Final answer:
The construction of membrane phospholipids does not involve the orientation of tails towards polar molecules or heads towards a non-polar side. Phospholipids have a specific orientation in cell membranes with their hydrophilic heads facing outward and hydrophobic tails inward. This precise orientation is crucial for the cell membrane's structure and function.
Step-by-step explanation:
The construction of membrane phospholipids involves two fatty acids forming diacylglycerol and a phosphate group modified by an alcohol; the two fatty acids are attached to a glycerol or sphingosine backbone. Unlike triglycerides which have three fatty acids, phospholipids have this distinct structure conducive to forming cell membranes.
The statement 'Phospholipids orient their tails towards the polar molecules and heads in the non-polar side of the membrane, forming a bilayer' is incorrect since phospholipid molecules align with their hydrophilic (water-attracting) heads towards the exterior, water-containing environment, and their hydrophobic (water-repelling) tails facing inward, away from water.
Therefore, the construction of membrane phospholipids does not involve the orientation of tails towards polar molecules or heads towards a non-polar side, as this would disrupt the bilayer formation and the dynamic nature essential to cell membrane function.
When phospholipids are placed in water, they form structures like micelles or bilayers, with the hydrophilic phosphate heads facing the aqueous environment and the hydrophobic tails sequestered away from water.
Because cell membranes are selectively permeable and contain a variety of phospholipids, the structure and proportion of phospholipids play a critical role in their function, but it is not accurate to say that 'only certain membranes contain phospholipids' as virtually all cell membranes in living organisms contain them.