What is the difference between the smooth endoplasmic reticulum and rough endoplasmic reticulum within the cell?

Answer all parts of the two questions asked below and the professor said the answer needs to be strong answers will reasoning to back it up.

Question 1:
Can all cells perform phagocytosis and how would a cell know when it is appropriate to do so?

Question 2:
What is the difference between the smooth endoplasmic reticulum and rough endoplasmic reticulum within the cell?