What is the zona pellucida composed of?
What is the zona pellucida composed of?
glycoproteins
The zona pellucida is an extracellular matrix composed of three glycoproteins: ZP1, ZP2, and ZP3. Receptors on the sperm plasma membrane attach to ZP3. Binding to ZP3 allows the sperm to adhere to the zona pellucida and is a critical step in fertilization.
What is the structure and function of zona pellucida?
The zona pellucida supports communication between oocytes and follicle cells during oogenesis; protects oocytes, eggs, and embryos during development, and regulates interactions between ovulated eggs and free-swimming sperm during and following fertilization.
How many layers are in zona pellucida?
The secondary follicle consists of a fully grown oocyte surrounded by a complete zona pellucida, two to eight layers of cuboidal or columnar granulosa cells, and a presumptive theca layer immediately peripheral to the basal lamina (see Fig. 125-4).
What is zona pellucida definition?
Definition of zona pellucida : the transparent more or less elastic noncellular outer layer or envelope of a mammalian ovum that is composed of glycoproteins.
What is zona pellucida 12?
Zona pellucida is the thick transparent membrane and it is surrounded by the mammalian ovum before implantation. It prevents polyspermy. Acrosome reaction is enabled by zona pellucida to produce the comfortness for the sperm.
Which glycoprotein component of Zona is responsible for species specificity?
Zona pellucida glycoproteins
Zona pellucida glycoproteins are responsible for species-restricted binding of sperm to unfertilized eggs, inducing sperm to undergo acrosomal exocytosis, and preventing sperm from binding to fertilized eggs.
How does zona pellucida prevent polyspermy?
To prevent polyspermy, the zona pellucida, a structure that surrounds mammalian eggs, becomes impermeable upon fertilization, preventing the entry of further sperm. The structural changes in the zona upon fertilization are driven by the exocytosis of cortical granules.
What is the role of zona pellucida Class 12?
Zona pellucida communicates with the follicle cells oocyte during oogenesis. It is used to protect the eggs, oocytes and embryos during the development process. It regulates and provides interaction between ovulated eggs and free sperm during fertilization.
Which chemical is secreted by sperm to destroy the zona pellucida?
In Eutherian mammals the acrosome contains degradative enzymes (including hyaluronidase and acrosin). These enzymes break down the outer membrane of the ovum, called the zona pellucida, allowing the haploid nucleus in the sperm cell to join with the haploid nucleus in the ovum.
What is a acrosome?
The acrosome is a special kind of organelle with a cap-like structure that covers the anterior portion of the head of the spermatozoon. The acrosome is derived from the Golgi apparatus and contains digestive enzymes.
Which protein present in zona pellucida acts as a receptor?
Zona pellucida sperm-binding protein 3, also known as zona pellucida glycoprotein 3 (Zp-3) or the sperm receptor, is a ZP module-containing protein that in humans is encoded by the ZP3 gene. ZP3 is the receptor in the zona pellucida which binds sperm at the beginning of fertilization.
What is the zona pellucida matrix made up of?
This thick matrix is thought to be formed by secretions from the oocyte and the follicle granulosa cells and in human oocytes consists of four types of zona pellucida glycoproteins ZP1, ZP2, ZP3 and ZP4 which have different roles in fertilization.
What is zona pellucida (ZP)?
(Latin, zona pellucida= transparent zone) The zona pellucida(ZP) is a specialized extracellular matrix surrounding the developing oocyte (egg, ovum) within each follicle within the ovary.
What is zona pellucida glycoprotein 3?
Zona Pellucida Glycoprotein 3 (ZP3) A 424 amino acid glycoprotein located in the zona pellucida, synthesized by and surrounding the oocyte required for initial zona matrix formation and during fertilization for species-specific sperm binding.
Where is the zona pellucida located in the ovum?
The zona pellucida first appears in unilaminar primary oocytes. It is secreted by both the oocyte and the ovarian follicles. The zona pellucida is surrounded by the corona radiata. The corona is composed of cells that care for the egg when it is emitted from the ovary.
