What macromolecule acts as a waterproofing molecule?
A. Carbohydrates B. Proteins C. Lipids D. Nucleic acids
The Correct Answer and Explanation is :
The correct answer is C. Lipids.
Explanation
Lipids are a diverse group of macromolecules that are primarily characterized by their hydrophobic (water-repelling) properties. This unique feature makes them crucial in various biological functions, particularly in waterproofing. Unlike carbohydrates, proteins, and nucleic acids, which are more polar and can interact with water, lipids are non-polar and do not dissolve in water.
The primary types of lipids include triglycerides, phospholipids, steroids, and waxes. Among these, waxes play a significant role in waterproofing. For example, plant cuticles are composed of cutin, a waxy lipid that forms a protective barrier on leaves and stems, preventing water loss and protecting against pathogens. This adaptation is vital for plants, especially in arid environments, as it helps conserve water and maintain hydration.
In animals, lipids also contribute to waterproofing through structures such as skin and fur. For instance, the sebaceous glands in the skin produce sebum, an oily substance that coats the skin and hair, creating a waterproof barrier that prevents excessive water loss and protects against environmental factors. Birds have a similar mechanism; they produce a waxy coating on their feathers to repel water, ensuring they remain buoyant and insulated.
Additionally, lipids play a crucial role in forming biological membranes, particularly phospholipids, which create a bilayer that serves as a barrier to water-soluble substances. This characteristic is fundamental in maintaining the integrity of cells and regulating the movement of materials in and out of the cell.
In summary, lipids are the macromolecules responsible for waterproofing due to their hydrophobic nature, which allows them to form protective barriers in various biological contexts.