Question 22

The plasma membrane regulates the transport of substances in and out of the cell.

The plasma membrane, also known as the cell membrane, is crucial for regulating the movement of substances into and out of the cell. It acts as a selective barrier, allowing essential nutrients to enter while keeping harmful substances out.

A) Cell membrane

While the term "cell membrane" is often used interchangeably with "plasma membrane," it is important to note that this option does not specifically indicate the correct terminology used in the context of the question. The plasma membrane is the precise term that encompasses the functional aspects of this structure.

B) Cell's cytoplasm

The cytoplasm is the gel-like substance within the cell, which houses organelles and other cellular components. However, it is not responsible for regulating the transport of substances; rather, it is the environment where various biochemical processes occur.

C) Nuclear membrane

The nuclear membrane surrounds the nucleus and regulates the exchange of materials between the nucleus and the cytoplasm. Although it plays a role in transport, it is not the primary structure that regulates the movement of substances in and out of the entire cell.

D) Plasma membrane

The plasma membrane is the correct answer as it precisely describes the structure that regulates the transport of substances in and out of the cell. It is selectively permeable, allowing certain molecules to pass while restricting others, thus maintaining homeostasis within the cell.

Conclusion

The plasma membrane is definitively the structure that regulates substance transport in and out of the cell, distinguishing it from other cellular structures. Other options like the cell membrane, cytoplasm, and nuclear membrane either do not serve this specific function or refer to structures that play different roles within cellular processes.