Question

what does the rough and smooth E.R do

Answer 1

The smooth ER is the site of lipid and steroid synthesis, while the rough ER is the site of protein synthesis.

Answer 2

Rough ER :stores and packs proteins which sugars can be added to then are further sent off to the Golgi apparatus for further manufacturing and production, manufactures membranes and secretory proteins.
Smooth ER: carbohydrate and lipid synthesis. It serves as a transitional area for vesicles that transport ER products to various destinations. In liver cells the smooth ER produces enzymes that help to detoxify certain compounds. In muscles the smooth ER assists in the contraction of muscle cells, and in brain cells it synthesizes male and female hormones.