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.
The atomic number of carbon (C) is 6. The atomic weight of C is 12.011 grams per mole. The atomic number of an element is the number of protons in the element. Carbon has 6 protons and therefore has an atomic number of 6 (See the Related Links below this answer for a periodic table with more information about this element)