Question

which structure is found in both eukaryotic and prokaryotic cells?
a. plasma membrane
b. mitochondrion
c. vacuole
d. nucleus

Explanation:

To determine the structure found in both eukaryotic and prokaryotic cells, we analyze each option:

• Option A: The plasma membrane (cell membrane) is a fundamental structure that encloses the cell, regulating the entry and exit of substances. Both prokaryotic (e.g., bacteria) and eukaryotic (e.g., plant, animal) cells have a plasma membrane.
• Option B: Mitochondria are organelles responsible for energy production (cellular respiration) and are only found in eukaryotic cells. Prokaryotic cells lack membrane - bound organelles like mitochondria.
• Option C: Vacuoles are storage organelles, and while they are present in many eukaryotic cells (e.g., plant cells have large central vacuoles), prokaryotic cells do not have vacuoles.
• Option D: The nucleus, which contains the cell's genetic material and is surrounded by a nuclear membrane, is a characteristic feature of eukaryotic cells. Prokaryotic cells do not have a true nucleus (their genetic material is in a nucleoid region without a nuclear membrane).

So, the structure found in both eukaryotic and prokaryotic cells is the plasma membrane.

Answer:

A. plasma membrane