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.
The transmembrane proteins that cross the bilayer are very important in the active transport of ions and small molecules. Different Membranes of the Cell As you learn more about cell organelles, you will find that they all have a membrane. Organelle membranes do not have the same chemical makeup as the cell membrane. They have different lipids and proteins that make them unique. The membrane that surrounds a lysosome is different from the membrane around the endoplasmic reticulum. Some organelles have two membranes.