Final answer:
Lipids synthesized by the endoplasmic reticulum are transported primarily by vesicular transport, involving transport vesicles bud off from the ER and fusing with target membranes.
Step-by-step explanation:
The endoplasmic reticulum (ER) is responsible for the synthesis of lipids, which are then transferred to other membranes within the cell. Lipids can be transported by various mechanisms, including vesicular transport. In vesicular transport, transport vesicles bud off from the ER and then fuse with the target membrane, such as the Golgi apparatus or plasma membrane, delivering their lipid cargo. This type of lipid transfer is essential for maintaining the proper function and distribution of lipids within cell compartments. The other mechanisms like simple diffusion might occur for small, nonpolar molecules, but it is not the primary mode of transport for lipids between the ER and other membranes.