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NYUCD GENERAL EMBRYOLOGY EXAMINATION 2026
COMPLETE (110) CURRENT TESTING QUESTIONS AND
CORRECT ANSWERS WITH DETAILED RATIONALES.
EMBRYOLOGY
Prepare for the NYUCD General Embryology Examination with this comprehensive
practice resource designed to strengthen your understanding of human embryonic
development and exam readiness. It features exam-style questions covering
gametogenesis, fertilization, early embryonic development, organogenesis,
congenital anomalies, developmental biology, and clinically relevant embryology
concepts. Use it to reinforce essential knowledge, assess your understanding, and
build confidence before test day. An excellent study aid for NYU College of Dentistry
students preparing for the General Embryology Examination.
MULTIPLE CHOICE.
DOMAIN 1: GAMETOGENESIS, FERTILIZATION, & THE FIRST WEEK OF
DEVELOPMENT (Questions 1–20)
Question 1: The geometric formula for the area of a triangle is:
A. (1/2)bh
B. πr²
C. 2πr
D. l × w
Correct answer: A. (1/2)bh
Rationale: The area of a triangle is calculated using (1/2) × base × height.
Question 2: Which of the following events marks the beginning of human
embryonic development?
A. The formation of the blastocyst
B. The union of sperm and egg (fertilization)
C. The start of implantation
D. The formation of the primitive streak
Correct answer: B. The union of sperm and egg (fertilization)
Rationale: Fertilization, which occurs in the ampulla of the uterine tube, is the
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first event of embryonic development, joining the haploid male and female
pronuclei to form a diploid zygote.
Question 3: The zona pellucida is a glycoprotein layer that surrounds the
oocyte and serves which function?
A. Stimulating the acrosome reaction
B. Preventing polyspermy after fertilization
C. Binding sperm during fertilization
D. All of the above
Correct answer: D. All of the above
Rationale: The zona pellucida binds sperm via ZP3 receptors, initiates the
acrosome reaction, and, after fertilization, undergoes a cortical reaction to
block polyspermy, thereby allowing only one sperm to fertilize the egg.
Question 4: Sperm must undergo which process in the female reproductive
tract to become capable of fertilization?
A. Capacitation
B. Acrosome reaction
C. Spermiogenesis
D. Meiosis
Correct answer: A. Capacitation
Rationale: Capacitation is a maturation process where the sperm's plasma
membrane changes, allowing it to become capable of the acrosome reaction.
This process occurs in the female reproductive tract and is required for
fertilization.
Question 5: The fusion of the sperm and oocyte membranes triggers which
event?
A. Completion of the second meiotic division
B. Cortical reaction
C. Formation of the male pronucleus
D. All of the above
Correct answer: D. All of the above
Rationale: Upon membrane fusion, the oocyte completes its second meiotic
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division, the cortical reaction occurs to prevent polyspermy, and the male
pronucleus forms.
Question 6: The fertilization process typically occurs in which part of the
uterine tube?
A. Isthmus
B. Ampulla
C. Infundibulum
D. Uterine portion
Correct answer: B. Ampulla
Rationale: Fertilization usually occurs in the ampulla, which is the widest and
longest portion of the uterine tube. The isthmus is narrower and closer to the
uterus.
Question 7: The cortical reaction in the oocyte is triggered by sperm fusion
and results in:
A. Release of lysosomal enzymes from cortical granules
B. Hardening of the zona pellucida
C. Prevention of polyspermy
D. All of the above
Correct answer: D. All of the above
Rationale: The cortical reaction involves the release of cortical granules that
contain enzymes which harden the zona pellucida and inactivate sperm
receptors, preventing polyspermy.
Question 8: The term "zona pellucida" refers to:
A. The inner layer of the blastocyst
B. A glycoprotein shell surrounding the oocyte
C. The outer layer of the trophoblast
D. The embryonic disc
Correct answer: B. A glycoprotein shell surrounding the oocyte
Rationale: The zona pellucida is the glycoprotein-rich extracellular matrix
surrounding the oocyte and early embryo until the blastocyst stage, where it
must be shed for implantation.
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Question 9: A sperm that has not undergone capacitation would be unable to:
A. Swim
B. Bind to the zona pellucida
C. Undergo the acrosome reaction
D. Both B and C
Correct answer: D. Both B and C
Rationale: Capacitation is necessary for the sperm to bind to the zona
pellucida and undergo the acrosome reaction. Without capacitation, these
processes cannot occur.
Question 10: Fertilization restores the diploid number of chromosomes. The
resulting cell is called:
A. A blastomere
B. A zygote
C. A morula
D. A blastocyst
Correct answer: B. A zygote
Rationale: The product of fertilization is a diploid zygote, which contains a
single diploid nucleus formed by the fusion of the male and female pronuclei.
Question 11: A sperm can fertilize an oocyte for approximately how long after
ejaculation?
A. 1–2 hours
B. 12–24 hours
C. 24–48 hours
D. 5–7 days
Correct answer: B. 12–24 hours
Rationale: Sperm can remain viable in the female reproductive tract for
approximately 24–48 hours, but the ability to fertilize a mature oocyte is
typically limited to 12–24 hours.
Question 12: The first mitotic division of the zygote occurs approximately:
A. 6 hours after fertilization
B. 12 hours after fertilization
NYUCD GENERAL EMBRYOLOGY EXAMINATION 2026
COMPLETE (110) CURRENT TESTING QUESTIONS AND
CORRECT ANSWERS WITH DETAILED RATIONALES.
EMBRYOLOGY
Prepare for the NYUCD General Embryology Examination with this comprehensive
practice resource designed to strengthen your understanding of human embryonic
development and exam readiness. It features exam-style questions covering
gametogenesis, fertilization, early embryonic development, organogenesis,
congenital anomalies, developmental biology, and clinically relevant embryology
concepts. Use it to reinforce essential knowledge, assess your understanding, and
build confidence before test day. An excellent study aid for NYU College of Dentistry
students preparing for the General Embryology Examination.
MULTIPLE CHOICE.
DOMAIN 1: GAMETOGENESIS, FERTILIZATION, & THE FIRST WEEK OF
DEVELOPMENT (Questions 1–20)
Question 1: The geometric formula for the area of a triangle is:
A. (1/2)bh
B. πr²
C. 2πr
D. l × w
Correct answer: A. (1/2)bh
Rationale: The area of a triangle is calculated using (1/2) × base × height.
Question 2: Which of the following events marks the beginning of human
embryonic development?
A. The formation of the blastocyst
B. The union of sperm and egg (fertilization)
C. The start of implantation
D. The formation of the primitive streak
Correct answer: B. The union of sperm and egg (fertilization)
Rationale: Fertilization, which occurs in the ampulla of the uterine tube, is the
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first event of embryonic development, joining the haploid male and female
pronuclei to form a diploid zygote.
Question 3: The zona pellucida is a glycoprotein layer that surrounds the
oocyte and serves which function?
A. Stimulating the acrosome reaction
B. Preventing polyspermy after fertilization
C. Binding sperm during fertilization
D. All of the above
Correct answer: D. All of the above
Rationale: The zona pellucida binds sperm via ZP3 receptors, initiates the
acrosome reaction, and, after fertilization, undergoes a cortical reaction to
block polyspermy, thereby allowing only one sperm to fertilize the egg.
Question 4: Sperm must undergo which process in the female reproductive
tract to become capable of fertilization?
A. Capacitation
B. Acrosome reaction
C. Spermiogenesis
D. Meiosis
Correct answer: A. Capacitation
Rationale: Capacitation is a maturation process where the sperm's plasma
membrane changes, allowing it to become capable of the acrosome reaction.
This process occurs in the female reproductive tract and is required for
fertilization.
Question 5: The fusion of the sperm and oocyte membranes triggers which
event?
A. Completion of the second meiotic division
B. Cortical reaction
C. Formation of the male pronucleus
D. All of the above
Correct answer: D. All of the above
Rationale: Upon membrane fusion, the oocyte completes its second meiotic
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division, the cortical reaction occurs to prevent polyspermy, and the male
pronucleus forms.
Question 6: The fertilization process typically occurs in which part of the
uterine tube?
A. Isthmus
B. Ampulla
C. Infundibulum
D. Uterine portion
Correct answer: B. Ampulla
Rationale: Fertilization usually occurs in the ampulla, which is the widest and
longest portion of the uterine tube. The isthmus is narrower and closer to the
uterus.
Question 7: The cortical reaction in the oocyte is triggered by sperm fusion
and results in:
A. Release of lysosomal enzymes from cortical granules
B. Hardening of the zona pellucida
C. Prevention of polyspermy
D. All of the above
Correct answer: D. All of the above
Rationale: The cortical reaction involves the release of cortical granules that
contain enzymes which harden the zona pellucida and inactivate sperm
receptors, preventing polyspermy.
Question 8: The term "zona pellucida" refers to:
A. The inner layer of the blastocyst
B. A glycoprotein shell surrounding the oocyte
C. The outer layer of the trophoblast
D. The embryonic disc
Correct answer: B. A glycoprotein shell surrounding the oocyte
Rationale: The zona pellucida is the glycoprotein-rich extracellular matrix
surrounding the oocyte and early embryo until the blastocyst stage, where it
must be shed for implantation.
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Question 9: A sperm that has not undergone capacitation would be unable to:
A. Swim
B. Bind to the zona pellucida
C. Undergo the acrosome reaction
D. Both B and C
Correct answer: D. Both B and C
Rationale: Capacitation is necessary for the sperm to bind to the zona
pellucida and undergo the acrosome reaction. Without capacitation, these
processes cannot occur.
Question 10: Fertilization restores the diploid number of chromosomes. The
resulting cell is called:
A. A blastomere
B. A zygote
C. A morula
D. A blastocyst
Correct answer: B. A zygote
Rationale: The product of fertilization is a diploid zygote, which contains a
single diploid nucleus formed by the fusion of the male and female pronuclei.
Question 11: A sperm can fertilize an oocyte for approximately how long after
ejaculation?
A. 1–2 hours
B. 12–24 hours
C. 24–48 hours
D. 5–7 days
Correct answer: B. 12–24 hours
Rationale: Sperm can remain viable in the female reproductive tract for
approximately 24–48 hours, but the ability to fertilize a mature oocyte is
typically limited to 12–24 hours.
Question 12: The first mitotic division of the zygote occurs approximately:
A. 6 hours after fertilization
B. 12 hours after fertilization
