Question

Where does protein and lipid synthesis occur?

Answer 1

protein synthesis occurs in cellular structures called ribosomes , found out-side the nucleus. and Membranes and their constituent proteins are assembled in the ER. This organelle contains the enzymes involved in lipid synthesis, and aslipids are manufactured in the ER, they are inserted into the organelle's own membranes. 

Answer 2

Proteins are synthesised in rough endoplasmic reticulum due to presence of ribosomes.
Lipids are synthesised in smooth endoplasmic reticulum

Hope it helps you.
Mark as brainlist if you like answer.