endoplazmatický

Endoplasmic reticulum (ER) is a network of membrane-bound organelles found in the cytoplasm of eukaryotic cells. It plays a crucial role in the synthesis, folding, and modification of proteins, as well as the synthesis and transport of lipids. The ER is divided into two main regions: the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER).

The RER is characterized by the presence of ribosomes attached to its surface, which are responsible for protein synthesis. The SER, on the other hand, lacks ribosomes and is involved in lipid synthesis and detoxification processes. The ER is connected to the Golgi apparatus via transport vesicles, allowing for the transport of proteins and lipids between these organelles.

The ER is also involved in the synthesis of certain molecules, such as steroids and phospholipids, which are essential for various cellular functions. Additionally, the ER plays a role in the regulation of calcium ion concentrations within the cell, which is important for various cellular processes, including muscle contraction and neurotransmitter release.

In summary, the endoplasmic reticulum is a vital organelle in eukaryotic cells, responsible for protein synthesis, lipid synthesis, and the regulation of calcium ion concentrations. Its structure and function are essential for the proper functioning of the cell and the organism as a whole.