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.
All cells have a plasma membrane, cytoplasm and ribosomes. Eukaryotic cells, like plants and animals, also have membrane-bound nuclei and organelles (e.g., mitochondria, endoplasmic reticulum, lysosomes).At the magnifications that are generally attainable in the K-12 classroom, many organelles are not visible.ll cells have a plasma membrane, cytoplasm and ribosomes. Eukaryotic cells, like plants and animals, also have membrane-bound nuclei and organelles (e.g., mitochondria, endoplasmic reticulum, lysosomes).