1. Ch.3 The Chemistry of Life

2. Elements found in living organisms:
The most frequently occurring elements in living things are:
Carbon (19%)
Oxygen (65%)
Hydrogen (10%)
Nitrogen (3%)

3. Foundation of organic molecules
Elements
Some Functions
Carbon
Foundation of organic molecules
Hydrogen
Ions used in photosynthesis, cell respiration, active transport
Oxygen
Aerobic respiration, oxidation reactions for ATP ADP
Nitrogen
Found in amino acids  proteins, forms of nitrogen include ammonium and nitrates

4. Water Molecule
The two hydrogen atoms bond covalently with the oxygen atom; this creates polarity
Hydrogen side is slightly positively charged while oxygen side is slightly negatively charged

5. Properties of Water
Because of water’s polarity, water molecules interact with each other in interesting ways
Some properties of water include
Thermal properties
Cohesive properties
Solvent properties

6. Thermal Properties
High Specific Heat – water can absorb or give off a great deal of heat without big temperature change
This is important for living organisms b/c blood (which is mainly water and therefore stable in temperature) can carry heat to our extremities when cold

7. Thermal Properties
High Heat of Vaporization – water absorbs a lot of heat when it evaporates
This is important for living organisms b/c they can use it as a cooling mechanism when internal heat results in perspiration, then perspiration evaporates by using your body’s heat which cools you down

8. Cohesive Properties
Water is cohesive meaning the molecules stick to each other
This is important for living organisms b/c it allows plants to pull water up from their roots against gravity and for animals it allows some insects to ‘walk on water’

9. Solvent Properties
Water is the Universal Solvent b/c it is polar and therefore other polar molecules like carbs, proteins, and DNA can dissolve in it
This is important for living organisms b/c water is the medium for metabolic reactions
Aqueous Solution
Location
Common Reactions
Cytoplasm
Fluid insides cells but outside organelles
Glycolysis, protein synthesis
Nucleoplasm
Fluid inside nuclear membrane
DNA replication, transcription
Stroma
Fluid inside chloroplast organelle in plants
Light dependent rxns of photosynthesis
Blood
Fluid in arteries, veins, capillaries
Exchange of gases (O2 and CO2), clotting

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