Deck 7: Development and Sex Determination

Question 1

An important role of the hormone oxytocin in reproduction is that it stimulates

A) meiosis.
B) ovulation.
C) implantation of the embryo.
D) development of the fetal heart.
E) contraction of uterine muscles during childbirth.

Answer 1

E

Question 2

Teratogens affect the ____ more than any other part of the fetal body.

A) central nervous system
B) upper limbs
C) heart
D) lower limbs
E) external genitalia

Answer 2

A

Question 3

Individuals with androgen insensitivity are abnormal because

A) their ovarian ducts do not develop.
B) their testes do not produce testosterone.
C) they have no Müllerian ducts.
D) they are missing a receptor protein for testosterone.
E) they have two copies of the SRY gene.

Answer 3

D

Question 4

The hormone that induces contractions that lead to birth is ____.

A) estrogen
B) prostaglandin
C) oxytocin
D) melatonin
E) progesterone

Question 5

The leading preventable cause of birth defects is exposure of the fetus to:

A) X-rays.
B) cigarette smoke.
C) alcohol.
D) the herpes virus.
E) mercury.

Question 6

Normally, only one sperm fertilizes an egg. What role do other sperm play?

A) They assist the fertilizing sperm in penetrating the egg.
B) They trigger chemical changes in the egg.
C) They dissolve the outer barriers surrounding the oocyte.
D) They assist the fertilizing sperm in penetrating the egg and trigger chemical changes in the egg.
E) They trigger chemical changes in the egg and dissolve the outer barriers surrounding the oocyte.

Question 7

Implantation of an embryo normally has occurred by how long after fertilization?

A) 3 days
B) 6 days
C) 12 days
D) 20 days
E) 1 month

Question 8

Typically, blastocyst implantation in the uterus takes place at day ___.

A) 1-2
B) 3
C) 4
D) 5
E) 6-7

Question 9

The initial reports on Bruce, who became Brenda, confirmed __________in determining sexual identity.

A) nature is more important than nurture
B) nurture is more important than nature
C) nature and nurture are equally important
D) nothing of interest

Question 10

Sex-influenced traits are

A) carried on the X chromosome and subject to dosage compensation.
B) expressed more in males than in females.
C) expressed in relation to hormone levels in males and females.
D) expressed only in one sex.
E) always expressed traits.

Question 11

The site of implantation of a blastocyst is the

A) myometrium.
B) oviduct.
C) endometrium.
D) vagina.
E) ovary.

Question 12

Meiosis in females is completed

A) at conception.
B) at ovulation.
C) at puberty.
D) at fertilization.
E) prior to conception.

Question 13

What is the function of polar bodies?

A) They provide nourishment for the developing embryo.
B) They prevent more than one sperm from entering the egg.
C) They produce hormones that allow ova to develop properly.
D) They provide fructose to the semen for sperm motility.
E) None of these are functions of polar bodies.

Question 14

In dosage compensation, females have the same amount of X-linked gene products as males. This is brought about by

A) the loss of one X chromosome from all somatic cells in females.
B) the accelerated production by genes on the Y chromosome.
C) the lowered rate of synthesis by genes on the X chromosome.
D) the inactivation of one X chromosome in all somatic cells of females.
E) none of these.

Question 15

At around ___ weeks of fetal life, genes are activated that initiate sexual differentiation.

A) 9
B) 12
C) 15
D) 21
E) 25

Question 16

The phenotypic sex depends most directly on

A) the presence of a Y chromosome.
B) the presence of the number of active X chromosomes.
C) the development of the ovaries.
D) the influence of hormones.
E) the degeneration of the Müllerian duct.

Question 17

The part of the male reproductive system where sperm complete fertilization is the

A) epididymis.
B) bulbourethral gland.
C) testis.
D) seminal vesicle.
E) ejaculatory duct.

Question 18

The undifferentiated genitalia of an early human embryo develops into male genitalia under the influence of

A) oxytocin.
B) prostaglandin and DHT.
C) prolactin.
D) testosterone and DHT.
E) Müllerian duct inhibitors.

Question 19

Guidelines for the assignment of sex for an individual include

A) karyotype results.
B) the presence of ovaries or testes.
C) the presence of penis or clitoris.
D) karyotype results and the presence of ovaries or testes.
E) the presence of ovaries or testes and the presence of a penis or clitoris.

Question 20

The gland that secretes fructose and prostagladins that become part of the semen is the

A) seminal vesicle.
B) bulbourethral gland.
C) prostate gland.
D) epididymus.
E) vas deferens.

Question 21

The duct between a testis and a seminal vesicle is the ____________________.

Question 22

DHT is less important in the fetal stage than at puberty.

Question 23

The ____________________ gene is Y-linked and plays a major role in causing the undifferentiated gonad to develop into a testis.

Question 24

Meiosis I in females is completed at ____________.

Question 25

The fusion of male and female gametes usually occurs in the upper third of the vagina.

Question 26

Androgen insensitivity is caused by lack of a specific ____________________ protein.

Question 27

The phenotypic, gonadal, and chromosomal sex are always consistent.

Question 28

____________________ equalizes the dosage of functional genes carried on the X chromosome in males and females.

Question 29

It would be possible for a Klinefelter (XXY) cat to have tortoise shell color.

Question 30

The expression of a trait in a child is always independent of which parent the gene for that trait was inherited from.

Question 31

The embryo is called a fetus at the beginning of the third trimester.

Question 32

The chorion develops from the trophoblasts and allows for the exchange of nutrients between embryonic and maternal tissues.

Question 33

Once formed, sperm are stored in the epididymus.

Question 34

The sex ratio of humans at conception is different from the sex ratio at birth.

Question 35

The phenotypic sex of a child depends on

A) gene action.
B) interactions with other embryos in the uterus.
C) interactions within the embryo.
D) interactions within the maternal environment.
E) all of these causes.

Question 36

The chorion develops from a part of the blastocyst called the ____________________.

Question 37

The teratogenic effects of alcohol can occur after all the organs of the embryo have been formed.

Question 38

X inactivation can lead to ____________________ in females.

Question 39

Human chorionic gonadotrophin (hCG) is produced during pregnancy by the ovaries.

Question 40

Barr bodies are found only in normal males.

Question 41

The result of X inactivation is ____________________ between the sexes.

Question 42

The embryonic genital tubercle that develops into part of the penis in male fetuses develops into the ____________________ in female fetuses.

Question 43

Compare and contrast gametogenesis in males and females.

Question 44

Distinguish between sex determination and sex differentiation.

Question 45

In the uterus, the ____________________ is shed during menstruation.

Question 46

In the male reproductive system, the vas deferens is connected to the urethra by a short tube called the ____________________.

Question 47

Explain how X inactivation can result in female mosaicism.

Question 48

In humans, the male is the sex whose gametes determine the sex of the offspring. Do you think this is a universal situation? Why or why not?

Question 49

Describe the changes that occur from fertilization of the egg to the formation of an early embryo.

Question 50

The limb deformities caused by the tranquilizer ____________________ helped focus attention on the issue of teratogens.

Question 51

Anhidrotic ectodermal dysplasia is the result of ____________________.

Question 52

Think about this: It has been proven absolutely that a certain chemical can never pass through the placenta from the mother's circulation into the fetus's circulation. Is it still possible for this chemical to be a teratogen? Why or why not?

Question 53

With all that you now know about sex determination and sex differentiation, can you satisfactorily define "male" and "female"?

Question 54

Describe in detail two different examples of individuals where chromosomal sex and phenotypic sex are not consistent. In each case, should these individuals be considered male or female?

Question 55

During the third trimester, calcium in the mother's diet is used for development of the ____________________.

Question 56

During oogenesis, cells divide unequally into a large functional oocyte and a small ____________________.

Question 57

The lower neck of the uterus, which opens into the vagina, is called the ____________________.

Question 58

Most of the protein eaten by the mother during the third trimester is used for the development of the ____________________ system.

Question 59

Anhidrotic ectodermal dysplasia is characterized by lack of normal ____________________ in the skin.