Humber Admissions Practice Test

What role does the endoplasmic reticulum play in a cell?

1. Storage of genetic information

2. Formation of structures for energy production

3. A cell structure that transports proteins and lipids

4. Regulation of cell divisions

The correct answer is: A cell structure that transports proteins and lipids

The endoplasmic reticulum plays a crucial role in a cell as a network of membranes that is essential for the synthesis and transportation of proteins and lipids. It exists in two forms: rough and smooth. The rough endoplasmic reticulum is studded with ribosomes, giving it the ability to create and initially modify proteins destined for export or for use within the cell. The smooth endoplasmic reticulum, on the other hand, is involved in lipid synthesis and metabolism, as well as detoxification processes. By serving as a transport system, the endoplasmic reticulum facilitates the movement of these macromolecules to various destinations within and outside the cell, significantly contributing to the overall cellular function and organization. This makes it a fundamental structure for maintaining the cell's physiological processes, ensuring that proteins and lipids are produced and distributed as needed. The other choices highlight functions that are not primarily associated with the endoplasmic reticulum. The storage of genetic information pertains to the nucleus, the formation of structures for energy production relates to mitochondria, and the regulation of cell divisions is a function carried out by the cell cycle machinery, primarily involving the nucleus and various regulatory proteins.