Holoaden Holoaden Holoaden (common name: highland frogs) is a small genus of craugastorid frogs endemic to southeastern Brazil. "Holoaden" is the type genus of subfamily Holoadeninae that was erected in 2008 and placed in family Strabomantidae, erected at the same time. Before that, it was in Brachycephalidae. However, later research has led the whole Strabomantidae, Holoadeninae included, to become included in Craugastoridae. This arrangement is not followed by all, and the AmphibiaWeb still keeps Holoadeninae, and consequently "Holoaden", in Strabomantidae. "Holoaden" grow to snout–vent length at most. Head is narrower than the body. Differentiated tympanic membrane and tympanic annulus are absent.
Cell membrane cells to hold them together to form tissues. Fungi, bacteria, most archaea, and plants also have a cell wall, which provides a mechanical support to the cell and precludes the passage of larger molecules. The cell membrane is selectively permeable and able to regulate what enters and exits the cell, thus facilitating the transport of materials needed for survival. The movement of substances across the membrane can be either "passive", occurring without the input of cellular energy, or "active", requiring the cell to expend energy in transporting it. The membrane also maintains the cell potential. The cell membrane thus works