Example 1:
Endoplasmic reticulum (ER) are like factories of cells. If we consider cell as a international clothing chain of companies, then ER are the ones which plan and design the clothing, sew those up, put additional buttons etc. on them, and then ship them on time. The workers (manual and automatic) do the whole procedure.
To understand it better in terms of cellular functions, ER create biomolecules essential for cells and the body as a whole. ribosomes are the workers which do the synthesis. With the help of ribosomes, ER makes the whole process of biomolecule synthesis, modification and delivery smooth, efficient and accurate.
Example 2:
Think of ER as Uber Eats. It provides you the catalogue of delicious food available and can be sent, then forwards your request to the restaurant, then sends a delivery person to wait and collect the order, and then orders the person to delivery food to the correct address on time.
Here, ribosomes would be the restaurants making the food.
**This is a simplification of the actual function of ER but I hope you get the gist. While talking about smooth and rough ER, the examples may change.
