Final answer:
Option (a) is the incorrect statement. This is because it claims that fruits and grains are good sources of lipids, which they typically are not, as they are associated more with carbohydrates. Lipids are found in foods like fats and oils.
Step-by-step explanation:
The question asks which statement is not true about the differences between proteins and lipids. Among the choices given, option (a) is incorrect. While lipids and proteins are essential macromolecules in living organisms, fruits, and grains are not typically significant sources of lipids; they are more commonly associated with carbohydrates. Lipid-containing foods usually include fats and oils, not fruits and grains. Nuts and meat are indeed good sources of proteins. Hence, statement (a) is not true about the differences between proteins and lipids.
Lipids are mainly composed of carbon, hydrogen, and oxygen, and consist of fats, oils, waxes, phospholipids, and steroids. They serve numerous functions, including energy storage, forming cellular membranes, and as precursors to hormones. On the other hand, proteins are polymers of amino acids and function in a variety of roles such as enzymes, hormones, structural elements, and much more.