Question

Non-membrane bound cell organelles found in both prokaryotic and eukaryotic cells are:

• A. Mitochondria
• B. Lysosomes
• C. Centrosomes
• D. Ribosomes

Hint:

Logic Tip: Remember the "Universal Organelle". Every living cell must make proteins to survive, so every living cell must have the machinery to do so (Ribosomes). Because prokaryotes lack internal membranes, this universal machine must be non-membrane bound.

Answer 1

The Correct Option is D

Concept:
Cells contain various specialized structures called organelles. While eukaryotic cells have many membrane-bound organelles, prokaryotic cells generally lack them. The question asks for an organelle that is non-membrane bound AND present in both cell types.
Step 1:
Mitochondria are the powerhouses of the cell. They are double-membrane bound organelles. Furthermore, they are only found in eukaryotic cells. Thus, this option is incorrect.
Step 2:
Lysosomes are vesicular structures formed by the Golgi apparatus, containing hydrolytic enzymes. They are single-membrane bound organelles and are found only in eukaryotic cells (primarily animal cells). Thus, this option is incorrect.
Step 3:
Centrosomes are organelles usually containing two cylindrical structures called centrioles. While they are non-membrane bound, they are found only in eukaryotic cells (specifically animal cells, where they aid in cell division). Prokaryotes do not have centrosomes. Thus, this option is incorrect.
Step 4:
Ribosomes are dense particles composed of RNA and proteins. They are the sites of protein synthesis. Crucially, ribosomes are not bound by any membrane. They are found universally in all living cells, both prokaryotic (70S type) and eukaryotic (80S type in cytoplasm, 70S type in organelles).
Step 5:
Ribosomes perfectly fit the criteria of being both non-membrane bound and universal to both prokaryotes and eukaryotes.