Deck 43: Animal Development

Question 1

Which germ layer forms the pancreas?

A) Ectoderm
B) Epidermis
C) Endoderm
D) Mesoderm
E) Endodermis

Answer 1

C

Question 2

The cells that line the inside of the blastopore become the

A) muscles.
B) digestive tract.
C) skin.
D) skeleton.
E) nervous system.

Answer 2

B

Question 3

As a morula, the embryo consists of

A) three differentiated layers of cells.
B) a solid mass of cells, each the size of the zygote.
C) a hollow ball of cells.
D) cells that have different DNA content.
E) a cluster of cells that are much larger than normal cells.

Answer 3

E

Question 4

If the formation of the endoderm does not take place in an embryo, yet the embryo, for whatever reason, continues to develop, which of the following structures will NOT develop?

A) Skin
B) Heart
C) Stomach
D) Kidneys
E) Nervous system

Question 5

Early animal embryos are composed of stem cells, unspecialized cells that are capable of dividing and renewing themselves for long periods. If a stem cell divides by mitosis so that one cell eventually becomes part of the brain and the other cell becomes part of a salivary gland, the cells have

A) differentiated.
B) increased their genetic variability.
C) lost genes.
D) taken up genes from surrounding cells.
E) diffused.

Question 6

The embryo of a __________undergoes direct development.

A) frog
B) lobster
C) snake
D) butterfly
E) dragonfly

Question 7

Which extraembryonic membrane lies immediately beneath the shell of a reptile embryo?

A) Allantois
B) Amnion
C) Placenta
D) Yolk sac
E) Chorion

Question 8

Birds hatch out of their eggs looking like small versions of the adult. This is an example of

A) direct development.
B) external development.
C) internal development.
D) genetic dwarfism.
E) indirect development.

Question 9

The nervous system forms from the

A) endoderm.
B) ectoderm.
C) yolk.
D) chorion.
E) mesoderm.

Question 10

In a reptile egg, which membrane is analogous to a lung?

A) Amnion
B) Allantois
C) Blastocyst
D) Chorion
E) Yolk sac

Question 11

What is differentiation?

A) The process in which different organ systems become specialized
B) The process in which different tissues specialize into specific organs
C) The process in which different organs specialize in function
D) The process in which different cells develop into different cell types

Question 12

The metamorphosis of a caterpillar into a butterfly is an example of

A) internal development.
B) external development.
C) indirect development.
D) placental development.
E) direct development.

Question 13

In placental organisms, the __________of the embryo merges with the endometrial lining of the uterus to form the placenta.

A) amnion
B) chorion
C) allantois
D) yolk sac
E) blastopore

Question 14

In a bird egg, the__________ provides the watery environment in which the embryo develops.

A) amnion
B) allantois
C) yolk sac
D) chorion
E) blastocyst

Question 15

Human embryos differ from bird embryos in that

A) human embryos do not undergo cleavage.
B) human embryos have a yolk sac, but it contains very little yolk.
C) human embryos have no yolk sac.
D) bird embryos have an extra membrane, the allantois, that is not found in human embryos.
E) bird embryos undergo metamorphosis to become sexually mature adults.

Question 16

One characteristic of animal development is the specialization in both structure and function that cells undergo. This is called

A) differentiation.
B) placental development.
C) indirect development.
D) direct development.
E) internal development.

Question 17

During the embryonic stage, a hollow ball of cells is known as a

A) gastrula.
B) blastula.
C) larva.
D) chorion.
E) morula.

Question 18

When a researcher transplanted the nucleus of an intestinal cell from a tadpole into an egg cell whose nucleus had been destroyed, the egg developed into a normal frog. This illustrates that

A) scientists can clone a human by putting one of his or her nuclei into an egg cell.
B) the homeobox genes in a transplanted nucleus undergo mutation.
C) genes are gained during the process of differentiation.
D) each cell of an organism has all the genes needed for development.
E) a nucleus that is removed from its normal location is influenced by adjoining cells.

Question 19

__________is the developmental event that results in the formation of a primitive gut and the three tissue layers.

A) Blastulation
B) Metamorphosis
C) Gastrulation
D) Induction
E) Cleavage

Question 20

Which of the following is the result of gastrulation?

A) A hollow ball of cells
B) The formation of organs
C) A zygote
D) A three-layered embryo
E) A blastula

Question 21

After induction occurs, the

A) fate of each cell is permanently fixed.
B) cells have different genes.
C) DNA of the mitochondria differentiates into new genes.
D) transcription of all genes stops.

Question 22

The proteins that bind to the DNA near regions where gene transcription begins are called

A) mRNA.
B) the gray crescent.
C) promoter genes.
D) transcription factors.
E) homeobox genes.

Question 23

Induction refers to

A) the migration of cells to form the gastrula.
B) the formation of the mesoderm layer in a gastrula.
C) hormones from the motherʹs blood altering the development of the embryo.
D) the formation of the nervous system.
E) chemical messengers from one embryonic cell influencing the development of other cells.

Question 24

What will occur if a morula divides into three masses of cells?

A) Normal identical triplets will be born.
B) The resulting embryos will develop, but they may be missing some organs based on which germ layers were transferred with each section.
C) The resulting embryos will die.
D) Three distinctly different embryos will develop, depending on which homeoboxes went with which mass of cells.
E) The resulting embryos will develop severe birth defects due to missing genes.

Question 25

In the 1920s, two German embryologists, Hans Spemann and Hilde Mangold, demonstrated that a small patch of cells, called the dorsal lip of the blastopore, would

A) induce the surrounding cells to differentiate.
B) form the chorion.
C) become the digestive tract.
D) become the neural tube.
E) lack the genes necessary to develop the embryo.

Question 26

The umbilical cord of a mammal connects the

A) yolk sac and the allantois.
B) embryo and the amnion.
C) amnion and the chorion.
D) fetus and the placenta.
E) maternal and fetal bloodstreams.

Question 27

In humans, fertilization occurs in the

A) uterus.
B) testes.
C) uterine tube.
D) vagina.
E) ovary.

Question 28

At which stage is the human embryo most susceptible to toxic substances?

A) During organogenesis
B) During the last trimester
C) During cleavage
D) During the fourth and fifth months
E) Just before birth

Question 29

At what stage does a human embryo implant in the uterus?

A) Morula
B) Fetal
C) Blastocyst
D) Gastrula
E) Embryonic disk

Question 30

During mammalian development, a

A) morula becomes a blastula.
B) morula becomes gastrula.
C) gastrula becomes a morula.
D) zygote becomes a blastula.
E) blastula becomes a zygote.

Question 31

A developing human is considered an embryo after__________ weeks.

A) 12
B) 8
C) 16
D) 4
E) 2

Question 32

Transplanting embryonic eye tissue into the back of a developing tadpole will cause a lens to grow on the back of the tadpole. This is an example of

A) metamorphosis.
B) programmed cell death.
C) cleavage.
D) gastrulation.
E) induction.

Question 33

The structure produced by cleavage of a human zygote is called a(n)

A) chorion.
B) blastocyst.
C) gastrula.
D) embryonic disk.
E) blastopore.

Question 34

In humans, implantation occurs

A) immediately after fertilization.
B) when the embryo is a gastrula.
C) after the formation of the neural tube.
D) just prior to fertilization.
E) when the zygote is a blastocyst.

Question 35

A human embryo is known as a fetus after__________ weeks.

A) 16
B) 8
C) 2
D) 4
E) 12

Question 36

Your biceps muscle is derived from the

A) mesoderm.
B) endoderm.
C) amnion.
D) blastopore.
E) ectoderm.

Question 37

Based on experiments with amphibian embryos, Spemann and Mangold found that

A) transplanted cells always formed a whole new embryo.
B) donor cells maintained their original differentiation no matter where in the host they were transplanted.
C) transplanted cells completely undifferentiated into random masses of tissue.
D) transplanted cells always died.
E) in most cases, transplanted donor cells assumed the developmental fate of the area to which they were transplanted in the host.

Question 38

Cells differentiate during development because

A) in each cell only some of the genes are expressed.
B) chemicals in the sperm cytoplasm determine which cells develop.
C) genes respond only to influences outside the motherʹs body.
D) each cell contains only a portion of the genes.

Question 39

What makes the cells of a developing embryo differentiate into various types of cells?

A) Special genes in the cytoplasm cause this differentiation.
B) They have different genes.
C) Different genes are activated.
D) Once certain genes of a cell have caused it to differentiate, the other genes are lost.
E) The DNA of their mitochondria is different.

Question 40

The birth defect spina bifida results in part of the spinal cord lying outside of the body. This defect is due to abnormal development of the

A) placenta.
B) embryonic disk.
C) allantois.
D) gill grooves.
E) neural tube.

Question 41

Stem cells developed by inserting genes that regulate the transcription of specific genes into cells from an adult are __________cells.

A) gastrula
B) embryonic stem
C) chorionic villi
D) embryonic disk
E) induced pluripotent stem

Question 42

In species with direct development, fewer offspring are produced, but a higher proportion survives to adulthood.

Question 43

Prior to birth, stretching of the cervix by the babyʹs head stimulates the release of

A) colostrum.
B) oxytocin.
C) estrogen.
D) prolactin.
E) progesterone.

Question 44

As early as the __________month, as the brain and spinal cord grow, the fetus can demonstrate movement and respond to stimuli.

A) fifth
B) sixth
C) fourth
D) third
E) second

Question 45

In animals that undergo indirect development, the newborn has a similar body structure to that of the adult.

Question 46

__________is the medication given to combat morning sickness that caused deformed and missing limbs in infants in the late 1950s and early 1960s.

A) Accutane
B) Thalidomide
C) Nicotine
D) Alcohol
E) Rubella

Question 47

The cells of an aging animal function less efficiently because

A) protein synthesis ceases.
B) damaged DNA cannot be repaired.
C) cell metabolism is slower.
D) cells can no longer mitotically divide.
E) organelles and cellular components decline.

Question 48

Which of the following occurs in the placenta?

A) All substances in maternal blood that may be harmful to the fetus are prevented from moving across the walls of the villi.
B) Fetal blood and maternal blood mix.
C) Eroding blood vessels in the endometrium bathe chorionic villi in pools of maternal blood.
D) Hormones are absorbed to prevent them from influencing the developing fetus.
E) The amnion and the chorion grow into the endometrium.

Question 49

Most fetuses can survive outside the womb after a minimum of __________weeks.

A) 45
B) 38
C) 32
D) 15
E) 20

Question 50

In indirect development, the embryo hatches into a sexually immature stage called a larva.

Question 51

__________diffuse(s) from fetal blood to maternal blood in the placenta.

A) Oxygen
B) Alcohol
C) Wastes
D) Nutrients
E) Infectious organisms

Question 52

All cells in an animal, with the exception of gametes, are genetically identical.

Question 53

The placental blood vessels

A) manufacture hormones that slow the growth of the embryo, preventing it from outgrowing the uterus.
B) mix maternal blood and fetal blood.
C) allow for the exchange of wastes and nutrients but keep the maternal and fetal circulations separate.
D) prevent all microbes and toxins from crossing from mother to child.
E) draw oxygen from the fetal blood and pass it to the mother.

Question 54

The process through which a human embryo develops into an adult is called metamorphosis.

Question 55

The outer cell layer of the blastocyst becomes the __________, which forms the embryonic portion of the placenta.

A) inner cell mass
B) primitive streak
C) chorion
D) embryonic disk
E) yolk sac

Question 56

A human embryologist examines a 3-week-old embryo and notices that it has not developed a notochord. If the embryo survives, it will lack

A) a stomach and a pancreas.
B) a heart and lungs.
C) a brain and a spinal cord.
D) skin and blood vessels.

Question 57

Which of these hormones stimulates the production of milk?

A) Estrogen
B) Prolactin
C) Progesterone
D) Colostrum
E) Oxytocin

Question 58

Suppose a pregnant woman took a drug that causes incomplete brain formation during fetal development. When must the woman have taken the drug for this effect to occur?

A) During labor
B) Between the seventh and eighth months of development
C) Between the fifth and sixth months of development
D) In the first month of development
E) Between the second and third months of development

Question 59

The last 7 months of pregnancy are devoted to

A) formation of the brain.
B) formation of tissue layers.
C) growth.
D) organization of organs into organ systems.
E) formation of major organs.

Question 60

Most microbes cannot gain access to the fetus. However,__________ , which causes syphilis in adults, can cross the placenta and attack the fetus, causing stillbirths and mental retardation.

A) HIV
B) Treponema pallidum
C) Listeria
D) rubella
E) Staphylococcus

Question 61

Yolk sacs are found only in animals with shelled eggs.

Question 62

Maternal blood and fetal blood are mixed in the placenta.

Question 63

At 10 weeks, the blastocyst becomes an embryo.

Question 64

The small, hollow ball of cells in early development is the zygote.

Question 65

In blastulas, if cells from an area that would normally become skin are transplanted into an area that would become the nervous system, the transplanted cells will form structures of the nervous system.

Question 66

The extraembryonic membrane that sends blood vessels into the endometrium is the chorion.

Question 67

The nervous system develops from the endoderm.

Question 68

Homeobox genes determine the overall shape of the body and the location of its parts.

Question 69

The blastopore forms during gastrulation.

Question 70

Amphibians, reptiles, and mammals pass through embryonic stages in which they have tails and webbed fingers and toes.

Question 71

Longevity in animals appears to be most related to their cellsʹ ability to repair damage to their own DNA.

Question 72

The developing fetus secretes chorionic gonadotropin only during the first 2 weeks of pregnancy.

Question 73

The placenta prevents pathogenic microbes such as HIV and chemicals such as alcohol from reaching the babyʹs bloodstream.

Question 74

Cellular differentiation depends on which genes are turned on or expressed in the cell.

Question 75

The most rapid differentiation in an embryo occurs during the first 2 months of pregnancy.

Question 76

Mitotic cell divisions of the zygote are collectively called cleavage.

Question 77

A morula is a solid ball of undifferentiated cells.

Question 78

The blastocyst implants in the endometrium about 7 days after fertilization.

Question 79

The mesoderm develops into the dermis of the skin and the skeleton.

Question 80

The amnion forms the watery environment that encloses the embryo.