D) is inherited from a mutation on the X chromosome.
E) is a matter of choice.

Question 8

Human males are the _______ sex.

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

Question 9

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.
E) it is very rare.

Question 10

The calculation for determining sex ratio is

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

Question 11

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

A) Mullerian ducts.
B) Cowper's glands.
C) Wolffian ducts.
D) oocytes.
E) Barr bodies.

Question 12

The pseudoautosomal regions of the Y chromosome correspond to

A) counterparts in other parts of the Y chromosome.
B) counterparts on certain autosomes.
C) counterparts on the X chromosome.
D) places on the interior of the nuclear membrane where the Y chromosome attaches during cell division.
E) regions that confer maleness.

Question 13

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

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

Question 14

Human females are the _______ sex.

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

Question 15

The male-specific region of the Y chromosome

A) lies between the two pseudoautosomal regions.
B) includes sequences that have counterparts on the X chromosome.
C) has few protein-encoding genes.
D) has regions called amplicons that include many palindromic sequences.
E) has all of the above.

Question 16

Two unusual type 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.
E) men and women who lack sex chromosomes.

Question 17

A male with a missing SRY gene would be phenotypically a

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

Question 18

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.
E) at puberty.

Question 19

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 male or female, depending on the hormones secreted into the uterine environment.
C) paired structures in the embryo, one of which follows a male developmental program and the other of which follows a female pathway, in the same person at the same time.
D) the gonads when a person uses birth control.
E) the substructures of the ovaries and testes.

Question 20

Sex ratio at birth is called the _______ sex ratio.

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

Question 21

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
E) 2/3

Question 22

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

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

Question 23

In males,genes on the X chromosome are

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

Question 24

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.
E) not inherited.

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.
E) to a child only if he never shaves off the extra hair.

Question 26

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.
E) chickens do not have hormones.

Question 27

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.
E) 2/3.

Question 28

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

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

Question 29

Plumage in chickens is of two varieties,a "hen" pattern and a "cock" pattern.They differ because the trait is sex-limited - that is,males have different feather arrangements than females.The autosomal gene H controls the trait in this manner: $$\begin{array} { l l } \underline{\text { Genotype } }& \underline{\text { Phenotype }} \\ H H & \text { hen pattern in both sexes } \\H h & \text { hen pattern in both sexes } \\h h & \text { hen pattern in females and cock pattern in males }\end{array}$$ 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.
E) 2/3.

Question 30

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) with equal severity in the sexes.
E) only if X-linked recessive conditions with similar symptoms are also inherited.

Question 31

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

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

Question 32

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) 1/4.
D) 3/16.
E) 1/3.

Question 33

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) females lack the Y chromosome.
E) males are hemizygous.

Question 34

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

A) wild type
B) autosomal dominant
C) heterozygous
D) homozygous
E) hemizygous

Question 35

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
E) 2/3

Question 36

Eight-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.
E) not possible to calculate with the given information.

Question 37

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.
E) there are two copies in males.

Question 38

A daughter can inherit an X-linked recessive disorder if

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

Question 39

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.
E) She is a new mutation.

Question 40

A human male inherits

A) an X chromosome from either parent.
B) one X from his mother and his father's Y.
C) the X and Y chromosomes from his father.
D) his father's Y and the X from either his father or mother.
E) two X chromosomes.

Question 41

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.
E) a sperm with two Y chromosomes.

Question 42

Imprinting disorders illustrate

A) epistasis.
B) epigenetics.
C) epidermics.
D) apogenetics.
E) Mendelian genetics.

Question 43

Marbles is a calico cat with a Manx tail.She wants to have kittens with a male calico,but can't seem to find one.Alas,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 that masks the calico gene on the X.
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) they die just after birth.
E) male calicos lack sex chromosomes.

Question 44

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 to look at dystrophin levels in various muscles,so has cells sampled from 10 different muscles.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) the mutation originated in the son.
E) Tamryn does not have a Y chromosome.

Question 45

A carrier of an X-linked recessive trait who experiences the phenotype is called a

A) manifesting homozygote.
B) manifesting mutant.
C) manifest destiny.
D) manifesting heterozygote.
E) imprinting heterozygote.

Question 46

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 is exposed to methyl groups.
E) an embryo arises from two female genomes or two male genomes.

Question 47

In female mammals,

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

Question 48

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

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

Question 49

X inactivation is controlled by

A) the SRY gene.
B) the XIST gene.
C) the XTASY gene.
D) whether or not a woman takes birth control pills.
E) the location of the spindle in mitosis.

Question 50

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.
E) protein imprinting.