Why are phospholipids hydrophobic?
Just having hydrogen doesn’t make something polar. In water, the oxygen has a lone pair of electrons and it’s electronegative, so it attracts the electrons away from the hydrogen atoms, making the molecular polar. Hydrocarbons (molecules made of only carbon and hydrogen), on the other hand, are non-polar and therefore, hydrophobic. This is because both the tetrahedral symmetry of the bonds (the electrons are spread out evenly) and the fact that carbon isn’t particularly electronegative (so the electrons are evenly spread out). Phospholipids have two long hydrocarbon chains, so most of the molecule is hydrophobic but the phosphate head is hydrophillic (because it’s charged/polar). I hope this helps! EDIT: Phospholipids are termed ‘amphipathic” because they are mostly lipids (hydrocarbons) and therefore hydrophobic, but they also have the charged phosphate head, which is hydrophillic. This is why phospholipids will spontaneously form different structures in order to bury the hydrophobic
