2. Carbon
Carbon—The Backbone of
Biological Molecules
All living organisms are
made up of chemicals
based mostly on the
element carbon
Carbon Chains & Rings
ETC
skeletons of most organic
molecules
3. Importance of Carbon
70 to 95% of cells are water
Carbon makes up the rest of the compounds.
2/3 of our dry weight (mostly proteins)
Organic compounds can range from the
simple (CO2 or CH4) to complex molecules,
like proteins.
While the percentages of major elements do
not vary within or amongst species, variations
in organic molecules can distinguish even
between individuals of a single species.
5. Isomers
Isomers
Are molecules with the same molecular
formula but different structures and
properties
Three types of isomers are
Structural
Geometric
Enantiomers
6. H H H H H
H
H H H H H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
CO2H
CH3
NH2
C
CO2H
H
CH3
NH2
X X
X
X
C C C C C
C
C
C C C
C C C C
C
(a) Structural isomers
(b) Geometric isomers
(c) Enantiomers
See fig 4.8 pg 63
H
7. Intro. Cont………
Combinations of carbon and hydrogen form
hydrocarbons, many of which we use:
Gasoline propane ect….
Organic compounds also form biological
molecules: Macromolecules. Ex.
Carbohydrates, lipids, proteins, and nucleic
acids.
These macromolecules are made from simple
sugars, amino acids, nucleotides, and fatty
acids.
8. Functional Groups of Carbon compounds.
Functional groups
The number and arrangement of functional
groups help give each molecule its distinctive
properties
There are 7 functional groups that are
important to the chemistry of life: hydroxyl,
carbonyl, carboxyl, amino, sulfhydryl, methyl,
and phosphate groups.
13. Amino Group
An amino group (-NH2)
Amines are organic compounds with amino groups
Amino acids, the building blocks of proteins, have amino
and carboxyl groups.
14. A sulfhydryl group (-SH)
Sulfhydryl groups help stabilize the structure of
proteins.
Sulfhydryl group
15. Phosphate group
A phosphate group (-OPO3
2-) consists of phosphorus
bound to four oxygen atoms (three with single bonds and
one with a double bond).
Ex. ATP
16. Macromolecules Introduction
Cells join small molecules to form large
molecules.
Macromolecules, thousands of atoms and
weigh over 100,000 daltons.
The four major classes of macromolecules are:
carbohydrates, lipids, proteins, and nucleic
acids
They have very complex structures esp.
proteins
17. The Synthesis and Breakdown of
Polymers
Condensation or dehydration synthesis
reactions
(a) Dehydration reaction in the synthesis of a polymer
HO H
1 2 3 HO
HO H
1 2 3 4
H
H2O
Short polymer Unlinked monomer
Longer polymer
Dehydration removes a water
molecule, forming a new bond
18. Polymers can disassemble by
Hydrolysis
(b) Hydrolysis of a polymer
HO 1 2 3 H
HO H
1 2 3 4
H2O
H
HO
Hydrolysis adds a water
molecule, breaking a bond
Figure 5.2B
19. Carbohydrates
Carbohydrates or sugars can be simple or
complex.
Simple sugars are called Monosaccharides.
Disaccharides
Polysaccharides
Carbs. Are the most numerous molecules in
life.
22. Polysaccharides
Polysaccharides hundreds to thousands of
monosaccharides joined by glycosidic linkages
One function is to store energy or serve as
building materials for the cell or whole organism.
Starch composed entirely of glucose monomers.
(plants)
Animals too store glucose glycogen.
25. Chitin, another important structural
polysaccharide
O
CH2O
H
OH
H
H OH
H
NH
C
CH3
O
H
H
(b) Chitin forms the exoskeleton
of arthropods.
(c) Chitin is used to make a
strong and flexible surgical
thread that decomposes
after
the wound or incision heals.
OH
Figure 5.10 A–C
26. Lipids or FATS
Hydrophobic
Lipids have 1-3 fatty acids attached to a glycerol
molecule.
There are saturated and unsaturated fats. Saturated
fats have double bond and unsaturated do not.
Triglycerides -energy source.
Phospholipids
Sterols- they have no fatty acids. Ex. Cholesterol
29. Proteins
Proteins are influential in about everything
Functions include storage, structural support,
transport of other substances, intercellular
signaling, movement, and defense against foreign
substances.
Enzymes
Humans have an estimated 200,000 various
proteins,
Most structurally complex molecules known.
Polymers of amino acids
32. Amino Acid Polymers
Peptide bonds OH
DESMOSOMES
DESMOSOMES
DESMOSOMES
OH
CH2
C
N
H
C
H O
H OH OH
Peptide
bond
OH
OH
OH
H H
H
H
H
H
H
H
H
H H
H
N
N N
N N
SH Side chains
SH
O
O
O O O
H2O
CH2 CH2
CH2 CH2 CH2
C C C C C C
C C
C C
Peptide
bond
Amino end
(N-terminus)
Backbone
(a)
Figure 5.18 (b)
Carboxyl end
(C-terminus)
33. Function of Proteins
depends on shape.
function depends on its capacity to recognize and bind to some
other molecule.
AB, Enzymes, and NT all based on shape
36. Chaperonins
Are protein molecules that assist in the proper
folding of other proteins
Hollow
cylinder
Cap
Chaperonin
(fully assembled)
Steps of Chaperonin
Action:
An unfolded poly-
peptide enters the
cylinder from one end.
The cap attaches, causing
the cylinder to change shape in
such a way that it creates a
hydrophilic environment for the
folding of the polypeptide.
The cap comes
off, and the properly
folded protein is
released.
Correctly
folded
protein
Polypeptide
2
1
3
Figure 5.23
37. Protein structure can change
Changes.
pH, salt
concentration,
temperature, or
other factors
can unravel or
denature a
protein
mutation Pg 48
38. How do we Know
X-ray crystallography helps determine protein
conformation.
This technique requires the formation of a crystal
of the protein being studied.
The pattern of diffraction of an X-ray by the atoms
of the crystal can be used to determine the location
of the atoms and to build a computer model of its
structure.
39.
40. The Instructions for Life Nucleic Acids
There are two types of nucleic acids: ribonucleic
acid (RNA) and deoxyribonucleic acid (DNA).
DNA gives direction for its own replication,
repair, and control.
DNA also directs RNA synthesis and through
RNA, controls protein synthesis.
Organisms inherit DNA from their parents.
41. Nucleic Acids
Nucleic acids are many nucleotides joined
together.
Each nucleotide consists of three parts: a
nitrogen base, a pentose, 5 carbon, sugar, and a
phosphate group
Pyrimidines have a single six-membered ring.
CTU
Purine have a six-membered ring joined to a five-
membered ring. So have 2 rings not 1
AG
