Question

Which among the following is not a part of the endomembrane system?

• A. Mitochondria
• B. Lysosomes
• C. Endoplasmic reticulum
• D. Vacuoles

Answer 1

The correct option is A Mitochondria

Endomembrane system includes ER, Golgi complex, lysosomes and vacuoles. It includes organelles whose functions are coordinated. They work together to modify, package, and transport lipids and proteins.

Endoplasmic reticulum (ER) is a membrane-bound network extending from the nuclear membrane to the plasma membrane. When ribosomes are found attached to the surface of the ER, it is called the rough endoplasmic reticulum (RER) and if there are no ribosomes attached to it, it is called the smooth endoplasmic reticulum (SER).

The vacuole is a single membrane-bound organelle and is part of the endomembrane system. In plants it is large and prominent, occupying nearly 90% of the cell whereas in animal cells it may be small and few or absent. The vacuole has water, sap, excretory products in it.

Lysosomes are single membrane-bound cell organelles that contain powerful enzymes called acid hydrolases that cause the breakdown of macromolecules.