Once a vessel, fuses with the plasma membrane or is internalized in the cell, what happens to this particular section of the membrane?
A it is degraded
B it is recycled
C it is expelled or D it is secreted
The correct answer and explanation is:
Correct Answer: B. It is recycled
When a vesicle fuses with the plasma membrane or is internalized into the cell, the particular section of the membrane involved is most commonly recycled. This recycling process is essential for maintaining membrane balance, conserving resources, and supporting cellular function.
The cell membrane is a dynamic structure made of lipids and proteins. During exocytosis, vesicles transport molecules such as proteins, hormones, or neurotransmitters to the plasma membrane. The vesicle membrane then merges with the plasma membrane to release its contents outside the cell. Instead of being wasted, the vesicle’s membrane components are integrated into the plasma membrane. Later, these parts can be retrieved by a process called endocytosis, which internalizes a small section of the plasma membrane back into the cell to form a new vesicle.
Similarly, during endocytosis, when the cell engulfs external substances or molecules, the membrane folds inward to form a vesicle. After the vesicle enters the cell, its membrane can undergo sorting in organelles like endosomes. The endosomal system determines whether the membrane components will be directed toward the lysosome for degradation or sent back to the plasma membrane for reuse. In most cases, the components are not destroyed but recycled to form new vesicles or returned to the cell surface.
This recycling process is crucial for cellular efficiency. It conserves energy by reusing materials instead of synthesizing new ones. It also helps regulate the amount of membrane and the number of receptors on the surface, ensuring proper communication and transport functions.
Thus, after vesicles fuse with or are taken into the plasma membrane, the involved section is not typically degraded, expelled, or secreted. It is usually recycled.