CHAP2

• Amphipathic liquids in water disperse lipid molecules, causing a decrease in entropy. Nonpolar portions aggregate, reducing water order and increasing entropy. Nonpolar groups are sequestered, and only polar "head groups" are exposed.
• with high enough concentration of amphipathic molecules, complete aggregation into micelles is possible
• Binding sites in enzymes and receptors are often hydrophobic. Such sites can bind hydrophobic substrates and ligands, such as steroid hormones, which displace water and increase entropy of the system ‐ Many drugs are designed to take advantage of the hydrophobic effect
• Colligative properties:

  • Boiling point, melting point, and osmolarity.
  • Do not depend on the nature of the solute, just the concentration − Compare glucose and salt (NaCl) → 1 mole glucose forms 1 mole solute, whereas 1 mole salt forms 2 moles of solute
• Non-colligative properties:

  • Viscosity, surface tension, taste, and colour

  • Depend on the chemical nature of the solute
• Cytoplasm of cells are highly concentrated solutions and have high osmotic pressure due to dissolved solutes.