AP Biology Chapter 3: The Importance of Water

Why is water considered essential for life as we know it?

• Because it can form hydrogen bonds

• Because it is a universal solvent

• Because it is found in all known living organisms

• Because it has a high specific heat

What makes water molecules highly polar?

• The linear shape of the molecule

• The bent shape and difference in electronegativity between hydrogen and oxygen

• The presence of ionic bonds

• The equal sharing of electrons between hydrogen and oxygen

How does cohesion benefit water?

• It enables water to stick to other substances

• It helps water molecules stick together

• It reduces water's surface tension

• It allows water to dissolve nonpolar substances

What is capillarity and why is it important for plants?

• The ability of water to evaporate quickly, helping plants cool down

• The ability of water to dissolve nutrients, aiding in plant growth

• The ability of water to climb against gravity, aiding in water transport

• The ability of water to form ice, protecting plant roots

Why does ice float on water?

• Because ice has a higher specific heat

• Because ice is denser than liquid water

• Because ice is nonpolar

• Because ice forms a lattice structure that is less dense

What is the significance of water's high specific heat?

• It allows water to dissolve more substances

• It helps maintain stable temperatures in environments

• It increases water's surface tension

• It makes water a good conductor of electricity

What happens to water molecules when they form hydrogen bonds?

• They become nonpolar

• They repel each other

• They stick together with a strong force

• They lose their partial charges

How does water act as a universal solvent?

• By dissolving only nonpolar substances

• By dissolving all substances equally

• By dissolving substances with full or partial charges

• By dissolving only ionic compounds

What is the role of buffers in biological systems?

• To prevent changes in pH

• To increase the acidity of solutions

• To make solutions more basic

• To dissolve nonpolar substances

Why is pH balance crucial for aquatic organisms?

• Because it affects their ability to float

• Because it influences their temperature regulation

• Because it impacts their survival and metabolic processes

• Because it determines their color