Question

Transporting channels of the cells are called
a. Endoplasmic reticulum
b. Golgi bodies
c. Lysosomes
d. Vacuoles

Answer 1

Hint: The endoplasmic reticulum connects the cell membrane to the nuclear membrane. It is usually involved in protein and lipid synthesis. The endoplasmic reticulum is divided into two types: the Rough ER and Smooth ER. Rough ER as the name suggests it has ribosomes attached on the surface, it is involved in protein synthesis and Smooth ER is involved in lipid synthesis.ER usually interacts with most of the organelles.

Complete answer:
- The endoplasmic reticulum is a continuous membrane system forming a series of flattened sacs within the cytoplasm of eukaryotic cells.
- It serves functions such as in the synthesis, folding, modification, and transport of proteins.
- The endoplasmic reticulum creates, packages, and secretes many of the products created by a cell.
- All eukaryotic cells contain an endoplasmic reticulum (ER). In animal cells, the ER constitutes more than half of the membranous content of the cell. Differences in the physical and functional characteristics distinguish the two types of ER, known as rough ER and smooth ER.
- The interconnected network of flattened, membrane-enclosed sacs formed by endoplasmic reticulum which is known as cisternae (in the RER), and tubular structures (in the SER).
- Rough ER has a rough appearance, which is due to the ribosomes attached to its outer (cytoplasmic) surface. Rough ER lies to the immediate adjacent cell nucleus, and its membrane is continuous with the outer membrane of the nuclear envelope.
- Smooth ER is involved in the synthesis of lipids, including cholesterol and phospholipids, which are used in the production of the new cellular membrane.
- This organelle acts as an important regulator of cell function because it interacts closely with several other organelles.
- Products of the endoplasmic reticulum often travel to the Golgi body for packaging and additional processing before being secreted.

Functions;
Cisternae, (small folds) of the endoplasmic reticulum, are associated with lipid metabolism.
They also appear to be important in maintaining the $Ca^{2+}$ balance within the cell and in the interaction of the ER with mitochondria. The interaction also influences the aerobic status of the cell
Protein synthesis occurs in RER.

- The ER acts as an internal delivery system because substances move through the ER to different places in the cell.
- One of their major functions is to act as a channel for transport. Secretory proteins, mostly glycoproteins, move across the endoplasmic reticulum membrane.
- Therefore, the Transporting channels of the cells are called Endoplasmic reticulum

Hence, the correct answer is option (B).

Note: The Golgi body packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination. The lysosome is a membrane-bound cell organelle that contains digestive enzymes. They are involved with various cell processes. They break down excess or worn-out cell parts.
Vacuoles are the storage organs found in plant cells. Vacuoles store food or nutrients a cell might need to survive.