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.
Membrane-bound organelles. Eukaryotic cells contain collections of proteins that function as a unit called organelles. Some of these organelles are surrounded by a membrane similar in structure to the cell membrane but with a different composition of protein and phospholipid.Membrane-bound organelles offer several advantages to eukaryotic cells.ome of these organelles are surrounded by a membrane similar in structure to the cell membrane but with a different composition of protein and phospholipid. Membrane-bound organelles offer several advantages to eukaryotic cells.