The structure is a phospholipid bilayer. There are many phospholipids which contain a water loving phosphate end and a water hating lipid (fatty) end. The phosphate ends all point out words while the fatty ends are inside.
The purpose is protection of the cell as well as allowing certain molecules to enter and exit the cell
The difference between them is that an ecosystem is a community of organisms and their environment. And a biosphere is all the living organisms.
