Examples of semi permeable membrane?
The cell surface membrane surrounding all cells of prokaryotes (like bacteria- don't have a perfect nucleus) and eukaryotes (like plants and animals- have a perfect nucleus).
The membranes surrounding all organelles (mitrochondria, lysosomes, chloroplasts).
The tonoplast surrounding the permenant vacuole in plants is semi-permeable.
This is due to the fact that they're made of the same structure which is your phospholipid bilayer . This bilayer allows the diffusion of polar molecules (like carbon dioxide and oxygen), while non-polar ones (like ions) have to pass through transport proteins in the membrane (channel and carrier proteins).