$(i)$ Differentiate between rough and smooth endoplasmic reticulum.
$(ii)$ How is endoplasmic reticulum important for membrane biogenesis?

(N/A) $(i)$

Rough endoplasmic reticulum $(RER)$	Smooth endoplasmic reticulum $(SER)$
$1.$ It appears rough under a microscope.	$1.$ It appears smooth under a microscope.
$2.$ It has ribosomes attached to its surface.	$2.$ It does not have ribosomes attached to its surface.
$3.$ It is involved in protein synthesis and transport.	$3.$ It is involved in lipid synthesis and detoxification of drugs and poisons.

$(ii)$ The proteins and lipids synthesized by the endoplasmic reticulum are essential for building the cell membrane, a process known as membrane biogenesis.