Rough endoplasmic reticulum definition and function

Rough endoplasmic reticulum is an organelle found in eukaryotic cells. Its main function is to produce proteins. It is made up of cisternae, tubules and vesicles. The cisternae are made up of flattened membrane disks, which are involved in the modification of proteins. Rough endoplasmic reticulum has a number of functions. One of the main functions of the rough endoplasmic reticulum is to produce and process specific proteins. These are the exported through the secretory pathway. After they are exported via membrane vesicles, they can be sent to the Golgi Apparatus to be further processed or to organelles. They can even be exported to outside the cell and into another part of the body. Ribosomes also create proteins which are embedded into the rough endoplasmic reticulum for further processing (integral membrane proteins). Water soluble proteins are created too, which are exported through the membrane into the lumen.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.