A TRiP to the plasma membrane

Cell division and enlargement are processes that require precise control. The control ensures that cell division cannot proceed unless the cell has grown to a specific size. A spherical, dividing cell requires an approximately 1.6X increase in its surface area to double its volume. The secretory pathway also has a significant role in cell membrane enlargement. Secretory vesicles that bud off from the Golgi apparatus and later fuse with the plasma membrane during exocytosis are a major source of...

A cell's plasma membrane demarcates the cell's borders and determines the nature of its interaction with the environment. Cells exclude certain substances, take in others, and excrete some others in controlled quantities. The plasma membrane must be flexible to allow certain cells, such as red and white blood cells, to change their shape while passing through narrow capillaries. These are the more obvious plasma membrane functions. In addition, the plasma membrane's surface carries...

A key characteristic of life is the ability to separate the external environment from the internal space. To do this, cells have evolved semi-permeable membranes that regulate the passage of biological molecules. Additionally, the cell membrane defines a cell’s shape and interactions with the external environment. Eukaryotic cell membranes also serve to compartmentalize the internal space into organelles, including the endomembrane structures of the nucleus, endoplasmic reticulum and...

The ER, Golgi apparatus, endosomes, and lysosomes work in tandem to modify, sort, and package proteins and lipids. An integrated membrane trafficking network facilitates the back and forth shuttling of molecules within different organelles in the same cell or across the cell membrane.
The transport of soluble and membrane proteins is mediated by transport vesicles that collect cargo from one cellular compartment and deliver it to another by fusing with the target organelle membrane. The Rab...

Scientists identified the plasma membrane in the 1890s and its principal chemical components (lipids and proteins) by 1915. The model for plasma membrane structure, proposed in 1935 by Hugh Davson and James Danielli, was the first model to be widely accepted in the scientific community. The model was based on the plasma membrane's "railroad track" appearance in early electron micrographs. Davson and Danielli theorized that the plasma membrane's structure resembled a sandwich...