1. Chemistry Review & Properties of Water Unit 1: Biochemistry

2. You must know! The three subatomic particles and their significance The three subatomic particles and their significance The types of bonds, how they form, and their relative strengths The types of bonds, how they form, and their relative strengths The importance of hydrogen bonding to the properties of water. The importance of hydrogen bonding to the properties of water. Four unique properties of water, and how each contributes to life on Earth. Four unique properties of water, and how each contributes to life on Earth.

3. Chemistry Review Subatomic particles = Protons Protons Neutrons Neutrons Electrons Electrons

4. Different Chemical Bonds Type:Strength: Ionic bonds (salts)strongest Ionic bonds (salts)strongest Covalent bonds (H 2 O)strong Covalent bonds (H 2 O)strong Hydrogen bonds (DNA)weak Hydrogen bonds (DNA)weak

5. Water Most important chemical compound in the living world: Most important chemical compound in the living world: –70-90% of an organism consists of water 2 Hydrogen (H) and 1 Oxygen (O) connected by covalent bonds 2 Hydrogen (H) and 1 Oxygen (O) connected by covalent bonds

6. Polar O is negatively charged, H is positively charged leading to the “magnet-like” behavior of water molecules O is negatively charged, H is positively charged leading to the “magnet-like” behavior of water molecules

7. Hydrogen Bonds Water molecules are drawn to each other Water molecules are drawn to each other Very weak hydrostatic attractions, called Hydrogen Bonds (formed between water molecules) Very weak hydrostatic attractions, called Hydrogen Bonds (formed between water molecules)

8. Water’s Polarity leads to: Cohesion: attraction of water molecules to each other (sticks to itself) Cohesion: attraction of water molecules to each other (sticks to itself) Adhesion: attraction of H 2 O to other polar molecules (sticks to other polar molecules) Adhesion: attraction of H 2 O to other polar molecules (sticks to other polar molecules) Capillary action: water binding to polar walls of plant vessels or glass capillaries Capillary action: water binding to polar walls of plant vessels or glass capillaries Surface tension: skin-like behavior of water surfaces (ants trapped in a bubble) Surface tension: skin-like behavior of water surfaces (ants trapped in a bubble)

9. Water’s Polarity leads to: High Specific Heat High Specific Heat –It takes lots of energy to vaporize water because the molecules stick together –This acts as a heat buffer for an organism’s body temp! Great solvent for other polar and charged substances (e.g. salts and sugars) Great solvent for other polar and charged substances (e.g. salts and sugars) Expansion when it freezes Expansion when it freezes –Ice floats because it is less dense –Insulation of ponds in winter