1. Water, pH, and Macromolecules
Unit 2, Part 1
Water, pH, and Macromolecules

2. Properties of Water Polar - due to the unequal sharing of electrons
Hydrogen Bonds - because of partial positive and negative charges, polar molecules, such as water, can attract each other
Adhesion - stickiness-attraction between molecules of a different substance
Cohesion - stickiness-attraction between molecules of the same substance

3. Where is water? What does it do?
2/3 of the cell is made of water
Most biochemical processes of life occur in water solutions
Water is able to dissolve many substances due to polarity
Water carries nutrients into the cell and waste away from the cell

4. Mixtures, Solutions and Suspensions
Two or more elements or compounds that are physically mixed together, but not chemically combined
Mixtures have the same properties as their components
There is no fixed proportion between the components
The components can be separated from the mixture
Examples
sugar and salt
air with nitrogen, oxygen

5. Solution
The components in a solution may not be separated from the solution by leaving it to stand, or by filtration
If a material dissolves in a liquid the material is said to be soluble. A solution is saturated if no more solute can be dissolved with temperature remaining constant. 
Examples
salt in sea water
Table salt placed in water dissolves forming a solution. The salt will settle out
Water = solvent
Salt = solute

6. Suspension
A suspension is a mixture of liquids with particles of a solid which may not dissolve in the liquid.
The solid may be separated from the liquid by leaving it to stand, or by filtration
Some materials do not dissolve, but separate into small particles. The movement of the solute keeps them suspended. They will not settle out.
Examples
sand in water

7. pH Scale Acid Base (Alkaline) Acids, Bases, pH
Concentration of H+ in solution
Figure 2-10, page 43
Acid
Contains more H+ than pure water, pH value below 7
Base (Alkaline)
Contains more OH- than pure water, pH value above 7
Acids, Bases, pH
H2O <=> H OH-
water hydrogen hydroxide
ion ion

8. pH Scale

9. Buffer
Weak acid or base that can react with strong acid or base used to prevent sharp, sudden changes in pH.

10. Macromolecules Four groups of organic compounds in living things
“giant” molecules
Made by polymerization
Made from monomers and polymers
Four groups of organic compounds in living things
Carbohydrates
Lipids
Nucleic Acids
Proteins

11. Carbohydrates Made of carbon, hydrogen, oxygen in a 1:2:1 ratio
Main energy source for living things
Structural for some plants
Monosaccharides - single, simple sugar
Polysaccharides – large, complex sugars

12. Lipids Made mostly of carbon and hydrogen Fats, oils, waxes, steroids
Used to store energy
Membranes and waterproof coverings
Glycerol plus fatty acids
Saturated and polyunsaturated

13. Nucleic Acids
Made up of carbon, hydrogen, oxygen, nitrogen, and phosphorous
Polymers assembled from monomers called nucleotides
Nucleotides consist of three parts; a five carbon sugar, a phosphate group and a nitrogenous base
They store and transmit hereditary or genetic information
Examples; DNA & RNA

14. Proteins Made up of carbon, hydrogen, oxygen, and nitrogen
Polymers of molecules called amino acids
Some control the rate of reactions and regulate cell processes
Some form bone and muscle
Others transport substances into and out of cells and fight disease

15. Macromolecules