1. Biological Molecules B2, B3, B4

2. Water and It’s role in biological Systems  describe how the polarity of the water molecule results in hydrogen bonding

3. Polar bonding o Unequal sharing of electrons o  (+) and  (-) charges on the molecule

4. Polarity creates Hydrogen bonds o H bonds are relatively weak

5. There’s strength in numbers!

6. Unique Properties of Water describe the role of water as a solvent, temperature regulator, and lubricant o 1. “Universal Solvent” o Dissolves all polar and ionic molecules.

7. Hydrophobic Vs Hydrophilic?

8. Hydrophobic Interactions: Oil cannot interact with the polar regions of H 2 O and actually interfere with the H bonds between H 2 O molecules.  interfering(breaking) with the H bonds requires ENERGY  When given the chance, oil droplets will cluster, reducing the surface area exposed to the H 2 O. (therefore using less ENERGY to break the H bonds)  *** the H Bonds “force” the oil droplets to stay together.

9. 2. Temperature Regulation by Water 1. High specific heat (the amount of Energy needed to raise 1gm of water 1 o C) 2. High heat of vaporization 3. High heat of fusion

10. Acids, Bases and pH differentiate among acids, bases, and buffers pH measures the [ ] of the H+ compared with OH- PURE H 2 O : Neutral, therefore pH 7 [H+] = [OH-] ** the pH scale is a log scale; a change in pH from 7 to 6 means there are 10x more H+ ions than in the neutral solution.

11. Acids o Dissociate to donate H + ions o pH < 7 o [H + ] > [OH - ]

12. Bases molecules that release OH- ions therefore pH > 7 (ex. NaOH) [H+] < [OH-]

13. Controlling pH in the Body BUFFERS are molecules that can either pick up or release hydrogen (or hydroxide) ions Eg. pH is too low: HCO 3 - + H + --> H 2 CO 3 (bicarbonate) (carbonic acid) pH is too high: H 2 CO 3 + OH - HCO 3 - + H 2 O (excess of OH-)