key term - Liquid water

Definition

Liquid water is the state of H2O that exists at temperatures between 0°C and 100°C under standard atmospheric pressure, characterized by its ability to act as a solvent and its unique physical properties. This form of water is vital in biological systems, playing essential roles in metabolic processes, cellular structure, and temperature regulation.

5 Must Know Facts For Your Next Test

1. Liquid water has a high specific heat capacity, which helps stabilize temperatures in living organisms and their environments.
2. It has strong hydrogen bonds that give it unique properties like high surface tension and solvent capabilities.
3. Liquid water is essential for biochemical reactions, as many enzymes and substrates function best in an aqueous environment.
4. Water's density is highest at 4°C, which means ice floats on liquid water, providing insulation for aquatic ecosystems.
5. Liquid water can dissolve a wide variety of substances due to its polarity, making it known as the 'universal solvent.'

Review Questions

• How does the unique property of cohesion in liquid water contribute to biological systems?
  • Cohesion in liquid water allows water molecules to stick together, creating surface tension that is crucial for various biological processes. For instance, this property enables the movement of water through plant capillaries during transpiration and supports small organisms like water striders that can walk on the surface. Cohesion also helps maintain the structure of cells by contributing to the fluidity of cellular membranes.
• Discuss how the high specific heat capacity of liquid water impacts temperature regulation in living organisms.
  • The high specific heat capacity of liquid water allows it to absorb significant amounts of heat without undergoing drastic temperature changes. This property is vital for temperature regulation in living organisms, as it helps maintain stable internal conditions despite external temperature fluctuations. For example, humans and other mammals use the thermal properties of water in sweat to cool down, preventing overheating during physical activity.
• Evaluate the role of liquid water as a solvent in biological systems and its implications for biochemical reactions.
  • Liquid water's role as a solvent is fundamental to biochemical reactions within living systems. Its polarity allows it to dissolve ionic compounds and polar molecules, facilitating nutrient transport and waste removal in cells. This solvation process is critical for enzyme-substrate interactions, where the aqueous environment helps stabilize the reactants and enhances reaction rates. As a result, the presence of liquid water is essential for life, influencing metabolic pathways and cellular function.

Related terms

Hydrophilicity: The property of molecules that are attracted to water, allowing them to dissolve or interact easily with liquid water.

Cohesion:

The intermolecular attraction between water molecules that allows them to stick together, leading to properties like surface tension.

pH: A scale used to specify the acidity or basicity of an aqueous solution, which is crucial for many biochemical reactions in liquid water.