1. Chemical Reactions

2. Chemical Bonds

3. Covalent Bonds
Sharing of a pair of valence electrons by two atoms.

4. Covalent Bonds Non-polar covalent bond: Polar covalent bond:
Occurs when the two atoms are equally electronegative (EN).
Electrons shared equally.
Polar covalent bond:
Occurs when one atom is more EN than the other.
Electrons are not shared equally.

5. Ionic Bonds
Difference in EN is so great that the less EN atom transfers its valence electron to the more EN atom.

6. Ionic Bonds
Charged atom/molecule is called an ion.

7. Anabolic Reactions (building up)

8. Dehydration (Condensation) Synthesis
Consume energy to build complex molecules (polymers) from smaller subunits (monomers).
Monomers covalently bond to each other through the loss of a water molecule.
One molecule loses a hydroxyl group, while the other loses a hydrogen atom. @

9. Formation of a Disaccharide
hydroxyl + hydroxyl  ether bond @
Ether bonds between sugar subunits are referred to as glycosidic linkages 9

10. Formation of a Triglyceride@
hydroxyl + carboxyl  ester bond
Linkage between glycerol and fatty acids are ester linkages 10

11. Formation of a Protein hydroxl + amino  peptide bond
Many amino acids together form a polypeptide; a protein is a polymer of amino acids. 11

12. Formation of DNA @
phospho + hydroxyl  phosphodiester bond 12

13. Catabolic Reactions (breaking down)

14. Hydrolysis
Release energy to break down complex molecules into smaller subunits.
Covalent bonds are broken by the addition of a water molecule. @

15. Oxidation-Reduction (Redox) Reactions

16. Redox Reactions
Releases energy as one or more electrons released from one substance move closer to EN atoms.
Oxidation:
Loss of electrons from one substance.
Reduction:
Addition of electrons to another substance.

17. Redox Reactions

18. Buffers Acid – produces H+ when dissolved in water
Base – produces OH- when dissolved in water
pH scale – numerical scale 0-14 where <7 is acidic, >7 is basic and =7 is neutral
Neutralization reaction – a chemical reaction between an acid and a base producing water and salt

19. Buffers
Substances that minimize changes in the [H+] and [OH-] in a solution.
Chemical Equilibrium between carbonic acid and bicarbonate acts as a pH regulator.