Question 22

The cell membrane can be functionally compared to a door of a house.

The cell membrane serves as a selective barrier that regulates what enters and exits the cell, akin to how a door controls access to a house.

A) Endoplasmic reticulum

The endoplasmic reticulum is primarily involved in the synthesis and transport of proteins and lipids within the cell. Unlike a door, it does not function as a barrier or control access to the cell, making it an incorrect comparison.

B) Cell membrane

The cell membrane is responsible for maintaining the integrity of the cell by selectively allowing substances to enter and exit. This function is similar to that of a door, which provides security and regulates entry, making this option the correct answer.

C) Nucleus

The nucleus contains the cell's genetic material and is primarily involved in regulating cellular activities and gene expression. While it is an essential organelle, it does not serve as a boundary or entry point for substances, thus making it an inappropriate comparison to a door.

D) Cytoplasm

The cytoplasm is the gel-like substance within the cell that houses organelles and facilitates biochemical reactions. It does not act as a barrier or control access to the cell, so it cannot be likened to a door.

Conclusion

The cell membrane is the only organelle that functions as a selective barrier, much like a door controls access to a house. The other options, while important to cell function, do not fulfill the role of regulating entry and exit, thus confirming that Option B is the definitive correct choice.