Problem 10
Question
The path of a sperm during fertilization is A. follicle cells, egg plasma membrane, zona pellucida; B. egg plasma membrane, zona pellucida, follicle cells; C. egg plasma membrane, follicle cells, zona pellucida; D. zona pellucida, follicle cells, egg plasma membrane; E. follicle cells, zona pellucida, egg plasma membrane
Step-by-Step Solution
Verified Answer
E. follicle cells, zona pellucida, egg plasma membrane
1Step 1: Identify the Initial Barrier
The first layer that a sperm encounters when approaching an egg is the follicle cells. These cells are a part of the protective layers surrounding the egg, providing a barrier that sperm must penetrate.
2Step 2: Understand the Role of Zona Pellucida
After passing through the follicle cells, the sperm must penetrate the zona pellucida. This glycoprotein layer is crucial, as it helps to prevent polyspermy and acts as a species-specific barrier.
3Step 3: Determine the Final Destination
The last barrier the sperm encounters is the egg's plasma membrane. Once the sperm successfully binds and merges with the plasma membrane, fertilization can occur, leading to the start of embryonic development.
Key Concepts
Follicle CellsZona PellucidaEgg Plasma MembraneEmbryonic Development
Follicle Cells
Follicle cells play an essential role in the initial stages of fertilization. Surrounding the egg, they form the outermost layer of protection. These cells originate from the ovarian follicle. When a sperm approaches the egg, it must first navigate through this layer to reach its destination.
The follicle cells provide not only physical protection but also a supportive environment by supplying nutrients to the egg. The interaction between the sperm and follicle cells is crucial as they help guide the sperm towards the egg. Their presence is a vital step in ensuring that only the most viable sperm reach the inner structures of the egg.
The follicle cells provide not only physical protection but also a supportive environment by supplying nutrients to the egg. The interaction between the sperm and follicle cells is crucial as they help guide the sperm towards the egg. Their presence is a vital step in ensuring that only the most viable sperm reach the inner structures of the egg.
Zona Pellucida
The zona pellucida is an incredibly important layer in the fertilization process. It is a thick glycoprotein shell that encases the egg beneath the follicle cells. This barrier is designed to protect the egg and control which sperm can proceed to fertilization.
One of its primary functions is to ensure species specificity. The zona pellucida contains specific binding sites that recognize and attach to sperm proteins, allowing only sperm from the same species to penetrate. It also plays a critical role in preventing polyspermy, which is the fertilization of an egg by multiple sperm. Once a sperm has successfully penetrated, this layer undergoes a biochemical change that blocks additional sperm from entering.
One of its primary functions is to ensure species specificity. The zona pellucida contains specific binding sites that recognize and attach to sperm proteins, allowing only sperm from the same species to penetrate. It also plays a critical role in preventing polyspermy, which is the fertilization of an egg by multiple sperm. Once a sperm has successfully penetrated, this layer undergoes a biochemical change that blocks additional sperm from entering.
Egg Plasma Membrane
The egg plasma membrane represents the final barrier a sperm must penetrate during fertilization. This membrane is the outermost layer of the egg cell itself and is highly selective.
Successful penetration of the egg plasma membrane by a sperm means that fertilization can officially begin. Upon contact, fusion of the sperm and egg membranes occurs. This process not only allows the genetic material from the sperm to enter the egg but also triggers changes within the egg. These changes initiate the processes that lead to the formation of a zygote, marking the start of embryonic development.
Successful penetration of the egg plasma membrane by a sperm means that fertilization can officially begin. Upon contact, fusion of the sperm and egg membranes occurs. This process not only allows the genetic material from the sperm to enter the egg but also triggers changes within the egg. These changes initiate the processes that lead to the formation of a zygote, marking the start of embryonic development.
Embryonic Development
Embryonic development kicks off once the sperm has successfully infused its genetic material into the egg. This process involves a series of highly coordinated events, beginning with the transformation of the fertilized egg into a zygote.
The zygote immediately starts a process called cleavage, where it undergoes multiple rounds of cell division. These divisions rapidly multiply the number of cells without increasing the overall size of the embryo initially. As development progresses, these cells start to differentiate and take on specific roles, forming various tissues and organs.
The zygote immediately starts a process called cleavage, where it undergoes multiple rounds of cell division. These divisions rapidly multiply the number of cells without increasing the overall size of the embryo initially. As development progresses, these cells start to differentiate and take on specific roles, forming various tissues and organs.
- Cleavage: Repeated cell division without growth.
- Blastulation: Formation of a hollow sphere of cells.
- Gastrulation: Formation of primary germ layers.
Other exercises in this chapter
Problem 8
The release of the oocyte from the follicle is caused by A. a decrease in estrogen; B. an increase in \(\mathrm{FSH} ;\) C. an increase in \(\mathrm{LH} ;\) D.
View solution Problem 9
Menstruation is regulated such that A. increasing estrogen levels have a positive feedback effect on FSH and LH; B. increasing FSH levels lead to ovulation; C.
View solution Problem 11
Development of female reproductive structures A. requires the SRY gene; B. requires that estrogen is secreted by the developing fetus; \(\mathrm{C} .\) will occ
View solution Problem 7
Gametogenesis A. begins at puberty in males and females; B. requires that the Leydig cells of males produce semen; C. results in the production of diploid cells
View solution