Distinguish between smooth endoplasmic reticulum and rough endoplasmic reticulum.(1 point)
The smooth endoplasmic reticulum (SER) and rough endoplasmic reticulum (RER) are two different structures found in eukaryotic cells. Here is a distinction between them:
1. Structure: The smooth endoplasmic reticulum appears as a network of tubules or vesicles lacking ribosomes on its surface, giving it a smooth appearance. On the other hand, the rough endoplasmic reticulum has ribosomes attached to its surface, making it appear rough or grainy.
2. Composition: The smooth endoplasmic reticulum consists of enzymes that are involved in lipid and carbohydrate metabolism, detoxification, and calcium storage. It is abundant in cells specialized for lipid synthesis, such as liver cells. In contrast, the rough endoplasmic reticulum is involved in the synthesis of proteins. The attached ribosomes on its surface are responsible for protein synthesis.
3. Functions: The smooth endoplasmic reticulum plays a role in various functions, such as the synthesis of lipids, including phospholipids and steroids, the detoxification of drugs and toxins in the liver, and the regulation of calcium ion concentration. It also participates in the metabolism of carbohydrates. The rough endoplasmic reticulum is mainly involved in protein synthesis and modification. It provides a surface for ribosomes to synthesize and modify proteins before they are transported to their final destinations.
4. Examples: Smooth endoplasmic reticulum is abundant in cells such as liver cells, adrenal cells, and muscle cells, where lipid synthesis, detoxification, and calcium storage are important. Rough endoplasmic reticulum is found in various cells involved in protein production, such as pancreatic cells and cells of the immune system.
In summary, the smooth endoplasmic reticulum lacks ribosomes and is involved in lipid and carbohydrate metabolism, while the rough endoplasmic reticulum has ribosomes attached to its surface and is responsible for protein synthesis and modification.