1. Elements of Life 25 elements Hint: Remember CHNOPS 96% : C, O, H, N
~ 4% : P, S, Ca, K & trace elements (ex: Fe, I)
Hint: Remember CHNOPS

2. Bonds Covalent Ionic Hydrogen All important to life
Form cell’s molecules
Quick reactions/ responses
H bonds to other electronegative atoms
Strong bond
Weaker bond (esp. in H2O)
Even weaker
Made and broken by chemical reactions

3. 1. Polarity of H2O
O- will bond with H+ on a different molecule of H2O = hydrogen bond
H2O can form up to 4 bonds

4. Examples of Benefits to Life
H2O Property
Chemical Explanation
Examples of Benefits to Life
Cohesion
polar
H-bond
like-like
↑gravity plants, trees
transpiration
Adhesion
unlike-unlike
plants xylem
bloodveins
Surface Tension
diff. in stretch
break surface
bugswater
Specific Heat
Absorbs & retains E
oceanmoderates temps protect marine life (under ice)
Evaporation
liquidgas KE
Cooling
Homeostasis
Universal Substance
Polarityionic
Good dissolver
solvent

5. ie. amino acid  peptide  polypeptide  protein
Monomers
Polymers
Macromolecules
Small organic
Used for building blocks of polymers
Connects with condensation reaction (dehydration synthesis)
Long molecules of monomers
With many identical or similar blocks linked by covalent bonds
Giant molecules
2 or more polymers bonded together
ie. amino acid  peptide  polypeptide  protein
larger
smaller

6. Dehydration Synthesis (Condensation Reaction)
Hydrolysis
Make polymers
Breakdown polymers
Monomers  Polymers
Polymers  Monomers
A + B  AB
AB  A + B
+ H2O +
+ H2O +

7. Differ in position & orientation of glycosidic linkage
I. Carbohydrates
Fuel and building
Sugars are the smallest carbs
Provide fuel and carbon
monosaccharide  disaccharide  polysaccharide
Monosaccharides: simple sugars (ie. glucose)
Polysaccharides:
Storage (plants-starch, animals-glycogen)
Structure (plant-cellulose, arthropod-chitin)
Differ in position & orientation of glycosidic linkage

8. II. Lipids Fats: store large amounts of energy
saturated, unsaturated, polyunsaturated
Steroids: cholesterol and hormones
Phospholipids: cell membrane
hydrophilic head, hydrophobic tail
creates bilayer between cell and external environment
Hydrophilic head
Hydrophobic tail

9. Four Levels of Protein Structure:
Primary
Amino acid sequence
20 different amino acids
peptide bonds
Secondary
Gains 3-D shape (folds, coils) by H-bonding
α helix, β pleated sheet
Tertiary
Bonding between side chains (R groups) of amino acids
H & ionic bonds, disulfide bridges
Quaternary
2+ polypeptides bond together

10. amino acids  polypeptides  protein

11. Protein structure and function are sensitive to chemical and physical conditions
Unfolds or denatures if pH and temperature are not optimal