Answer:
Introduction:
In order to determine which organelle among the given options is semipermeable, we need to understand the concept of semipermeability and the functions of each organelle.
Semipermeability:
Semipermeability refers to the property of a membrane that allows certain substances to pass through while blocking others. It is crucial for maintaining the internal environment of a cell and controlling the movement of molecules in and out of the cell.
Organelles:
Let's analyze each of the given organelles and determine if they are semipermeable or not:
- Cell membrane: The cell membrane is a thin, flexible barrier that surrounds the cell. It regulates the movement of substances in and out of the cell. The cell membrane is indeed semipermeable, as it selectively allows the passage of certain molecules while blocking others.
- Plasma membrane: The plasma membrane is another term for the cell membrane. It functions in the same way as the cell membrane and is also semipermeable.
- Cell wall: The cell wall is a rigid layer found in plant cells, fungi, and some bacteria. It provides structural support and protection to the cell. However, the cell wall is not semipermeable. It is permeable to certain substances but does not possess selective permeability like the cell membrane.
- Nucleus: The nucleus is the control center of the cell and contains the genetic material. It is surrounded by a nuclear envelope, which consists of a double membrane. While the nuclear envelope regulates the passage of molecules in and out of the nucleus, it is not considered semipermeable. The nuclear envelope has specific channels called nuclear pores that allow the selective movement of molecules, but it does not possess the same level of selectivity as the cell membrane.
Conclusion:
Based on the analysis above, we can conclude that the cell membrane (option B) is the organelle that is semipermeable. It selectively allows the passage of molecules in and out of the cell, ensuring proper regulation of the cell's internal environment.