Which type of organelles are membranous?

• A. Cytosol
• B. Membranous
• C. Ribosomes
• D. Non-Membranous

Answer: (B)

Membranous organelles are those enclosed by a phospholipid membrane, creating a distinct internal environment and allowing regulated transport between compartments. This membrane boundary is what defines them as membranous, enabling specialized tasks like energy production, protein processing, and genetic control. Examples include the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes. In contrast, cytosol is the cell’s fluid, not an organelle, and ribosomes are molecular machines that lack a surrounding membrane, so they are non-membranous. Since the question describes organelles that have membranes, the appropriate descriptor is membranous.