Which statement is not true? A) Lipids are found in cell membranes. B) Lipids are soluble in organic solvents. C) There are many different types of lipids. D) All lipids contain fatty acids. E) Some hormones are lipids.

D. all lipids contain fatty acids.

Explanation:

A. Lipids are fats, like oil, that are insoluble in water ... The most abundant class of lipid molecule found in cell membranes is the phospholipid. The phospholipid molecule's polar head group contains a phosphate group. It also sports two nonpolar fatty acid chain groups as its tail.

B. The simplest definition is a lipid as any molecule that is insoluble in water and soluble in organic solvents. Most lipids are soluble to some extent in organic solvents such as hexane, ether, chloroform or benzene. They constitute a complex collection organic compounds that include fatty acids, (A, D, E and K).

C. There are two major types of lipids - simple lipids and complex lipids. Simple lipids are esters of fatty acids with various alcohols. For eg., fats and waxes.

D. Not all lipids have fatty acids. The operational definition of a lipid is a biomolecule is that is sufficiently hydrophobic to be more soluble in an organic solvent than in water. The common theme to their structures is a high percentage of hydrocarbon character.

E. Most lipid hormones are steroid hormones, which are usually ketones or alcohols and are insoluble in water. Steroid hormones (ending in '-ol' or '-one') include estradiol, testosterone, aldosterone, and cortisol ... Amino acid-derived hormones and protein hormones are water-soluble and insoluble in lipids.