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185 terms

exam 4

STUDY
PLAY
Regeneration, the regrowth of lost body parts, normally follows
a) fragmentation.
b) all types of sexual reproduction.
c) fission.
d) parthenogenesis.
e) all types of asexual reproduction.
a) fragmentation
Genetic mutations in asexually reproducing organisms lead to more evolutionary change than do genetic mutations in sexually reproducing ones because
a) asexually reproducing organisms devote more time and energy to the process of reproduction than do sexually reproducing organisms.
b) asexually reproducing organisms, but not sexually reproducing organisms, pass all mutations to their offspring.
c) sexually reproducing organisms can produce more offspring in a given time than can sexually reproducing organisms.
d) more genetic variation is present in organisms that reproduce asexually than is present in those that reproduce sexually.
e) asexually reproducing organisms have more dominant genes than organisms that reproduce sexually.
b) asexually reproducing organisms, but not sexually reproducing organisms, pass all mutations to their offspring.
Asexual reproduction results in greater reproductive success than does sexual reproduction
a) when a species has accumulated numerous deleterious mutations.
b) when a species is expanding into diverse geographic settings.
c) when a species is in stable and favorable environments.
d) when pathogens are rapidly diversifying.
e) when there is some potential for rapid overpopulation.
c) when a species is in stable and favorable environments.
One of the evolutionary "enigmas," or unsolved puzzles, of sexual reproduction is due to the fact 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) asexual reproduction produces offspring of greater genetic variety.
e) only half of the offspring from sexually reproducing females are also females.
e) only half of the offspring from sexually reproducing females are also females.
An advantage of asexual reproduction is that
a) asexual reproduction enables the species to rapidly colonize habitats that are favorable to that species.
b) asexual reproduction produces offspring that respond effectively to new pathogens.
c) asexual reproduction allows a species to readily rid itself of harmful mutations.
d) asexual reproduction enhances genetic variability in the species.
e) asexual reproduction allows the species to endure long periods of unstable environmental conditions.
a) asexual reproduction enables the species to rapidly colonize habitats that are favorable to that species.
Sexual reproduction patterns include the example of
a) hermaphroditism.
b) fragmentation.
c) fission.
d) budding.
e) parthenogenesis.
a) hermaphroditism
If you observe vertebrate organisms with parthenogenetic reproduction, internal development of embryos, and the lack of parental care for its young, you should categorize these organisms as
a) frogs.
b) birds.
c) lizards.
d) earthworms.
e) mammals.
c) lizards
Environmental cues that influence the timing of reproduction generally do so by
a) direct effects on hormonal control mechanisms.
b) providing access to water for external fertilization.
c) increasing ambient temperature to that which is comfortable for sex.
d) increasing the body temperature.
e) direct effects on gonadal structures.
a) direct effects on hormonal control mechanisms.
Sexual reproduction
a) yields more numerous offspring more rapidly than is possible with asexual reproduction.
b) guarantees that both parents will provide care for each offspring.
c) allows animals to conserve resources and reproduce only during optimal conditions.
d) can produce diverse phenotypes that may enhance survival of a population in a changing environment.
e) enables males and females to remain isolated from each other while rapidly colonizing habitats.
d) can produce diverse phenotypes that may enhance survival of a population in a changing environment.
For water fleas of the genus Daphnia, switching from a pattern of asexual reproduction to sexual reproduction coincides with
a) completion of puberty.
b) greater abundance of food resources.
c) exhaustion of an organism's supply of eggs.
d) periods of temperature or food stresses.
E) environmental conditions becoming more favorable.
d) periods of temperature or food stresses.
All individuals of a particular species of whiptail lizards are females. Their reproductive efforts depend on
A) gonadal structures that only undergo mitosis.
B) fragmentation via autolysis.
C) budding prior to the development of a sexual phenotype.
D) meiosis followed by a doubling of the chromosomes in eggs.
E) fertilization of their eggs by males of other lizard species.
D) meiosis followed by a doubling of the chromosomes in eggs.
Evidence that parthenogenic whiptail lizards are derived from sexually reproducing ancestors includes
A) the observation that all of the offspring are haploid.
B) dependence on favorable weather conditions for ovulation to occur.
C) the requirement for male-like behaviors in some females before their partners will ovulate.
D) the development and then regression of testes prior to sexual maturation.
E) the persistence of a vestigial penis among some of the females.
C) the requirement for male-like behaviors in some females before their partners will ovulate.
Like many other fishes, bluehead wrasses utilize harem mating as they reproduce sexually, but unlike most fish,
A) their offspring can be either haploid or diploid.
B) they function without any signaling by steroid hormones.
C) they undergo a prolonged diapause during low tide.
D) they are simultaneous hermaphrodites.
E) large females morph into reproductively competent males.
E) large females morph into reproductively competent males.
Animals with reproduction dependent on internal fertilization need not have
A) behavioral interaction between males and females.
B)any copulatory organs.
C) receptacle that receives sperm.
D) HAPLOID GAMETES
E) INTERNAL DEVELOPMENT OF EMBRYOS
E) INTERNAL DEVELOPMENT OF EMBRYOS
In close comparisons, external fertilization often yields more offspring than does internal fertilization, but internal fertilization offers the advantage that
A)it is the only way to ensure the survival of the species.
B) it requires expression of fewer genes and maximizes genetic stability.
C) the smaller number of offspring produced often receive a greater amount of parental investment.
D) it permits the most rapid population increase.
E) it requires less time and energy to be devoted to reproduction.
C) the smaller number of offspring produced often receive a greater amount of parental investment.
Internal and external fertilization both
A) depend on the use of intromittent copulatory organs.
B) occur only among terrestrial animals.
C) occur only among invertebrates.
D) occur only among birds.
E) produce zygotes.
E) PRODUCE ZYGOTES
Organisms with a reproductive pattern that produce shelled amniotic eggs generally
A) invest most of their reproductive energy in the embryonic and early postnatal development of their offspring.
B) invest more energy in parenting than do placental animals.
C) produce more gametes than do those animals with external fertilization and development.
D) end up having a higher embryo mortality rate than do organisms with unprotected embryos.
E) lower their embryo mortality rate to less than one in a thousand.
A) invest most of their reproductive energy in the embryonic and early postnatal development of their offspring.
Which statement is false concerning reproduction in invertebrate animals?
A) Some have both sexes within one individual organism.
B) Some utilize internal fertilization.
C) Separate sexes are not observed among any invertebrates.
D) Some utilize external fertilization.
E) None of the invertebrates have structures that store sperm.
E) None of the invertebrates have structures that store sperm.
A cloaca is an anatomical structure found in many nonmammalian vertebrates, which functions as
A) a specialized sperm-transfer device produced by males.
B) a source of nutrients for developing sperm in the testes.
C) a common exit for the digestive, excretory, and reproductive systems.
D) a region bordered by the labia minora and clitoris in females.
E) a gland that secretes mucus to lubricate the vaginal opening.
C) a common exit for the digestive, excretory, and reproductive systems.
Chemical signals exchanged between potential reproductive partners are called
A) pheromones.
B) cytokines.
C) paracrine signals.
D) hormones.
E) gametes.
A) PHEROMONES
Females of many insect species, including honeybee queens, can store gametes shed by their mating partners in
A) their nests.
B) the uterus.
C) the abdominal tract.
D) the spermatheca.
E) the cloaca.
D) the spermatheca.
Most flatworms, including parasitic liver flukes, are hermaphrodites where zygotes form as the result of
A) eggs and sperm mixing together in wastewater.
B) internal fertilization.
C) eggs and sperm mixing together in excreted feces.
D) external fertilization.
E) parthenogenesis.
B) INTERNAL FERTILIZATION
When female fruit flies mate with two different males on the same day,
A) the second male's sperm fertilizes most of the eggs.
B) the first and second males fertilize equal numbers of eggs.
C) the first male's sperm fertilizes most of the eggs.
D) none of the eggs become fertilized.
E) the first male's sperm fertilizes all of the eggs
A) the second male's sperm fertilizes most of the eggs.
The junction of the upper vagina and the uterus is called the
A) clitoris.
B) cervix.
C) oviduct.
D) labia majora.
E) fallopian tube.
B) CERVIX
An oocyte released from a human ovary enters the oviduct as a result of
A) movement of the oocyte through the pulsing uterus into the oviduct.
B) the beating action of the flagellum on the oocyte.
C) Peristaltic contraction of ovarian muscles.
the force of the follicular ejection directing the
D) oocyte into the oviduct.
E) the wavelike beating of cilia lining the oviduct.
E) the wavelike beating of cilia lining the oviduct.
In humans, the follicular cells that remain behind in the ovary following ovulation become
A) the placenta, which secretes cervical mucus.
B) a steroid-hormone synthesizing structure called the corpus luteum.
C) swept into the fallopian tube.
D) ovarian endometrium shed at the time of menses.
E) the thickened portion of the uterine wall.
B) a steroid-hormone synthesizing structure called the corpus luteum.
The male and female structures that consist mostly of erectile tissue include
A) seminiferous tubules and hymen.
B) penis and clitoris.
C) prostate and ovaries.
D) vas deferens and oviduct.
E) testes and ovaries.
B) penis and clitoris.
Testosterone is synthesized primarily by the
A) anterior pituitary gland.
B) hypothalamus.
C) seminiferous tubules.
D) Leydig cells.
E) sperm cells.
D) Leydig cells.
Sperm cells are stored within human males in the
A) seminal vesicles.
B) epididymis.
C) bulbourethral gland.
D) prostate.
E) urethra.
B) EPIDIDYMIS
Among human males, both semen and urine normally travel along the
A) seminal vesicle.
B) vas deferens.
C) urinary bladder.
D) urethra.
E) ureter.
D) URETHRA
Human sperm cells first arise in the
A) epididymis.
B) vas deferens.
C) seminiferous tubules.
D) Sertoli cells.
E) prostate gland.
C) seminiferous tubules.
The surgical removal of the seminal vesicles would likely
A) cause sterility because sperm would not be produced.
B) greatly reduce the volume of semen.
C) cause sterility because sperm would not be able to exit the body.
D) enhance the fertilization potency of sperm in the uterus.
E) cause the testes to migrate back into the abdominal cavity.
B) greatly reduce the volume of semen.
Most of the noncellular fluid in ejaculated human semen is composed of
A) anticoagulant enzymes.
B) the secretions of the seminiferous tubules.
C) the secretions of the bulbourethral glands.
D) the secretions of the seminal vesicles.
E) the secretions of the prostate gland.
D) the secretions of the seminal vesicles.
Increasing and holding the temperature of the scrotum by 2°C, near the normal body-core temperature, would
A) reduce the fertility of the man by impairing by abolishing sexual interest.
B) reduce the fertility of the man by impairing spermatogenesis.
C) reduce the fertility of the man by impairing the production of gonadal steroid hormones.
D) increase the fertility of the affected man by enhancing the rate of spermatogenesis.
E) have no effect on male reproductive processes.
B) reduce the fertility of the man by impairing spermatogenesis.
During human heterosexual (mutual) excitement, vasocongestion
A) occurs only in the clitoris.
B) occurs only in the penis.
C) occurs only in the upper vagina.
D) occurs in the clitoris, vagina, and penis.
E) occurs only in the testes.
D) occurs in the clitoris, vagina, and penis.
The moment of orgasm is characterized by
A) the ovulation of the oocyte from the ovary.
B) rhythmic contraction of many parts of the reproductive system.
C) the release of sperm from the seminiferous tubules.
D) increased synthesis and release of testicular steroid hormones.
E) increased synthesis and release of ovarian steroid hormones.
B) rhythmic contraction of many parts of the reproductive system.
At the time of fertilization, the complete maturation of each oogonium has resulted in
A) two primary oocytes.
B) one secondary oocyte.
C) four zygotes.
D) four secondary oocytes.
E) four primary oocytes.
B) one secondary oocyte.
In vertebrate animals, spermatogenesis and oogenesis differ, in that
A) oogenesis ends at menopause, whereas spermatogenesis is finished before birth.
B) oogenesis produces four haploid cells, whereas spermatogenesis produces only one functional spermatozoon.
C) spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed by the time a girl is born.
D) oogenesis begins at the onset of sexual maturity, whereas spermatogenesis happens in embryonic development.
E) cytokinesis is unequal in oogenesis, whereas it is equal in spermatogenesis.
E) cytokinesis is unequal in oogenesis, whereas it is equal in spermatogenesis.
Mature human sperm and ova are similar in that
A) they are produced from puberty until death.
B) they are formed before birth.
C) they both have the same number of chromosomes.
D) they are approximately the same size.
E) they each have a flagellum that provides motility.
C) they both have the same number of chromosomes.
The primary difference between estrous and menstrual cycles is that
A) behavioral changes during estrous cycles are much less apparent than those of menstrual cycles.
B) copulation normally occurs across the estrous cycle, whereas in menstrual cycles copulation only occurs during the period surrounding ovulation.
C) the endometrium shed by the uterus during the estrous cycle is reabsorbed but the shed endometrium is excreted from the body during the menstrual cycle.
D) season and climate have less pronounced effects on estrous cycle than they do on menstrual cycles.
E) most estrous cycle are of much longer duration compared to menstrual cycles.
C) the endometrium shed by the uterus during the estrous cycle is reabsorbed but the shed endometrium is excreted from the body during the menstrual cycle.
A male's "primary" sex characteristics include
A) embryonic differentiation of the seminal vesicles.
B) deepening of the voice at puberty.
C) onset of growth of facial hair at puberty.
D) elongation of the skeleton prior to puberty.
E) growth of skeletal muscle.
A) embryonic differentiation of the seminal vesicles.
The breakdown and discharge of the soft uterine tissues that occurs if no egg is fertilized is called
A) menstruation.
B) fertilization.
C) menopause.
D) lactation.
E) ovulation
A) menstruation.
correct chronological order, the three phases of the uterine cycle are
menstrual, proliferative, and secretory ...
In correct chronological order, the three phases of the ovarian cycle are
follicular, ovulation, luteal
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) progesterone.
B) prolactin.
C) oxytocin.
D) testosterone.
E) inhibin.
D) TESTOSTERONE
This hormone is secreted directly from a structure in the brain:
A) follicle stimulating hormone
B) gonadotropin-releasing hormone
C) testosterone
D) progesterone
E) estradiol
B) gonadotropin-releasing hormone
The primary function of the corpus luteum is to
A) support pregnancy in the second and third trimesters.
B) maintain progesterone and estrogen synthesis after ovulation has occurred.
C) stimulate the development of the mammary glands.
D) produce prolactin in the alveoli.
E) nourish and protect the egg cell.
B) maintain progesterone and estrogen synthesis after ovulation has occurred.
For the 10 days following ovulation in a nonpregnant menstrual cycle, the main source of progesterone is the
A) placenta.
B) adrenal cortex.
C) anterior pituitary.
D) developing follicle.
E) corpus luteum.
E) CORPUS LUTEUM
Prior to ovulation, the steroid hormone secreted by the growing follicle is
A) FSH.
B) GnRH.
C) estradiol.
D) LH.
E) inhibin.
C) ESTRADIOL
Ovulation is the follicular response to a burst of secretion of
A) prolactin.
B) LH.
C) estradiol.
D) inhibin.
E) progesterone.
B) LH
The hypothalamic hormone that stimulates hormone secretion by the anterior pituitary gland is
A) GnRH.
B) estradiol.
C) Inhibin.
D) FSH.
E) LH.
A) GnRH.
Fertilization of human eggs usually takes place in the
A) vagina.
B) cervix.
C) oviduct.
D) uterus.
E) ovary
C) OVIDUCT
For normal human fertilization to occur,
A) the secondary oocyte must implant in the uterus.
B) secretion of pituitary FSH and LH must decrease.
C) the uterus must be enlarged.
D) many ova must be released.
E) only one sperm need penetrate one egg.
E) only one sperm need penetrate one egg.
This embryonic hormone maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy:
A) gonadotropin-releasing hormone (GnRH)
B) follicle-stimulating hormone (FSH)
C) progesterone
D) human chorionic gonadotropin (HCG)
E) luteinizing hormone (LH)
D) human chorionic gonadotropin (HCG)
The hormone progesterone is produced
A) in the pituitary and acts directly on the uterus.
B) in the uterus and acts directly on the pituitary.
C) in the uterus and acts directly on the pituitary.
D) in the pituitary and acts directly on the ovary.
E) in the ovary and acts directly on the uterus.
E) in the ovary and acts directly on the uterus.
Which hypothalamic hormone triggers the secretion of FSH?
A) follicle-stimulating hormone (FSH)
B) luteinizing hormone (LH)
C) human chorionic gonadotropin (HCG)
D) gonadotropin-releasing hormone (GnRH)
E) progesterone
D) gonadotropin-releasing hormone (GnRH)
A high rate of metabolic activity is maintained in the pregnant uterus by
A) testosterone.
B) inhibin.
C) prolactin.
D) progesterone.
E) oxytocin
D) progesterone.
The secretion of follicle stimulating hormone from the pituitary is reduced by
A) luteinizing hormone.
B) vasopressin.
C) oxytocin.
D) prolactin.
E) inhibin.
E) INHIBIN
Human fertility drugs increase the chance of multiple births, probably because they
A) stimulate follicle development.
B) enhance implantation.
C) prevent parturition.
D) mimic progesterone.
E) stimulate spermatogenesis.
A) stimulate follicle development.
The drug RU486 functions by
A) preventing release of the secondary oocyte from the ovary.
B) inhibiting release of gonadotropins from the pituitary.
C) blocking progesterone receptors in the uterus.
D) inhibiting release of gonadotropins from the pituitary, and blocking progesterone receptors in the uterus.
E) inhibiting release of gonadotropins from the pituitary, blocking progesterone receptors in the uterus, and preventing release of the secondary oocyte from the ovary
C) blocking progesterone receptors in the uterus.
A reliable "marker" that a pregnancy has initiated, and that is detectable in excreted urine, is
A) follicle-stimulating hormone.
B) estrogen.
C) chorionic gonadotropin.
D) hypothalamus releasing factors.
E) progesterone.
C) chorionic gonadotropin.
Menopause is caused by
A) an increase in the blood supply to the ovaries.
B) a decline in production of the gonadotropin hormones by the anterior pituitary gland.
C) wearing away of the uterine endometrium.
D) reduced synthesis of ovarian steroids despite high levels of gonadotropin hormones.
E) a halt in the synthesis of gonadotropin-releasing hormone by the brain.
D) reduced synthesis of ovarian steroids despite high levels of gonadotropin hormones.
A thin layer of the developing embryo that secretes the hormone that keeps the corpus luteum functioning is
A) chorion.
B) plasma membrane.
C) endometrium.
D) amnion.
E) cervix.
A) chorion.
A woman in the final week of pregnancy who is given an injection of oxytocin would likely
A) stop secreting prostaglandins from the placenta.
B) be prevented from lactation.
C) undergo the loss of oxytocin receptors from her uterine smooth muscle cells.
D) undergo vigorous contractions of her uterine muscles.
E) increase the synthesis and secretion of progesterone.
D) undergo vigorous contractions of her uterine muscles.
The "immunotolerance" of a pregnant woman toward her unborn child is the result of
A) the complete physical separation from her cells and those of the unborn child.
B) the relative quiescence of a pregnant woman's immune system compared to when she was not pregnant.
C) the tenacity with which the unborn child's immune system counteracts the woman's immune system.
D) modern medical intervention during every pregnancy.
E) the unborn child having enough of the woman's identity so as to escape detection as foreign.
B) the relative quiescence of a pregnant woman's immune system compared to when she was not pregnant.
The use of birth-control pills (oral contraceptives)
A) prevents oocytes from entering the uterus.
B) prevents sperm from exiting the male urethra.
C) prevents fertilization by keeping sperm and egg physically separated by a mechanical barrier.
D) reduces the incidence of ovulation.
E) prevents implantation of an embryo.
D) reduces the incidence of ovulation.
Among these contraception methods, which has the highest risk of accidental pregnancy?
A) diaphragm
B) rhythm method
C) condom
D) vasectomy
E) coitus interruptus
E) coitus interruptus
Which pair includes two contraceptive methods that are generally irreversible means to block gametes from moving to a site where fertilization can occur?
A) male condom and oral contraceptives
B) male condom and female condom
C) diaphragm and subcutaneous progesterone implant
D) vasectomy and tubal ligation
E) coitus interruptus and rhythm method
D) vasectomy and tubal ligation
Tubal ligation
A) prevents fertilization by preventing sperm from entering the uterus.
B) reduces the incidence of ovulation.
C) prevents sperm from exiting the male urethra.
D) prevents oocytes from entering the uterus.
E) prevents implantation of an embryo.
D) prevents oocytes from entering the uterus.
Vasectomy
A) prevents sperm from exiting the male urethra.
B) eliminates testosterone synthesis.
C) prevents oocytes from entering the uterus.
D) eliminates spermatogenesis.
E) prevents implantation of an embryo.
A) prevents sperm from exiting the male urethra.
For lactation to take place, __________ stimulates the synthesis of breast milk and __________ causes milk expulsion.
A) prolactin; oxytocin
B) estrogen; progesterone
C) cortisol; testosterone
D) testosterone; dihydrotestosterone
E) luteinizing hormone; follicle stimulating hormone
A) prolactin; oxytocin
So-called "combination" birth-control pills function in contraception by
A) inhibiting the release of GnRH, FSH, and LH.
B) binding to and inactivating any sperm that enter the oviduct.
C) blocking progesterone receptors, so that pregnancy cannot be maintained.
D) irritating the uterine lining so as to prevent implantation.
E) causing spontaneous abortions.
A) inhibiting the release of GnRH, FSH, and LH.
A contraceptive pill that continuously inhibits the release of GnRH from the hypothalamus will
A) initiate ovulation.
B) increase the flow phase of the menstrual cycle.
C) reduce the secretion of gonadotropins from the anterior pituitary gland.
D) stimulate the secretion of LH and FSH from the posterior pituitary gland.
E) increase the production of estrogen and progesterone by the ovaries.
C) reduce the secretion of gonadotropins from the anterior pituitary gland.
A function-disrupting mutation in the progesterone receptor gene would likely result in
A) enlarged and hyperactive uterine endometrium.
B) the inability of the uterus to support pregnancy.
C) the absence of pituitary gonadotropin hormones.
D) the absence of mammary gland development.
E) the absence of secondary sex characteristics.
B) the inability of the uterus to support pregnancy.
Time-release progesterone implants function in contraception by
A) increasing gonadotropin secretion to abnormally high levels.
B) activating inflammation responses in the uterus.
C) reducing libido.
D) thickening the cervical and uterine mucus to impair sperm movement.
E) increasing the frequency of ovulation.
D) thickening the cervical and uterine mucus to impair sperm movement.
The secretion of hormone A causes a change in the amount of protein X in an organism. If this mechanism works by positive feedback, which of the following statements represents that fact?
a) A decrease in A produces an increase in X.
b) An increase in X produces a decrease in A.
c) An increase in A produces an increase in X.
d) an increase in A produces an increase in X, and an increase in X produces a decrease in A.
e) an increase in X produces a decrease in A, and a decrease in A produces in an increase in X.
c) An increase in A produces an increase in X.
Which of the following is a local regulator responsible for activating an enzyme that relaxes smooth muscle cells?
a) prostaglandin F
b) nitric oxide
c) epinephrine
d) nitric oxide and prostaglandin F only
e) nitric oxide, prostaglandin F, and epinephrine
Correct
b) nitric oxide
Prostaglandins are local regulators whose basic structure is derived from
a) nitric oxide
b) fatty acids.
c) oligosaccharides.
d) amino acids.
e) steroids.
b) fatty acids.
Which of the following examples is incorrectly paired with its class?
a) ecdysone-steroid hormone
b) neurotransmitter-local regulator
c) estrogen-steroid hormone
d) cytokines-local regulator
e) prostaglandin-peptide hormone
e) prostaglandin-peptide hormone
What is the mode of action of aspirin and ibuprofen?
a) They inhibit the synthesis of prostaglandins.
b) They inhibit the release of nitric oxide, a potent vasodilator.
c) They block paracrine signaling pathways.
d) They stimulate the release of endorphins.
d) They stimulate the release of oxytocin.
a) They inhibit the synthesis of prostaglandins.
A cell that contains proteins enabling a hormone to selectively bind to its plasma membrane is called a(n)
a) endocrine cell.
b) target cell.
c) secretory cell.
d) plasma cell.
e) regulatory cell.
b) target cell.
Only certain cells in the body are target cells for the steroid hormone aldosterone. Which of the following is the best explanation for why these are the only cells that respond to this hormone?
a) Aldosterone is unable to enter nontarget cells.
b) Only target cells contain receptors for aldosterone.
c) Nontarget cells destroy aldosterone before it can produce its effect.
d) Nontarget cells convert aldosterone to a hormone to which they do respond.
e) Only target cells are exposed to aldosterone.
b) Only target cells contain receptors for aldosterone.
Why is it that some body cells respond differently to the same peptide hormones?
a) Different target cells have different genes.
b) The circulatory system regulates responses to hormones by routing the hormones to specific targets.
c) A target cell's response is determined by the product of a signal transduction pathway.
d) The hormone is chemically altered in different ways as it travels through the circulatory system.
e) Each cell knows how it fits into the body's master plan.
c) A target cell's response is determined by the product of a signal transduction pathway.
Which of the following statements about hormones is incorrect?
a) They travel through a dedicated pathway.
b) Not all cells respond to a particular hormone.
c) They communicate messages throughout the body.
d) They circulate in blood or hemolymph.
e) They are secreted into the extracellular fluid.
a) They travel through a dedicated pathway.
Which of the following statements about hormones is incorrect?
a) Glands that produce them are ductless glands.
b) Some are water soluble and some are not.
c) They may turn genes off or on.
d) They often maintain steady-state conditions.
e) They are produced only by organs called endocrine organs.
e) They are produced only by organs called endocrine organs.
Which of the following does not represent a chemical signal?
a) movement of a signal from one nerve to the next
b) an immune cell releasing a cytokine
c) chemicals released into the bloodstream from nerve cells
d) movement of a signal from one end of a nerve to the other end of the nerve
e) a chemical released that affects the cell that releases
d) movement of a signal from one end of a nerve to the other end of the nerve
Hormone X produces its effect in its target cells via the cAMP second messenger system. Which of the following will produce the greatest effect in the cell?
a) a molecule of activated, cAMP-dependent protein kinase injected into the cytoplasm of the cell
b) a molecule of hormone X applied to the extracellular fluid surrounding the cell
c) a molecule of cAMP applied to the extracellular fluid surrounding the cell
d) a molecule of hormone X injected into the cytoplasm of the cell
e) a molecule of cAMP injected into the cytoplasm of the cell
b) a molecule of hormone X applied to the extracellular fluid surrounding the cell
Which of the following is (are) true?
a) Hormones regulate cellular functions, and generally negative feedback regulates hormone levels.
b) The circulating level of a hormone is held constant through a series of positive feedback loops.
c) Both lipid-soluble hormones and water-soluble hormones bind to intracellular protein receptors.
d) The ducts of endocrine organs release their contents into the bloodstream.
e) Hormones regulate cellular functions, generally negative feedback regulates hormone levels, and both lipid-soluble hormones and water-soluble hormones bind to intracellular protein receptors.
a) Hormones regulate cellular functions, and generally negative feedback regulates hormone levels.
What do nitric oxide and epinephrine have in common?
a) They both function as hormones.
b) They bind the same receptors.
c) They are both involved in the "fight-or-flight" response.
d) They both function as neurotransmitters.
e) They both function as neurotransmitt ers, and they both function as hormones.
e) They both function as neurotransmitt ers, and they both function as hormones.
Substance X is secreted by one cell, travels a short distance through interstitial fluid, and produces an effect in a cell immediately adjacent to the original secreting cell. All of the following terms could describe this substance except
a) growth factor.
b) prostaglandin.
c) pheromone.
d) neurotransmitter.
e) nitric oxide.
c) pheromone.
Which of the following statements about hormones that promote homeostasis is incorrect?
a) This response feeds back to promote the release of more hormone.
b) A stimulus causes an endocrine cell to secrete a particular hormone.
c) Signal transduction brings about a response in the target cell.
d) The hormone travels in the bloodstream to target cells.
e) Specific receptors bind with the hormone.
a) This response feeds back to promote the release of more hormone.
Which of the following are not part of homeostasis promotion or maintenance?
a) A stimulus causes an endocrine cell to secrete a particular hormone, which decreases the stimulus.
b) Signal transduction brings about a response in the target cell.
c) A hormone acts in an antagonistic way with another hormone.
d) Secretin promotes an increase in the pH of the duodenum.
e) A hormone is involved in a positive feedback loop.
e) A hormone is involved in a positive feedback loop.
When an individual is subject to short-term starvation, most available food is used to provide energy (metabolism) rather than building blocks (growth and repair). Which hormone would be particularly active in times of food shortage?
a) epinephrine
b) antidiuretic hormone
c) insulin
d) glucagon
e) oxytocin
d) glucagon
Based on their effects, which pair below could be considered antagonistic?
a) endocrine and exocrine glands
b) hormones and target cells
c) growth hormone and ecdysone
d) neurosecretory cells and neurotransmitters
e) prostaglandin F and nitric oxide
e) prostaglandin F and nitric oxide
The endocrine system and the nervous system are structurally related. Which of the following cells best illustrates this relationship?
a) a brain cell in the cerebral cortex
b) a neurosecretory cell in the hypothalamus
c) a neuron in the spinal cord
d) a cell in the pancreas that produces digestive enzymes
e) a steroid-producing cell in the adrenal cortex
b) a neurosecretory cell in the hypothalamus
The hypothalamus controls the anterior pituitary by means of
a) antibodies.
b) third messengers.
c) releasing hormones.
d) second messengers.
e) cytokines.
c) releasing hormones.
Short blood vessels connect two capillary beds lying in which of the following?
a) hypothalamus and anterior pituitary
b) anterior pituitary and posterior pituitary
c) anterior pituitary and adrenal gland
d) posterior pituitary and thyroid gland
e) hypothalamus and thalamus
a) hypothalamus and anterior pituitary
If a person drinks a large amount of water in a short period of time, he or she may die from water toxicity. ADH can help prevent water retention through interaction with target cells in the
anterior pituitary.
bladder.
kidney.
posterior pituitary.
adrenal gland.
kidney
Which of the following statements about the hypothalamus is incorrect?
a) It is part of the central nervous system.
b) It is subject to feedback inhibition by certain hormones.
c) It secretes tropic hormones that act directly on the gonads.
d) Its neurosecretory cells terminate in the posterior pituitary.
e) It functions as an endocrine gland.
c) It secretes tropic hormones that act directly on the gonads.
Prolactin stimulates mammary gland growth and development in mammals and regulates salt and water balance in freshwater fish. Many scientists think that this wide range of functions indicates which of the following?
a) Prolactin interacts with many different receptor molecules.
b) Prolactin has a unique mechanism for eliciting its effects.
c) Prolactin is an evolutionary conserved hormone.
d) Prolactin is a nonspecific hormone.
e) Prolactin is derived from two separate sources.
c) Prolactin is an evolutionary conserved hormone.
Which of the following have nontropic effects only?
ACTH
TSH
FSH
MSH
LH
MSH
Synthetic versions of which of the following hormones are being used as insecticides to prevent insects from maturing into reproducing adults?
A) oxytocin
B) brain hormone
C) ecdysone
D) prothoracic hormone
E) juvenile hormone
E) juvenile hormone
Which of the following is a steroid hormone that triggers molting in arthropods?
A) ecdysone
B) oxytocin
C) thyroxine
D) glucagon
E) growth hormone
A) ecdysone
Which of the following statements about hormones is incorrect?
A) They are carried by the circulatory system.
B) They are used to communicate between different organisms.
C) They are produced by endocrine glands.
D) They are modified amino acids, peptides, or steroid molecules.
E) They elicit specific biological responses from target cells.
B) They are used to communicate between different organisms.
Oxytocin and ADH are produced by the __________ and stored in the __________.
A) hypothalamus; neurohypophysis
B) posterior pituitary; anterior pituitary
C) anterior pituitary; thyroid
D) adrenal cortex; adrenal medulla
E) adenohypophysis; kidneys
A) hypothalamus; neurohypophysis
Which combination of hormones helps a mother to produce milk and nurse her baby?
A) oxytocin and prolactin
B) oxytocin, prolactin, and luteinizing hormone
C) prolactin and calcitonin
D) follicle-stimulating hormone and luteinizing hormone
E) luteinizing hormone and oxytocin
A) oxytocin and prolactin
Iodine is added to commercially-prepared table salt to help prevent deficiencies of this essential mineral. Which gland(s) require(s) iodine to function properly?
adrenal
thyroid
pancreas
ovaries and testes
parathyroids
THYROID
Tropic hormones from the anterior pituitary directly affect the release of which of the following?
calcitonin
parathyroid hormone
glucagon
epinephrine
thyroxine
THYROXINE
Which of the following endocrine disorders is not correctly matched with the malfunctioning gland?
A) diabetes and pancreas
B) giantism and pituitary
C) tetany and parathyroid
D) goiter and adrenal medulla
E) dwarfism and pituitary
D) goiter and adrenal medulla
One reason a person might be severely overweight is due to
A) a lower than normal level of insulin-like growth factors.
B) a defect in hormone release from the posterior pituitary.
C) an undersecretion of thyroxine.
D) hyposecretion of oxytocin.
E) a higher than normal level of melatonin.
C) an undersecretion of thyroxine.
Which of the following glands is controlled directly by the hypothalamus or central nervous system but not the anterior pituitary?
testis
ovary
adrenal cortex
adrenal medulla
thyroid
ADRENAL CORTEX
Which of the following are synthesized from the amino acid tyrosine?
A) thyroxin
B) epinephrine
C) catecholamines
D) epinephrine and catecholamines only.
E epinephrine, catecholamines, and thyroxin.
E epinephrine, catecholamines, and thyroxin.
The endocrine system and the nervous system are chemically related. Which of the following substances best illustrates this relationship?
ecdysone
norepinephrine
estrogen
calcitonin
calcium
NOREPINEPHRINE
Which of the following endocrine structures are derived from nervous tissue?
A) ovaries and the testes
B) anterior pituitary and the adrenal cortex
C) thymus and thyroid glands
D) liver and the pancreas
E) posterior pituitary and the adrenal medulla
E) posterior pituitary and the adrenal medulla
What happens when beta cells of the pancreas release insulin into the blood?
A) The liver breaks down glycogen to glucose.
B) Body cells take up more glucose.
C) Alpha cells are stimulated to release glucose into the blood.
D) Blood glucose levels rise to a set point and stimulate glucagon release.
E) Body cells take up more glucose, and alpha cells are stimulated to release glucose into the blood.
B) Body cells take up more glucose.
Blood samples taken from an individual who had been fasting for 24 hours would have which of the following?
A) high levels of insulin
B) low levels of insulin
C) high levels of glucagon
D) low levels of glucagon
E) both high levels and glucagon and low levels of insulin
E) both high levels and glucagon and low levels of insulin
All of the following are steroid hormones except
androgen.
estrogen.
cortisol.
insulin.
testosterone.
INSULIN
If the adrenal cortex were removed, which group of hormones would be most affected?
peptide
paracrine
steroid
tropic
amino acid-derived
STEROID
The results most likely occurred because progesterone exerts an effect on the
A) size of the fetus.
B) number of eggs fertilized.
C) maintenance of the uterus.
D) gestation period of rats.
E) general health of the rat
C) maintenance of the uterus.
Melatonin has been found to participate in all of the following except
A) skin pigmentation.
B) calcium deposition in bone.
C) monitoring day length.
D) reproduction.
E) biological rhythms.
B) calcium deposition in bone.
Which combination of gland and hormone would be linked to winter hibernation and spring reproduction in bears?
A) pineal gland, estrogen
B) anterior pituitary gland, gonadotropin-releasing hormone
C) pineal gland, melatonin
D) hypothalamus gland, melatonin
E) posterior pituitary gland, thyroid-stimulating hormone
C) pineal gland, melatonin
Which of the following is secreted by the pancreas?
oxytocin
ecdysone
growth hormone
glucagon
thyroxine
GLUCAGON
Which of the following stimulates and maintains metabolic processes?
ecdysone
glucagon
thyroxine
growth hormone
oxytocin
THYROXINE
Which of the following stimulates the contraction of uterine muscle?
oxytocin
ecdysone
thyroxine
growth hormone
glucagon
OXYTOCIN
Which of the following is secreted by the anterior pituitary?
ecdysone
thyroxine
oxytocin
growth hormone
glucagon
GROWTH HORMONE
Which of the following endocrine structures is (are) not controlled by a tropic hormone from the anterior pituitary?
testes
adrenal cortex
ovaries
pancreatic islet cells
thyroid glandF
PANCREATIC ISLET CELLS
Testosterone is an example of
an estrogen.
a progestin.
melatonin.
an androgen.
a catecholamine.
ANDROGEN
Estradiol is an example of
an androgen.
an estrogen.
melatonin.
a progestin.
a catecholamine.
ESTROGEN
Which of the following hormones is (are) secreted by the adrenal gland in response to stress and promote(s) the synthesis of glucose from noncarbohydrate substrates?
epinephrine
ACTH
thyroxine
glucocorticoids
glucagon
GLUCOCORTICOIDS
Which of the following statements about hormones is correct?
A) Steroid hormones affect the synthesis of proteins to be exported from the cell, whereas peptide hormones affect the synthesis of proteins that remain in the cell.
B) Steroid hormones affect the synthesis of proteins, whereas peptide hormones affect the activity of proteins already present in the cell.
C) Steroid hormones affect the activity of certain proteins within the cell, whereas peptide hormones directly affect the processing of mRNA.
D) Steroid and peptide hormones produce different effects but use the same biochemical mechanisms.
E) Steroid and peptide hormones produce the same effects but differ in the mechanisms that produce the effects.
B) Steroid hormones affect the synthesis of proteins, whereas peptide hormones affect the activity of proteins already present in the cell.
The star of a recent movie was a caterpillar that never matured into an adult. It simply got larger with each molt. What is the probable reason why the caterpillar did not mature into an adult?
A) lack of ecdysone
B) lack of the melatonin hormone
C) lack of juvenile hormone
D) decreased level of ecdysone
E) increased level of juvenile hormone
E) increased level of juvenile hormone
Which of the following statements about the adrenal gland is correct?
A) During stress, the alpha cells of islets secrete insulin and simultaneously the beta cells of the islets secrete glucagon.
B) During stress, TSH stimulates the adrenal cortex and medulla to secrete acetylcholine.
C) During stress, ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla.
D) At all times, the adrenal gland monitors calcium levels in the blood and regulates calcium by secreting the two antagonistic hormones, epinephrine and norepinephrine.
E) At all times, the anterior portion secretes ACTH, while the posterior portion secretes oxytocin.
C) During stress, ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla.
You buy a pie that contains a swirled mixture of chocolate and vanilla filling. When you cut the pie up, you notice that some slices have more chocolate than vanilla and that other slices have more vanilla than chocolate. This uneven distribution of chocolate and vanilla is most like the uneven distribution of
a) nuclei in a zygote.
b) nuclei in an egg.
c) nuclei in an early embryo.
d) cytoplasmic determinants in a zygote.
e) cytoplasmic determinants in an early embryo.
d) cytoplasmic determinants in a zygote.
A puppy is born with a malformed right leg. A veterinarian studies the animal and determines that all of the correct types of cells are present, but that the leg simply took on the wrong shape. This is most likely a problem of
preformation.
histogenesis.
morphogenesis.
cell differentiation.
fertilization.
morphogenesis
Molecular genetic evidence that certain genes shared by both humans and fruit flies initiate eye development in both species suggest a common
a) duration of pregnancy.
b) homunculi.
c) complete genome.
d) use of ATP in energy-transfer reactions.
e) genetic toolkit for development.
e) genetic toolkit for development.
As an embryo develops, new cells are produced as the result of
differentiation.
preformation.
epigenesis.
cell division.
morphogenesis.
cell division
Fertilization of an egg without activation is most like
a) resting during halftime of a basketball game.
b) walking to the cafeteria and eating lunch.
c) dropping a rock off a cliff and watching it land in the valley below.
d) placing the key in the ignition of a car but not starting the engine.
e) preparing a pie from scratch and baking it in the oven.
d) placing the key in the ignition of a car but not starting the engine.
Assume that successful reproduction in a rare salamander species, wherein all individuals are females, relies on those females having access to sperm from males of another species but that the resulting embryos show no signs of a genetic contribution from the sperm. In this case, the sperm appear to be used only for
a) morphogenesis.
b) epigenesis.
c) egg activation.
d) cell differentiation.
e) the creation of a diploid cell.
c) egg activation.
Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo
depolarization.
apoptosis.
the acrosomal reaction.
vitellogenesis.
mitosis.
the acrosomal reaction
Contact of an egg with signal molecules on sperm causes the egg to undergo a brief
mitosis.
vitellogenesis.
apoptosis.
the acrosomal reaction.
membrane depolarization
membrane depolarization
During fertilization, the acrosomal contents
a) help propel more sperm toward the egg.
b) digest the protective coat on the surface of the egg.
c) block polyspermy.
d) trigger the completion of meiosis by the sperm.
e) nourish the mitochondria of the sperm.
b) digest the protective coat on the surface of the egg.
The vitelline layer of the sea urchin egg
a) is first visible only when organogenesis is nearly completed.
b) is a mesh of proteins crossing through the cytosol of the egg.
c) releases calcium, which initiates the cortical reaction.
d) has receptor molecules that are specific for binding acrosomal proteins.
e) is outside of the fertilization membrane.
d) has receptor molecules that are specific for binding acrosomal proteins.
From earliest to latest, the overall sequence of early development proceeds as follows:
a) cleavage, gastrulation, organogenesis
b) gasrulation, organogenesis, cleavage
c) ovulation, gasturlation, fertilization
d) preformation, morphogenesis, neurulation
e) gastrulation, blasturlation, neurulation
a) cleavage, gastrulation, organogenesis
From earliest to latest, the overall sequence of early development proceeds as follows:
a) Cortical reaction, synthesis of embryo's DNA begins, crosomal reaction, first cell division
b) acrosomal reaction, cortical reaction, synthesis of embryo's DNA begins, first cell division
c) first cell division, synthesis of embryo's DNA begins, acrosomal reaction, cortical reaction
d) first cell division, synthesis of embryo's DNA begins, cortical reaction, acrosomal reaction
e) cortical reaction, acrosomal reaction, first cell division, synthesis of embryo's DNA begins
b) acrosomal reaction, cortical reaction, synthesis of embryo's DNA begins, first cell division
The cortical reaction functions directly in the
a) production of a fast block to polyspermy.
b) generation of a nerve-like impulse by the egg cell.
c) fusion of egg and sperm nuclei.
d) formation of a fertilization envelope.
e) release of hydrolytic enzymes from the sperm cell.
d) formation of a fertilization envelope.
The "slow block" to polyspermy is due to
a) the jelly coat blocking sperm penetration.
b) formation of the fertilization envelope.
c) a transient voltage change across the membrane.
d) inactivation of the sperm acrosome.
e) the consumption of yolk protein.
b) formation of the fertilization envelope.
In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the
a) acrosomal reaction would be blocked.
b) fertilization envelope would not be formed.
c) fast block to polyspermy would not occur.
d) zygote would not contain maternal and paternal chromosomes.
e) fusion of sperm and egg nuclei would be blocked.
b) fertilization envelope would not be formed.
In mammals, the nuclei resulting from the union of the sperm and the egg are first truly diploid at the end of the
a) acrosomal reaction.
b) initial cleavage.
c) completion of gastrulation.
d) activation of the egg.
e) completion of spermatogenesis.
b) initial cleavage.
Fertilization normally
a) follows gastrulation.
b) merges two dipoloid cells into one haploid cell.
c) reinstates diploidy.
d) is required for parthenogenesis.
e) precedes ovulation.
c) reinstates diploidy.
In mammalian eggs, the receptors for sperm are found in the
cytosol of the egg.
mitochondria of the egg.
zona pellucida.
nucleus of the egg.
fertilization membrane
zona pellucida
Compared to sea urchin eggs, those of mammals
a) complete the fertilization process more rapidly.
b) have not already completed meiosis at the time of ovulation.
c) have no requirement for the cortical reaction.
d) have a more distinct animal pole.
e) have a more distinct vegetal pole.
b) have not already completed meiosis at the time of ovulation.
As cleavage continues during frog development, the size of the blastomeres
a) increases as the number of the blastomeres stays the same.
b) decreases as the number of the blastomeres increases.
c) increases as the number of the blastomeres increases.
d) increases as the number of the blastomeres decreases.
e) decreases as the number of the blastomeres decreases.
b) decreases as the number of the blastomeres increases.
During the early part of the cleavage stage in frog development, the rapidly developing cells
a) skip the S phase of the cell cycle.
b) skip the mitosis phase of the cell cycle.
c) rapidly increase the volume and mass of the embryo.
d) skip the cytokinesis phase of the cell cycle.
e) skip the G1 and G2 phases of the cell cycle.
e) skip the G1 and G2 phases of the cell cycle.
The vegetal pole of the zygote differs from the animal pole in that
a) the vegetal pole cells undergo mitosis but not cytokinesis.
b) the polar bodies bud from this region.
c) the blastomeres originate only in the vegetal pole.
d) the posterior end of the embryo forms at the vegetal pole.
e) the vegetal pole has a higher concentration of yolk.
e) the vegetal pole has a higher concentration of yolk.
The small portion of the embryo that will become its dorsal side develops from the
morula.
gray crescent.
blastocoel.
primitive streak.
archenteron.
gray crescent
The yolk of the frog egg
a) impedes the formation of a primitive streak.
b) supports the higher rate of cleavage at the animal pole compared to the vegetal pole.
c) is concentrated at the animal pole.
d) prevents gastrulation.
e) is homogeneously arranged in the egg.
b) supports the higher rate of cleavage at the animal pole compared to the vegetal pole.
An embryo with meroblastic cleavage, extra-embryonic membranes, and a primitive streak must be that of
an insect.
a bird.
a fish.
a sea urchin.
an amphibian.
a bird
Meroblastic cleavage occurs in
a) humans, but not sea urchins or birds.
b) both sea urchins and birds, but not humans.
c) both humans and birds, but not sea urchins.
d) birds, but not sea urchins or humans.
e) sea urchins, but not humans or birds.
d) birds, but not sea urchins or humans.
The sequence of developmental milestones proceeds as follows:
a) cleavage blastula gastrula morula
b) cleavage gastrula morula blastula
c) gastrula morula blastula cleavage
d) morula cleavage gastrula blastula
e) cleavage morula blastula gastrula
e) cleavage morula blastula gastrula
The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is
a) ectoderm endoderm mesoderm.
b) endoderm ectoderm mesoderm.
c) mesoderm endoderm ectoderm.
d) ectoderm mesoderm endoderm.
e) endoderm mesoderm ectoderm.
d) ectoderm mesoderm endoderm.
Cells move to new positions as an embryo establishes its three germ tissue layers during
fertilization.
gastrulation.
induction.
cleavage.
determination.
gastrulation
If gastrulation was blocked by an environmental toxin, then
a) embryonic germ layers would not form.
b) the blastopore would form above the gray crescent in the animal pole.
c) the blastula would not be formed.
d) fertilization would be blocked.
e) cleavage would not occur in the zygote.
a) embryonic germ layers would not form.
The archenteron of the developing frog eventually develops into the
the blastocoel.
brain and spinal cord.
heart and lungs.
reproductive organs.
digestive tract.
digestive tract
The vertebrate ectoderm is the origin of the
heart.
kidneys.
nervous system.
liver.
pancreas
nervous system
In frog embryos, the blastopore becomes the
mouth.
ears.
anus.
eyes.
nose.
anus
In a frog embryo, gastrulation
a) occurs along the primitive streak in the animal hemisphere.
b) proceeds by involution as cells roll over the lip of the blastopore.
c) produces a blastocoel displaced into the animal hemisphere.
d) occurs within the inner cell mass that is embedded in the large amount of yolk.
e) is impossible because of the large amount of yolk in the ovum.
b) proceeds by involution as cells roll over the lip of the blastopore.
The earliest developmental stage among these choices is
invagination.
morula.
germ layers.
blastopore.
gastrulation.
morula
A correct statement is:
a) The mesoderm gives rise to the lungs.
b) The mesoderm gives rise to the notochord.
c) The endoderm gives rise to the hair follicles.
d) The ectoderm gives rise to the liver.
b) The mesoderm gives rise to the notochord.
An open space within the gastrula is the
ectoderm.
endoderm.
mesoderm.
neural crest cells.
archenteron.
archenteron
The ectoderm should give rise to tissues containing
brain and lens of the eye
The mesoderm was probably stained with a
notochord
The endoderm was probably stained with
liver and lining of the digestive tract
Although it contributes no cells to the embryo, this structure guides the formation of the primitive streak:
mesoderm
endoderm
neural crest
ectoderm
hypoblast
hypoblast
The primitive streak in a bird is the functional equivalent of
a) the archenteron in a frog.
b) the lip of the blastopore in the frog.
c) the notochord in a mammal.
d) neural crest cells in a mammal.
e) polar bodies in a sea urchin.
b) the lip of the blastopore in the frog.
In all vertebrate animals, development requires
a) an amnion.
b) extraembryonic membranes.
c) an aqueous environment.
d) a primitive streak.
e) a large supply of yolk.
c) an aqueous environment.
A primitive streak forms during the early embryonic development of
a) humans, but not birds or frogs.
b) frogs, but not birds or humans.
c) humans and birds, but not frogs.
d) birds, but not frogs or humans.
e) birds and frogs, but not humans.
c) humans and birds, but not frogs.
The least amount of yolk would be found in the egg of a
bird.
eutherian (placental) mammal.
reptile.
fish.
frog.
eutherian (placental) mammal
Extraembryonic membranes develop in
birds, but not mammals or lizards.
mammals and birds, but not lizards.
lizards, but not mammals or birds.
mammals, birds, and lizards.
mammals, but not birds or lizards
mammals, birds, lizards
At the time of implantation, the human embryo is called a
fetus.
gastrula.
blastocyst.
zygote.
somite.
blastocyst
Uterine implantation due to enzymatic digestion of the endometrium is initiated by
the endoderm.
the inner cell mass.
the trophoblast.
the mesoderm.
the chorion.
the trophoblast
In placental mammals, the yolk sac
a) becomes a fluid-filled sac that surrounds and protects the embryo.
b) produces blood cells that then migrate into the embryo.
c) transfers nutrients from the yolk to the embryo.
d) stores waste products from the embryo until the placenta develops.
e) differentiates into the placenta.
b) produces blood cells that then migrate into the embryo.
Gases are exchanged in a mammalian embryo in the
hypoblast.
yolk sac.
amnion.
chorion.
trophoblast.
chorion
Thalidomide, now banned for use as a sedative in pregnancy, was used in the early 1960s by many women in their first trimester of pregnancy. Some of these women gave birth to children with arm and leg deformities, suggesting that the drug most likely influenced
a) differentiation of bone tissue.
b) organogenesis.
c) determination of the polarity of the zygote.
d) early cleavage divisions.
e) morphogenesis.
e) morphogenesis.
The migratory neural crest cells
a) form most of the central nervous system.
b) form the spinal cord in the frog.
c) form the lining of the lungs and of the digestive tract.
d) form neural and non-neural structures in the periphery.
e) serve as precursor cells for the notochord.
d) form neural and non-neural structures in the periphery.
The proposal that a human sperm contained a miniature human being is consistent with the now-discredited theory of development known as
epigenesis.
preformation.
cell differentiation.
cell theory.
morphogenesis.
preformation