An alkene is a hydrocarbon containing double bonds. An alkyne is a hydrocarbon containing triple bonds. Ethene, C 2 H 4, is an example of an unsaturated hydrocarbon with a double bond.ethyne (acetylene), C 2 H 2 is an example of an unsaturated hydrocarbon with a triple bond.thene, C 2 H 4, is an example of an unsaturated hydrocarbon with a double bond. ethyne (acetylene), C 2 H 2 is an example of an unsaturated hydrocarbon with a triple bond.
Mitochondria and chloroplasts are also surrounded by membranes, but they have unusual membrane structures â specifically, each of these organelles has two surrounding membranes instead of just one. The outer membrane of mitochondria and chloroplasts has pores that allow small molecules to pass easily.
In addition to large membrane-bound organelles, such as the nucleus, cells have small membrane-bound pouches called vesicles. These vesicles are structures that separate small molecules and enzymes into one place, away from the rest of the cellâs internal fluid. The skin of these vesicles is also a phospholipid bilayer.ukaryotes have membrane-bound organelles, which include the nucleus, endoplasmic reticulum, and Golgi body. The phospholipid membranes of these organelles are connected and are collectively referred to as the endomembrane system. The structural role of the endomembrane system is to separate the cell into compartments.