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Chapter 4: Carbon and the Molecular Diversity of Life. Essential Knowledge. 1.d.1 – There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence (4.1). - PowerPoint PPT Presentation
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Chapter 4: Carbon and the
Molecular Diversity of Life
Essential Knowledge 1.d.1 – There are several hypotheses
about the natural origin of life on Earth, each with supporting scientific evidence (4.1).
2.a.3 – Organisms must exchange matter with the environment to grow, reproduce, and maintain organization (4.1 & 4.2).
Organic Chemistry The study of carbon compounds. Usually involves the study of living
things
Major Elements Of Organic Molecules Carbon: +4 or -4 Hydrogen: +1 Oxygen: -2 Nitrogen: -3
Hydrocarbons Organic
molecules made of only carbon and hydrogen.
Carbon’s versatility Forms 4 covalent bonds
(because it has 4 valence e-)
Molecular shape is tetrahedral
Bonds very easily to itself
Carbon, continued Can form nearly 10 million
compounds 15 known isotopes: C-14 (age of
fossils), C-13, C-12 Naturally occurring in hardest
(diamonds) and one of softest (graphite) forms on Earth
Carbon, continued Very small size (capable of forming
multiple bonds) Major economic use—petroleum,
other fossil fuels Others: pencil “lead”, steel, charcoal,
medicine
Organic Isomers Compounds with the same molecular
formula but have different structures. Result: Different molecular and
chemical properties.
Which of these are isomers?
No Yes
Yes No
3 Types Of Isomers1. Structural2. Geometric (cis/trans)3. Enantiomers
1. Structural Isomers Different in covalent arrangements
of their atoms.
Butane Isobutane
2. Geometric Isomers Same covalent partnership but differ
in spatial arrangements. Arise from the inflexibility of double
bonds. Also known as cis/trans isomers
3. Enantiomers Molecules
that are mirror images of each other.
Usually involve an asymmetric carbon.
Comment Organisms are sensitive to even the
most subtle variations in molecular architecture.
This is why isomers (and their shape/characteristics) are critical to biochemistry
Example - Thalidomide Cells can’t distinguish between two
isomers. One is an effective drug. The other causes birth defects. Used (in 1970s) as a “cure” for mornin
g sickness
Functional Groups A group of atoms attached to a
carbon skeleton. Have consistent properties. Their number and kind give
properties to the molecule.
Importance of Functional Groups
Figure 4.9
Memorize!!!
Hydroxyl Group A hydrogen atom bonded to an
oxygen atom. Ex. -OH Very polar. Allows the material to be
hydrophilic. Forms alcohols.
Carbonyl Group A carbon atom joined to an oxygen
atom by a double bond. Ex. - C=O Polar tendencies Two types of Carbonyl Group
compounds:• Aldehydes• Ketones
Carbonyl: Aldehydes A carbonyl group at the end of a
carbon skeleton. Ex. - C=O
H
Sometimes written as - CHO
Carbonyl: Ketones A carbonyl group in the middle of a
carbon chain. Ex. -C-C-C- || O
Carboxyl Group Group with a carbon double
bonded to an oxygen and to a hydroxyl group.
Ex. - C=O| OH
Written as: -COOH Also called Carboxylic Acids
• Donate H+ (acid).• Form many weak organic acids.
Amino Group Nitrogen bonded to two hydrogens.
Ex. – N-H
| H Forms compounds called amines. Act as a base. IF combined with
carboxyl, can act as an acid!• Ex: amino acids
Sulfhydryl Group Sulfur bonded to a hydrogen. Ex. -SH Forms compounds called thiols. Help with protein structure. Acidic properties
Phosphate Group Phosphorus with four oxygens. Ex. -PO4 Has a net -2 charge. Sometimes written as “Pi”. Involved with energy transfers.
Methyl Group Carbon bonded to three hydrogens. -
CH3 Very non-polar and hydrophobic. Ex: fossil fuels (any other
hydrocarbon)
Summary Identify what is meant by organic
chemistry. Recognize the valences for the major
elements of organic molecules. Recognize various types of isomers. Identify the functional groups and
their structure and properties.
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