1. Which of the following structures is present in both prokaryotic and eukaryotic cells?
Answer: C
Cell membrane is present in both prokaryotic and eukaryotic cells.
Both prokaryotic and eukaryotic cells have a cell membrane, which serves as a protective barrier that regulates the entry and exit of substances.
A) Chloroplast
Chloroplasts are organelles found only in plant cells and some protists, which means they are absent in prokaryotic cells and animal eukaryotic cells. Therefore, this option is incorrect.
B) Golgi apparatus
The Golgi apparatus is an organelle that is specific to eukaryotic cells and is involved in modifying, sorting, and packaging proteins. Since prokaryotic cells do not have this structure, this option is incorrect.
C) Cell membrane
The cell membrane is a fundamental structure found in both prokaryotic and eukaryotic cells. It is essential for maintaining cell integrity and facilitating communication and transport of materials in and out of the cell.
D) Endoplasmic reticulum
The endoplasmic reticulum is an organelle present only in eukaryotic cells, playing a role in protein and lipid synthesis. Prokaryotic cells lack this structure, making this option incorrect.
Conclusion
The cell membrane is the only structure listed that is common to both prokaryotic and eukaryotic cells, serving critical functions in cellular protection and transport. The other options represent organelles or structures that are exclusive to eukaryotic cells, thus confirming that the cell membrane is the definitive answer.