This is false. Organisms may play several important roles in an ecosystem. Consider for example and ocean shore environment occupied by a particular species of crab. The crabs are scavengers and eat any organic matter they encounter. They therefore play an important role in the cycling of nutrients in the ecosystem. The crabs are however also an important source of food for a range of other species occupying the same habitat, including octopi, certain fishes and sea otters. Therefore, the crabs are an important part of the food web in the ecosystem. Many species similarly occupy multiple important roles in an ecosystem.
This is because the seven-sugar intermediate is synthesized by sugar addition to cytosolic-facing dolichol phosphate. The intermediate is flipped from the cytosol face of the ER membrane to the the luminal face. Additionally, the sugar additions then occur within the lumen of the ER. The short forms of the intermediate are on the wrong side of the membrane to add to nascent polypeptides within the ER lumen. Incomplete adductants within the ER lumen are located appropriately to N-glycosylate nascent polypeptide.
Facilitated transport ! this is passive transport but with specific proteins !
