Chapter 29 - Development and Inheritance

During early development, the Y chromosome produces a substance called "testis determining factor" (TDF) that causes the indifferent gonad to become a testis. This would be an example of A) capacitation. B) activation. C) differentiation. D) induction. E) predilection.

D) induction.

The period from 1 month after birth to 1 year is known as A) childhood. B) post-fetal. C) neogen. D) infancy. E) neonatal.

D) infancy (some places say 2 years)

Which embryonic germ layer forms connective tissues such as bone and cartilage? A) epiderm B) trophoderm C) ectoderm D) mesooderm E) endoderm

D) mesooderm

The region known as the primitive streak is the site of A) migration of mesodermal cells to form the endoderm. B) endoderm formation. C) ectoderm formation. D) migration of ectodermal cells to form the mesoderm. E) amnion formation.

D) migration of ectodermal cells to form the mesoderm.

The solid ball of cells that has been likened to a mulberry is called a A) blastocyst. B) gastrula. C) blastula. D) morula.

D) morula.

The hormone called the hormone of pregnancy, inhibiting uterine contractions, is A) hCG. B) relaxin. C) placental lactogen. D) progesterone. E) All of the answers are correct.

D) progesterone.

The stretching of the myometrium is associated with a gradual increase in the __________. A) amount of fluid in the uterus B) size of the developing fetus C) secretion of progesterone D) rates of spontaneous smooth muscle contractions

D) rates of spontaneous smooth muscle contractions

Exchange between the embryonic and the maternal circulations occurs by diffusion across the syncytial and cellular trophoblast layers via __________. A) the chorionic blood vessels B) the allantois C) the yolk sac D) the umbilicus

A) the chorionic blood vessels

The developmental period that is the period of all embryological and early fetal development is A) the first trimester. B) the second trimester. C) the third trimester. D) infancy. E) adolescence.

A) the first trimester.

During implantation, the A) trophoblast erodes a path through the endometrium. B) inner cell mass begins to form the placenta. C) maternal blood vessels in the endometrium are walled off from the blastocyst. D) entire trophoblast becomes syncytial. E) inner cell mass is temporarily deprived of nutrients.

A) trophoblast erodes a path through the endometrium.

The ________ is formed by the allantois, blood vessels, and yolk sac. A) umbilical cord B) chorion C) chorioallantoic membrane D) trophoblast E) amnion

A) umbilical cord

The blood vessel that carries oxygenated blood away from the placenta is the A) umbilical vein. B) iliac veins. C) umbilical arteries. D) uterine veins. E) uterine arteries.

A) umbilical vein.

Sperm cannot fertilize an oocyte until they A) undergo capacitation. B) undergo meiosis. C) lose their flagellum. D) are in the vagina for 3 days. E) are activated by sustentacular cells of the vagina.

A) undergo capacitation.

The formation of extraembryonic membranes occurs in the correct sequential steps, which include: A) yolk sac, amnion, allantois, and chorion B) blastomeres, morula, blastocyst, and trophoblast C) blastocyst, trophoblast, amnion, and chorion D) amnion, allantois, chorion, and yolk sac

A) yolk sac, amnion, allantois, and chorion

The extraembryonic membrane that forms blood is the A) yolk sac. B) amnion. C) allantois. D) chorion. E) decidua.

A) yolk sac.

The extraembryonic membrane that gives rise to the umbilical cord is the A) yolk sac. B) allantois. C) amnion. D) chorion. E) decidua.

B) allantois.

The extraembryonic membrane that forms a fluid-filled sac is the A) yolk sac. B) amnion. C) allantois. D) chorion. E) decidua.

B) amnion.

Non-sex chromosomes are called A) heterozygous. B) autosomal. C) chromatids. D) homozygous.

B) autosomal.

The trophoblast has many of the characteristics of ________ cells. A) cardiac B) cancer C) infectious D) rejuvenating E) epithelial

B) cancer

The layer of follicle cells that surround the unfertilized egg is called the A) zona pellucida. B) corona radiata. C) Graafian follicle. D) functional zone. E) tunica follicularis.

B) corona radiata.

In polygenic inheritance, phenotypic characters are A) determined by a double pair of alleles. B) determined by interactions among several genes. C) determined by multiple copies of a single gene. D) always controlled by genes on the same chromosome. E) determined by the genes on the Y chromosome.

B) determined by interactions among several genes.

Initially, the nutrients absorbed by the trophoblast easily reach the inner cell mass by simple A) osmosis. B) diffusion. C) peristalsis. D) ciliary action. E) convection.

B) diffusion.

The neonatal period extends A) for the first 24 hours of life. B) for the first month of life. C) until the first birthday. D) from day 1 until day 60. E) until breast feeding stops.

B) for the first month of life.

By day 12 of embryonic development, mesoderm begins to form through A) embryolization. B) gastrulation. C) mitosis. D) meiosis. E) None of the answers is correct.

B) gastrulation.

If an individual carries a pair of alleles that are the same, the individual is ________ for the trait. A) homologous B) homozygous C) heterozygous D) autosomous E) polygenic

B) homozygous

Proteolytic enzymes that digest a path through the zona pellucida include A) hyaluronidase and hCG. B) hyaluronidase and acrosin. C) acrosin and collagenase. D) relaxin and hyalouronidase. E) acetic acid and hydrochloric acid.

B) hyaluronidase and acrosin.

Which of these hormones helps to prevent premature labor? A) human chorionic gonadotropin B) progesterone C) gonadotropin-releasing hormone D) estradiol

B) progesterone

Which placental hormone keeps the myometrium relaxed during pregnancy? A) relaxin B) progesterone C) placental lactogen D) estrogen

B) progesterone

The period of gestation when organs and organ systems complete most of their development and the fetus looks distinctly human is the ________ trimester. A) first B) second C) third

B) second

The 23rd set of chromosomes determines A) characteristics of the brain. B) sex. C) body characteristics. D) blood type. E) sex drive.

B) sex.

The prostaglandins produced in the endometrium A) initiate the release of oxytocin for parturition. B) stimulate smooth muscle contractions. C) initiate secretory activity in the mammary glands. D) promote breast development. E) All of the answers are correct.

B) stimulate smooth muscle contractions.

The zygote forms when __________. A) the female pronucleus complete meiosis II B) the male and female pronuclei fuse C) the spermatozoan contacts the oocyte D) sperm penetrates the oocyte

B) the male and female pronuclei fuse

The blood vessels that carry deoxygenated blood to the placenta are the A) uterine arteries. B) umbilical arteries. C) umbilical veins. D) uterine veins.

B) umbilical arteries.

Which of the following is not one of the extraembryonic membranes? A) amnion B) umbilical cord C) allantois D) yolk sac

B) umbilical cord

Oxygenated blood from the placenta returns to the fetus in the A) allantois. B) umbilical vein. C) umbilical arteries. D) decidua capsularis. E) umbilical capillaries.

B) umbilical vein.

The extraembryonic membranes that develop from the endoderm and the mesoderm are the __________. A) yolk sac and the amnion B) yolk sac and the allantois C) amnion and the chorion D) allantois and the chorion

B) yolk sac and the allantois

If one parent is homozygous for a trait that exhibits simple dominance and the other parent is heterozygous for that trait, their offspring will have a __________ chance of possessing that trait. A) 25% B) 50% C) 100% D) 0%

C) 100%

How many chromosomes do human somatic cells contain? A) 12 B) 23 C) 46 D) 92 E) 6

C) 46

By the end of gestation, maternal blood volume normally increases by almost ________ percent. A) 20 B) 25 C) 50 D) 80 E) 100

C) 50

Which membrane becomes an organ in the developing fetus? A) Chorion B) Amnion C) Allantois D) Yolk Sac

C) Allantois (bladder)

Which extraembryonic membrane partially originates from tissue that is not part of the three germ layers? A) Allantois B) Amnion C) Chorion D) Yolk Sac

C) Chorion

If both parents are heterozygous dominant for a trait, what is the probability of an offspring inheriting the recessive trait? A) 10% B) 25% C) 50% D) 75% E) 100%

D) 75%

A 5-6-kg (11-13-lb) infant usually requires about ________ of milk per day. A) 250 ml B) 1.5 quarts C) 100 ml D) 850 ml E) 1 cup

D) 850 ml

The ectoderm forms A) muscle. B) blood. C) neural tissues. D) the lining of the digestive tract. E) the urinary system.

C) neural tissues.

Stretching of the cervix causes an increase in the blood levels of A) estrogen. B) progesterone. C) oxytocin. D) relaxin. E) chorionic gonadotropin.

C) oxytocin.

The last stage of labor is __________. A) dilation B) gestation C) parturition D) loss of amniotic fluid

C) parturition

The traits of an individual controlled by his or her genotype are his or her A) pleiotype. B) allotype. C) phenotype. D) isotype. E) genotype.

C) phenotype.

A ________ allele is expressed only when homozygous. A) homologous B) homocentric C) recessive D) maternal E) dominant

C) recessive

During gastrulation the three germ layers are formed. Which germ layer will ultimately give rise to all of the neural system? A) allantois B) endoderm C) mesoderm D) ectoderm

D) ectoderm

The amnion contains contributions from the __________ germ cell layer(s). A) mesoderm B) ectoderm C) endoderm D) ectoderm and mesoderm

D) ectoderm and mesoderm

Shortly after gastrulation, the body and organs of the embryo begin to form. This process is called A) cleavage. B) implantation. C) placentation. D) embryogenesis. E) germination.

D) embryogenesis.

Which embryonic germ layer forms the linings of the respiratory and digestive tracts? A) mesoderm B) ectoderm C) trophoderm D) endoderm E) epiderm

D) endoderm

Uterine contractions that are irregular and brief that occur toward the end of gestation are called A) parturition. B) expulsion. C) true labor. D) false labor. E) dilation.

D) false labor.

Germ-layer formation results from the process of __________. A) organogenesis B) parturition C) embryogenesis D) gastrulation

D) gastrulation

The term ________ refers to the time spent in prenatal development. A) transformation B) micturition C) parturition D) gestation E) cleavage

D) gestation

Prostaglandins in the endometrium __________. A) initiate the process of organogenesis B) cause the mammary glands to begin secretory activity C) stimulate smooth muscle contractions D) cause an increase in maternal blood volume

C) stimulate smooth muscle contractions

The blood vessels that carry deoxygenated blood to the placenta are the A) umbilical veins. B) iliac veins. C) umbilical arteries. D) uterine veins. E) uterine arteries.

C) umbilical arteries.

Which of these does not increase during pregnancy? A) glomerular filtration rate B) respiratory rate C) urinary bladder capacity D) blood volume

C) urinary bladder capacity

The extraembryonic membranes that develop from the endoderm and mesoderm are: A) amnion and chorion B) allantois and chorion C) yolk sac and amnion D) yolk sac and allantois

C) yolk sac and amnion

A woman who is heterozygous for blood type A mates with a man who is homozygous for blood type O. What blood type(s) would their children have? A) 75% heterozygous type A B) 100% type A C) 75% homozygous type O D) 100% type O E) 50% type A, 50% type O

E) 50% type A, 50% type O

Contact of a sperm with the oocyte membrane causes A) oocyte activation. B) completion of the second meiosis. C) extrusion of the second polar body. D) membrane fusion. E) All of the answers are correct.

E) All of the answers are correct.

If an individual has a functional allele on one chromosome but a non-functional allele at the same position on the homologous chromosome, they are genetically __________ for the trait. A) homologous B) polygenic C) homozygous D) heterozygous

D) heterozygous

What is meant by the term differentiation? A) All of the listed changes are characteristic of differentiation. B) Changes in the structure of the cell C) Changes in cytoplasmic composition D) Changes in the genetic activity of the cell

A) All of the listed changes are characteristic of differentiation.

During gestation, the primary compensatory adjustments include which of the following? A) All of the listed responses are correct. B) Increasing the glomerular filtration rate C) Increasing the respiratory rate and tidal volume D) Increasing the requirements for nutrients

A) All of the listed responses are correct.

Gastrulation produces three germ layers. Which of the following is NOT one of those layers? A) Blastocoele B) Endoderm C) Mesoderm D) Ectoderm

A) Blastocoele

What is the difference between colostrum and breast milk? A) Colostrum has more protein and less fat than breast milk. B) Colostrum has more fat than breast milk. C) Colostrum has more carbohydrate and fats than breast milk. D) Colostrum has more carbohydrates than breast milk.

A) Colostrum has more protein and less fat than breast milk.

What is the hormone that causes milk letdown? A) Oxytocin B) LH C) Prolactin D) Progesterone

A) Oxytocin

What is the biggest change in the baby's cardiovascular system after birth? A) Separation of the pulmonary and systemic blood circuits B) Increased heart rate after birth C) Greater cardiac output after birth D) Decrease in the baby's blood volume

A) Separation of the pulmonary and systemic blood circuits

What is the type of inheritance in which the allele is found on the X chromosome and therefore most often affects males? A) Sex-linked inheritance B) Strict dominance C) Incomplete dominance D) Polygenic inheritance

A) Sex-linked inheritance

What is the fate of the cluster of cells in the blastocyst known as the inner cell mass? A) The cells will develop into the embryo. B) The cells will develop into chorion. C) The cells will develop into the placenta. D) The cells will develop into the amnion.

A) The cells will develop into the embryo.

Which of the following does NOT happen during oocyte activation? A) The first cleavage is completed. B) Meiosis II is completed. C) Enzymes are activated to increase the ovum's metabolic rate. D) Cortical reaction prevents polyspermy.

A) The first cleavage is completed.

Which systems that are relatively nonfunctional during the fetus' prenatal period must become functional at birth? A) The respiratory, digestive, and urinary systems B) The circulatory, muscular, and skeletal systems C) The endocrine, nervous, and circulatory systems D) The integumentary, reproductive, and nervous systems

A) The respiratory, digestive, and urinary systems

What does the term inheritance refer to? A) The transfer of genetically determined characteristics from generation to generation B) The development occurring at birth and continuing to maturity C) None of the listed responses is correct. D) The study of the mechanisms responsible for passing on traits

A) The transfer of genetically determined characteristics from generation to generation

Why does a pregnant women experience breathing difficulty? A) The uterus infringes on the diaphragm. B) The mother has to breath for two people. C) The mother's blood has reduced oxygen and elevated carbon dioxide levels. D) The airways are compressed.

A) The uterus infringes on the diaphragm.

What happens in the process of hatching? A) The zona pellucida is shed from the blastocyst. B) The fertilized egg becomes the new baby. C) The zygote begins to divide. D) The blastocyst contacts the uterine lining.

A) The zona pellucida is shed from the blastocyst.

The normal male genotype is __________, and the normal female genotype is __________. A) XY; XX B) X; Y C) XX; XY D) Y; X

A) XY; XX

A sequence of cell divisions that begin after fertilization is called __________. A) cleavage B) gastrulation C) implantation D) placentation

A) cleavage

Polyspermia is prevented by the ________ reaction. A) cortical B) polarity C) gollumina D) gamete

A) cortical

The inner cell mass of the blastocyst will A) form the embryo. B) form blood vessels of the placenta. C) form the placenta. D) form the morula.

A) form the embryo.

What is the hormone that is produced by the placenta and stimulates the mother's ovaries to continue the production of progesterone? A) hCG B) Estrogen C) Relaxin D) hPL

A) hCG

The chorion develops from the __________. A) mesoderm and the trophoblast B) endoderm and the mesoderm C) ectoderm and the mesoderm D) trophoblast and the endoderm

A) mesoderm and the trophoblast

The umbilical cord, or umbilical stalk, contains __________. A) the allantois, blood vessels, and yolk stalk B) a single umbilical vein and the chorion C) paired umbilical arteries and the amnion D) the amnion, allantois, and chorion

A) the allantois, blood vessels, and yolk stalk

Which of the following forms the placenta? A) Yolk sac B) Amnion C) Chorion D) Allantois

C) Chorion

__________ is the gradual modification of the organism from __________ to maturity. A) Differentiation; birth B) Development; birth C) Development; conception D) Differentiation; conception

C) Development; conception

What is the "moment of conception"? A) Binding of the sperm to the sperm receptors B) Penetration of the sperm nucleus into the secondary oocyte C) Fusion of the male and female pronuclei D) Fusion of the sperm and oocyte membranes

C) Fusion of the male and female pronuclei

Which of the following is NOT a factor that opposes the calming effect of progesterone on uterine smooth muscle (the myometrium) and may lead to the onset of labor? A) Prostaglandin production B) Increasing oxytocin levels C) Increasing relaxin levels D) Increasing estrogen levels

C) Increasing relaxin levels

What is the term for a gene's position on a chromosome? A) Allele B) None of the listed responses is correct. C) Locus D) Karyotype

C) Locus

The fusion of male and female pronuclei is termed __________. A) polyspermy B) fertilization C) amphimixis D) oocyte activation

C) amphimixis

Which of the following events does NOT occur during the third trimester of prenatal development? A) large weight gain B) accumulation of adipose tissue C) blood formation begins in the liver D) organ systems fully functional

C) blood formation begins in the liver

The layer of follicle cells that surround the unfertilized egg is called the A) tunica follicularis. B) functional zone. C) corona radiata. D) zona pellucida.

C) corona radiata.

The creation of different types of cells during the processes of development is called __________. A) implantation B) fertilization C) differentiation D) maturity

C) differentiation

What term refers to the fusion of two haploid gametes, each containing 23 chromosomes, producing a zygote that contains 46 chromosomes? A) ovulation B) cleavage C) fertilization D) differentiation

C) fertilization

The most dangerous period in prenatal or postnatal life is the __________. A) third trimester B) expulsion stage C) first trimester D) second trimester

C) first trimester

For a given trait, if the genotype is aa, the individual is __________. A) homozygous dominant B) heterozygous C) homozygous recessive D) homozygous

C) homozygous recessive

The term for what occurs when the blastocyst touches and grows into the endometrium is __________. A) gastrulation B) cleavage C) implantation D) placentation

C) implantation

Throughout embryonic and fetal development, metabolic wastes generated by the fetus are eliminated by their transfer to the __________. A) allantois B) amniotic fluid C) maternal circulation D) chorion

C) maternal circulation

Twins that occur when blastomeres separate are called A) blastulatory. B) dizygotic. C) monozygotic. D) fraternal.

C) monozygotic.

After three days of cleavage divisions, the pre-embryo is a solid ball of blastomeres. What is the name of the pre-embryo at this stage? A) blastocyst B) inner cell mass C) morula D) zona pellucida

C) morula

Ectoderm is to ________ as mesoderm is to ________. A) neural tissue; epithelial tissue B) muscle tissue; nerve tissue C) neural tissue; muscle tissue D) cardiovascular system; neural tissue

C) neural tissue; muscle tissue

If an allele is dominant, it will be expressed in the phenotype __________. A) if both alleles agree on the outcome of the phenotype B) by the use of capitalized abbreviations C) regardless of any conflicting instructions carried by the other allele D) by the use of lowercase abbreviations

C) regardless of any conflicting instructions carried by the other allele

Which of these hormones is/are secreted by the placental tissues? A) placental lactogen B) hCG C) progesterone D) All of the listed hormones are secreted by placental tissues.

D) All of the listed hormones are secreted by placental tissues.

If a color-blind (X-linked recessive trait) man marries a woman who is heterozygous for the trait, what proportion of their male offspring can be expected to be color blind? A) 1/2 B) 1/4 C) 1/8 D) 3/4 E) 100 (all)

A) 1/2

________ are nearly identical cells that are produced by early cleavages. A) Blastomeres B) Morulas C) Gastrulas D) Amnions E) Blastulas

A) Blastomeres

Gestation can be divided into three-month periods; during the 3rd trimester, many organ systems complete most of their development. Are these two statements true or false? A) The first statement is true; the second is false. B) Both statements are true. C) The first statement is false; the second is true. D) Both statements are false.

A) The first statement is true; the second is false (organ systems complete development by end of first trimester)

In simple autosomal inheritance, phenotypic characters are determined, or controlled, by A) a single pair of alleles. B) multiple alleles. C) the action of a single gene. D) regulator genes on a different chromosome. E) the genes on the Y chromosome.

A) a single pair of alleles.

The fetus develops within a membranous cavity called the __________. A) amnion B) chorion C) decidua D) allantois

A) amnion

Where in the embryo does mesoderm first appear? A) between the cell layers of the inner cell mass B) within the blastocoele C) in the chorionic villi D) above the epiblast E) around the trophoblast

A) between the cell layers of the inner cell mass

The yolk sac contains contributions from the __________ germ cell layer(s). A) both mesoderm and endoderm B) ectoderm C) mesoderm D) endoderm

A) both mesoderm and endoderm

The formation of different types of cells required in development, or ________, occurs through selective changes in genetic activity. A) differentiation B) cupellation C) deployment D) gametogenesis E) phylogeny

A) differentiation

Which is the correct sequence of labor and delivery stages, arranged from first to last? A) dilation, parturition, placental B) placental, parturition, dilation C) dilation, placental, parturition D) parturition, dilation, placental

A) dilation, parturition, placental

Which embryonic germ layer forms the brain and spinal cord? A) ectoderm B) endoderm C) trophoderm D) epiderm E) mesooderm

A) ectoderm

In ________, implantation occurs somewhere other than in the uterus. A) ectopic pregnancy B) hydramnios C) placenta previa D) abortion E) spontaneous abortion

A) ectopic pregnancy

The process by which a viable embryo is formed is called A) embryogenesis. B) organogenesis. C) gametogenesis. D) morphogenesis. E) blastogenesis.

A) embryogenesis.

In a(n) ________, an incision is made in the perineal musculature. A) episiotomy B) lumbar puncture C) crowning D) epidural E) peritoneal cut

A) episiotomy

The period of gestation when the rudiments of all major organ systems are established is the ________ trimester. A) first B) second C) third

A) first

The presence of a recessive gene can be detected (seen) only if the individual is A) homozygous recessive. B) heterozygous dominant. C) heterozygous recessive. D) homozygous dominant. E) epistatic recessive.

A) homozygous recessive.

A mother has a lot of milk stored in the breast and mammary glands but cannot seem to expel the milk for her newborn. Her doctor thinks that the cause may be A) low levels of oxytocin. B) high levels of HCG. C) low levels of estrogen. D) low levels of progesterone. E) unresponsive smooth muscle around the mammary glands.

A) low levels of oxytocin.

Twins that occur when blastomeres separate are called A) monozygotic. B) blastulatory. C) zygoblastic. D) dizygotic. E) fraternal.

A) monozygotic.

The mesoderm forms A) muscle. B) epidermis. C) the brain. D) the lining of the digestive tract. E) respiratory epithelium.

A) muscle.

Events in the first 12 weeks of gestation establish the basis for ________, the process of organ formation. A) organogenesis B) morphogenesis C) gametogenesis D) teratogenesis E) embryogenesis

A) organogenesis

During gestation, contraction of the myometrium is inhibited by ________, produced by the corpus luteum. A) progesterone B) estrogen C) oxytocin D) prostaglandins E) inhibin

A) progesterone

Which of the following is not part of oocyte activation? A) softening of the zona pellucida B) influx of sodium ion C) membrane depolarization D) release of calcium ion from smooth ER E) discharge of exocytotic vesicles

A) softening of the zona pellucida

The gene for normal skin pigment (A) can also code for the recessive trait of albinism (a). An albino man and a homozygous normal pigmented woman marry and have four children. What is the phenotype of the children? A) 75% normal skin pigment and 25% albino B) 100% normal skin pigment C) 50% normal skin pigment and 50% albino D) 100% normal skin pigment E) 100% albino

B) 100% normal skin pigment

Blood flows to the placenta through ________ umbilical artery(ies). A) 1 B) 2 C) 3 D) 4 E) 5

B) 2

As identified by the Human Genome Project, the total number of genes in human DNA is __________. A) 50,000 to 100,000 B) 25,000 to 30,000 C) 100,000 to 500,000 D) more than 1 million

B) 25,000 to 30,000

If both mother and father are heterozygous for a trait showing simple dominance, what is the probability that one of their future children will show that trait? A) 25 percent B) 75 percent C) 100 percent D) zero percent

B) 75 percent

The hormones produced by the placenta include which of the following? A) Relaxin and human placental lactogen B) All of the listed responses are correct. C) Estrogen and progesterone D) Human chorionic gonadotropin hormone

B) All of the listed responses are correct.

What is the correct sequence of events going from the zygote to the fetus? A) Implantation; cleavage; embryogenesis; placentation B) Cleavage; implantation; placentation; embryogenesis C) Cleavage; embryogenesis; placentation; implantation D) Implantation; cleavage; embryogenesis; placentation

B) Cleavage; implantation; placentation; embryogenesis

________ is the percentage of individuals with a particular genotype that actually show the "expected" phenotype. A) Blending B) Penetrance C) Codominance D) Genome imprinting E) Pangenesis

B) Penetrance

Which of these statements about the contents of the acrosomal cap is false? A) The contents include hydrolases. B) The contents block polyspermy. C) The contents assist in fertilization. D) The contents digest the zona pellucida.

B) The contents block polyspermy.

During the 2nd trimester, most organ systems retain their simple organization; the organ systems become fully functional toward the end of the 3rd trimester. Are these two statements true or false? A) The first statement is true; the second is false. B) The first statement is false; the second is true. C) Both statements are false. D) Both statements are true.

B) The first statement is false; the second is true.

The developmental period heralded by the onset of puberty is known as A) post-infancy. B) adolescence. C) early childhood. D) teenage years. E) pre-teen.

B) adolescence.

Which of the following statements concerning development is false? A) The term induction refers to the chemical interplay between developing cells. B) The developing oocyte receives molecules that affect development from the surrounding granulosa cells. C) Each blastomere in the blastula receives exactly the same cytoplasmic composition. D) Differences in a cell's cytoplasmic makeup affect the cell's genetic activity. E) Cells release molecules that affect the developmental process of neighboring cells.

C) Each blastomere in the blastula receives exactly the same cytoplasmic composition.

During implantation the inner cell mass of the blastocyst separates from the trophoblast, creating a fluid-filled chamber called the: A) blastocoele B) allantois C) amniotic cavity D) blastodisc

C) amniotic cavity

A space opens within the inner cell mass that will form the A) blastocoele. B) lacunae. C) amniotic cavity. D) chorion. E) allantois.

C) amniotic cavity.

Differentiation among blastomeres is the result of A) enzymes introduced by the sperm. B) hormones produced by the ovum. C) an unequal distribution of regulatory molecules in the cytoplasm of the ovum. D) regulator molecules supplied by cells of the uterus. E) enzymes activated by the sperm.

C) an unequal distribution of regulatory molecules in the cytoplasm of the ovum.

The hollow cavity within the blastocyst is the A) blastula. B) gastrula. C) blastocoele. D) trophoblast. E) ootid.

C) blastocoele.

Under the influence of the trophoblast, maternal blood vessels in the endometrium A) disappear. B) attach to the inner cell mass. C) break down and form sinuses or lacunae. D) form a capillary network in the trophoblast. E) increase in size and penetrate the blastocyst.

C) break down and form sinuses or lacunae.

The mesoderm and the trophoblast combine to form the A) amnion. B) amniotic sac. C) chorion. D) allantois. E) inner cell mass.

C) chorion.

The process that divides different portions of the zygote's cytoplasm among blastomeres is called __________. A) embryogenesis B) placentation C) cleavage D) fertilization

C) cleavage

Identical twins that share body structures are called Siamese or ________ twins. A) zygotic B) attached C) conjoined D) nonidentical E) partotic

C) conjoined

The completion of metaphase II, anaphase II, and telophase II produces: A) four gametes, each containing 46 chromosomes B) one gamete containing 46 chromosomes C) four gametes, each containing 23 chromosomes D) one gamete containing 23 chromosomes

C) four gametes, each containing 23 chromosomes

If an individual carries two different alleles for the same trait, the individual is ________ for the trait. A) homologous B) homozygous C) heterozygous D) autosomous E) polygenic

C) heterozygous

A blastocyst is a(n) A) extraembryonic membrane. B) solid ball of cells. C) hollow ball of cells. D) portion of the placenta. E) origin of the urinary bladder.

C) hollow ball of cells.

If a sperm carrying the "Y" chromosome fertilizes the ovum, the resulting offspring will be A) haploid. B) Rh positive blood type. C) male. D) fraternal twins. E) female.

C) male.

Increased release of which of these hormones triggers the onset of puberty? A) androgenic steroids B) FSH C) LH D) GnRH

D) GnRH

Which of the following statements about the trophoblast is false? A) It secretes hyalouronidase to erode endometrial cell adhesion. B) It absorbs nutrients released by degenerating endometrial glands. C) It has both an acellular and cellular component. D) It is derived from the inner cell mass. E) It causes maternal blood vessels to break down.

D) It is derived from the inner cell mass.

Which of these statements about monozygotic twins is false? A) They may form when the inner cell mass splits. B) They are identical. C) They share the same genome. D) They form when blastomeres fuse in the pre-embryonic stage.

D) They form when blastomeres fuse in the pre-embryonic stage.

During gestation the primary major compensatory adjustment(s) is (are): A) increasing respiratory rate and tidal volume B) increasing glomerular filtration rate C) increasing maternal requirements for nutrients D) all of the above

D) all of the above

The extraembryonic membrane that forms the fetal portion of the placenta is the A) yolk sac. B) amnion. C) allantois. D) chorion. E) decidua.

D) chorion.

Placental functions are concentrated in a disc-shaped area in the endometrium called the A) trophoblast. B) allantois. C) deciduas capsularis. D) decidua basalis. E) decidua parietalis.

D) decidua basalis.

The part of the endometrium that covers the implanted embryo and lacks chorionic villi is the A) decidua parietalis. B) decidua albicans. C) decidua functionalis. D) decidua capsularis. E) decidua basalis.

D) decidua capsularis.

Progesterone calms the myometrium and prevents contraction. What factors antagonize progesterone and trigger labor and delivery? A) Rising estrogen levels increase sensitivity. B) Rising oxytocin levels lead to uterine contractions. C) distortion of the myometrium D) distortion of the cervix E) All of the answers are correct.

E) All of the answers are correct.

The placenta is a source of which of the following hormones? A) hCG B) relaxin C) placental lactogen D) progesterone E) All of the answers are correct.

E) All of the answers are correct.

Which of the following are recognized classes of abortion? A) spontaneous B) therapeutic C) induced D) spontaneous and induced E) All of the answers are correct.

E) All of the answers are correct.

Which of the following is a critical event of the first trimester? A) cleavage B) implantation C) placentation D) embryogenesis E) All of the answers are correct.

E) All of the answers are correct.

Which of the following is false concerning the allantois? A) It derives partly from endoderm. B) It projects into the umbilical cord. C) It stores nitrogenous wastes. D) Part will develop as the urinary bladder. E) It acts as the fetal bone marrow.

E) It acts as the fetal bone marrow.

Which of these statements about ectopic pregnancy is false? A) It does not yield a viable embryo. B) The embryo may implant in the uterine tube. C) It occurs in less than 1 percent of pregnancies. D) The mother's life may be endangered. E) Vaginal delivery is often possible.

E) Vaginal delivery is often possible.

Polyspermy results in A) twins. B) fetuses with different fathers. C) haploid individuals. D) chimeric adults. E) a nonfunctional zygote.

E) a nonfunctional zygote.

The alternate forms of any one gene are called A) homologous. B) homozygous. C) heterozygous. D) autosomes. E) alleles.

E) alleles.

The ________ is the portion of the endometrium not in contact with the chorion. A) trophoblast B) allantois C) deciduas capsularis D) decidua functionalis E) decidua parietalis

E) decidua parietalis

A ________ allele will always be expressed regardless of what the other allele happens to be. A) homologous B) homocentric C) recessive D) maternal E) dominant

E) dominant

The full set of genetic information in an individual's chromosomes is called A) pleiotype. B) allotype. C) phenotype. D) isotype. E) genome.

E) genome.

After fertilization, the first cell division is completed A) within a few seconds. B) within the hour. C) about 6 hours later. D) in 12 hours. E) more than a day later.

E) more than a day later.

As a person ages, A) the skin becomes more elastic. B) lung tissue becomes more elastic. C) peristalsis and muscle tone decrease. D) all hormone levels decrease. E) peristalsis and muscle tone decrease and some hormone levels decrease.

E) peristalsis and muscle tone decrease and some hormone levels decrease.

During the ________ stage, the placenta is expelled from the uterus. A) expulsion B) dilation C) crowning D) exit E) placental

E) placental

The hormone that increases the flexibility of the pubic symphysis during pregnancy is A) luteinizing hormone. B) progesterone. C) human chorionic gonadotropin. D) human placental lactogen. E) relaxin.

E) relaxin.

The Y chromosome carries information for A) the penis. B) the development of the brain. C) sexual drive. D) fertility ability. E) the development of the testes.

E) the development of the testes.

The endoderm forms A) muscle. B) blood. C) neural tissue. D) skin. E) the urinary bladder.

E) the urinary bladder.

The outer layer of the blastocyst that can penetrate the endometrium is the A) archegonium. B) chorion. C) gastrula. D) blastula. E) trophoblast.

E) trophoblast.

Which of the following is not one of the extraembryonic membranes? A) yolk sac B) amnion C) allantois D) chorion E) umbilical cord

E) umbilical cord

The cell that directly results from the fusion of a secondary oocyte and a spermatozoon is called a(n) A) ootid. B) gastrula. C) blastula. D) morula. E) zygote.

E) zygote.

What are the criteria for a premature delivery? A) Delivery from 25 to 27 weeks B) Delivery from 28 to36 weeks C) Delivery before 23 weeks D) Delivery from 23 to 24 weeks

B) Delivery from 28 to36 weeks

Which of the following is the term for the developmental events that occur from nine weeks to birth? A) Gastrulation B) Fetal development C) Embryological development D) Postnatal development

B) Fetal development

What triggers the activation of the secondary oocyte? A) Penetration of the sperm head through the oocyte membrane B) Fusion of the sperm and secondary oocyte membranes C) Multiple sperm contacting the membrane of the secondary oocyte D) The presence of the sperm nucleus in the cytoplasm of the secondary oocyte

B) Fusion of the sperm and secondary oocyte membranes

Which of the following events is NOT part of oocyte activation? A) Completion of meiosis B) Fusion of the sperm pronucleus and egg pronucleus C) Cortical reaction D) Increase in oocyte's metabolic rate

B) Fusion of the sperm pronucleus and egg pronucleus

How do gametes differ from ordinary somatic cells? A) Gametes contain the full complement of chromosomes. B) Gametes contain only half the normal number of chromosomes. C) The chromosome number doubles in gametes. D) Gametes are diploid, or 2n.

B) Gametes contain only half the normal number of chromosomes.

What is the term that describes the existence of two different alleles for one gene? A) Dominant B) Heterozygous C) Homozygous D) Homologous

B) Heterozygous

Which of the following is NOT an effect of pregnancy on the mother? A) The mother's nutrient requirements increase. B) Maternal blood volume decreases. C) The uterus increases in size. D) Mammary glands increase in size, and secretory activity begins.

B) Maternal blood volume decreases.

Which of the following is the term for aging, or growing old? A) Geriatrics B) Senescence C) Pediatrics D) Adolescence

B) Senescence

Which extraembryonic membrane is responsible for red blood cell production during early development? A) Amnion B) Yolk Sac C) Chorion D) Allantois

B) Yolk Sac

In ________, a sample of amniotic fluid is removed and the fetal cells it contains are analyzed. A) thoracentesis B) amniocentesis C) chorionic villus sampling D) amniosis

B) amniocentesis

Senescence involves all of the following EXCEPT __________. A) a decrease in glomerular filtration rate B) an increased stem cell mitotic rate C) a loss of elasticity in tissues D) a weaker immune response

B) an increased stem cell mitotic rate

Implantation of the __________ occurs about 7 days after __________. A) zygote; ovulation B) blastocyst; fertilization C) zygote; fertilization D) blastocyst; ovulation

B) blastocyst; fertilization

For a given trait, if the genotype is Aa, the individual is __________. A) homozygous B) heterozygous C) homozygous dominant D) homozygous recessive

B) heterozygous

If an individual has a dominant allele on one chromosome but a recessive allele at the same position on the homologous chromosome, he or she is genetically __________ for the trait. A) abnormal B) heterozygous C) homozygous D) homologous

B) heterozygous

For a given trait, if the genotype is AA, the individual is __________. A) heterozygous recessive B) homozygous dominant C) heterozygous dominant D) homozygous recessive

B) homozygous dominant

Which of the following hormones does NOT play a role in initiating labor contractions? A) prostaglandin B) progesterone C) oxytocin D) estrogen

B) progesterone

The first meiotic division __________. A) yields four functional spermatids in the male B) reduces the number of chromosomes from 46 to 23 C) results in the separation of duplicate chromosomes D) produces one functional ovum in the female

B) reduces the number of chromosomes from 46 to 23

Which these oocyte processes is not activated by sperm penetration? A) influx of sodium ions B) softening of the zona pellucida C) membrane depolarization D) discharge of exocytotic vesicles

B) softening of the zona pellucida

Alterations in genetic activity during development result from __________. A) the maturation of the sperm and the ovum B) the differences in the cytoplasmic compositions of individual cells C) conception D) the chromosome complement in the nucleus of the cell

B) the differences in the cytoplasmic compositions of individual cells

Which of these processes occurs after oocyte activation and the completion of meiosis II? A) The nuclear material within the ovum reorganizes into a female pronucleus. B) The head, neck, and middle pieces of the sperm cell break down. C) The nucleus of the sperm cell swells. D) All of the listed processes occur after oocyte activation and the completion of meiosis II.

D) All of the listed processes occur after oocyte activation and the completion of meiosis II.

What causes maternal blood volume to increase during pregnancy? A) Increased blood flow in the placenta B) Rapid fetal metabolic activity C) Decreased maternal blood PO2 D) All of the the listed choices are correct.

D) All of the the listed choices are correct.

What is the extraembryonic membrane that gives rise to the urinary bladder? A) Amnion B) None of the listed responses is correct. C) Chorion D) Allantois

D) Allantois

Which of the following events happens during the expulsion stage? A) Infrequent contractions increase in frequency and intensity. B) The placenta is ejected. C) The amniochorionic membrane ruptures. D) Contractions reach maximum intensity, occur in two- to three-minute intervals, and last a full minute.

D) Contractions reach maximum intensity, occur in two- to three-minute intervals, and last a full minute.

What is the correct sequence of stages in the process of delivering a baby? A) Expulsion; dilation; placental B) Dilation; placental; expulsion C) Placental; dilation; expulsion D) Dilation; expulsion; placental

D) Dilation; expulsion; placental

Which of the following is the term for the events that occur during the first two months of development after fertilization? A) Fetal development B) Gametogenesis C) Postnatal development D) Embryological development

D) Embryological development

What event marks the onset of development? A) Meiosis B) Embryo formation C) Implantation D) Fertilization

D) Fertilization

What are the enzymes that the acrosome of the sperm contains? A) Hyaluronidase and pepsin B) Acrosin and pepsin C) Trypsin and pepsin D) Hyaluronidase and acrosin

D) Hyaluronidase and acrosin

Which of the following is true concerning the onset of labor contractions? A) Progesterone is a major stimulus of labor. B) Prostaglandins suppress contractions. C) Oxytocin from the mother makes the fetus irritable and active. D) Labor contractions work through positive feedback to help expel the fetus.

D) Labor contractions work through positive feedback to help expel the fetus.

Increases in GnRH, FSH, and LH mark the onset of which stage of development? A) Senescence B) Maturity C) Neonatal D) Puberty

D) Puberty

Which of the following is NOT a physiological effect on the mother's body during pregnancy? A) There is an increase in tidal volume. B) There is an increase of roughly 50 percent in the maternal glomerular filtration rate. C) There is an increase in the size and activity of mammary glands. D) There is a decrease in folic acid need

D) There is a decrease in folic acid need

What is meant by the term dizygotic twins? A) One oocyte is ovulated and fertilized. B) Identical twins C) Two babies share the same placenta. D) Two separate oocytes are ovulated and fertilized.

D) Two separate oocytes are ovulated and fertilized.

Genes that appear on the X chromosome are said to be A) somatic. B) polygenic. C) chromosomal. D) X-linked.

D) X-linked.

What prevents more than one sperm from fertilizing the secondary oocyte? A) Chemicals released from the penetrating sperm B) Chemical changes in the oocyte membrane C) Inactivation of other sperm D) Zonal inhibiting proteins

D) Zonal inhibiting proteins

Embryogenesis is the process that establishes the foundation for __________. A) implantation to occur B) the formation of the placenta C) the formation of the blastocyst D) all the major organ systems

D) all the major organ systems

The alternate forms of any one gene are called A) homozygous. B) autosomes. C) homologous. D) alleles.

D) alleles.

A hollow ball of cells created by cleavage is called a __________. A) fetus B) gastrula C) morula D) blastocyst

D) blastocyst

The gradual modification of an organism from conception to maturity is called __________. A) embryonic development B) fertilization C) differentiation D) development

D) development

Which of these is NOT a stage in development? A) embryonic development B) postnatal development C) prenatal development D) differentiation

D) differentiation

Given that albinism is a recessive trait, if an albino mother and a normal father with the genotype AA have a child, that child will __________. A) have abnormal pigmentation B) have blue eyes because of a lack of pigmentation C) be an albino D) have normal coloration

D) have normal coloration

In an ectopic pregnancy, __________. A) implantation occurs within the endometrium B) extraembryonic membranes form in the uterus C) a gestational neoplasm forms D) implantation occurs somewhere other than within the uterus

D) implantation occurs somewhere other than within the uterus

Which of these pairs of terms is mismatched? A) third trimester - largest size gain B) first trimester - placentation C) second trimester - organogenesis D) second trimester - embryogenesis

D) second trimester - embryogenesis

Fraternal, or dizygotic, twins result from __________. A) incomplete splitting of the embryonic disc B) one egg that splits after fertilization C) separation of the blastomeres D) two oocytes being ovulated in one cycle

D) two oocytes being ovulated in one cycle

In strict dominance, a dominant allele __________. A) will be found only on the X chromosome B) will have its expression blended with that of the recessive allele C) will not be expressed when paired with a recessive allele D) will be expressed 100 percent of the time when paired with a recessive allele

D) will be expressed 100 percent of the time when paired with a recessive allele

If fertilization occurs, the ________ is maintained because the embryo secretes ________. A) corpus albicans; human chorionic gonadotrophin B) corpus luteum; luteinizing hormone C) corpus cavernosum; human chorionic gonadotrophin D) corpus albicans; placental prolactin E) corpus luteum; human chorionic gonadotrophin

E) corpus luteum; human chorionic gonadotrophin

The site where fertilization normally occurs is in the A) fimbrae. B) uterine wall near the fundus. C) cervix. D) union of the vagina and uterus. E) outer one-third of the uterine tube

E) outer one-third of the uterine tube