A Level Biology Practice Exam

What does hydrophilic mean when describing a substance?

1. Repels water

2. Attracts water

3. Insoluble in water

4. Completely dissolves in water

The correct answer is: Attracts water

Hydrophilic refers to substances that have an affinity for water, meaning they attract water molecules. These substances typically contain polar groups or charged regions that can interact with water, leading to a tendency to dissolve or mix with it. For example, salts and sugars are considered hydrophilic because they easily dissolve in water. The other options describe properties contrary to hydrophilic characteristics. While some substances might be insoluble in water or repel it, hydrophilic substances are specifically defined by their attraction to water, making the second option the most accurate descriptor of hydrophilic substances.