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Chapter 4
Cool and Crazy Carbon
*Carbon is responsible for the large diversity of biological molecules.
I. Organic Molecules
*
*These compounds can contain thousands of atoms.
*Overall percentages of major elements (C,H,O,N,S,P) are the same
from one organism to the next. Because Carbon is so versatile, it can
used to build bzillions of organic molecules.
*Variations in organic molecules distinguish different species
II. Very Versatile Building Blocks
A. Chemical Structure
*Carbon has __electrons, __in the first shell, __in the outer
shell.
*So....Valence of Carbon is ___ (tetravalence)
*It can bond to four other molecules
*Carbon completes it’s valence by sharing electrons, forming
_____________ bonds
*Shape is a tetrahedron (109 )
*Most frequent partners are __________, ____________,
____________,
B. Simple Carbon Molecules
*CH4-*CO2-
**Chemical formula O=C=O
C. Complex Carbon Molecules
*Carbon can bond to other carbon molecules forming long chains
These are the skeletons of organic molecules
*Carbon skeletons can be ____________, ____________, or
arranged in ____________.
*Hydrocarbons: Long chains containing only carbon and hydrogen
*Major component of petroleum
*Not prevalent in living things, but some organic molecules,
like fat, have regions of hydrocarbons.
*Hydrocarbons are ____________ because the bonds are
____________.
be
*Store lots of energy (gas in a car, fat in animals)
III. Interesting Isomers
*Same molecular formula, but different structure and different
properties.
A. Structural Isomers
*
The longer the carbon skeleton, the more structural isomers.
*Location of double bonds can also differ
B. Geometric Isomers
*
*Result of inflexible double bonds (atoms attached to a double
bond can’t rotate freely)
*The different shapes affect biological activities.
ex. Vision involves light changing chemical rhodopsin from
one geometric isomer to another.
C. Enantiomers
*Mirror images formed when carbon is attached to four different
atoms. The middle Carbon is _______________!!
*Cells can distinguish enantiomers based on their different
shapes. One is “active” and the other is “inactive”.
ex. Pharmaceuticals....sometimes drug isomers produce no
effect or harmful effects on patients
IV. Functional Groups
*
*Number and arrangement of functional groups give molecules their
unique properties.
*
*Usually attached to a carbon on the skeleton
ex. Estradiol and Testosterone--have same structural backbone,
but different functional groups that cause one to take care
of feminine qualities and other one mighty maleness.
A. Hydroxyl -OH or -HO
*Organic compounds containing hydroxyl groups are called
____________
*Polar because O is really _______________!!!! This attracts
water molecules and helps dissolve
ex. Sugars
*
B. Carbonyl > CO
*Carbon atom joined to oxygen by a double bond
*Aldehydes:
*Ketones:
*Variations in location of carbonyl group is source of molecular
diversity
ex. Acetone (ketone) an Propanol (aldehyde) are structural
isomers with different properties
*
*
C. Carboxyl -COOH
*Oxygen double bonded to carbon that is also bonded to a hydroxyl
(-OH)
*Form ____________ ___________ (organic acids)
*Has acidic properties because it is a source of ____ ions. Bond
between O and H is so polar that hydrogen tends to dissociate.
ex. Acetic Acid (vinegar), substance in ant stings
*
D. Amino -NH2
*Nitrogen atom bonded to two hydrogen atoms and to carbon
skeleton
*Compounds of this group are called _____________.
*Acts as a base because NH2 is able to pick up H+ ions from the
surrounding solution and become NH3+. This lowers the H+
concentration!!!
ex. Amino Acids...The building blocks of proteins!!
*
E. Sulfhydryl -SH
*Sulfur atom bonded to an atom of hydrogen
*Organic compounds with this group are called ____________.
ex. Help stabilize protein structure
*
F. Phosphate -OPO32*Anion formed by dissociation of phosphoric acid (H3PO4)
*Loss of hydrogen ions by dissociation leaves phosphate with a
negative charge.
*Form ____________ ____________.
ex. Function in transfer of energy between organic
molecules, ATP (adenosine triphosphate)
G. Methyl -CH3
*Methyl group attached to carbon skeleton
ex. Methyl groups may be added to DNA to inactivate
certain genes
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