Question 1

The earliest developmental stage among these choices is

Accepted Answer

A)  germ layers.
B)  morula.
C)  blastopore.
D)  gastrulation.
E)  invagination.F) B) and C)
G) A) and C)

Question 2

The small portion of the embryo that will become its dorsal side develops from the

Accepted Answer

A)  morula.
B)  primitive streak.
C)  archenteron.
D)  grey crescent.
E)  blastocoel.F) A) and B)
G) B) and C)

Question 3

In sea urchins, the "fast block" and the longer-lasting "slow block" to polyspermy, respectively, are

Accepted Answer

A)  the acrosomal reaction and the formation of egg white.
B)  the cortical reaction and the formation of yolk protein.
C)  the jelly coat of the egg and the vitelline membrane.
D)  membrane depolarization and the cortical reaction.
E)  inactivation of the sperm acrosome.F) C) and D)
G) D) and E)

Question 4

The vertebrate ectoderm is the origin of the

Accepted Answer

A)  nervous system.
B)  liver.
C)  pancreas.
D)  heart.
E)  kidneys.F) A) and E)
G) A) and D)

Question 5

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Accepted Answer

A)  first cell division → synthesis of embryo's DNA begins → acrosomal reaction → cortical reaction
B)  cortical reaction → synthesis of embryo's DNA begins → acrosomal reaction → first cell division
C)  cortical reaction → acrosomal reaction → first cell division → synthesis of embryo's DNA begins
D)  first cell division → acrosomal reaction → synthesis of embryo's DNA begins → cortical reaction
E)  acrosomal reaction → cortical reaction → synthesis of embryo's DNA begins → first cell divisionF) C) and D)
G) B) and D)

Question 6

Use the following information as background for the next few questions.
Imagine that you are a paleontologist and have discovered a 375-million-year-old transitional species between fish and the first legged animals. This species reveals that the evolution of hind legs began as enhanced hind fins.
-Upon moving from the water onto land, which of the following would be necessary to ensure continued reproductive success on land?

Accepted Answer

A)  a thick, waxy ectoderm
B)  external fertilization
C)  elongated flagella
D)  evolution of extraembryonic membranes
E)  formation of an acrosome on sperm cellsF) A) and B)
G) B) and C)

Question 7

Select the choice that correctly associates the organ with its embryonic sources.

Accepted Answer

A)  anterior pituitary gland-mesoderm and endoderm
B)  thyroid gland-mesoderm and ectoderm
C)  adrenal gland-ectoderm and mesoderm
D)  skin-endoderm and mesoderm
E)  brain-mesoderm and endodermF) D) and E)
G) None of the above

Question 8

In all vertebrate animals, development requires

Accepted Answer

A)  a large supply of yolk.
B)  an aqueous environment.
C)  extraembryonic membranes.
D)  an amnion.
E)  a primitive streak.F) A) and C)
G) A) and E)

Question 9

Compared to sea urchin eggs, those of mammals

Accepted Answer

A)  complete the fertilization process more rapidly.
B)  have not already completed meiosis at the time of ovulation.
C)  have a more distinct animal pole.
D)  have a more distinct vegetal pole.
E)  have no requirement for the cortical reaction.F) D) and E)
G) All of the above

Question 10

In placental mammals, the yolk sac

Accepted Answer

A)  transfers nutrients from the yolk to the embryo.
B)  differentiates into the placenta.
C)  becomes a fluid-filled sac that surrounds and protects the embryo.
D)  produces blood cells that then migrate into the embryo.
E)  stores waste products from the embryo until the placenta develops.F) A) and C)
G) B) and C)

Question 11

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Accepted Answer

A)  gastrulation → organogenesis → cleavage
B)  ovulation → gastrulation → fertilization
C)  cleavage → gastrulation → organogenesis
D)  gastrulation → blastulation → neurulation
E)  preformation → morphogenesis → neurulationF) B) and C)
G) C) and E)

Question 12

As an embryo develops, new cells are produced as the result of

Accepted Answer

A)  differentiation.
B)  preformation.
C)  cell division.
D)  morphogenesis.
E)  epigenesis.F) B) and C)
G) A) and C)

Question 13

Extraembryonic membranes develop in

Accepted Answer

A)  mammals, but not birds or lizards.
B)  birds, but not mammals or lizards.
C)  lizards, but not mammals or birds.
D)  mammals and birds, but not lizards.
E)  mammals, birds, and lizards.F) A) and C)
G) None of the above

Question 14

During fertilization, the acrosomal contents

Accepted Answer

A)  block polyspermy.
B)  help propel more sperm toward the egg.
C)  digest the protective jelly coat on the surface of the egg.
D)  nourish the mitochondria of the sperm.
E)  trigger the completion of meiosis by the sperm.F) C) and E)
G) B) and C)

Question 15

A human blastomere is

Accepted Answer

A)  an embryonic cell that is much smaller than the ovum.
B)  an embryonic structure that includes a fluid-filled cavity.
C)  that part of the acrosome that opens the egg's membrane.
D)  a component of the zona pellucida.
E)  a cell that contains a (degenerating) second polar body.F) C) and E)
G) C) and D)

Question 16

Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo

Accepted Answer

A)  mitosis.
B)  depolarization.
C)  apoptosis.
D)  vitellogenesis.
E)  the acrosomal reaction.F) C) and D)
G) B) and E)

Question 17

A reproductive difference between sea urchins and humans is

Accepted Answer

A)  the sea urchin egg completes meiosis prior to fertilization, but meiosis in humans is completed after fertilization.
B)  sea urchin eggs are produced by meiosis, but human eggs are produced by mitosis.
C)  sea urchin eggs and sperm are of equal size, but human eggs are much bigger than human sperm.
D)  sea urchins, but not humans, have a need to block polyspermy because only in sea urchins can there be more than one source of sperm to fertilize the eggs.
E)  sea urchin zygotes get their mitochondria from the sperm but human zygotes get their mitochondria from the egg.F) A) and B)
G) None of the above

Question 18

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the

Accepted Answer

A)  acrosomal reaction would be blocked.
B)  fusion of sperm and egg nuclei would be blocked.
C)  fast block to polyspermy would not occur.
D)  fertilization envelope would not be formed.
E)  zygote would not contain maternal and paternal chromosomes.F) B) and D)
G) B) and E)

Question 19

Human trophoblasts

Accepted Answer

A)  form the inner cell mass.
B)  form from ectoderm.
C)  are the precursors of the mesoderm.
D)  are of embryonic origin and function in embryo nutrition.
E)  are of maternal origin and function in embryo gas exchange.F) C) and D)
G) B) and C)

Question 20

In a newly fertilized egg, the vitelline layer

Accepted Answer

A)  opens the egg's nuclear membrane to allow haploid sperm DNA to enter.
B)  hardens to form a protective cover.
C)  secretes hormones that enhance steroidogenesis by the ovary.
D)  reduces the loss of water from the egg and prevents desiccation.
E)  provides most of the nutrients used by the zygote.F) D) and E)
G) C) and E)

Exam 47: Animal Development

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the

Correct Answer
verified

Extraembryonic membranes develop in

Correct Answer
verified

Select the choice that correctly associates the organ with its embryonic sources.

Correct Answer
verified

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Correct Answer
verified

In a newly fertilized egg, the vitelline layer

Correct Answer
verified

Correct Answer
verified

As an embryo develops, new cells are produced as the result of

Correct Answer
verified

During fertilization, the acrosomal contents

Correct Answer
verified

Compared to sea urchin eggs, those of mammals

Correct Answer
verified

The earliest developmental stage among these choices is

Correct Answer
verified

The small portion of the embryo that will become its dorsal side develops from the

Correct Answer
verified

In sea urchins, the "fast block" and the longer-lasting "slow block" to polyspermy, respectively, are

Correct Answer
verified

In all vertebrate animals, development requires

Correct Answer
verified

A human blastomere is

Correct Answer
verified

A reproductive difference between sea urchins and humans is

Correct Answer
verified

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Correct Answer
verified

The vertebrate ectoderm is the origin of the

Correct Answer
verified

Human trophoblasts

Correct Answer
verified

Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo

Correct Answer
verified

In placental mammals, the yolk sac

Correct Answer
verified

Exam 47: Animal Development

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the

Correct AnswerverifiedShow Answer

Extraembryonic membranes develop in

Correct AnswerverifiedShow Answer

Select the choice that correctly associates the organ with its embryonic sources.

Correct AnswerverifiedShow Answer

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Correct AnswerverifiedShow Answer

In a newly fertilized egg, the vitelline layer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

As an embryo develops, new cells are produced as the result of

Correct AnswerverifiedShow Answer

During fertilization, the acrosomal contents

Correct AnswerverifiedShow Answer

Compared to sea urchin eggs, those of mammals

Correct AnswerverifiedShow Answer

The earliest developmental stage among these choices is

Correct AnswerverifiedShow Answer

The small portion of the embryo that will become its dorsal side develops from the

Correct AnswerverifiedShow Answer

In sea urchins, the "fast block" and the longer-lasting "slow block" to polyspermy, respectively, are

Correct AnswerverifiedShow Answer

In all vertebrate animals, development requires

Correct AnswerverifiedShow Answer

A human blastomere is

Correct AnswerverifiedShow Answer

A reproductive difference between sea urchins and humans is

Correct AnswerverifiedShow Answer

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Correct AnswerverifiedShow Answer

The vertebrate ectoderm is the origin of the

Correct AnswerverifiedShow Answer

Human trophoblasts

Correct AnswerverifiedShow Answer

Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo

Correct AnswerverifiedShow Answer

In placental mammals, the yolk sac

Correct AnswerverifiedShow Answer

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