Question

Which of the following divides the intracellular space into two distinct compartments?
A. Cell Membrane
B. Plasma Membrane
C. Endoplasmic reticulum
D. None of the above

Answer 1

It is an organelle that exists in two forms: Rough and smooth. It is a network of membrane tubules in the cytoplasm of eukaryotic cells, continuous with the outer nuclear membrane. It is usually attached to ribosomes and participates in the synthesis of proteins and lipids.

Complete answer: The endoplasmic reticulum is a network of tiny tubular structures scattered in the cytoplasm. ER divides the intracellular space into two different compartments. The chamber inside the ER is called the chamber cavity, and the chamber in the cytoplasm is called the extraluminal chamber. It acts as a secretory, storage and a circulatory system for the cell. ER may be rough or smooth. The rough endoplasmic reticulum has attached ribosomes, whereas the smooth ER doesn’t.
i. Cell Membrane: The cell membrane is composed of lipids, which are arranged in double layers. The polar head of the lipid faces the outside, and the hydrophobic end faces the inside. This ensures that the nonpolar tails of saturated hydrocarbons are protected from aqueous environments. In addition, protein and carbohydrates are also present in the plasma membrane. The ratio of protein to lipid varies greatly in different types of cells. The peripheral protein is located on the surface of the membrane, while the intact protein is partially or completely located in the membrane.
ii. Plasma Membrane: The transport of molecules across the membrane is one of the most important functions of the plasma membrane. The plasma membrane is selectively permeable. Many molecules can move across membranes without requiring any energy. A movement that does not consume energy is called passive transportation. Passive transportation occurs through diffusion and penetration.
Thus, the option (C) is correct.

Note: The endoplasmic reticulum (ER) is a large dynamic structure that plays many roles in cells, including calcium storage, protein synthesis, and lipid metabolism. The various functions of ER are performed by different fields; it is composed of small tubes, sheets and nuclear envelopes.