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 nucleus is an organelle that is surrounded by a double membrane called the nuclear envelope. The nuclear envelope separates the contents of the nucleus from the rest of the cell. Eukaryotic cells also have a cell membrane (plasma membrane), cytoplasm, cytoskeleton, and various cellular organelles. Animals, plants, fungi, and protists are examples of eukaryotic organisms. Animal and plant cells contain many of the same kinds or organelles.