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.
Membranes are sheets of tissue that cover or line surfaces or separate organs or parts (lobes) of organs from each other. Many membranes provide specialized secretions. The two major categories of membranes are epithelial (serous and mucus) and connective tissue. Membrane is a term that has more than one meaning. For example, at the cellular level, membranes are lipid bilayers that restrict the passage of ions and other solutes.