Chapter 4: Carbon and the Molecular Diversity of Life

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Chapter 4Carbon and theMolecularDiversity of
Life
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Important Point
If you are having trouble understanding lecture
material Try reading your text before
attending lectures. And take the time to read it
well!
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Carbon Chemistry
Hydrocarbons are Simpler
Isomers are compounds that share molecular
formulas but differ in some way in terms of their
structure
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CarbonValence 4
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Representational Models
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Rotation Around Single Bonds
Free rotation
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Hydrocarbons Isomers
Linear Alkanes
Branching Creates Structural Isomers
Structural Isomers Same Formula, Different
Structure
Methyl Propane Isobutane
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Double Bonds Rings
No rotation
No rotation
No rotation
These are all planar molecules
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Implicitly Depicting Carbons
Carbons shown as corners
Double bonds
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Double Bonds
Note that these all the above have different
molecular formulas
They are not isomeric!
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Geometric Isomers
Geometric isomers vary about double bonds
A
B
A
B
B
A
A
B
No rotation about double bonds
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Geometric Isomers
Geometric Isomers have same structure but
different Geometry!
A
B
A
B
B
A
A
B
You need to break bonds to convert Fumerate to
Maleate
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Chiral Carbons
Chiral carbons have four different groups around
them
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Chiral Carbons
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Enantiomers
Chiral carbons have four different groups around
them and give rise to enantiomeric Pairs
Enantiomers Same geometry, different spatial
arrangement
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Enantiomers are Mirror Images
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Enantiomeric Handidness
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Enantiomers and Bioactivity
Bioactive molecule
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Hydrophilic Functional Groups
Functional groups behave consistently from one
organic molecule to another, and the number and
arrangement of the groups help give each molecule
its unique properties.
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Hydrophilic Functional Groups
e.g., ethanol
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Important of Functional Groups
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Hydrophilic Functional Groups
Know Example names structures at the level of
recognizing rather than regurgitating
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Hydrophilic Functional Groups
Amino groups function as weak bases
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Carbonyl Groups
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Carboxylic Acid Ionization
Typical physiological state
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Phosphoric Acid /Inorganic Phosphate
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Oxidation of Carbon (1/4)
C-H carbon bonded to hydrogen
C-OH carbon bonded to a hydroxyl group, an alcohol, for example, 3H-C-OH, for example
CO carbon double-bonded to oxygen, 2H-CO, for example
COOH carbon as part of a carboxyl group, HO-CO
CO2 carbon double-bonded, OCO, to two oxygen atoms
Increasing Oxidation
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Oxidation of Carbon (2/4)
structure name C-Hs Os C-Os
CH4 methane 4 0 0
CH3OH methanol 3 1 1
CH2O formaldehyde 2 1 2
H-COOH formic acid 1 2 3
CO2 carbon dioxide 0 2 4
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Oxidation of Carbon (3/4)

• As carbon becomes more oxidized the total energy
  associated with the bonds to carbon decrease
• Roughly, a carbon-containing molecule becomes
  more soluble in water the more oxygens associated
  with the molecule
• As organisms extract energy from
  carbon-containing molecules, they tend to remove
  hydrogen atoms and add oxygen atoms
• Ultimately, a molecule that contains abundant
  obtainable energy is oxidized down to the most
  oxidized common form of carbon, carbon dioxide
• Carbon dioxide, which contains no readily
  obtainable energy, is released as a waste product
  (e.g., you exhale)

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Oxidation of Carbon (4/4)
O- H-CO
H H H-C-O H
O-H H-CO
O-H H-CO
H H-CO
H H-C-H H
OCO
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Dysfunctional Groups
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Our First Lab

• Please read the assigned laboratory exercise
  before showing up for lab see laboratory
  schedule for the assignment
• Ultimately you will be tested in labs on your
  knowledge of your lab text the lab exams (2)
  will be open book
• I am looking for a conscientious participation in
  lab in which you read and following the
  directions in your lab text answer all questions
  except those I indicate not to (in lab schedule)
• Dont blow off labs earning the points
  associated with the lab portion of this course
  will require that you successfully engage your
  brain, as well as your body, during laboratory
  periods
• Our first lab, however, will be a particularly
  weird one, consisting mostly of my lecturing

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The End