Question

The luminal compartment in intracellular space refers to space inside the

• A. cytoplasm
• B. endoplasmic reticulum (ER)
• C. nucleus
• D. vacuole

Answer 1

The correct option is B endoplasmic reticulum (ER)

Endoplasmic reticulum (ER) is a membrane-bound network extending from the nuclear membrane to the plasma membrane. ER divides the space within the cell into the luminal space (within the ER) and the extra-luminal space (outside the ER).

The cytoplasm is the semi-fluid like matrix that is found within the cell. This is the medium in which all the organelles are suspended.

The nucleus is the ‘brain of the cell’. It is the largest organelle in the cell and in eukaryotes, it is bound by a nuclear membrane. It has a jelly-like matrix called the nucleoplasm in which we find the chromatin (DNA associated with proteins) network and the nucleolus.

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.