11)Fertilization Process Quiz

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Questions and Answers

What is the purpose of capacitation?

To remove the glycoprotein coat and seminal plasma proteins from the sperm's plasma membrane

To increase the sperm's motility and initiate complex signal transduction pathways

To prepare the sperm for the acrosome reaction and fertilization of the oocyte

All of the above (correct)

What is the primary characteristic of capacitated sperm?

Increased intracellular pH

Remodeling of the cell surface architecture

Hyperactivated flagellum motility

All of the above (correct)

What is the purpose of the hyperactivated motility pattern in capacitated sperm?

To increase the sperm's lifespan

To increase the sperm's speed

To help the sperm penetrate through the cumulus cell layer and zona pellucida (correct)

To make the sperm more attractive to the oocyte

When does capacitation occur?

When the sperm enters the female genital tract Signup and view all the answers

Which of the following is NOT a characteristic of capacitated sperm?

Decreased motility Signup and view all the answers

How do capacitated sperm interact with the cumulus cells surrounding the oocyte?

They easily pass between the cumulus cells due to their hyperactivated motility Signup and view all the answers

Where does fertilization typically occur?

In the fallopian tube Signup and view all the answers

What is the outcome of fertilization?

Formation of a new zygote Signup and view all the answers

Why do variations occur among species during fertilization?

Due to natural selection Signup and view all the answers

How many sperm are typically ejaculated, and how many reach the site of fertilization?

~300 million ejaculated, ~200 reach site Signup and view all the answers

What is the viability period of a mature oocyte?

~12-24 hours Signup and view all the answers

What is the role of acrosomal enzymes during fertilization?

Assisting sperm penetration through the zona pellucida Signup and view all the answers

How do sperm receptors on the oocyte contribute to fertilization?

Aid in the interaction between sperm and oocyte Signup and view all the answers

What is capacitation in the context of fertilization?

Changes in sperm enabling penetration through the zona pellucida Signup and view all the answers

How long does capacitation of sperm typically last?

7 hours Signup and view all the answers

Which enzyme is involved in enzymatically breaking down the zona pellucida during fertilization?

Hyaluronidase Signup and view all the answers

What is the first response of the oocyte when a sperm enters the zona pellucida?

Cortical reaction Signup and view all the answers

What is released into the perivitelline space during the cortical reaction to prevent polyspermy?

Cortical granules Signup and view all the answers

What is the function of the cortical granules during fertilization?

Create a barrier to sperm entry Signup and view all the answers

What happens to the binding activity of ZP3 during the zona reaction?

It is lost Signup and view all the answers

At what stage do oocytes experience an arrest in Meiosis I prophase?

Before ovulation Signup and view all the answers

What happens to the secondary oocyte 2-3 hours before ovulation?

It expels the first polar body Signup and view all the answers

What is the function of the zona pellucida?

All of the above Signup and view all the answers

Which glycoprotein(s) of the zona pellucida are involved in the initial interaction with the sperm head?

ZP3 Signup and view all the answers

What is the role of the acrosome in the sperm during fertilization?

It contains enzymes that help digest the zona pellucida Signup and view all the answers

Which enzyme(s) released during the acrosome reaction help(s) the sperm bypass the zona pellucida barrier?

Both hyaluronidase and trypsin-like substances Signup and view all the answers

What is the role of acrosine in the fertilization process?

It facilitates the fusion of the sperm and oocyte membranes Signup and view all the answers

Which process occurs after the sperm passes through the zona pellucida?

The oolemma fuses with the sperm membrane Signup and view all the answers

Study Notes

Capacitation and Its Purpose

Capacitation is a physiological process enabling sperm to penetrate and fertilize an egg.
Primary characteristic of capacitated sperm includes increased motility and altered plasma membrane composition.
Hyperactivated motility provides enhanced movement and force to help sperm navigate through the female reproductive tract.

Timing and Interaction

Capacitation generally occurs in the female reproductive tract after ejaculation.
Capacitated sperm interact with cumulus cells surrounding the oocyte through the release of hyaluronidase, aiding in the cumulus layer penetration.

Fertilization Overview

Fertilization usually occurs in the fallopian tubes.
Successful fertilization results in the formation of a zygote, leading to embryonic development.
Variations during fertilization among species arise from differences in reproductive strategies and environments.

Sperm Statistics

Approximately 100-300 million sperm are ejaculated, but only a few reach the site of fertilization.
Mature oocytes remain viable for about 12-24 hours post-ovulation.

Role of Enzymes and Receptors

Acrosomal enzymes facilitate sperm penetration by breaking down the zona pellucida during fertilization.
Sperm receptors on the oocyte recognize and bind with specific glycoproteins on the zona pellucida, initiating fertilization.

Capacitation Specifics

Capacitation typically lasts from 7 to 10 hours within the female reproductive tract.
Enzymes like acrosin assist in breaking down the zona pellucida during fertilization.

Oocyte Reactions and Preventing Polyspermy

Upon sperm entry into the zona pellucida, the oocyte undergoes a cortical reaction, releasing factors that prevent polyspermy.
Cortical granules play a crucial role in this process by modifying the zona pellucida.

ZP3 and Zona Reaction

The binding activity of ZP3 diminishes during the zona reaction, preventing further sperm from binding once fertilization has occurred.

Oocyte Arrest and Ovulation

Oocytes typically experience an arrest in Meiosis I prophase until ovulation.
The secondary oocyte completes the second meiotic division shortly before ovulation, around 2-3 hours prior.

Zona Pellucida Functions

Zona pellucida serves as a protective barrier for the oocyte, facilitating sperm binding and penetration.
Glycoproteins (ZP1, ZP2, ZP3) within the zona pellucida are involved in the initial interactions with the sperm head.

Acrosome Role in Fertilization

The acrosome contains enzymes critical for the sperm's ability to bypass the zona pellucida barrier during fertilization.
Acrosine, an enzyme released during the acrosome reaction, aids the sperm in penetrating the zona pellucida.

Post-Zona Pellucida Passage

After sperm successfully passes through the zona pellucida, fusion with the oocyte membrane occurs, resulting in fertilization.

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Description

Test your knowledge on the process of fertilization, where the sperm and oocyte unite to form a new zygote. Learn about the production of a new organism, stabilization of chromosome number, and the role of natural selection in the process.