🧪 Topic A1: Water and Life Flashcards
(15 cards)
What is the significance of water for life?
Life began in water. Most cellular processes occur in aqueous environments (inside cytoplasm, blood, xylem/phloem, etc). Enzymes and metabolic reactions need water.
What is the molecular structure of water?
Water (H₂O) is a polar molecule. Oxygen pulls electrons more strongly than hydrogen, creating partial charges (δ- on O, δ+ on H).
What allows hydrogen bonds to form between water molecules?
The polarity of water allows hydrogen bonds to form between water molecules.
What is cohesion in water?
Cohesion is water sticking to itself via hydrogen bonds. It allows water to be pulled up xylem vessels in plants and causes surface tension.
What is the importance of cohesion in plants?
Cohesion allows water to be pulled up xylem vessels in plants, which is important for transpiration.
What is adhesion in water?
Adhesion is water sticking to other polar surfaces (e.g., cellulose in cell walls).
How does adhesion help water movement?
Adhesion helps water move via capillary action in soil and in plant tissues.
What are the solvent properties of water?
Water is a universal solvent for hydrophilic substances (ions, sugars, amino acids). Most metabolic reactions occur in aqueous solution.
What types of molecules do not dissolve in water?
Some molecules like lipids are hydrophobic, so they don’t dissolve.
What are the physical properties of water that benefit aquatic life?
Water has high buoyancy, high specific heat capacity, high viscosity, and high thermal conductivity.
How does buoyancy benefit aquatic animals?
High buoyancy helps animals float (e.g., fish, seals).
What is the significance of high specific heat capacity in water?
High specific heat capacity provides a stable aquatic environment temperature.
How does viscosity affect aquatic life?
High viscosity provides resistance to movement, affecting body shape for swimming.
What role does high thermal conductivity play in water?
High thermal conductivity distributes heat effectively.
Can you give an example of an animal adapted to aquatic life?
Black-throated loon: streamlined for efficient swimming. Ringed seal: thick blubber for insulation in cold water.
