A phospholipid molecules head is considered to be polar, although I dont understand why. Polar refers to the uneven distribution of charges. The phospholipid head is made up of a nitrogenous compound which is positively charged, a phosphate bridge which is negatively charged, and a glycerol molecule. Wouldnt the charges of the nitrogenous compound and the phosphate bridge cancel out and therefore be non-polar? Or is one charge predominant over the other?

Question

anonymous · Answer

@Preetha

anonymous · Answer

@paki

anonymous · Answer

@Cuanchi

preetha · Answer

Purple, here is the deal.  A phospho lipid has a Phosphate group and one of the O- of the PO4 is connected to the lipid part.  The lipid part has Carbons, Hydrogens and Oxygens.With me so far?

anonymous · Answer

yep

preetha · Answer

OK, now the way it is laid out the PO4 part is at one end and the lipid part stretches out like a long tail.  So the charged part is at the PO4 end.  It is negatively charged.  The rest of the tail part is mostly H and C so it is not charged. With me?

preetha · Answer

The distribution of charge is uneven along the molecule - focused on the P end.  In fact one end is very polar (the phosphate end) and the other end is pretty non polar (the lipid end)  If the phosphate is connected to other pieces with nitrogen it still doesn't remove this polarity.

preetha · Answer

Short answer - no the charges don't cancel out.  Molecule is polar - one end where the Os and P and possibly Ns are - being polar and hydrophilic and the other end - tail - non polar and hydrophobic.