Final answer:
Both the assertion that lipids are not strictly macromolecules and the reason regarding their arrangement in cell membranes are true. However, the reason is not the correct explanation of the assertion, making the correct answer option C.
Step-by-step explanation:
The question deals with the classification and solubility properties of lipids and their relationship to the structures found in cell membranes. Lipids are a diverse group of compounds united by their common characteristic: they are nonpolar, hydrophobic ("water fearing"), and are insoluble in water due to their nonpolar carbon-carbon or carbon-hydrogen bonds.
This physical property of solubility is what classifies compounds as lipids, and this includes not only fats and oils, which are esters of glycerol and fatty acids, but also steroids like cholesterol, and other compounds. Although lipids may not be traditional macromolecules like nucleic acids or proteins, they are considered part of the acid insoluble fraction due to their arrangement in cell membranes and membrane fragments, where they create acid-insoluble vesicles.
Thus, both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation for Assertion (A), because the primary reason why lipids are considered part of the acid insoluble fraction is due to their physical solubility properties rather than their structural role in cell membranes.
The correct answer is: C. Both (A) & (R) are true and (R) is not the correct explanation of (A).