This document discusses the chemistry of life, including different types of bonds (polar covalent, nonpolar covalent, ionic, hydrogen bonds, van der Waals forces) and how they relate to biomolecules. It covers Stanley Miller's primordial soup hypothesis for how organic molecules formed abiotically on the early Earth. Key biomolecules like carbohydrates, lipids, proteins, and nucleic acids are made of hydrocarbons with different functional groups that allow for their diverse roles in living organisms.

1. The
Chemistry of Life
AP Biology 2009-2010

2. Outline
 Review of bonds
 Mr. Stanley Miller
 Organic Molecules
 Biomolecules
AP Biology

3. Bonds in Biology
 Strong bonds
 A. Nonpolarcovalent bonds
 B. Polar covalent bonds
 Weak bonds
 A. Ionic
 B. Hydrogen bonds
 C. Van der Waals forces
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4. Why do we care?? Bonds matter!
Eugenol Isoeugenol
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5. Electronegativity Review
 Electronegativity = the tendency of an
atom to attract electrons
It’s better to
be negative
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6. What’s up POLAR BEAR???
 A molecule is polar if its components
don’t share electrons equally.
 One component will pull the electrons
harder.
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7. Strong BONDS
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8. A. Polar covalent bonds
 Pair of electrons shared
unequally by 2 atoms
+ –
H –
Oxygen pulls the
Oxygen shared electrons
toward itself –
– oxygen “wins!”
H
+ –
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9. B. Nonpolarcovalent bond
 Pair of electrons shared equally by 2
atoms
 example: hydrocarbons = CxHx
 methane (CH4 )
Lots of
energy stored…
& released
balanced, stable,
good building block
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10. ARE YOU WITH ME?
 Polar covalent or Nonpolar covalent?
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11. ARE YOU WITH ME?
 Polar covalent or Nonpolar covalent?
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12. ARE YOU WITH ME?
 I AM SO FUNNY.
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13. WEAK BONDS
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14. A. Ionic Bonds
 The more electronegative atom
DOMINATES (steals the electron
completely)
Greedy polar bear
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15. B. Hydrogen bonding
1) Between molecules
2) Between H+and an electronegative ion
 Common electronegative ions =
O, N, F
3) WEAK
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16. Examples of Hydrogen Bonds
Hydrogen Bonds are common in
Biology!
H
H
O
H bonds
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17. C. Van der Waals forces (aka
interactions) = STICKINESS
 When molecules are really close, they
sometimes “STICK” because of
charges
 Only lasts a short amount of time
 SUPER WEAK
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18. Why are we studying chemistry?
Chemistry is the origin of life.
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19. Mr. Stanley Miller and the
Primordial Soup Hypothesis
 In the beginning… there was only H2O,
H2, CH4 (methane), and NH3 (ammonia).
Why is the primordial
soup hypothesis also
known as the “abiotic
synthesis of life?”
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20. Organic Molecules
 Made up of Carbon and Hydrogen.
 Why Carbon?
 Carbon makes 4 stable _________ bonds
with hydrogen
H
C
H H
H
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21. Hydrocarbons
 Special name given to
chains of C &H
Polar or Nonpolar?
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22. Hydrocarbons can grow and change
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23. Hydrocarbons can have functional groups
H H
H CC H
OH
H H
H H
H C C =O
H
H H
H H
H CC H
H H
H H
H CC H
H H
H H
H CC H
H H
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24. Viva la difference!
 Basic structure of male & female
hormones is identical
 identical carbon skeleton
 attachment of different functional groups
 interact with different targets in the body
 different effects
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25. BIOMOLECULES
 Hydrocarbon chain with functional
groups
 4 major types  STAY TUNED!!
 Carbohydrates
 Lipids
 Proteins
 Nucleic acids Is water a
biomolecule?????
AP Biology