Exploring Twinning and Embryology

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Which part of the female reproductive tract does fertilization normally take place in?

Cervix

Uterus

Uterine tube (correct)

Vagina

What is the purpose of capacitation in the process of fertilization?

To facilitate penetration of the zona pellucida

To stimulate the acrosome reaction

To remove a glycoprotein layer from the sperm membrane (correct)

To increase sperm motility

Which layer must the sperm penetrate in order to reach the egg?

Corona radiata

Zona pellucida

Perivitelline space

All of the above (correct)

What triggers the acrosome reaction in the sperm?

Binding of ZP3 receptors to ZP3 in the zona pellucida Signup and view all the answers

Which type of twinning occurs when a single egg is fertilized by separate sperm?

Dizygotic twinning Signup and view all the answers

What is the rate of occurrence for monozygotic twins?

3 to 4 per 1,000 births Signup and view all the answers

During implantation, which cells give rise to the cytotrophoblast and syncytiotrophoblast?

Trophoblast cells Signup and view all the answers

Where does implantation normally take place?

Posterior wall of the uterus Signup and view all the answers

Which of the following represents the key features of the acrosome reaction during fertilization?

Capacitation and acrosome reaction Signup and view all the answers

Which cells represent the inner cell mass and its immediate derivatives?

Compaction and blastocyst Signup and view all the answers

What do trophoblast cells differentiate into and what do they produce if a blastocyst successfully implants?

Cytotrophoblast and syncytiotrophoblast; they produce the placenta Signup and view all the answers

Which of the following is true about the acrosome reaction?

It is triggered by the interaction of sperm fertilin α/β with egg integrins and CD9 Signup and view all the answers

What is the role of acrosin in fertilization?

It breaks down the zona pellucida Signup and view all the answers

What is the purpose of the zona reaction?

To prevent other sperm from fertilizing the same oocyte Signup and view all the answers

What is the term used to describe the mass of cells at the 56-cell stage?

Morula Signup and view all the answers

Which of the following statements accurately describes the process of creating a knockout mouse?

The DNA fragments replace the normal gene in the genome, resulting in a knockout mouse. Signup and view all the answers

What is the purpose of using gene-targeted mice in the creation of a knockout mouse?

To swap out the normal gene in the genome Signup and view all the answers

What is the significance of breeding chimeric mice with normal mice in the creation of a knockout mouse?

To isolate mice that have both alleles of the gene mutated Signup and view all the answers

How does CRISPR-Cas9 technology impact the study of protein roles in mice?

It is replacing the traditional methods of creating knockout mice Signup and view all the answers

Which of the following is NOT a way in which large doses of progestin compounds can prevent pregnancies?

Prevent fertilization Signup and view all the answers

What is the main difference between transgenic mice and gene-targeted mice?

Transgenic mice have randomly integrated DNA fragments, while gene-targeted mice have DNA fragments that replace part of the endogenous gene. Signup and view all the answers

What is the purpose of generating transgenic mice?

To study the function of the protein encoded by the DNA fragment Signup and view all the answers

What is the term used to describe the process by which gene-targeted mice are created?

Homologous recombination Signup and view all the answers