One of the evolutionary "enigmas," or unsolved puzzles, of sexual reproduction is that

A sexual reproduction allows for more rapid population growth than does asexual reproduction.
B asexual reproduction is better suited to environments with extremely varying conditions.
C sexual reproduction is completed more rapidly than asexual reproduction.
D sexual reproduction is maintained even in animal species that can also reproduce asexually.
E asexual reproduction produces offspring of greater genetic variety.

D

Peaks of LH and FSH production occur during

A the period just before ovulation.
B the menstrual flow phase of the uterine cycle.
C the end of the luteal phase of the ovarian cycle.
D the beginning of the follicular phase of the ovarian cycle.
E the secretory phase of the menstrual cycle

A

Which statement about human reproduction is false?

A Fertilization occurs in the oviduct.
B Spermatogenesis and oogenesis require different temperatures.
C Effective hormonal contraceptives are currently available only for females.
D An oocyte completes meiosis after a sperm penetrates it.
E The earliest stages of spermatogenesis occur closest to the lumen
of the seminiferous tubules.

E

What is the “twofold” cost of sex?

A The cost of finding and courting a mate
B The higher number of female offspring produced by an asexual female
C The cost of producing sexual structures and sex hormones

B

Which hormone’s secretion is controlled by a positive feedback mechanism?

A Progesterone
B Testosterone
C Oxytocin

C

Select the correct statement about reproduction and eukaryotic life cycles.

A Animal reproduction is exclusively sexual.
B In all eukaryotic life cycles, the products of meiosis are gametes.
C Some animal adults are haploid.

C

What is the fundamental difference between male and female vertebrates?
A Male and female vertebrates are genetically distinct.
B A plant seed and a bird egg

 C Males produce many, motile gametes and females produce few, stationary gametes.

C

Select all that apply.
A FSH triggers ovulation.
> B FSH stimulates the growth of new follicles in the ovary.
> C FSH promotes the activity of Sertoli cells, which nourish sperm developing
within seminiferous tubules.

B & C

Tubal ligation

A reduces the incidence of ovulation.
B prevents oocytes from entering the uterus.
C prevents fertilization by preventing sperm from entering the uterus.
D prevents sperm from exiting the male urethra.
E prevents implantation of an embryo.

B

What normal process was blocked in Jost's experiment?

A hormone production by the embryo’s chromosomes during development
B hormone production by the mother’s gonads during development
C hormone production by the embryo’s gonads during development
D hormone transfer from mother to embryo during development

C

Normally, the gonads of a developing embryo produce hormones during development. How did Jost block this process?

A Jost removed the portion of each embryo that would form the gonads.
B Jost examined the animals very early in development, when their gonads were too immature to produce hormones.
C Jost transplanted embryonic male gonads into female embryos and vice versa.
D Jost used animals that produced nonfunctional versions of the hormones.

A

If you were to repeat Jost's experiment, how might you test the validity of this alternative hypothesis?

A Remove the gonads from only some of the embryos in the mother's uterus. The rest of the embryos would receive no surgery.
B Perform a different surgery on some embryos. For example, remove the pancreas instead of the embryonic gonads.
C Perform a sham surgery on some embryos. For example, open the embryo but do not remove the gonads.
D Remove the gonads from all the developing embryos in some mothers. Developing embryos in other mothers would receive no surgery.

C

What result would Jost have obtained if both male and female genital development required signals from the gonads?

A None of the female embryos that had surgery would have developed normal female genitalia, but all the males that had surgery would have developed normal male genitalia.
B All of the embryos that had surgery would have developed normal, sexually differentiated genitalia.
C None of the male embryos that had surgery would have developed normal male genitalia, but all the females that had surgery would have developed normal female genitalia.
D None of the embryos that had surgery would have developed normal, sexually differentiated genitalia.

D

To test the hypothesis that the signal is the hormone testosterone, which of the following experiments should you perform?

A Leave in the embryonic gonads and add another source of testosterone.
B Perform a sham surgery. Open the embryo, but do not remove the gonads.
C Transplant male gonads into female embryos.
D Remove the embryonic gonads and replace them with another source of testosterone.

D

Which of the following results would support your hypothesis

A Female genitalia develop in the rabbits.
B The genitalia do not sexually differentiate in the rabbits.
C Some of the rabbits develop male genitalia, and others develop female genitalia.
D Male genitalia develop in the rabbits.

D

Animals with reproduction dependent on internal fertilization need not have

A internal development of embryos.
B haploid gametes.
C a receptacle that receives sperm.
D any copulatory organs.
E behavioral interaction between males and females.

A

True or false? Humans form gametes by a process called gametogenesis.

A True
B False

A

What role do germ cells play in gametogenesis?

A They produce cells that undergo meiosis and develop into gametes.
B They produce gametes.
C They produce cells that divide by mitosis to form gametes.
D They produce cells that divide by mitosis and then undergo meiosis to form gametes.

D

Which of the following statements about oogenesis in humans is true?

A Oogenesis takes place within the oviduct.
B The ooctye released from the ovary during ovulation is fully mature.
C Oogonia can reproduce mitotically within an adult female ovary to produce more oogonia, which differentiate into primary oocytes.
D Beginning at puberty, a primary oocyte completes its first meiotic division to form a secondary oocyte and a polar body approximately every month.

D

What products are formed when a diploid cell undergoes meiosis?

A Two haploid cells.
B Two diploid cells.
C Four haploid cells.
D Four diploid cells.

C

Which diploid cells are produced by an embryonic germ cell?

A Ovum.
B Spermatid.
C Polar body.
D Spermatogonia.

D

True or false? The production of sperm begins at puberty when spermatogonia undergo meiosis I to form primary spermatocytes, which then undergo meiosis II to form secondary spermatocytes. These secondary spermatocytes go on to form spermatids, which mature into sperm cells.

A True
B False

B

How does spermatogenesis differ from oogenesis?

A Diploid cells give rise to four functional gametes in spermatogenesis.
B Gametes are produced by meiosis in spermatogenesis.
C Gamete maturation occurs after fertilization in spermatogenesis.
D Production of the cells that will mature into gametes is complete by birth in spermatogenesis.

A

Which of the following correctly traces the path of sperm from their site of production to their exit from a man's body?

A seminiferous tubule → vas deferens → epididymis → urethra
B vas deferens → epididymis → urethra → seminiferous tubule
C epididymis → urethra → seminiferous tubule → vas deferens
D seminiferous tubule → epididymis → vas deferens → urethra
E epididymis → seminiferous tubule → vas deferens → urethra

D

In humans, oogenesis in comparison to spermatogenesis is different in that

A oogenesis continues throughout life, but spermatogenesis typically ends at age 55 years
B oogenesis does not complete meiosis until after fertilization, but
spermatogenesis is complete before the sperm leave the body
C female puberty typically occurs much later than the age of male puberty
D oocyte production works best at cooler temperatures than those that
support spermatogenesis
E the names and chemical identities of the pituitary hormones are completely
different between males and females

B

Sperm cells are stored within human males in the

A bulbourethral gland.
B epididymis.
C prostate.
D seminal vesicles.
E urethra.

B

Sperm become capable of movement while in the _____.

A seminiferous tubules
B vas deferens
C ejaculatory ducts
D urethra
E epididymis

E

The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____.

A positive ... hypothalamus ... pituitary gland
B negative ... hypothalamus ... pituitary gland
C positive ... thyroid ... pituitary gland
D negative ... pancreas ... pituitary gland
E negative ... seminal vesicles ... prostate glan

B

Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth?

A androgens
B thymosin
C epinephrine
D insulin
E parathyroid hormone

A

Which pituitary secretion stimulates sperm production?

A LH
B ACTH
C TSH
D PRL
E FSH

E

Which pituitary secretion stimulates the testes to secrete androgens?

A LH
B ACTH
C TSH
D PRL
E FSH

A

A fertilized egg usually implants itself and develops in the _____.

A uterus
B ovary
C oviduct
D abdominal cavity
E none of these

A

A rapid increase in the _____ level stimulates ovulation.
A progesterone
B estrogen
C luteinizing hormone
D follicle-stimulating hormone
E human chorionic gonadotropin

C

After ovulation, high levels of _____ inhibit _____ secretion.

A estrogen and progesterone ... FSH and LH
B FSH and LH ... estrogen and progesterone
C HCG ... estrogen and progesterone
D estrogen ... FSH
E androgens ... FSH and LH

A

Developing ovarian follicles primarily secrete _____.

A progesterone
B estrogens
C luteinizing hormone
D follicle-stimulating hormone
E human chorionic gonadotropin

B

If there is no fertilization, degeneration of the corpus luteum results in a drop in _____, which results in the sloughing off of the uterus's endometrium.

A FSH
B estrogen and progesterone
C hypothalamic secretion of releasing hormones
D HCG
E LH

B

Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle.

A 1
B 7
C 14
D 21
E 28

C

Which characteristic of the male reproductive system is not variable among animal species that reproduce sexually?

A Shape of genitalia.
B Presence of a scrotum.
C Presence of genitalia.
D Composition of accessory fluids.

C

The basic functions of the human female reproductive system are to produce eggs, develop offspring, and make hormones.
A TRUE
B FALSE

TRUE

Which function is not performed by the male reproductive system?

A Production and storage of sperm.
B Transport of semen.
C Production and storage of oogonia..
D Synthesis of accessory fluids.

C

Which hormone spikes midway through the menstrual cycle and triggers ovulation?

A Progesterone.
B Luteinizing hormone (LH).
C Follicle-stimulating hormone (FSH).
D Estradiol.

B

Which male reproductive structures are responsible for the transport and delivery of sperm?

A Seminal vesicles, prostate gland, and bulbourethral gland.
B Seminal vesicles, vas deferens, and urethra.
C Testis and epididymis.
D Vas deferens, urethra, and penis.

D

Where does a human fetus develop? >
A Uterus.
B Ovary.
C Vagina.
D Cervix

A

Which of the following events occurs at the onset of the luteal phase of the menstrual cycle?

A Development of the corpus luteum.
B Shedding of the endometrium.
C Release of high levels of FSH.
D Maturation of the follicle.

A

A surge in which hormone(s) immediately precedes ovulation?

A LH and FSH
B progesterone only
C LH only
D FSH only

A

Elevated levels of which hormone(s) most likely stimulate the LH/FSH surge just before ovulation?

A testosterone
B progesterone and estradiol
C progesterone
D estradiol

D

A contraceptive pill that continuously inhibits the release of GnRH from the hypothalamus will

A reduce the secretion of gonadotropins from the anterior pituitary gland.
B increase the production of estrogen and progesterone by the ovaries.
C initiate ovulation.
D increase the flow phase of the menstrual cycle.
E stimulate the secretion of LH and FSH from the posterior pituitary gland.

A

An inactivating mutation in the progesterone receptor gene would likely result in

A the absence of secondary sex characteristics.
B the absence of mammary gland development.
C enlarged and hyperactive uterine endometrium.
D the inability of the uterus to support pregnancy.
E the absence of pituitary gonadotropin hormones.

D

Human pregnancy is indicated by the presence of chorionic-gonadotropin metabolites in the urine until _____.

A the child is delivered (born)
B 48 hours after conception
C the placenta takes over for the ovaries in producing the steroid hormones needed during pregnancy
D the fetus grows to about 3-3.5 kg
E the end of parturition

C

A primary response by the Leydig cells in the testes to the presence of luteinizing hormone is an increase in the synthesis and secretion of

A oxytocin.
B inhibin.
C progesterone.
D testosterone.
E prolactin.

D

A reproductive hormone that is secreted directly from a structure in the brain is

A testosterone.
B gonadotropin-releasing hormone.
C follicle-stimulating hormone.
D estradiol.
E progesterone.

B

The primary function of the corpus luteum is to

A support pregnancy in the second and third trimesters.
B nourish and protect the egg cell.
C stimulate the development of the mammary glands.
D maintain progesterone and estrogen synthesis after ovulation has occurred.
E produce prolactin in the alveoli.

D

For the 10 days following ovulation in a nonpregnant menstrual cycle, the main source of progesterone is the
A developing follicle.
B adrenal cortex.
C anterior pituitary.
D placenta.
E corpus luteum.

E

Ovulation is the follicular response to a burst of secretion of
A LH.
B inhibin.
C estradiol.
D prolactin.
E progesterone.

A

Prior to ovulation, the primary steroid hormone secreted by the growing follicle is

A GnRH.
B LH.
C FSH.
D estradiol.
E inhibin.

D

The hypothalamic hormone that stimulates hormone secretion by the anterior pituitary gland is

A GnRH.
B inhibin.
C LH.
D estradiol.
E FSH.

A

The hypothalamic hormone that triggers the secretion of FSH is

A progesterone.
B estradiol.
C human chorionic gonadotropin (HCG).
D gonadotropin-releasing hormone (GnRH).
E luteinizing hormone (LH).

D

What embryo-produced hormone maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy?

A progesterone
B human chorionic gonadotropin (HCG)
C gonadotropin-releasing hormone (GnRH)
D luteinizing hormone (LH)
E follicle-stimulating hormone (FSH)

B