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 cell biology, an organelle is a specialized subunit within a cell that has a specific function. Individual organelles are usually separately enclosed within their own lipid bilayers. The name organelle comes from the idea that these structures are parts of cells, as organs are to the body, hence organelle, the suffix -elle being a diminutive. Organelles are identified by microscopy, and can also be purified by cell fractionation. There are many types of organelles, particularly in eukaryotic