Question 1

Which statement about conjoined twins is true?

Accepted Answer

A)  They result from the fertilization of two separate eggs. 
B)  They are always non-identical twins. 
C)  They result from the joining of trophoblasts of two separate blastocysts. 
D)  They usually share some organs and limbs. 
E)  They are often different sexes. 
A)  They result from the fertilization of two separate eggs. 
B)  They are always non-identical twins. 
C)  They result from the joining of trophoblasts of two separate blastocysts. 
D)  They usually share some organs and limbs. 
E)  They are often different sexes.

Question 2

Which statement about the blastula stage is true?

Accepted Answer

A)  When a cell becomes determined, it has differentiated into a specific cell type. 
B)  A fate map of a blastula indicates what tissues specific blastomeres have formed. 
C)  Cells in a blastula exhibit extensive movement and interaction. 
D)  The end result of cleavage is a large number of small differentiated cells. 
E)  Cells in different regions of a blastula contain different cytoplasmic determinants. 
A)  When a cell becomes determined, it has differentiated into a specific cell type. 
B)  A fate map of a blastula indicates what tissues specific blastomeres have formed. 
C)  Cells in a blastula exhibit extensive movement and interaction. 
D)  The end result of cleavage is a large number of small differentiated cells. 
E)  Cells in different regions of a blastula contain different cytoplasmic determinants.

Question 3

Which feature characterizes the yolk sac of developing chicks?

Accepted Answer

A)  It is the last of four extraembryonic membranes to form. 
B)  It is tube-shaped at the top and continuous with the gut of the embryo. 
C)  Yolk passes through its tube for digestion in the chick's gut. 
D)  Ectoderm and mesoderm extend to enclose the yolk. 
E)  It is avascular. 
A)  It is the last of four extraembryonic membranes to form. 
B)  It is tube-shaped at the top and continuous with the gut of the embryo. 
C)  Yolk passes through its tube for digestion in the chick's gut. 
D)  Ectoderm and mesoderm extend to enclose the yolk. 
E)  It is avascular.

Question 4

Refer to the figure showing a scanning electron micrograph and figure of a chick embryo.   What are the number, letter, and name of the structure immediately ventral to the neural tube? What is one of its functions?

Accepted Answer

A)  5, b, epidermal ectoderm; functions to form epidermis 
B)  4, d, neural crest; functions to form spinal cord 
C)  2, d, chordamesoderm; functions to initiate neurulation 
D)  2, e, notochord; functions as structural support 
E)  1, c, somite; functions to form muscles 
A)  5, b, epidermal ectoderm; functions to form epidermis 
B)  4, d, neural crest; functions to form spinal cord 
C)  2, d, chordamesoderm; functions to initiate neurulation 
D)  2, e, notochord; functions as structural support 
E)  1, c, somite; functions to form muscles

Question 5

Which statement about cleavage patterns is true?

Accepted Answer

A)  In radial cleavage, mitotic spindles of successive cell divisions form parallel or perpendicular to the animal-vegetal axis of the zygote. 
B)  Spiral cleavage is found in animals with incomplete cleavage. 
C)  Radial cleavage is found in animals with incomplete cleavage. 
D)  Frogs display spiral cleavage. 
E)  Snails display radial cleavage. 
A)  In radial cleavage, mitotic spindles of successive cell divisions form parallel or perpendicular to the animal-vegetal axis of the zygote. 
B)  Spiral cleavage is found in animals with incomplete cleavage. 
C)  Radial cleavage is found in animals with incomplete cleavage. 
D)  Frogs display spiral cleavage. 
E)  Snails display radial cleavage.

Question 6

Which event occurs during cleavage?

Accepted Answer

A)  Rapid transcription of genes 
B)  Differential distribution of nutrients and information molecules 
C)  Cell growth 
D)  Rapid translation of mRNA into protein 
E)  A decrease in the DNA-to-cytoplasm ratio 
A)  Rapid transcription of genes 
B)  Differential distribution of nutrients and information molecules 
C)  Cell growth 
D)  Rapid translation of mRNA into protein 
E)  A decrease in the DNA-to-cytoplasm ratio

Question 7

Superficial cleavage occurs in

Accepted Answer

A)  frogs. 
B)  birds. 
C)  fruit flies. 
D)  fish. 
E)  placental mammals. 
A)  frogs. 
B)  birds. 
C)  fruit flies. 
D)  fish. 
E)  placental mammals.

Question 8

Which gastrulation event in the sea urchin occurs later than the others?

Accepted Answer

A)  Flattening of the vegetal hemisphere 
B)  Formation of primary mesenchyme when some cells at the vegetal pole break away and move into the blastocoel 
C)  Extension of filopodia from secondary mesenchyme to attach to the ectoderm 
D)  Cuboidal cells becoming wedge-shaped at the vegetal pole 
E)  Cell invagination to form the archenteron 
A)  Flattening of the vegetal hemisphere 
B)  Formation of primary mesenchyme when some cells at the vegetal pole break away and move into the blastocoel 
C)  Extension of filopodia from secondary mesenchyme to attach to the ectoderm 
D)  Cuboidal cells becoming wedge-shaped at the vegetal pole 
E)  Cell invagination to form the archenteron

Question 9

Choose the correct pairing of the germ layer and the structure it gives rise to.

Accepted Answer

A)  Endoderm: nervous system 
B)  Ectoderm: lining of digestive tract 
C)  Mesoderm: liver 
D)  Endoderm: lining of pancreas 
E)  Mesoderm: hair 
A)  Endoderm: nervous system 
B)  Ectoderm: lining of digestive tract 
C)  Mesoderm: liver 
D)  Endoderm: lining of pancreas 
E)  Mesoderm: hair

Question 10

Which feature is characteristic of cleavage in placental mammals?

Accepted Answer

A)  Begins after the fertilized egg reaches the uterus 
B)  Is slowed down by large amounts of yolk in the vegetal hemisphere 
C)  Produces a spherical blastula that is one cell layer thick, similar to that of the sea urchin 
D)  Has two different planes of cleavage in the second cleavage 
E)  Undergoes nuclear division in the absence of cytoplasmic division during the first several division cycles 
A)  Begins after the fertilized egg reaches the uterus 
B)  Is slowed down by large amounts of yolk in the vegetal hemisphere 
C)  Produces a spherical blastula that is one cell layer thick, similar to that of the sea urchin 
D)  Has two different planes of cleavage in the second cleavage 
E)  Undergoes nuclear division in the absence of cytoplasmic division during the first several division cycles

Question 11

Which feature characterizes nervous system development in humans?

Accepted Answer

A)  The brain begins functioning just prior to birth. 
B)  The brain undergoes cycles of sleep and waking in the third trimester. 
C)  The brain begins its development during neurulation in the second trimester. 
D)  Brain development is not dependent on Hox gene expression. 
E)  It is only susceptible to disruption in the third trimester, when the brain is forming. 
A)  The brain begins functioning just prior to birth. 
B)  The brain undergoes cycles of sleep and waking in the third trimester. 
C)  The brain begins its development during neurulation in the second trimester. 
D)  Brain development is not dependent on Hox gene expression. 
E)  It is only susceptible to disruption in the third trimester, when the brain is forming.

Question 12

What medical condition can result if a human blastocyst hatches too early from the zona pellucida?

Accepted Answer

If a blastocyst hatches from the zona pe

Question 13

Which of these gastrulation events occurs after the others in sea urchins?

Accepted Answer

A)  Changes in the shape of individual blastomeres in the vegetal hemisphere 
B)  Elongation of the archenteron when filopodia of secondary mesenchyme cells contract 
C)  Invagination 
D)  Formation of the archenteron 
E)  Formation of the mouth 
A)  Changes in the shape of individual blastomeres in the vegetal hemisphere 
B)  Elongation of the archenteron when filopodia of secondary mesenchyme cells contract 
C)  Invagination 
D)  Formation of the archenteron 
E)  Formation of the mouth

Question 14

A researcher is interested in studying the maternal behavior shown by placental mammals in the hours immediately after giving birth.To ensure timely collection of data, she would like a study species with a short gestation period.Which placental mammal would you recommend?

Accepted Answer

A)  Cat 
B)  Hamster 
C)  Dog 
D)  Horse 
E)  Elephant 
A)  Cat 
B)  Hamster 
C)  Dog 
D)  Horse 
E)  Elephant

Question 15

Initiation of nervous system development in amphibians occurs when organizer cells

Accepted Answer

A)  block BMP proteins from inducing ectoderm to become epidermis. 
B)  activate BMP proteins to induce ectoderm to become neural tissue. 
C)  block Goosecoid from inducing ectoderm to become epidermis. 
D)  block BMP proteins from inducing mesoderm to become epidermis. 
E)  activate BMP proteins that induce mesoderm to form dermis. 
A)  block BMP proteins from inducing ectoderm to become epidermis. 
B)  activate BMP proteins to induce ectoderm to become neural tissue. 
C)  block Goosecoid from inducing ectoderm to become epidermis. 
D)  block BMP proteins from inducing mesoderm to become epidermis. 
E)  activate BMP proteins that induce mesoderm to form dermis.

Question 16

Chorionic villus sampling, one method of prenatal genetic testing, involves taking a small sample of chorionic villi from the placenta.Why would cells from this region of the placenta reveal the genetic makeup of the fetus?

Accepted Answer

The placenta is formed from the chorion

Question 17

In developing humans, the first trimester is a time of extreme sensitivity to environmental risks, because

Accepted Answer

A)  the placenta is most efficient at this time. 
B)  the embryo is very small at this time. 
C)  tissue differentiation is occurring at this time. 
D)  it is a period of dramatic growth. 
E)  the organ systems are maturing and particularly sensitive to disruption at this time. 
A)  the placenta is most efficient at this time. 
B)  the embryo is very small at this time. 
C)  tissue differentiation is occurring at this time. 
D)  it is a period of dramatic growth. 
E)  the organ systems are maturing and particularly sensitive to disruption at this time.

Question 18

If a researcher studying amphibian development blocked the secretion of BMP proteins by mesoderm under the embryo's dorsal surface, the likely result would be that the

Accepted Answer

A)  overlying ectoderm would become epidermis. 
B)  overlying ectoderm would become dermis. 
C)  overlying ectoderm would become neural tissue. 
D)  underlying endoderm would form neural tissue. 
E)  underlying endoderm would form dermis. 
A)  overlying ectoderm would become epidermis. 
B)  overlying ectoderm would become dermis. 
C)  overlying ectoderm would become neural tissue. 
D)  underlying endoderm would form neural tissue. 
E)  underlying endoderm would form dermis.

Question 19

The gene Hoxb1 is close to the 3ʹ end of a Hox gene complex.Where in a vertebrate embryo might expression of Hoxb1 occur?

Accepted Answer

A)  Anterior portion 
B)  Middle portion 
C)  Posterior portion 
D)  Along the entire length of the embryo 
E)  On the ventral surface 
A)  Anterior portion 
B)  Middle portion 
C)  Posterior portion 
D)  Along the entire length of the embryo 
E)  On the ventral surface

Question 20

Working with salamander embryos, Hans Spemann transplanted a piece of a late gastrula that would normally form epidermis of the skin to the region of another late gastrula that would normally form neural tissue.Which result did he get?

Accepted Answer

A)  The recipient gastrula developed a secondary embryo at the transplant site. 
B)  The transplanted tissue formed epidermis. 
C)  The recipient gastrula rejected the tissue transplant. 
D)  The transplanted tissue formed neural tissue. 
E)  The recipient of the transplant died. 
A)  The recipient gastrula developed a secondary embryo at the transplant site. 
B)  The transplanted tissue formed epidermis. 
C)  The recipient gastrula rejected the tissue transplant. 
D)  The transplanted tissue formed neural tissue. 
E)  The recipient of the transplant died.

Exam 43: Animal Development

Which statement about conjoined twins is true?

Which statement about the blastula stage is true?

Which feature characterizes the yolk sac of developing chicks?

Refer to the figure showing a scanning electron micrograph and figure of a chick embryo. What are the number, letter, and name of the structure immediately ventral to the neural tube? What is one of its functions?

Which statement about cleavage patterns is true?

Which event occurs during cleavage?

Superficial cleavage occurs in

Which gastrulation event in the sea urchin occurs later than the others?

Choose the correct pairing of the germ layer and the structure it gives rise to.

Which feature is characteristic of cleavage in placental mammals?

Which feature characterizes nervous system development in humans?

What medical condition can result if a human blastocyst hatches too early from the zona pellucida?

Which of these gastrulation events occurs after the others in sea urchins?

A researcher is interested in studying the maternal behavior shown by placental mammals in the hours immediately after giving birth.To ensure timely collection of data, she would like a study species with a short gestation period.Which placental mammal would you recommend?

Initiation of nervous system development in amphibians occurs when organizer cells

Chorionic villus sampling, one method of prenatal genetic testing, involves taking a small sample of chorionic villi from the placenta.Why would cells from this region of the placenta reveal the genetic makeup of the fetus?

In developing humans, the first trimester is a time of extreme sensitivity to environmental risks, because

If a researcher studying amphibian development blocked the secretion of BMP proteins by mesoderm under the embryo's dorsal surface, the likely result would be that the

The gene Hoxb1 is close to the 3ʹ end of a Hox gene complex.Where in a vertebrate embryo might expression of Hoxb1 occur?

Working with salamander embryos, Hans Spemann transplanted a piece of a late gastrula that would normally form epidermis of the skin to the region of another late gastrula that would normally form neural tissue.Which result did he get?

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

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Salt and Water Balance and Nitrogen Excretion

Animal Behavior

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