What 3 functions do proteins have in a plasma membrane?*

Explanation:

Proteins in the plasma membrane have several functions based on their components, location etc. For instance, if the protein transcends the entire plasma membrane it could be a transport protein, responsible for the import and export of certain molecules between the cell and the extracellular matrix (ECM). If the proteins are resting at the surface of the cell, facing the ECM, their role could be to detect components in the ECM, relaying a series of messages back to the nucleus so that the cell can ‘decide’ what it should do with this information (is it being told it should undergo apoptosis, should it begin to divide, should it migrate?). As well as this, it could be involved in the detection of foreign bodies such as pathogens. This is an extremely job for these proteins because if the cell does come in contact with a pathogen, the cell can use these proteins to engulf the pathogen and through a series of steps, present the antigen on their major histocompatibility complexes (either 1 or 2 depending on the cell type) or HLA’s for human cells. Thus it can be concluded that protein functions vary widely in the plasma membrane and due to the vast number of proteins that can be found there, it’s difficult to narrow down the exact main of functions of all these proteins put together.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.