A1.1.3 Cohesion of water molecules due to hydrogen bonding and consequences for organisms Flashcards
What role does cohesion play in xylem vessels?
Cohesion ensures that water molecules form an unbroken column from the roots to the leaves.
Why doesn’t the water column in xylem break under tension?
Breaking the water column would require breaking numerous hydrogen bonds simultaneously, which demands a significant amount of energy.
What is surface tension?
Surface tension is the inward pull on water molecules at the surface due to hydrogen bonds with neighboring molecules.
How do plants transport water without a pump?
Plants rely on the cohesive property of water to overcome gravity and move fluids.
Give an example of an organism that utilizes surface tension.
Pond skaters walk on water by distributing their weight across their legs, which do not break the water’s surface.
Why are water’s hydrogen bonding properties important?
They underpin water’s cohesion, adhesion, and surface tension, which are vital for plant survival and ecosystem balance.
Why is surface tension important for small organisms?
Surface tension enables water to support small objects or organisms that would otherwise sink.
How do cohesion and adhesion benefit plants?
Cohesion and adhesion enable plants to transport water and nutrients from roots to leaves, where photosynthesis occurs.
How does soap affect surface tension?
Soap disrupts hydrogen bonding, reducing surface tension, which can cause objects to sink.
What is the difference between intramolecular and intermolecular bonding?
- Intramolecular: Occurs within a single molecule (e.g., covalent bonds).
- Intermolecular: Occurs between separate molecules (e.g., hydrogen bonding).
What role does surface tension play in ecosystems?
Surface tension creates unique habitats for surface-dwelling organisms and those just below the surface, supporting biodiversity.
What are the two key properties that enable water transport in xylem?
- Cohesion: Keeps water molecules connected.
- Adhesion: Helps water stick to the xylem walls.
What is the analogy for water being pulled up through the xylem?
Water being pulled up through the xylem is like sucking liquid up through a straw.
How does transpiration create tension in the water column?
As water evaporates, it creates a negative pressure or tension in the water column.
What initiates the upward movement of water in plants?
The upward movement of water begins with transpiration, the evaporation of water from the stomata in leaves.
