BIO Chapter 46-47

C (A surge in LH levels is responsible for triggering ovulation.)

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

A (By secreting estrogen and progesterone, the corpus luteum maintains the endometrium and inhibits FSH and LH secretion.)

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

B (Fusion of the membranes of the egg and sperm causes membrane depolarization, known as the "fast" block to polyspermy, i.e., the prevention of additional sperm binding to the egg.)

Among the following, the earliest consequence of the acrosomal reaction is _____. A. the cortical reaction B. the membrane of the egg depolarizing C. cleavage D. the slow block to polyspermy E. the development of the fertilization envelope

B

An ectopic pregnancy occurs when a fertilized egg implants somewhere other than in the lining of the uterus. Usually it implants in the oviduct. Which of the following would be the most likely explanation for such a pregnancy being unsuccessful? A. The orientation of the baby would be sideways. B. The lining of the oviduct is unable to support the developing fetus. C. The necessary hormones cannot reach the developing fetus in the oviduct. D. Human chorionic gonadotropin (hCG) cannot be produced in the oviduct.

C

An inactivating mutation in the progesterone receptor gene would likely result in _____. A. the absence of mammary gland development B. the absence of secondary sex characteristics C. the inability of the uterus to support pregnancy D. enlarged and hyperactive uterine endometrium

C

Asexual reproduction results in offspring that are genetically identical to their parent. What type of cell process occurs to generate this type of offspring? A. cell fusion B. meiosis C. mitosis

D

At the time of fertilization, the maturation of the human oogonium has resulted in _____. A. four secondary oocytes B. four zygotes C. one secondary oocyte D. two primary oocytes

A

At the time of implantation, the human embryo is called a _____. A. blastocyst B. fetus C. zygote D. gastrula

A

Cells move to new positions as an embryo establishes its three germ-tissue layers during _____. A. gastrulation B. cleavage C. induction D. determination

C

Changes in the shape of a cell usually involve a reorganization of the _____. A. transport proteins B. extracellular matrix C. cytoskeleton D. nucleus

B ( Developing ovarian follicles secrete estrogen)

Developing ovarian follicles primarily secrete _____. A. progesterone B. estrogens C. luteinizing hormone D. follicle-stimulating hormone E. human chorionic gonadotropin

B

During metamorphosis, a tadpoles tail is reduced in size by the process of _____. A. oxidative phosphorylation B. apoptosis C. regeneration D. re-differentiation

B (The migration and differentiation of epiblast cells produce the embryo proper and its three basic tissues.)

During the early development of a human embryo, the _____ eventually forms the _____. A. epiblast ... placenta B. epiblast ... ectodermal, mesodermal, and endodermal tissues C. blastocoel ... archenteron D. trophoblast ... embryo proper E.hypoblast ... amniotic cavity

B

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences? A. cortical reaction → synthesis of embryo's DNA begins → acrosomal 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. cortical reaction → acrosomal reaction → first cell division synthesis of embryo's DNA begins

B

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences? A. preformation → morphogenesis → neurulation B. cleavage → gastrulation → organogenesis C. gastrulation → organogenesis → cleavage D. gastrulation → blastulation → neurulation

E (HCG, secreted by the early embryo, maintains the corpus luteum. The corpus luteum secretes estrogen and progesterone, which maintain the endometrium for implantation.)

If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum. A. progesterone B. estrogen C. luteinizing hormone D. follicle-stimulating hormone E. human chorionic gonadotropin

B (Estrogen and progesterone are responsible for maintaining the endometrium in the event that the egg has been fertilized.)

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

C

In a developing frog embryo, most of the yolk is _____. A. distributed equally throughout the embryo B. located near the animal pole C. located near the vegetal pole D. found within the cleavage furrow

C

In a newly fertilized egg, the vitelline layer _____. A. secretes hormones that enhance steroidogenesis by the ovary B. provides most of the nutrients used by the zygote C. lifts away from the egg and hardens to form a fertilization envelope D. reduces the loss of water from the egg and prevents desiccation

A (Cleavage refers to the rapid cell division that takes place in animals after fertilization. Cleavage partitions the egg cytoplasm without additional cell growth taking place.)

In animal development, which of the following best describes the process of cleavage? A. Mitosis B. Fertilization C. Meiosis D. Differentiation

C (This is true. The second division is completed only after a sperm penetrates the egg. But is this the only correct answer?)

In humans, oogenesis in comparison to spermatogenesis is different in that _____. A. female puberty typically occurs much later than the age of male puberty B. oogenesis continues throughout life, but spermatogenesis typically ends at age 55 years C. oogenesis does not complete meiosis until after fertilization, but spermatogenesis is complete before the sperm leave the body 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 (Hint: Think of the products and timing of the stages of meiosis in oogenesis and spermatogenesis)

C

In humans, the follicular cells that remain behind in the ovary following ovulation become _____. A. the placenta, which secretes cervical mucus B. the ovarian endometrium that is shed at the time of the menses C. a steroid-hormone synthesizing structure called the corpus luteum D. the thickened portion of the uterine wall

B

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspermy, respectively, are _____. A. the cortical reaction and the formation of yolk protein B. membrane depolarization and the cortical reaction C. the jelly coat of the egg and the vitelline membrane D. the acrosomal reaction and the formation of egg white

C

Labor contractions can be increased by the medical use of a synthetic drug that mimics the action of _____. A. luteinizing hormone B.prolactin C. oxytocin D. inhibin

B

On a submarine expedition to the ocean bottom, you discover a population of fish that are only female. What type of reproduction does this fish most likely use? A. budding B. parthenogenesis C. sexual D. cloning

C (Ovulation usually occurs about halfway through the 28-day ovarian cycle.)

Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle. A. 1 B. 7 C. 14 D. 21 E. 28

C

Peaks of LH and FSH production occur during A. the beginning of the follicular phase of the ovarian cycle. B. the end of the luteal phase of the ovarian cycle. C. the period just before ovulation. D. the menstrual flow phase of the uterine cycle. E. the secretory phase of the menstrual cycle.

B (In hermaphroditism a single individual produces both sperm and ova; although some individuals fertilize themselves, most must mate with another member of the same species.)

Sexual reproduction includes a reproductive pattern called _____. A. fission B. hermaphroditism C. fragmentation D. budding E. regeneration Hint: Consider which of these requires two individuals

D (Sperm mature and become motile while in the epididymis.)

Sperm become capable of movement while in the _____. A. seminiferous tubules B. vas deferens C. ejaculatory ducts D. urethra epididymis

C (Sperm develop in seminiferous tubules, found within testes.)

Sperm develop in the _____. A. prostate gland B. bulbourethral glands C. seminiferous tubules D. hypothalamus E. seminal vesicles

B (The urethra carries both sperm and urine out of a male's body.)

Sperm exit a male's body via the _____. A. ejaculatory duct B. urethra C. oviduct D. ureter E. epididymis

B

The archenteron of the developing sea urchin eventually develops into the _____. A. brain and spinal cord B. digestive tract C. heart and lungs D. blastocoel

D (Gastrulation and organogenesis are developmental stages that follow cleavage.)

The first stage of embryonic development is _____. This process produces _____. A. neurulation ... a neurula B. parturition ... a fetus C. gastrulation ... a three-layered embryo D. cleavage ... a cluster of cells E. ovulation ... a zygote

A (The muscles and skeleton are of mesodermal origin.)

The mesoderm gives rise to _____. A. skeletal and muscular systems B. the central nervous system C. the lining of the lungs D. jaws and teeth E. the gastrointestinal tract and pancreas

D

The migratory neural crest cells _____. A. form the spinal cord in the frog B. form the lining of the lungs and of the digestive tract C. form most of the central nervous system D. form a variety of neural and non-neural structures

B

The plasma membrane of the sea urchin egg _____. A. releases calcium, which initiates the cortical reaction B. has receptor molecules that are specific for binding acrosomal proteins C. is a mesh of proteins crossing through the cytosol of the egg D. is outside of the fertilization membrane

B (An increase in androgens inhibits the secretion of releasing hormones by the hypothalamus and LH secretion by the pituitary gland. A decrease in androgens stimulates the secretion of releasing hormones by the hypothalamus and LH secretion by the pituitary gland.)

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 gland

B

The term applied to a morphogenetic process whereby cells extend themselves, making the mass of the cells narrower and wider, is _____. A. bi-axial elongation B. convergent extension C. elongational streaming D. induction

B (The formation of a gastrula is the last stage in early animal development; the zygote undergoes cleavage to form a blastula, which eventually forms a gastrula.)

True or false? Early animal development progresses through distinct stages: first the production of the zygote through fertilization, then cleavage, then the formation of the gastrula, and then the formation of the blastula. A.True B. False

A

Uterine implantation due to enzymatic digestion of the endometrium is initiated by the _____. A. trophoblast B. inner cell mass C. mesoderm D. endoderm

B

What are the cells created by cleavage called? A. Blastulas B. Blastomeres C. Blastocoels D. Blastopores

C (During organogenesis, embryonic cells become progressively more specialized as they develop into their specific cell type (brain, muscle, etc.)

What happens to a cell during the process of differentiation? A. It divides to produce a cell with the same number of chromosomes. B. Material moves across the cell membrane from a region of higher concentration to a region of lower concentration. C. It undergoes a change toward a more specialized form or function. D. It divides to produce a cell with one-half the number of original chromosomes.

C (The oviducts are the usual sites of fertilization.)

What is the usual site of the fertilization of an egg cell? A. uterus B. ovary C. oviduct D. abdominal cavity E. vagina

A (Androgens, such as testosterone, are responsible for both sperm production and the secondary sex characteristics of males.)

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 of the following are the three germ layers contained in the gastrula? A. Ectoderm, mesoderm, endoderm B. Ectoderm, mesoderm, epidermis C. Ectotherm, mesoderm, endoderm D. Ectoderm, mesoderm, echinoderm

D

Which of the following correctly describes a difference between spermatogenesis and oogenesis? A. Spermatogenesis results in four mature sperm cells, while oogenesis results in one mature egg cell. In spermatogenesis, mitosis occurs twice and meiosis once, while in oogenesis, mitosis occurs once and meiosis twice. B. In spermatogenesis, mitosis occurs twice and meiosis once, while in oogenesis, mitosis occurs once and meiosis twice. C. Spermatogenesis results in one mature sperm cell, while oogenesis results in four mature egg cells. D. Spermatogenesis results in four mature sperm cells, while oogenesis results in one mature egg cell.

A (Gastrulation is the process that leads to the formation of the gastrula, which contains the three embryonic tissue layers.)

Which of the following stages of development is defined by the three embryonic tissue layers (ectoderm, mesoderm, and endoderm)? A. Gastrula B. Zygote C. Blastula D. Yolk

E (In males, follicle-stimulating hormone (FSH) stimulates sperm production.)

Which pituitary secretion stimulates sperm production? A. LH B. ACTH C. TSH D. PRL E. FSH

A (In males, luteinizing hormone (LH) stimulates the testes to secrete androgens.)

Which pituitary secretion stimulates the testes to secrete androgens? A. LH B. ACTH C. TSH D. PRL E. FSH

C

Which statement about human reproduction is correct? A. The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules. B. Fertilization occurs in the uterus. C. A human oocyte completes meiosis after a sperm penetrates it. D. In humans, spermatogenesis and oogenesis function best at normal, core body temperatures.

A

n excreted urine, a reliable "marker" that a pregnancy has initiated is _____. A. human chorionic gonadotropin (hCG) B. progesterone C. estrogen D. follicle-stimulating hormone

D (The endoderm provides the cells that develop into the lining of the digestive and respiratory tracts, as well as the liver and pancreas. Problems with its formation could result in an unformed pancreas.)

A child is born without a fully developed pancreas. He is normal in all other respects, and thus doctors believe that the problem most likely began early in development. During which of the following processes did the original error most likely occur? A. Mesoderm formation B. Cleavage C. Ectoderm formation D. Endoderm formation

A (The uterus is the usual site of the implantation and development of the fertilized egg.)

A fertilized egg usually implants itself and develops in the _____. A. uterus B. ovary C. oviduct D. abdominal cavity E. none of these