BIOL 301 Chapter 2: chap 2
Document Summary
Hydrogen bonds between water molecules provide cohesive forces that make water liquid at room temp and crystalline solid at cold temps. Water has high melting pt, boiling pt, and heat of vaporization. Consequence of attractions between adjacent water molecules. Electrostatic attraction between oxygen atom of one water molecule and hydrogen of another -- hydrogen bond. Water forms hydrogen bonds w polar solutes. Water readily dissolves most biomolecules - hydrophilic. Nonpolar solvents - hydrophobic, like lipids or waxes. This is why it is a favorable free-energy change. Nonpolar gases are poorly soluble in water. Nonpolar compounds force energetically unfavorable changes in the structure of water. Amphipathic compounds contain regions that are polar and regions that are nonpolar. Stable structures of amphipathic compounds in water, called micelles, may contain hundreds or thousands of molecules. Van der waals interactions are weak interatomic attractions. Weak interactions are crucial to macromolecular structure and function. Most stable structure in macromolecules is when weak interactions are maximized.
