quiz14

All of the following are examples of amplification of a hormone signal except ________. 1. epineephrine intiates an enzyme cascade 11. steroids bind hormone reponse elements in the cell adn intiate the transcription of genes 111. a quantity of 0,09mg of Growth hormone leads to 10,000mg weight gain of a cow 1V. diff. cell types have diff. receptors capable of binding the same hormone

1V

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 likely use. A) Sexual B) Budding C) Cloning D. Parthenogenesis

D

Which of the following is a correct description of the fate of the germ layers? A)The ectoderm gives rise to the liver. B)The endoderm gives rise to the hair follicles. C)The mesoderm gives rise to the lungs. D)The mesoderm gives rise to the notochord.

D

Fertilization normally A) reinstates diploidy. B) follows gastrulation. C) is required for parthenogenesis. D) merges two dipoloid cells into one haploid cell. E) precedes ovulation.

a

Genetic mutations in asexually reproducing organisms lead to more evolutionary change than do genetic mutations in sexually reproducing ones because A) asexually reproducing organisms, but not sexually reproducing organisms, pass all mutations on to their offspring. B) asexually reproducing organisms devote more time and energy to the process of reproduction than do sexually reproducing organisms. 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.

a

In experiments where researchers suspect that a hormone may be responsible for a certain physiological effect, they may cut the neurons leading to the organ where the effect being studied occurs. What is the purpose of cutting these neurons? A) to make sure that the effect is not occurring through actions in the nervous system B) to make sure that the organ being affected cannot function unless the researchers stimulate it with an external electrical probe C) to impair the normal functions of the organ so that the hormonal effect can be more easily studied D) to numb the organ so that it can be probed without inducing pain in the lab animal

a

Removing which of the following glands would have the most wide-reaching effect on bodily functions of an adult human? a. pituitary glands b. ovaries or testes c. thyroid glands d. adrenal glands

a

The primary difference between estrous and menstrual cycles is that A) the endometrium shed by the uterus during the estrous cycle is reabsorbed, whereas the shed endometrium of menstrual cycles is excreted from the body. B) behavioral changes during estrous cycles are much less apparent than those of menstrual cycles. C) season and climate have less pronounced effects on estrous cycles than they do on menstrual cycles. D) copulation normally occurs across the estrous cycle, whereas in menstrual cycles copulation only occurs during the period surrounding ovulation. E) most estrous cycles are of much longer duration compared to menstrual cycles.

a

The regulation of blood sugar levels and our stress responses are controlled in part by a negative feedback loop involving cortisol, ACTH, and CRH. What would likely be the result during times of stress if cortisol receptors in the hypothalamus were nonfunctional? A. blood sugar levels would rise to dangerous levels B. blood sugar levels would be unaffected C. ACTH production would cease D. cortisol production would cease

a

What property of steroid hormones allows them to cross the phospholipid bilayer? a. Steroid hormones are lipid soluble and easily cross the phospholipid bilayer. b. Steroid hormones can act in very small concentrations and very few molecules of steroids need to cross the lipid bilayer. c. Steroid hormones act on cells close to where they were produced and very few molecules are required to travel such a short distance to cross the lipid bilayer. d. Steroid hormones act on the same cells in which they are produced and, therefore, are within the cell they are acting upon.

a

Which of the following best describes the neuroendocrine-to-endocrine pathway of hormone action? a.)a neural organ that produces hormones regulates another gland through the release of hormones into the circulation that travel to the affected gland b. a gland exhibits negative feed back on the nervous system, by releasing hormones into neural tissue both directly and indirectly through he circulation c. a neural organ that produces hormones releases directly into a neural structure, thus regulating neural functions. d. a gland releases hormones directly into the neural tissue, thus regulating neural functions

a

Analysis of a blood sample from a fasting individual who had not eaten for 24 hours would be expected to reveal high levels of A) insulin. B) glucagon. C) secretin. D) gastrin. E) glucose.

b

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

b

External chemical signals that coordinate potential reproductive partners are called A) hormones. B) pheromones. C) paracrine signals. D) cytokines. E) gametes.

b

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

b

Sexual reproduction _____. A) allows animals to conserve resources and reproduce only during optimal conditions B) can produce diverse phenotypes that may enhance survival of a population in a changing environment C) enables males and females to remain isolated from each other while rapidly colonizing habitats D) guarantees that both parents will provide care for each offspring

b

Suppose an antibody to bindin and sea urchin sperm were mixed together and the mixture was added to eggs. You predict that the antibody-treated sperm will _____. A) fertilize the eggs normally B) not bind to the egg membrane C) not be able to swim toward the egg D) fertilize eggs from other species not bind to the egg membrane

b

Tadpoles must undergo a major metamorphosis to become frogs. This change includes reabsorption of the tail, growth of limbs, calcification of the skeleton, increase in rhodopsin in the eye, development of lungs, change in hemoglobin structure, and reformation of the gut from the long gut of an herbivore to the short gut of a carnivore. Amazingly, all of these changes are induced by thyroxine. What is the most likely explanation for such a wide array of effects of thyroxine? A) There are many different forms of thyroxine, each specific to a different tissue. B) Different tissues have thyroxine receptors that activate different signal transduction pathways. C) Some tissues have membrane receptors for thyroxine, while other tissues have thyroxine receptors within the nucleus. D) Different releasing hormones release thyroxine to different tissue

b

The hormone that stimulates the production of red blood cells, and the organ where this hormone is synthesized, are A) growth hormone and pancreas, respectively. B) erythropoietin and kidney, respectively. C) cortisol and adrenal gland, respectively. D) epinephrine and adrenal gland, respectively. E) acetylcholine and bone marrow, respectively.

b

The mammalian zona pellucida is structurally and functionally most similar to which one of the following structures in a sea urchin egg? a. the jelly layer (coat) b. the vitelline envelope c. the cortical granules d. the plasma membrane

b

The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that A) only its target cells get exposed to aldosterone. B) only its target cells contain aldosterone receptors. C) it is unable to enter nontarget cells. D) nontarget cells destroy aldosterone before it can produce any effect. E) nontarget cells convert aldosterone to a hormone to which they do respond.

b

To prevent insect pests from maturing into reproducing adults, pest controllers use synthetic agonists of A) ecdysone. B) juvenile hormone. C) oxytocin. D) brain hormone. E) prothoracic hormone.

b

Which of the following is the most likely explanation for the lack of a filter blocking the passage of alcohol between the maternal and fetal circulations in humans? a. there has not been enough time to evolve b. such a barrier would probably block important molecules that need to be passed to the fetus c. the maternal and fetal blood mix directly together in an are with many villi, so a barrier is impossible

b

A contraceptive pill that continuously inhibits the release of GnRH from the hypothalamus will A) increase the production of estrogen and progesterone by the ovaries. B) initiate ovulation. 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 flow phase of the menstrual cycle.

c

Among these contraception methods, the highest risk of accidental pregnancy accompanies A) the use of a diaphragm. B) the use of a condom. C) the practice of coitus interruptus. D) a verified vasectomy. E) the practice of the "rhythm method."

c

During a stressful interval A) TSH stimulates the adrenal cortex and medulla to secrete acetylcholine. B) the alpha cells of islets secrete insulin and simultaneously the beta cells of the islets secrete glucagon. C) ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla. D) the posterior pituitary gland secretes more growth hormones. E) the calcium levels in the blood are increased due to actions of two antagonistic hormones, epinephrine and norepinephrine.

c

Gastrulation is an important event in early embryonic development. Which of the following is NOT a result of gastrulation? A) the formation of a gastrula B) formation of three embryonic cell layers C) the formation of specialized adult tissues D) movement and alignment of many embryonic cells

c

In human embryonic development, which of the following pairs of hormones are released by the developing testes and result in development of the male reproductive tract and inhibition of the female reproductive tract? a. estrogen and estradoil b. test. and estrogen c.test. and mullerian inhibitory substance d. estrogen and progesterone e. testostorone and estradiol

c

In vertebrate animals, spermatogenesis and oogenesis differ in that A) oogenesis begins at the onset of sexual maturity, whereas spermatogenesis begins during embryonic development. B) oogenesis produces four haploid cells, whereas spermatogenesis produces only one functional spermatozoon. C) cytokinesis is unequal in oogenesis, whereas it is equal in spermatogenesis. D) oogenesis ends at menopause, whereas spermatogenesis is finished before birth. E) spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed by the time a girl is born.

c

Sperm cells are stored within human males in the A) urethra. B) prostate. C) epididymis. D) seminal vesicles. E) bulbourethral gland.

c

The surgical removal of the seminal vesicles would likely A) cause sterility because sperm would not be produced. B) cause sterility because sperm would not be able to exit the body. C) greatly reduce the volume of semen. D) enhance the fertilization potency of sperm in the uterus. E) cause the testes to migrate back into the abdominal cavity.

c

Why does external fertilization typically occur much more often in aquatic animals than in terrestrial animals? A) The gametes are hydrophobic, so they must be suspended in water to avoid clumping. B) The gametes must be produced in large numbers, which can occur only in aquatic environments. C) The gametes must be kept wet to avoid desiccation.

c

fter drinking alcoholic beverages, increased urine excretion is the result of A) increased aldosterone production. B) increased blood pressure. C) inhibited secretion of antidiuretic hormone (ADH). D) increased reabsorption of water in the proximal tubule. E) the osmoregulator cells of the brain increasing their activity

c

uring mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of A) a negative feedback system. B) a hormone that acts in an antagonistic way with another hormone. C) a hormone that is involved in a positive feedback loop. D) signal transduction immediately changing gene expression in its target cells. E) the key role of the anterior pituitary gland in regulating uterine contraction.

c

which hormone is correctly paired with its function? a. melatonin- stimulates the release of glucocorticoids by the adrenal cortex b. insulin- stimulates glycogen breakdown in the liver. c. oxytocin- stimulates uterine contractions during childbirth d. thyroxine- affects biological rhythms, seasonal reproduction e. adrenocorticoptropic hormone(ACTH)- stimulates metabolic processes

c

The correct sequence of events in the development of chordates is _____. gastrulation, formation of a blastula, cleavage, and then organogenesis cleavage, formation of a blastula, gastrulation, and then organogenesis cleavage, gastrulation, organogenesis, and then formation of a blastula gastrulation, organogenesis, formation of a blastula, and then cleavage

cleveage formation of blastula gastrulation and then organogeneisis

A physician finds that a nine-year-old male patient is entering puberty much earlier than is usual. Such a condition is most likely the result of a tumor in the _____. A) hypothalamus, producing elevated levels of testosterone B) anterior pituitary, producing elevated levels of testosterone C) testes, producing elevated levels of estrogen D) anterior pituitary, producing elevated levels of gonadotropin-stimulating hormone

d

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

Fertilization of human eggs usually takes place in the A) ovary. B) uterus. C) vagina. D) oviduct. E) labia minora.

d

Fight-or-flight reactions include activation of A) the parathyroid glands, leading to increased metabolic rate. B) the thyroid gland, leading to an increase in the blood calcium concentration. C) the anterior pituitary gland, leading to cessation of gonadal function. D) the adrenal medulla, leading to increased secretion of epinephrine. E) the pancreas, leading to a reduction in the blood sugar concentration.

d

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the A) acrosomal reaction would be blocked. B) fusion of sperm and egg nuclei would be blocked. C) fast block to polyspermy would not occur. D) fertilization envelope would not be formed. E) zygote would not contain maternal and paternal chromosomes. fertilization envelope would not be formed.

d

In correct chronological order, the three phases of the human ovarian cycle are A) menstrual → ovulation → luteal. B) follicular → luteal → secretory. C) menstrual → proliferative → secretory. D) follicular → ovulation → luteal. E) proliferative → luteal → ovulation.

d

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

d

Spina bifida is one of the most prevalent human birth defects. It usually involves the spinal cord or the spinal canal opening to the outside of the body. At which stage of development is this defect likely to occur? a. Somite formation b. Lateral mesoderm formation c. Gastrula formation d. Neural tube formation e. Notochord formation

d

A pregnant woman comes into the hospital past her due date. The doctor decides it is time for the baby to be delivered. Before performing a cesarean section, the doctor wants to try to induce labor. Which of the following would she most likely inject? a. follicle stimulating hormone b. luteinizing hormone c.estrogen d.progesterone e.oxytocin

e

Testosterone is an example of a chemical signal that affects the very cells that synthesize it, the neighboring cells in the testis, along with distant cells outside the gonads. Thus, testosterone is an example of A) an autocrine signal. B) a paracrine signal. C) an endocrine signal. D) both an autocrine signal and a paracrine signal. E) an autocrine signal, a paracrine signal, and an endocrine signal.

e

how does the pill work to prevent pregnancy

it delivers progesterone leading the ovary to discontinue ovulating a new oocyte

the correct sequence of events for sexual reproduction?

meiosis- gametes- zygote- mitosis- embryo