Question

What makes phospholipids ideal molecules for forming the cell membrane?

A.Their complex folded shape allows them to link together

B. Their polar and nonpolar regions allow them to form an amphipathic bilayer

C. Their hydrogen bonds help hold the together but also allow movement

D. Their glycosidic bonds create a strong backbone

Answer 1

B). Their polar and nonpolar regions allow them to form an amphipathic bilayer

The phospholipid heads are hydrophilic ( water-soluble) so they point out into the watery tissue fluid that surrounds a cell. They also point into the cell cytoplasm on the opposite side of the membrane. The tails of phospholipids have fatty acid chains that are uncharged so they are hydrophobic ( water-insoluble), so they point inwards. This creates a barrier between the internal and external water environments of the cell. The tails effectively create a barrier to the movement of charged molecules. Phospholipid molecules spontaneously form bilayers in the aqueous environment and this layer makes the cell membrane and is critical to a cell's ability to function.

amphipathic means _ A molecule that contains both hydrophilic(water-soluble) and hydrophobic (water-insoluble) regions is called amphipathic