Which of the following structures is present in both prokaryotic and eukaryotic cells?
A.
Cell membrane.
B.
Golgi apparatus
C.
Chloroplast
D.
Endoplasmic reticulum.
The Correct answer and Explanation is:
The correct answer is A. Cell membrane.
Explanation:
Both prokaryotic and eukaryotic cells share several structural components, and the cell membrane is one of the most fundamental. The cell membrane, also known as the plasma membrane, serves as a barrier that regulates what enters and exits the cell. Its primary structure consists of a phospholipid bilayer with embedded proteins that aid in various cellular functions such as nutrient transport and cell signaling.
In prokaryotic cells, which include bacteria and archaea, the cell membrane is essential for maintaining the internal environment since these cells lack complex membrane-bound organelles. Prokaryotes do not have internal compartments such as a nucleus or other organelles like the Golgi apparatus, chloroplasts, or endoplasmic reticulum.
On the other hand, eukaryotic cells—found in plants, animals, fungi, and protists—are more complex. They also have a cell membrane but possess additional membrane-bound organelles like the nucleus, endoplasmic reticulum (ER), Golgi apparatus, and chloroplasts (in plants and some protists). These organelles enable eukaryotic cells to compartmentalize functions, making them highly efficient at processes like protein synthesis and energy production.
However, prokaryotes can carry out all necessary life functions despite the absence of these organelles, thanks to their simpler structure. For example, while they lack an endoplasmic reticulum for protein synthesis, they rely on ribosomes in their cytoplasm.
The other options (Golgi apparatus, chloroplast, and endoplasmic reticulum) are only found in eukaryotic cells, making the cell membrane the correct answer as it is universally present in both types of cells. Without this shared structure, neither cell type could regulate its internal environment effectively, impacting cellular survival.