Question 1

What is the external layer of the head of a sperm cell called?

Accepted Answer

A) vitelline envelope 
B) zona pellucida 
C) acrosome 
D) cortical granules 
A) vitelline envelope 
B) zona pellucida 
C) acrosome 
D) cortical granules C

Question 2

If microtubule formation were disrupted experimentally by the use of drugs,the effects might include all of the following EXCEPT

Accepted Answer

A) failure of cytoplasmic RNAs to be translated into zygote proteins. 
B) failure of organizer formation in the fertilized egg. 
C) failure of gastrulation of the embryo. 
D) failure of transcription of tissue-specific mRNAs. 
A) failure of cytoplasmic RNAs to be translated into zygote proteins. 
B) failure of organizer formation in the fertilized egg. 
C) failure of gastrulation of the embryo. 
D) failure of transcription of tissue-specific mRNAs. A

Question 3

What happens during gastrulation?

Accepted Answer

A) The neural tube-precursor of the spinal cord and brain-forms. 
B) Basal and apical cells-precursors of the suspensor and embryo,respectively-form. 
C) The fertilized egg divides without growth occurring,forming a ball of cells. 
D) Massive movements of cells make the primary body axes visible and organize the three embryonic tissues. 
A) The neural tube-precursor of the spinal cord and brain-forms. 
B) Basal and apical cells-precursors of the suspensor and embryo,respectively-form. 
C) The fertilized egg divides without growth occurring,forming a ball of cells. 
D) Massive movements of cells make the primary body axes visible and organize the three embryonic tissues. D

Question 4

Which of the following directors of embryonic development can be found in the unfertilized egg?

Accepted Answer

A) tissue-specific proteins 
B) proteins in the organizer region 
C) cytoplasmic determinants 
D) mRNAs from embryonic genome 
E) proteins in the gray crescent 
A) tissue-specific proteins 
B) proteins in the organizer region 
C) cytoplasmic determinants 
D) mRNAs from embryonic genome 
E) proteins in the gray crescent

Question 5

Why would an increased level of calcium ions be observed in a newly fertilized sea urchin egg?

Accepted Answer

A) Calcium facilitates the binding of bindin to the bindin receptor. 
B) Increased calcium allows the sperm and egg nuclei to join efficiently,resulting in the formation of a zygote nucleus. 
C) Calcium promotes release of proteases from the egg,which digest the egg-cell receptor and prevent polyspermy. 
D) Calcium promotes an influx of water that results in a fertilization envelope. 
E) Answers C and D 
A) Calcium facilitates the binding of bindin to the bindin receptor. 
B) Increased calcium allows the sperm and egg nuclei to join efficiently,resulting in the formation of a zygote nucleus. 
C) Calcium promotes release of proteases from the egg,which digest the egg-cell receptor and prevent polyspermy. 
D) Calcium promotes an influx of water that results in a fertilization envelope. 
E) Answers C and D

Question 6

Suppose an antibody to bindin was introduced into a chamber containing sea urchin sperm and eggs.What might be the result of this experiment?

Accepted Answer

A) Sperm would fertilize the eggs normally. 
B) Sperm would not clump together. 
C) Sperm would not be attracted to the egg surface. 
D) Sperm would not be motile. 
A) Sperm would fertilize the eggs normally. 
B) Sperm would not clump together. 
C) Sperm would not be attracted to the egg surface. 
D) Sperm would not be motile.

Question 7

Which of the following is the most basic process in the developing embryo because all of the other processes listed can occur only after or in conjunction with it?

Accepted Answer

A) organogenesis 
B) cell differentiation 
C) mitosis 
D) morphogenesis 
E) germ layer formation 
A) organogenesis 
B) cell differentiation 
C) mitosis 
D) morphogenesis 
E) germ layer formation

Question 8

Bicoid is a cytoplasmic determinant that is highly concentrated in the anterior end of a fly egg.Which of the following is most likely to result if there was a mutation that resulted in Bicoid being expressed equally throughout the egg?

Accepted Answer

A) All the blastomeres would be similar to each other. 
B) The blastomeres in the anterior end would produce posterior structures. 
C) All of the blastomeres would produce anterior structures. 
D) Blastomeres in the posterior would produce anterior structures. 
A) All the blastomeres would be similar to each other. 
B) The blastomeres in the anterior end would produce posterior structures. 
C) All of the blastomeres would produce anterior structures. 
D) Blastomeres in the posterior would produce anterior structures.

Question 9

In many animal embryos,the eye is the first organ to develop.The Pax6 protein is important to eye development;its absence may prevent the formation of eyes in mice and humans.Pax6 probably acts as a(n)

Accepted Answer

A) structural protein in cells of the retina. 
B) intercellular signal between retinal and lens cells. 
C) transcriptional factor for photoreceptors. 
D) extracellular matrix protein secreted by the retina. 
A) structural protein in cells of the retina. 
B) intercellular signal between retinal and lens cells. 
C) transcriptional factor for photoreceptors. 
D) extracellular matrix protein secreted by the retina.

Question 10

In Xenopus embryos,which developmental sequence is correct?

Accepted Answer

A) neurula,blastula,gastrula,cleavage 
B) cleavage,neurula,gastrula,blastula 
C) gastrula,neurula,cleavage,blastula 
D) cleavage,blastula,gastrula,neurula 
E) cleavage,gastrula,blastula,neurula 
A) neurula,blastula,gastrula,cleavage 
B) cleavage,neurula,gastrula,blastula 
C) gastrula,neurula,cleavage,blastula 
D) cleavage,blastula,gastrula,neurula 
E) cleavage,gastrula,blastula,neurula

Question 11

One difference between early development in humans and in Xenopus is that

Accepted Answer

A) in humans,there is no formation of the blastula;in Xenopus,the blastula is a critical stage in early embryogenesis. 
B) in humans,blastocysts implant into the uterine wall;there is no implantation in Xenopus. 
C) in humans,gastrulation is delayed as the egg moves along the fallopian tube;in Xenopus,gastrulation takes place immediately after blastula formation. 
D) in humans,the yolk sac is much smaller than that seen in Xenopus. 
E) in humans,neurulation occurs immediately after cleavage;in Xenopus,neurulation is delayed until after gastrulation. 
A) in humans,there is no formation of the blastula;in Xenopus,the blastula is a critical stage in early embryogenesis. 
B) in humans,blastocysts implant into the uterine wall;there is no implantation in Xenopus. 
C) in humans,gastrulation is delayed as the egg moves along the fallopian tube;in Xenopus,gastrulation takes place immediately after blastula formation. 
D) in humans,the yolk sac is much smaller than that seen in Xenopus. 
E) in humans,neurulation occurs immediately after cleavage;in Xenopus,neurulation is delayed until after gastrulation.

Question 12

The TUNEL assay detects apoptotic cells through a dye or precipitate.What does this dye/precipitate bind to?

Accepted Answer

A) extracellular receptors 
B) mRNAs and tRNAs 
C) gastrulating embryos 
D) mesodermal tissues 
E) damaged DNA 
A) extracellular receptors 
B) mRNAs and tRNAs 
C) gastrulating embryos 
D) mesodermal tissues 
E) damaged DNA

Question 13

Cytoplasmic contents in the fertilized egg move along microtubule networks.What kinds of proteins would you predict would facilitate these movements?

Accepted Answer

A) enzymes 
B) kinesins 
C) tubulins 
D) keratins 
E) collagens 
A) enzymes 
B) kinesins 
C) tubulins 
D) keratins 
E) collagens

Question 14

Why is the fertilized egg considered totipotent,while the cells of the inner cell mass (ICM)are pluripotent?

Accepted Answer

A) The egg produces all cells of the embryo and the extra-embryonic tissues,while the ICM form only cells of the embryo. 
B) The egg produces only the cells of the embryo,while the ICM will form all the cells of the extra-embryonic tissues. 
C) The egg produces only the cells of the extra-embryonic tissues,while the ICM produces both the embryonic and extra-embryonic tissues. 
A) The egg produces all cells of the embryo and the extra-embryonic tissues,while the ICM form only cells of the embryo. 
B) The egg produces only the cells of the embryo,while the ICM will form all the cells of the extra-embryonic tissues. 
C) The egg produces only the cells of the extra-embryonic tissues,while the ICM produces both the embryonic and extra-embryonic tissues.

Question 15

What would be one clue that you are observing cell differentiation in a frog embryo?

Accepted Answer

A) Somites are forming as distinct masses on either side of the neural tube. 
B) Cells of the lateral mesoderm are undergoing rapid cell division. 
C) Cells of the primitive retina are beginning to synthesize pigment molecules. 
D) The embryo has developed a chambered heart. 
A) Somites are forming as distinct masses on either side of the neural tube. 
B) Cells of the lateral mesoderm are undergoing rapid cell division. 
C) Cells of the primitive retina are beginning to synthesize pigment molecules. 
D) The embryo has developed a chambered heart.

Question 16

During gastrulation in amphibians,the presumptive mesoderm moves into the interior of the embryo by following fibrils of fibronectin.The fibronectin is probably secreted by which cells?

Accepted Answer

A) endodermal cells on the exterior of the embryo 
B) mesodermal cells that develop on the inside of the blastocyst 
C) ectodermal cells that line the inside of the blastocoel 
D) endodermal cells that migrate to the inside of the blastoceol 
A) endodermal cells on the exterior of the embryo 
B) mesodermal cells that develop on the inside of the blastocyst 
C) ectodermal cells that line the inside of the blastocoel 
D) endodermal cells that migrate to the inside of the blastoceol

Question 17

During fertilization in sea urchins,the protein bindin binds to a bindin receptor on the egg.How would the process of fertilization be affected if a mutation was present in the binding receptor?

Accepted Answer

A) The sperm would still penetrate the egg but further cell division would not occur. 
B) The sperm would not bind to the surface of the egg and so fertilization will not occur. 
C) The mutated receptor would allow multiple sperm cells to enter the egg (polyspermy). 
A) The sperm would still penetrate the egg but further cell division would not occur. 
B) The sperm would not bind to the surface of the egg and so fertilization will not occur. 
C) The mutated receptor would allow multiple sperm cells to enter the egg (polyspermy).

Question 18

Where do you suppose the first microtubules will be observed in the fertilized egg?

Accepted Answer

A) immediately beneath the plasma membrane 
B) at the site of sperm entry 
C) opposite the site of sperm entry 
D) around the nucleus 
A) immediately beneath the plasma membrane 
B) at the site of sperm entry 
C) opposite the site of sperm entry 
D) around the nucleus

Question 19

During organogenesis,the first organ system to begin forming in animal embryos is

Accepted Answer

A) the digestive system. 
B) the nervous system. 
C) the endocrine system. 
D) the circulatory system. 
E) the excretory system. 
A) the digestive system. 
B) the nervous system. 
C) the endocrine system. 
D) the circulatory system. 
E) the excretory system.

Question 20

A sea urchin egg has a membrane "envelope" around it.What does this tell you about the egg?

Accepted Answer

A) The egg is ready to be fertilized by the sperm cell. 
B) The egg has recently been fertilized by a sperm cell. 
C) The egg is developing and is not ready to be fertilized. 
D) The sperm entered the egg,but further cell division did not occur. 
A) The egg is ready to be fertilized by the sperm cell. 
B) The egg has recently been fertilized by a sperm cell. 
C) The egg is developing and is not ready to be fertilized. 
D) The sperm entered the egg,but further cell division did not occur.

Exam 22: An Introduction to Animal Development

What is the external layer of the head of a sperm cell called?

If microtubule formation were disrupted experimentally by the use of drugs,the effects might include all of the following EXCEPT

What happens during gastrulation?

Which of the following directors of embryonic development can be found in the unfertilized egg?

Why would an increased level of calcium ions be observed in a newly fertilized sea urchin egg?

Suppose an antibody to bindin was introduced into a chamber containing sea urchin sperm and eggs.What might be the result of this experiment?

Which of the following is the most basic process in the developing embryo because all of the other processes listed can occur only after or in conjunction with it?

Bicoid is a cytoplasmic determinant that is highly concentrated in the anterior end of a fly egg.Which of the following is most likely to result if there was a mutation that resulted in Bicoid being expressed equally throughout the egg?

In many animal embryos,the eye is the first organ to develop.The Pax6 protein is important to eye development;its absence may prevent the formation of eyes in mice and humans.Pax6 probably acts as a(n)

In Xenopus embryos,which developmental sequence is correct?

One difference between early development in humans and in Xenopus is that

The TUNEL assay detects apoptotic cells through a dye or precipitate.What does this dye/precipitate bind to?

Cytoplasmic contents in the fertilized egg move along microtubule networks.What kinds of proteins would you predict would facilitate these movements?

Why is the fertilized egg considered totipotent,while the cells of the inner cell mass (ICM)are pluripotent?

What would be one clue that you are observing cell differentiation in a frog embryo?

During gastrulation in amphibians,the presumptive mesoderm moves into the interior of the embryo by following fibrils of fibronectin.The fibronectin is probably secreted by which cells?

During fertilization in sea urchins,the protein bindin binds to a bindin receptor on the egg.How would the process of fertilization be affected if a mutation was present in the binding receptor?

Where do you suppose the first microtubules will be observed in the fertilized egg?

During organogenesis,the first organ system to begin forming in animal embryos is

A sea urchin egg has a membrane "envelope" around it.What does this tell you about the egg?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, membranes, and the First Cells

Inside the Cell

Cell-Cell Interactions

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, RNA Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

Analyzing and Engineering Genes

Genomics

Principles of Development

An Introduction to Plant Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, signals, and Responses

Plant Reproduction

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Electrical Signals in Animals

Animal Sensory Systems and Movement

Chemical Signals in Animals

Animal Reproduction

The Immune System in Animals

An Introduction to Ecology

Behavioural Ecology

Population Ecology

Community Ecology

Ecosystems

Biodiversity and Conservation Biology

Filters