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Chapter 4
Carbon and the Molecular
Diversity of Life
PowerPoint® Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 4-2 If Miller had
increased the
concentration of NH3 in
his experiment, how might
the relative amounts of the
products HCN and CH2O
have differed?
EXPERIMENT
“Atmosphere”
Water vapor
CH4
Electrode
Condenser
Cooled water
containing
organic
molecules
H2O
“sea”
Sample for
chemical analysis
Cold
water
Fig. 4-4 Refer to Figure 2.9 and draw the Lewis dot structures for sodium, phosphorus, sulfur, and chlorine.
Hydrogen
(valence = 1)
Oxygen
(valence = 2)
Nitrogen
(valence = 3)
Carbon
(valence = 4)
H
O
N
C
Molecular Diversity Arising from Carbon Skeleton
Variation
Animation: Carbon Skeletons
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 4-5a Why are these molecules called hydrocarbons?
Ethane
(a) Length
Propane
Fig. 4-5b What do these hydrocarbons illustrate?
Butane
(b) Branching
2-Methylpropane
(commonly called isobutane)
Fig. 4-6 What happens to the hydrocarbon tails of a fat molecule?
Fat droplets (stained red)
100 µm
(a) Mammalian adipose cells
(b) A fat molecule
Isomers
Animation: Isomers
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 4-7a Underline/highlight why these two molecules are structural isomers.
Pentane
(a) Structural isomers
2-methyl butane
Fig. 4-7b Highlight/underline why these two molecules are geometric isomers.
cis isomer: The two Xs are
on the same side.
(b) Geometric isomers
trans isomer: The two Xs are
on opposite sides.
Fig. 4-7c There are three structural isomers of C5H12. Draw the one not shown in (a).
L isomer
(c) Enantiomers
D isomer
Animation: L-Dopa
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 4-8 What is the pharmacological importance of enantiomers?
Drug
Condition
Ibuprofen
Pain;
inflammation
Albuterol
Effective
Enantiomer
Ineffective
Enantiomer
S-Ibuprofen
R-Ibuprofen
R-Albuterol
S-Albuterol
Asthma
Fig. 4-9 True or False. The function of these two molecules differ because of the number of ring structures present.
Estradiol
Testosterone
Fig. 4-10c Organic acid or base?
Carboxyl
STRUCTURE
Carboxylic acids, or organic
acids
EXAMPLE
Has acidic properties
because the covalent bond
between oxygen and hydrogen
is so polar; for example,
Acetic acid, which gives vinegar
its sour taste
Acetic acid
Acetate ion
Found in cells in the ionized
form with a charge of 1– and
called a carboxylate ion (here,
specifically, the acetate ion).
NAME OF
COMPOUND
FUNCTIONAL
PROPERTIES
Fig. 4-10d Organic acid or base?
Amino
STRUCTURE
NAME OF
COMPOUND
Amines
EXAMPLE
Acts as a base; can
pick up an H+ from
the surrounding
solution (water, in
living organisms).
Glycine
Because it also has a
carboxyl group, glycine
is both an amine and
a carboxylic acid;
compounds with both
groups are called
amino acids.
(nonionized)
(ionized)
Ionized, with a
charge of 1+, under
cellular conditions.
FUNCTIONAL
PROPERTIES
Fig. 4-10e How does it affect protein structure?
Sulfhydryl
STRUCTURE
Thiols
NAME OF
COMPOUND
(may be
written HS—)
EXAMPLE
Two sulfhydryl groups
can react, forming a
covalent bond. This
“cross-linking” helps
stabilize protein
structure.
Cysteine
Cysteine is an important
sulfur-containing amino
acid.
Cross-linking of
cysteines in hair
proteins maintains the
curliness or straightness
of hair. Straight hair can
be “permanently” curled
by shaping it around
curlers, then breaking
and re-forming the
cross-linking bonds.
FUNCTIONAL
PROPERTIES
Fig. 4-10f How does its negative charge affect its ability to interact with water?
Phosphate
STRUCTURE
Organic phosphates
EXAMPLE
Glycerol phosphate
In addition to taking part in
many important chemical
reactions in cells, glycerol
phosphate provides the
backbone for phospholipids,
the most prevalent molecules in
cell membranes.
Contributes negative charge
to the molecule of which it is
a part (2– when at the end of
a molecule; 1– when located
internally in a chain of
phosphates).
Has the potential to react
with water, releasing energy.
NAME OF
COMPOUND
FUNCTIONAL
PROPERTIES
Fig. 4-10g Describe the two functional properties of the methyl group
Methyl
STRUCTURE
Methylated compounds
EXAMPLE
NAME OF
COMPOUND
FUNCTIONAL
PROPERTIES
5-Methyl cytidine
5-Methyl cytidine is a
component of DNA that has
been modified by addition of
the methyl group.
Fig. 4-Predict which of the following molecules would be the stronger acid. Explain your answer.