ANSC 333 REVIEW MODULE QUESTION
BANK 2026 AND EXPLANATIONS
◉ What is released during the acrosome reaction?
Answer: Enzymes from acrosomal granules that soften the zona
pellucida.
◉ What is the significance of local softening of the zona pellucida?
Answer: It allows the winning sperm to penetrate while preventing
others from entering.
◉ What happens after the sperm penetrates the zona pellucida?
Answer: The sperm binds to the plasma membrane of the oocyte,
initiating the cortical reaction.
◉ What is the cortical reaction?
Answer: A process that releases contents from cortical granules,
hardening the zona pellucida.
◉ What is polyspermy?
Answer: A condition where multiple sperm fertilize an oocyte, which
is prevented by the cortical reaction.
,◉ What occurs to sperm that bind to the zona pellucida but do not
penetrate?
Answer: They are frozen in place as the zona pellucida hardens.
◉ What is the role of the acrosome during fertilization?
Answer: To release enzymes that help the sperm penetrate the zona
pellucida.
◉ What is recapacitation in sperm?
Answer: The process where capacitated sperm can regain their
ability to bind after being mixed with seminal plasma.
◉ What triggers the completion of capacitation in sperm?
Answer: The sperm's entry into the oviduct.
◉ What is the perivitelline space?
Answer: The space between the zona pellucida and the plasma
membrane of the oocyte.
◉ How does the sperm's tail contribute to fertilization?
Answer: It provides the force needed to penetrate the softened zona
pellucida.
,◉ What is the first binding event during fertilization?
Answer: Binding of sperm to the zona pellucida.
◉ What is the second binding event during fertilization?
Answer: Binding of the sperm's equatorial segment to the plasma
membrane of the oocyte.
◉ What happens to the zona pellucida after fertilization?
Answer: It becomes impenetrable due to the cortical reaction.
◉ What is the significance of the acrosome reaction in the
fertilization process?
Answer: It allows the sperm to penetrate the zona pellucida by
softening it.
◉ What happens to the sperm during the journey through the
female reproductive tract?
Answer: It undergoes capacitation and hyperactive motility.
◉ What is the role of the zona binding regions on the sperm?
Answer: To specifically bind to the zona pellucida proteins during
fertilization.
, ◉ What is the relationship between sperm and zona pellucida
proteins analogous to?
Answer: A hormone-receptor interaction.
◉ What happens if an oocyte is fertilized by multiple sperm?
Answer: The embryo is destined to die due to having three halves of
genetic material.
◉ Why is the prevention of polyspermy important?
Answer: Preventing polyspermy is crucial to avoid embryonic death.
◉ How do local actions of the acrosome help prevent polyspermy?
Answer: They weaken the zona pellucida, making it difficult for
additional sperm to penetrate.
◉ What occurs after the first sperm binds to the oocyte's plasma
membrane?
Answer: A barrier is formed to prevent other sperm from entering.
◉ What is DNA decondensation in the context of fertilization?
Answer: It is the process where the sperm DNA unpacks to combine
with the oocyte's DNA.
BANK 2026 AND EXPLANATIONS
◉ What is released during the acrosome reaction?
Answer: Enzymes from acrosomal granules that soften the zona
pellucida.
◉ What is the significance of local softening of the zona pellucida?
Answer: It allows the winning sperm to penetrate while preventing
others from entering.
◉ What happens after the sperm penetrates the zona pellucida?
Answer: The sperm binds to the plasma membrane of the oocyte,
initiating the cortical reaction.
◉ What is the cortical reaction?
Answer: A process that releases contents from cortical granules,
hardening the zona pellucida.
◉ What is polyspermy?
Answer: A condition where multiple sperm fertilize an oocyte, which
is prevented by the cortical reaction.
,◉ What occurs to sperm that bind to the zona pellucida but do not
penetrate?
Answer: They are frozen in place as the zona pellucida hardens.
◉ What is the role of the acrosome during fertilization?
Answer: To release enzymes that help the sperm penetrate the zona
pellucida.
◉ What is recapacitation in sperm?
Answer: The process where capacitated sperm can regain their
ability to bind after being mixed with seminal plasma.
◉ What triggers the completion of capacitation in sperm?
Answer: The sperm's entry into the oviduct.
◉ What is the perivitelline space?
Answer: The space between the zona pellucida and the plasma
membrane of the oocyte.
◉ How does the sperm's tail contribute to fertilization?
Answer: It provides the force needed to penetrate the softened zona
pellucida.
,◉ What is the first binding event during fertilization?
Answer: Binding of sperm to the zona pellucida.
◉ What is the second binding event during fertilization?
Answer: Binding of the sperm's equatorial segment to the plasma
membrane of the oocyte.
◉ What happens to the zona pellucida after fertilization?
Answer: It becomes impenetrable due to the cortical reaction.
◉ What is the significance of the acrosome reaction in the
fertilization process?
Answer: It allows the sperm to penetrate the zona pellucida by
softening it.
◉ What happens to the sperm during the journey through the
female reproductive tract?
Answer: It undergoes capacitation and hyperactive motility.
◉ What is the role of the zona binding regions on the sperm?
Answer: To specifically bind to the zona pellucida proteins during
fertilization.
, ◉ What is the relationship between sperm and zona pellucida
proteins analogous to?
Answer: A hormone-receptor interaction.
◉ What happens if an oocyte is fertilized by multiple sperm?
Answer: The embryo is destined to die due to having three halves of
genetic material.
◉ Why is the prevention of polyspermy important?
Answer: Preventing polyspermy is crucial to avoid embryonic death.
◉ How do local actions of the acrosome help prevent polyspermy?
Answer: They weaken the zona pellucida, making it difficult for
additional sperm to penetrate.
◉ What occurs after the first sperm binds to the oocyte's plasma
membrane?
Answer: A barrier is formed to prevent other sperm from entering.
◉ What is DNA decondensation in the context of fertilization?
Answer: It is the process where the sperm DNA unpacks to combine
with the oocyte's DNA.
