Which of the following is NOT a function of the Endoplasmic Reticulum?

The Endoplasmic Reticulum (ER) is a critical organelle within eukaryotic cells, primarily involved in the synthesis and processing of proteins and lipids. The rough ER is studded with ribosomes and is specifically the site of protein synthesis and processing. It plays a pivotal role in folding and modifying proteins that are then sent to their respective destinations within or outside the cell.

The smooth ER, on the other hand, is involved in lipid synthesis and metabolism, as well as detoxification processes. It helps in the synthesis of fatty acids and phospholipids and plays a role in the detoxification of various drugs and toxins, making it central to metabolic functions.

Cell respiration, however, is not a function of the Endoplasmic Reticulum. It primarily occurs in the mitochondria, where biochemical processes like the Krebs cycle and oxidative phosphorylation take place, converting biochemical energy from nutrients into adenosine triphosphate (ATP). Therefore, identifying cell respiration as a function that does not involve the Endoplasmic Reticulum is accurate.