Membranes â¢ Provide barrier function â Extracellular â Organelles â¢ Barrier can be overcome by âtransport proteinsâ â To mediate transmembrane movements of ions, Na + , K + â Nutrients, glucose, amino acids etc. â Water (aquaporins).
Boron is a chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar system and in the Earth's crust.
Start by writing the complete electron configuration of boron, #B#. Boron is located in period 2, group 13, and has an atomic number equal to #5#. This means that the electron configuration of a neutral boron atom must account for a total of #5# electrons. The complete electron configuration for a boron atom will look like this #B:  1s^2 2s^2 2p^1#