Which of the following organelles functions as the site where most cell membrane components, as well as materials destined for export from the cell, are made?
a.) golgi apparatus
b.) endoplasmic reticulum
c.) mitochondrion
d.) peroxisome
e.) lysosome

B.) Endoplasmic reticulum

Explanation:

The endoplasmic reticulum is a complex system of membranes arranged in the form of flattened sacs and tubules that are interconnected with each other sharing the same internal space. Its membranes continue with those of the nuclear envelope and can extend to the vicinity of the plasma membrane, reaching more than half of the membranes of a cell. Its membranes are thinner than those of other cellular compartments (about 5 nm).

The reticle organizes its membranes in regions or domains that perform different functions. The two easiest domains to distinguish are the rough endoplasmic reticulum, with its membranes forming flattened cisterns, sometimes also more or less straight tubules, and with numerous associated ribosomes, and the smooth endoplasmic reticulum, without associated ribosomes and with organized membranes forming tubules. Very curved and irregular.

The main mission of the rough endoplasmic reticulum is the synthesis of proteins that will go to different places: the cellular exterior, the interior of other organelles that participate in the vesicular route, such as lysosomes, or will form an integral part of the membranes, both plasma and of other organelles of the vesicular route. Transmembrane proteins of the plasma membrane are synthesized in the endoplasmic reticulum.

The smooth endoplasmic reticulum is involved in a series of important cellular processes that can be highlighted:

- Lipid synthesis

-  Detoxification

- Dephosphorylation of glucose-6 phosphate

-  Intracellular calcium reservoir