Question 27

Lipids are not water-soluble.

Lipids are characterized by their hydrophobic nature, meaning they do not dissolve in water. This property distinguishes them from many other organic molecules, which are often polar and can interact with water.

A) They are indivisible.

This statement is incorrect because lipids can be broken down into smaller units, such as fatty acids and glycerol. While they may form complex structures, they are not indivisible as they can be hydrolyzed or metabolized.

B) They are not water-soluble.

This statement accurately describes lipids. Their hydrophobic properties prevent them from dissolving in water, which is a key characteristic that sets them apart from other organic molecules like carbohydrates and proteins that are typically soluble in water.

C) They contain zinc.

This option is incorrect because lipids do not inherently contain zinc as a structural component. Zinc is a trace element often associated with proteins and enzymes, but it is not a defining characteristic of lipids.

D) They form long proteins.

This statement is incorrect because lipids do not form proteins. Instead, proteins are made up of amino acids, while lipids are a separate class of organic molecules characterized by their fatty acid composition and hydrophobic properties.

Conclusion

The correct answer is that lipids are not water-soluble, which is a fundamental distinction from other organic molecules. Options A, C, and D fail to accurately describe lipids' characteristics, highlighting their unique hydrophobic nature. This property is essential for their roles in biological membranes and energy storage, further emphasizing why option B is the only accurate choice.