Chapter 27 Development and Inheritance

55) Embryonic and early fetal development occurs in the ________ trimester. A) first B) second C) third

A) first

23) What is the developmental fate of "9?" A) forms the embryo B) forms the trophoblast C) forms the chorion D) forms the placenta E) dissolves completely

A) forms the embryo

98) A pre-embryo that consists of a solid ball of cells is known as what type of structure? A) blastomere B) morula C) trophoblast D) cytotrophoblast E) blastocyst

B) morula

51) Deoxygenated blood is carried to the placenta by the A) umbilical vein. B) umbilical arteries.

B) umbilical arteries.

4) 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.

104) Identify the structure connecting the fetus to the placenta, and name the extra-embryonic membrane from which it is derived. A) yolk sac; allantois B) yolk sac; chorion C) umbilical cord; allantois D) umbilical cord; chorion E) umbilical cord; amnion

C) umbilical cord; allantois

103) Describe the chorionic villi A) The chorionic villi contain fluid that surrounds and cushions the embryo or fetus. B) The chorionic villi forms the interface between the embryonic/fetal system and the amniotic fluid. C) The chorionic villi forms the umbilical cord. D) The chorionic villi are structures that extend into the maternal tissues through which maternal blood flows. E) The chorionic villi form the yolk sac.

D) The chorionic villi are structures that extend into the maternal tissues through which maternal blood flows.

9) Fertilization is complete when which of the follow occurs? A) oocyte activation B) pronucleus formation C) spindle formation D) amphimixis and cleavage E) formation of blastomeres

D) amphimixis and cleavage

37) The extra-embryonic membrane that forms the fetal portion of the placenta is the A) yolk sac. B) amnion. C) allantois. D) chorion.

D) chorion.

33) The oval, three-layered sheet produced by gastrulation is called the A) embryo. B) ectoderm. C) inner cell mass. D) embryonic disc. E) yolk sac.

D) embryonic disc.

61) The stage of labor during which the fetus emerges from the vagina is called the ________ stage. A) emergence B) dilation C) placental D) expulsion E) fetal

D) expulsion

7) The individual cells produced by cleavage are called A) embryos. B) blastomeres. C) blastocytes. D) blastocysts. E) zygotes

B) blastomeres.

31) The trophoblast has many of the characteristics of ________ cells. A) cardiac B) cancer C) infectious D) smooth muscle E) None of the answers is correct.

B) cancer

42) Identify the structure labeled "7." A) amnion B) chorion C) myometrium D) placenta E) endometrium

B) chorion

17) A blastocyst is a(n) A) extra-embryonic 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.

28) The ectoderm forms A) muscle. B) blood. C) neural tissues. D) the lining of the stomach and small intestine. E) the urinary system.

C) neural tissues.

62) 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.

69) The clinical term for "growing old" is A) maturation. B) aging. C) senescence. D) apoptosis. E) senility.

C) senescence.

68) The infancy stage of life is considered to be over when the baby reaches ________ of age. A) 1 year B) 2 years C) 6 months D) 1 month E) 18 months

A) 1 year

85) 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) All E) None

A) 1/2

99) Describe the trophoblast. A) The trophoblast is the cell layer surrounding the blastocyst. B) The trophoblast is the fluid-filled chamber filled with amniotic fluid. C) The trophoblast is a solid ball of cells. D) The trophoblast is the inner cavity within the blastocyst. E) The trophoblast is a pre-embryo at the four-cell stage.

A) The trophoblast is the cell layer surrounding the blastocyst.

102) Describe the placenta. A) The placenta is a layer of cells that surround the yolk sac. B) The placenta forms the interface between the inner cell mass and the trophoblast. C) The placenta forms the interface between the embryonic/fetal system and the maternal system. D) The placenta forms the interface between the blastocoele and the amniotic cavity. E) The placenta contains fluid that surrounds and cushions the embryo or fetus.

C) The placenta forms the interface between the embryonic/fetal system and the maternal system.

13) 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.

2) Each of the following statements concerning development is true except A) embryonic development includes the events that occur in the first 2 months. B) fetal development occurs from the 9th week until birth. C) the first trimester is when the fetus first looks distinctively human. D) postnatal development begins at birth. E) organ development is complete by the end of the 6th month.

C) the first trimester is when the fetus first looks distinctively human.

5) During amphimixis, A) sperm become capacitated. B) the zygote is formed with 46 chromosomes. C) the male and female pronuclei fuse. D) meiosis occurs. E) gametes are formed.

C) the male and female pronuclei fuse.

54) The period of gestation that is characterized by the largest fetal weight gain and fat deposition is the ________ trimester. A) first B) second C) third

C) third

26) During gastrulation, A) the blastomeres fuse. B) the placenta penetrates the endometrium. C) three germ layers are formed. D) blastomeres form. E) the neural tube closes.

C) three germ layers are formed.

75) How many chromosomes do human somatic cells contain? A) 22 B) 23 C) 44 D) 46 E) 92

D) 46

96) How many chromosomes are contained within a human zygote? (Module 27.2B) A) 8 B) 23 C) 32 D) 46 E) 64

D) 46

70) The developmental period heralded by the onset of puberty is known as A) the neonatal stage. B) infancy. C) childhood. D) adolescence. E) maturity.

D) adolescence.

41) Identify the structure labeled "4." A) amnion B) chorion C) myometrium D) placenta E) endometrium

D) placenta

11) The almost identical cells produced by cleavage divisions are called A) morulas. B) blastomeres. C) trophoblasts. D) blastocoeles. E) ova.

B) blastomeres.

83) 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.

73) Which of the following is a puberty-related change caused by increased testosterone levels? A) accelerated bone deposition and skeletal growth B) loss of terminal hairs on the face and chest C) replication of skeletal muscle fibers D) thinning of the vocal folds E) decreased erythropoiesis

A) accelerated bone deposition and skeletal growth

45) Identify the structure labeled "5." A) amniotic cavity B) chorion C) amnion D) placenta E) endometrium

A) amniotic cavity

14) The process of cell division that divides the cytoplasm of the zygote among blastomeres is called A) cleavage. B) implantation. C) placentation. D) embryogenesis. E) blastulation.

A) cleavage.

1) The gradual modification of anatomical structures during the period from conception to maturity is A) development. B) differentiation. C) embryogenesis. D) capacitation. E) All of the answers are correct.

A) development.

60) The first stage of labor is the ________ stage. A) dilation B) expulsion C) placental D) contraction E) neonate

A) dilation

72) Which of the following hormones is the cause of most puberty-related changes in a female? A) estrogen B) progesterone C) oxytocin D) relaxin E) chorionic gonadotropin

A) estrogen

53) 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

87) A zygote whose genotype is XY will develop as a A) male. B) female.

A) male.

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

A) muscle.

65) The placenta is expelled from the uterus during the ________ stage of labor. A) placental B) expulsion C) dilation D) contraction E) afterbirth

A) placental

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

A) progesterone

19) During implantation, the A) syncytial 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) syncytial trophoblast erodes a path through the endometrium.

43) Identify the structure labeled "3." A) umbilical cord B) placenta C) myometrium D) amniotic cavity E) yolk sac

A) umbilical cord

44) Identify the structure labeled "6." A) umbilical cord B) placenta C) chorion D) amnion E) myometrium

A) umbilical cord

52) Oxygenated blood is carried away from the placenta by the A) umbilical vein. B) umbilical arteries.

A) umbilical vein.

35) The extra-embryonic membrane that forms blood cells is the A) yolk sac. B) amnion. C) allantois. D) chorion.

A) yolk sac.

100) Describe the process that forms the primary germ layers and cite the layer that contributes to nearly all body systems. (Module 27.4A) A) Gastrulation forms the primary germ layers from the embryonic disc. The endoderm contributes to nearly all body systems. B) Gastrulation forms the primary germ layers from the embryonic disc. The mesoderm contributes to nearly all body systems. C) Formation of the primitive streak gives rise to the primary germ layers. The ectoderm contributes to nearly all body systems. D) Formation of the primitive streak gives rise to the primary germ layers. The endoderm contributes to nearly all body systems. E) Gastrulation forms the primary germ layers from the embryonic disc. The ectoderm contributes to nearly all body systems.

B) Gastrulation forms the primary germ layers from the embryonic disc. The mesoderm contributes to nearly all body systems.

3) ________ is the time spent in growing within the uterus. A) Gastrulation B) Gestation C) Development D) Pregnancy E) Embryonization

B) Gestation

71) All of the following occur at puberty except A) FSH levels rise. B) GnRH levels decline. C) levels of sex hormones rise. D) skeletal muscle fibers are stimulated. E) secondary sexual characteristics begin to develop.

B) GnRH levels decline.

81) Molly is homozygous for the dominant black hair trait. Therefore, A) Molly is a carrier for the black hair trait. B) Molly has black hair. C) Molly has red hair. D) Molly's hair color cannot be determined from this information

B) Molly has black hair.

82) A ________ is used to show all possible combinations of genes that can result from a given parental cross. A) pedigree B) Punnett square C) karyotype D) phenotype E) family tree

B) Punnett square

90) A child born with one lone X chromosome will have A) Klinefelter's syndrome. B) Turner's syndrome. C) Down syndrome. D) Tay-Sachs disease. E) acromegaly.

B) Turner's syndrome.

36) The extra-embryonic membrane that forms a fluid-filled sac is the A) yolk sac. B) amnion. C) allantois. D) All of the answers are correct. E) None of the answers is correct.

B) amnion.

84) 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.

86) A zygote whose genotype is XX will develop as a A) male. B) female.

B) female.

66) 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.

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

B) gastrulation.

76) A person's original chromosomes and their component genes constitute that person's A) autosomal inheritance. B) genotype. C) phenotype. D) allele. E) locus.

B) genotype.

74) Which of the following does not describe non-sex chromosomes? A) diploid B) haploid C) produced by mitosis D) genetically identical E) called somatic cells

B) haploid

79) 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) autosomal E) polygenic

B) homozygous

58) In pregnancy, expansion of the uterus results from A) increased production of additional smooth muscle cells. B) hypertrophy of smooth muscle cells.

B) hypertrophy of smooth muscle cells.

15) Attachment to and penetration of the endometrium by the blastocyst is referred to as A) cleavage. B) implantation. C) placentation. D) embryogenesis. E) fertilization.

B) implantation.

67) Which hormone stimulates the milk let-down reflex? A) progesterone B) oxytocin C) estrogen D) relaxin E) GnRH

B) oxytocin

64) 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) constrict the cervix. E) None of the answers is correct.

B) stimulate smooth muscle contractions.

57) By the end of gestation, which of the following has not occurred? A) Maternal blood volume has increased 50%. B) Maternal nutritional requirements has increased 30%. C) The uterus has increased in size by 10 fold. D) The kidney's GFR has increased 2 fold. E) The bladder size has been reduced.

C) The uterus has increased in size by 10 fold.

12) 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 lacunae. D) form a capillary network in the trophoblast. E) increase in size and penetrate the blastocyst.

C) break down and form lacunae.

34) The mesoderm and the cytotrophoblast combine to form the A) amnion. B) amniotic sac. C) chorion. D) allantois. E) None of the answers is correct.

C) chorion.

25) Identify what process is occurring at the structure labeled "6." A) fertilization B) ovulation C) cleavage D) migration E) gastrulation

C) cleavage

18) The inner cell mass of the blastocyst will A) form the placenta. B) form the morula. C) form the embryo. D) form blood vessels of the placenta. E) provide nutrients for early growth.

C) form the embryo

88) Which of the following traits is a sex-linked inheritance? A) albino pigmentation B) red hair C) hemophilia D) Huntington's disease E) sickle cell anemia

C) hemophilia

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

C) heterozygous

24) Which of the following descriptors regarding the trophoblast is false? A) spreads into the endometrium B) absorbs nutrients released by degenerating endometrial glands C) has both a syncytial and cellular component D) is derived from the inner cell mass E) causes maternal blood vessels to break down

D) is derived from the inner cell mass

27) 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.

16) After 3 days, a pre-embryo becomes a solid ball of cells known as a A) chorion. B) blastomere. C) lacuna. D) morula. E) blastocyst.

D) morula.

77) The traits of an individual controlled by his or her genotype are his or her A) epigenome. B) genotypical inheritances. C) alleles. D) phenotype. E) karyotype.

D) phenotype

89) The "P" in the abbreviation SNP stands for A) pronucleus. B) phenotype. C) prenatal. D) polymorphism. E) placental.

D) polymorphism.

21) Identify the stage labeled "12." A) zygote B) morula C) blastocyst D) trophoblast E) cytotrophoblast

D) trophoblast

46) The ________ is formed by a portion of the allantois, blood vessels, and remnants of the yolk sac. A) amnion B) body stalk C) chorion D) umbilical cord E) placenta

D) umbilical cord

47) The embryonic heart starts beating as blood begins to flow through chorionic vessels at approximately ________ of development. A) day 3 B) day 12 C) week 2 D) week 3 E) the second trimester

D) week 3

91) Trisomy 21 is the clinical term for A) Marfan's syndrome. B) Klinefelter syndrome. C) amyotrophic lateral sclerosis. D) fetal alcohol syndrome. E) Down syndrome.

E) Down syndrome.

92) Define gestation. A) Gestation is the moment of fertilization. B) Gestation is the time after fertilization until implantation. C) Gestation is the time of development during the first and second trimesters. D) Gestation is the time of development during the third trimester. E) Gestation is the time a developing embryo and fetus spends in the uterus.

E) Gestation is the time a developing embryo and fetus spends in the uterus.

8) Contact of a sperm with the oocyte membrane does not cause A) oocyte activation. B) completion of the second meiosis. C) formation of the second polar body. D) membrane fusion. E) a decrease in calcium released from the oocyte.

E) a decrease in calcium released from the oocyte.

56) All of the following occur during pregnancy except A) a woman's respiratory rate and tidal volume increase. B) maternal blood volume increases. C) maternal nutrient requirements increase. D) a woman's glomerular filtration rate increases. E) a woman's bladder capacity increases.

E) a woman's bladder capacity increases.

22) Identify the stage labeled "8." A) zygote B) early morula C) blastomere D) trophoblast E) advanced morula

E) advanced morula

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

E) alleles.

40) Endoderm + mesoderm = which extra-embryonic membrane(s)? A) chorion B) amnion C) allantois D) yolk sac E) both yolk sac and allantois

E) both yolk sac and allantois

6) Which of the following is not part of fertilization? A) release of acrosomal enzymes B) oocyte activation C) completion of meiosis II D) amphimixis E) completion of meiosis I

E) completion of meiosis I

10) Completion of cytokinesis does not lead to A) production of two blastomeres. B) division of the cytoplasm into two portions. C) initiation of interphase. D) completion of cleavage. E) formation of a polar body.

E) formation of a polar body.

38) All of the following are true of the allantois except A) it derives partly from endoderm. B) it projects into the umbilical stalk. C) it derives partly from mesoderm. D) part will develop as the urinary bladder. E) it acts as the fetal bone marrow.

E) it acts as the fetal bone marrow.

48) Which of the following does not occur during the first trimester? A) cleavage B) implantation C) separation of blastomeres to form monozygotic twins D) gastrulation E) organs become functional

E) organs become functional

20) Identify the structures labeled "4." A) zygotic twins B) morula C) blastomere D) trophoblast E) polar bodies

E) polar bodies

50) The placenta is not a source of which of the following hormones? A) hCG B) relaxin C) placental lactogen D) progesterone E) prolactin

E) prolactin

63) Progesterone calms the myometrium and prevents contraction. What factor does not 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) relaxation of the cervix

E) relaxation of the cervix

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

E) relaxin.

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

E) the urinary bladder.

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

E) umbilical cord

101) Name the four extra-embryonic membranes. (Module 27.5A) A) yolk sac, amnion, blastocoele, and the trophoblast B) endoderm, mesoderm, ectoderm, gastroderm C) blastodisc, embryonic disc, cytotrophoblast, and syncytiotrophoblast D) amnion, placenta, umbilical stalk, and chorion E) yolk sac, amnion, allantois, and the chorion

E) yolk sac, amnion, allantois, and the chorion