CHAPTER 46 Flashcards
Suppose you wanted to start an animal-breeding business. For most of the following animals, you could start out with just a single animal. Which of the animals below would require that you start with at least two individuals?
A stony corals
B sea anemones
C whiptail lizards in the genus Aspidoscelis
The "reproductive handicap" for sexual reproduction refers to ___
A the need for maturation prior to reproduction
B the difficulty of finding mates
C the need to provide energy for the offspring
D have only half the offspring are females
E dependence on hormonal cycles
Animals utilizing external fertilization are typically _____.
A land animals
C aquatic animals
D animals that reproduce asexually
Salamander and insect populations consisting only of genetically identical females lack males because _____
A a mutation in the population has eliminated the salamander equivalent of the Y chromosome
B a sex-linked, dominant, lethal mutation is fixed in the population
C males are killed at birth by their mothers
D sperm do not fuse with eggs during reproduction, but the eggs develop
into embryos anyway
E these ancient forms preceded sexual evolution
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.
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
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.
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
Which hormone’s secretion is controlled by a positive feedback mechanism?
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.
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.
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
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.
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
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.
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.
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.
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.
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.
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.
True or false? Humans form gametes by a process called gametogenesis.
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.
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.
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.
Which diploid cells are produced by an embryonic germ cell?
C Polar body.
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.
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.
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
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
E the names and chemical identities of the pituitary hormones are completely
different between males and females
Sperm cells are stored within human males in the
A bulbourethral gland.
D seminal vesicles.
Sperm become capable of movement while in the _____.
A seminiferous tubules
B vas deferens
C ejaculatory ducts
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
Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth?
E parathyroid hormone
Which pituitary secretion stimulates sperm production?
Which pituitary secretion stimulates the testes to secrete androgens?
A fertilized egg usually implants itself and develops in the _____.
D abdominal cavity
E none of these
A rapid increase in the _____ level stimulates ovulation.
C luteinizing hormone
D follicle-stimulating hormone
E human chorionic gonadotropin
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
Developing ovarian follicles primarily secrete _____.
C luteinizing hormone
D follicle-stimulating hormone
E human chorionic gonadotropin
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.
B estrogen and progesterone
C hypothalamic secretion of releasing hormones
Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle.
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.
The basic functions of the human female reproductive system are to produce eggs, develop offspring, and make hormones.
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.
Which hormone spikes midway through the menstrual cycle and triggers ovulation?
B Luteinizing hormone (LH).
C Follicle-stimulating hormone (FSH).
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.
Where does a human fetus develop? >
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 surge in which hormone(s) immediately precedes ovulation?
A LH and FSH
B progesterone only
C LH only
D FSH only
Elevated levels of which hormone(s) most likely stimulate the LH/FSH surge just before ovulation?
B progesterone and estradiol
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.
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.
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
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 reproductive hormone that is secreted directly from a structure in the brain is
B gonadotropin-releasing hormone.
C follicle-stimulating hormone.
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.
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.
E corpus luteum.
Ovulation is the follicular response to a burst of secretion of
Prior to ovulation, the primary steroid hormone secreted by the growing follicle is
The hypothalamic hormone that stimulates hormone secretion by the anterior pituitary gland is
The hypothalamic hormone that triggers the secretion of FSH is
C human chorionic gonadotropin (HCG).
D gonadotropin-releasing hormone (GnRH).
E luteinizing hormone (LH).
What embryo-produced hormone maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy?
B human chorionic gonadotropin (HCG)
C gonadotropin-releasing hormone (GnRH)
D luteinizing hormone (LH)
E follicle-stimulating hormone (FSH)