Surface Tension

Definition

Surface tension is the property of a liquid that causes its surface to behave like a stretched elastic membrane. This phenomenon occurs due to the cohesive forces between liquid molecules, which create a strong intermolecular attraction at the surface, resulting in a minimized surface area. In biological systems, surface tension plays a crucial role in various processes, including the formation of cell membranes and the behavior of liquids within cells and tissues.

5 Must Know Facts For Your Next Test

1. Surface tension is measured in force per unit length, commonly expressed in dynes per centimeter or newtons per meter.
2. In water, surface tension is particularly high compared to most other liquids due to strong hydrogen bonding between water molecules.
3. Biological structures like alveoli in lungs rely on surface tension to function properly, as surfactants are used to reduce tension and prevent collapse.
4. Surface tension allows certain small organisms, like water striders, to walk on water without sinking due to their lightweight bodies and unique leg structures.
5. In cells, surface tension can influence processes such as vesicle formation and membrane dynamics, impacting overall cellular function.

Review Questions

• How does surface tension relate to cohesion and its importance in biological systems?
  • Surface tension is a direct result of cohesive forces between molecules in a liquid. In biological systems, this property is crucial because it allows for the formation of droplets and influences how cells interact with their environment. For example, the high surface tension of water supports processes such as nutrient uptake and the movement of fluids through narrow spaces in tissues.
• Discuss the role of surface tension in alveolar function and how surfactants affect this process.
  • In the lungs, alveoli are small air sacs where gas exchange occurs, and they rely on surface tension for their structural integrity. However, high surface tension can cause alveoli to collapse. Surfactants are substances that reduce surface tension, allowing alveoli to remain open during respiration. By lowering surface tension, surfactants facilitate easier breathing and efficient gas exchange.
• Evaluate how understanding surface tension can impact medical treatments or technologies related to cellular functions.
  • Understanding surface tension is critical for developing medical treatments such as drug delivery systems that target specific cells. Manipulating surface tension can enhance the effectiveness of these treatments by improving how drugs interact with cell membranes. Additionally, technologies that mimic natural surfactants could be employed in respiratory therapies to aid patients with conditions affecting lung function by maintaining alveolar stability and preventing collapse.

Related terms

Cohesion:

The attraction between molecules of the same substance, which is responsible for the formation of droplets and contributes to surface tension.

Adhesion: The attraction between different substances or molecules, which influences how liquids interact with surfaces, like when water spreads on a leaf.

Capillary Action:

The ability of a liquid to flow in narrow spaces without the assistance of external forces, largely driven by the effects of cohesion and adhesion.