Name two cell organelles that are double membrane bound. What are their characteristics ? State their functions and draw labelled diagrams of both

Golgi body and Endoplasmic reticulum (ER)
(1) Golgi body : (1) They consist of many disc-shaped flat cisternae of 0.5 pm to 1.0 pm diameter.
(2) The golgi cisternae are concentrically arranged near the nucleus.
(3) These are stalked parellel to each other.
(4) Golgi body remains in dose association with ER. Function : (1) It is the important site of fomation of glycoproteins and glycolipids.
(2) It perform the function of packaging materials, to be delivered either to the intracellular targets or secreted outside the cell.

Characteristics of endoplasmic reticulum:
(1) Endoplasmic reticulum are tiny tubular structures scattered in the cytoplasm.
(2) ER divides the intracellular space into two distinct compartments, luminal and extra luminal
(3) Ribosomes are attached to the outer surface of ER. It is called rough endoplasmic reticulum (RER).
(4) In the absence of ribosomes they apppear smooth and called’smooth endoplasmic reticulum (SER) or agranular endoplasmic reticulum (AGR).

Functions: (1) RER helps in protein synthesis
(2) SER helps in lipid synthesis