Question

which of the following organelles is not surrounded by a membrane?
○ lysosome
○ ribosome
○ mitochondria
○ nucleus

Explanation:

• Lysosome: Surrounded by a single - membrane, contains hydrolytic enzymes.
• Ribosome: Composed of rRNA and protein, has no membrane structure, functions in protein synthesis.
• Mitochondria: Surrounded by a double - membrane, is the site of cellular respiration.
• Nucleus: Surrounded by a nuclear envelope (a double - membrane structure) and contains genetic material.

Answer:

B. ribosome