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Chemistry Review
What are we made of, chemically? Reduce human body to elements
Oxygen
65%
Carbon
18.5%
Hydrogen
9.5%
Nitrogen
3.3
Calcium
1.5
Phosphorous 1.0
Potassium 0.4
Sulfur
0.3
Sodium
0.2
Chlorine
0.2
Mg
0.1
Trace of B Cr, Co, F, I, Fe, Mn, Mo, Se, Si, V, Zn
"organic molecules" carbon compounds.
Each element is a different type of atom
Atomic number versus atomic mass
Characteristic electron shells, 2 in first shell 8 in second
2 in 1s orbital, 2 in 2s, 6 in 2p
Valence? Number of unpaired electrons, 1 for H, 2 for O, 3 for N, 4 for C, 5 for P
Compounds, molecules
Single double and triple bonds
Ionic bonds versus covalent bonds (
Some molecules have intermediate (ionic/covalent) bonds (like water)
Molarity versus moles
Difference between concentration and amount
In biology we frequently use nM, µM and mM
In cells, abundant molecules are present in mM concentrations
Low levels are µM
Scarce molecules are nM
Sizes in biology Å, nm, um
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Energetics
Chemical equilibrium
ATP + H2O -> ADP + Pi Explain
Potential energy versus kinetic energy
An atom with an excited electron has potential energy
An atom has kinetic energy proportional to its degree of motion
"heat" is directly related to molecular motion, hotter molecules are bouncing
around more vigorously.
The probability of a chemical reaction can be predicted by
ΔG = ΔH - TΔS
ΔG is the change in free energy for a reaction
ΔH is the change in the potential energy (usually in the form of heat) in the
chemical bonds
T is the absolute temperature (higher temps, more kinetic energy)
ΔS is the entropy, the amount of disorder in the molecules
Endothermic versus exothermic
Oxidation versus reduction, gaining or losing an electron
Functional groups, know structure, chemical properties
Amino
Carboxyl
Hydroxyl
Phosphate
Sulfhydryl
Water
H2O, pr