Solvent

Definition

A solvent is a substance that dissolves a solute, resulting in a solution. In biological systems, water is the most common solvent and plays a crucial role in various biochemical processes, allowing substances to interact and react effectively within living organisms.

5 Must Know Facts For Your Next Test

1. Water's polarity allows it to interact with various ions and molecules, making it an excellent solvent for many biological reactions.
2. The ability of water to dissolve more substances than any other liquid earns it the title 'universal solvent.'
3. Solvents can be classified as polar or nonpolar, with polar solvents like water being able to dissolve ionic and other polar compounds effectively.
4. In biological systems, the solvent's properties influence the rate of chemical reactions and the transport of nutrients and waste products in cells.
5. Temperature and pressure can affect a solvent's ability to dissolve solutes, impacting biochemical processes within organisms.

Review Questions

• How does the polarity of water contribute to its function as a solvent in biological systems?
  • The polarity of water molecules creates a positive end (hydrogen atoms) and a negative end (oxygen atom), allowing water to effectively surround and interact with various ions and polar molecules. This property enables water to dissolve many substances essential for life, such as salts, sugars, and proteins. As a result, many biochemical reactions occur in aqueous environments where water acts as the solvent, facilitating the movement of nutrients and waste products within cells.
• Compare and contrast polar and nonpolar solvents, providing examples of each and their relevance in biological systems.
  • Polar solvents, like water, have molecules with unequal charge distribution that allow them to dissolve ionic and other polar compounds efficiently. In contrast, nonpolar solvents like hexane do not have this charge separation and are better at dissolving nonpolar substances like lipids. In biological systems, polar solvents are crucial for dissolving nutrients and enabling metabolic reactions, while nonpolar solvents are important for processes involving lipids, such as membrane formation.
• Evaluate the impact of temperature on the solubility of substances in solvents and its implications for biological processes.
  • Temperature significantly influences the solubility of substances in solvents. As temperature increases, most solids become more soluble due to increased molecular motion that helps break solute-solvent interactions. However, gases generally become less soluble at higher temperatures. This has critical implications for biological processes; for example, higher temperatures can enhance nutrient uptake in organisms but may also reduce oxygen availability in aquatic environments, affecting respiration rates in fish and other aerobic organisms.

Related terms

solute: The substance that is dissolved in a solvent to form a solution.

solution: A homogeneous mixture composed of two or more substances, where a solute is dissolved in a solvent.

polarity: The property of having distinct and opposite charges; in water, the polar nature contributes to its ability to dissolve many ionic and polar substances.