10 Questions
What is the main function of the acrosome at the tip of the sperm during fertilization?
Release hydrolytic enzymes
Which structure prevents polyspermy, the entry of multiple sperm nuclei into the egg?
Cortical granule
What is the first major phase of embryonic development after fertilization?
Cleavage
What happens during cleavage in embryonic development?
Cells divide without growth
What is formed after the zygote divides into two identical cells by mitosis?
Morula
What is the function of the acrosome at the tip of the sperm during fertilization?
To release hydrolytic enzymes that digest material surrounding the egg
Which of the following best describes what happens to the egg's surface to prevent polyspermy?
The egg surface thickens to block sperm penetration
Which term describes the process of unspecialized embryonic cells changing into specialized cells, tissues, and organs?
Differentiation
What is the first major phase of embryonic development known for its emphasis on cell division without growth?
Cleavage
What initiates a series of mitotic cell divisions in the zygote following fertilization?
Fertilization of an egg
Study Notes
Fertilization
- Fertilization occurs when sperm penetrate the protective layer around the egg and bind to receptors on the egg surface.
- The acrosome at the tip of the sperm releases hydrolytic enzymes that digest material surrounding the egg.
- Changes at the egg surface prevent polyspermy, the entry of multiple sperm nuclei into the egg.
Embryonic Development
- After fertilization, embryonic development in animals begins, following a well-defined pattern of growth and differentiation.
- Development involves the changing of unspecialized embryonic cells into specialized cells, tissues, and organs.
- It is controlled mainly by genes, the hereditary material from the parent cells.
Cleavage Stage
- The zygote begins a series of mitotic cell divisions known as cleavage, which is the first major phase of embryonic development.
- During cleavage, cells don't grow, just divide; therefore, cell size decreases.
- Stages of cleavage include:
- Morula: a solid ball of cells.
- Blastula: a developing embryo with a hollow center filled with fluid (blastocoel).
- Gastrulation: the "horse shoe stage" when the blastula reaches several hundred cells.
Learn about the molecules and events at the egg surface involved in the fertilization process. Understand how sperm penetrates the protective layer around the egg and the role of receptors in binding during fertilization.
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