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Chapter 5
Macromolecules
Macromolecules
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Four Classes
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids
Polymer
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Chain of linked monomers
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polymer
Carbohydrates
Proteins
Nucleic acids
monomer
sugar
amino acids
nucleotides
Composite molecule

Lipids
glycerol + fatty acid(s)
Bonds
macromolecule
Carbohydrates
Lipids
Proteins
Nucleic acids
bond/link type
glycosidic linkage
ester linkage
peptide bond
phosphodiester bond
Chemical Reactions
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Dehydration synthesis (Condensation) - remove
a water molecule, polymerize
Requires enzymes
HO
1
2
3
H
H
OH
short polymer
H20
HO
1
2
longer polymer
3
4
H
Chemical Reactions
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Hydrolysis - add a water molecule, depolymerize
HO
H
H2O
HO
H
OH
H
Metabolism
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Anabolism - synthesize molecules
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polymerization
dehydration
Catabolism - breakdown molecules
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depolymerization
hydrolysis
Carbohydrates
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CHO sugars
function: energy storage (fuel for cellular
work), most are hydrophilic
three groups:
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monosaccharides
disaccharides
polysaccharides
Monosaccharides
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empirical formula = (CH2O) n
n = 3 to 7
n=5
pentose
n=6
hexose
Examples of hexoses (C6H12O6)
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glucose
fructose
galactose
Disaccharides
monosaccharides
glucose + glucose =
glucose + galactose =
glucose + fructose =
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disaccharide
maltose
lactose
sucrose
formed through dehydration
Formation of Disaccharaides
glucose
glucose
glucose
fructose
maltose
sucrose
Polysaccharide
Covalently bonded glucose units
Glycosidic linkage - covalent bond between glucose units
Glycogen
(animals)
Starch
(plants)
glycogen
granules
amylose
(unbranched)
amylopectin
Cellulose
cell wall
cellulose microfibrils in a plant
cell wall (about 8O molecules)
unbranched,
alternating OH groups
found in plant cell walls
unbranched β glucose
polymer
Chitin
Present in exoskeleton of
arthropods
Glucose plus a nitrogen apendage
used to make strong and flexible surgical thread
Lipids
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CHO
Function: long-term energy storage
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fats
other lipids: phospholipids, steroids, pigments
water-insoluble, nonpolar
Fats
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Glycerol + fatty acid (s)
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monoglyceride
diglyceride
triglyceride
monoglyceride
(palmitic acid)
glycerol - 3C alcohol
trigryceride (triacylglycerol)
Fats, cont.
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ester linkage - bond between carboxyl (f.a.)
and hydroxyl (glycerol)
fatty acids
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saturated
unsaturated
esther linkage
Saturated Fatty Acids
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maximum number of H
no double/triple bonds
usually solid
ex. animal fats
(butter, lard)
Unsaturated Fatty Acids
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usually liquid
1 double bond
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more than 1 double bond
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monounsaturated
polyunsaturated
ex. Oils (nut and seed)
hydrogenation causes it
to solidify
peanut oil peanut butter
fats yeald 9 cal/gr
oleic acid
Other Lipids
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Phospholipids
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Steroids
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phosphate + 2 f.a. + glycerol
Hormones and cholesterol
Pigments
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chlorophylls
xanthophylls
carotenes
anthocyanins
hydrophilic
hydrophobic
choline
phosphate
glycerol
fatty acids
Proteins
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CHON
Function: diverse
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structures, contraction, storage, defense,
transport, messengers, enzymes
monomer: amino acid
Proteins cont.
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amino acids (20):
most contain
-central C
-amino group
-carboxyl group
-H atom
-functional group (R)
R-group
Non polar
glycine
alanine
methionine
valine
phenylalanine
leucine
tryptophan
isoleusine
proline
polar
serine
threonine cysteine tyrosine aspargine glutamine
acidic
basic
electrically
charged
asparctic ac. glutamic acid
lysine
arginine
histine
Proteins cont.
*Peptide bonds
*between 2 amino acids
*dehydration reaction
protein synthesis
side chain
backbone
Levels of Protein Structure
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The following determine the shape of the
protein (polypeptides):
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primary
secondary
tertiary
quaternary
Primary Structure of a Protein
Start: N-terminus (amino)
End: C-terminus (carboxyl)
+H3N
(amino end)
amino acid subunits
(carboxyl end)
O
C OH-
Secondary Structure of a Protein
Bending and H-bonding to form coils and folds forming
alpha helices (coils) and beta pleated sheets (folds)
β pleated sheet
α- helix
Tertiary Structure of a Protein
overall conformation of the polypeptide
 hydrophobic interactions
 ionic and hydrogen bonds
 disulfide bridges
polypeptide
backbone
Quaternary Structure of a Protein
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Relationship between 2 or more polypeptides
that make up the protein
Protein Conformation
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Altering any level will change the final
conformation
denaturation - unravel the protein
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caused by several different factors
Nucleic Acids
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CHONP
Function: store information
monomer - nucleotide
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ex. DNA, RNA
RNA Genomics - branch of biotech concerned
with mapping and sequencing DNA (genomes)
Nucleotide
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Phosphate + sugar + N-base
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phosphodiester bond
between phosphate and sugar
DNA
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nucleus
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Deoxyribonucleic acid
double strand
A, G, C, T
nucleotide: phosphate + sugar + N-base
The sequence of nitrogenous bases in DNA
carries genetic information
stretches of DNA are genes
RNA
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cytoplasm
Ribonucleic acid
single strand RNA
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nucleotide: phosphate + sugar +
A, G, C, U
N-base
N-bases
Purines (A, G)
Pyrimidines (C, T, U)
Purine-Pyrimidine
=T
C=G
A
Activity: DNA
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What will the other strand be?
5'
A
3'
DNA
?
G
?
C
?
T
?
DNA
Activity
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What will the RNA strand be?
5'
A
3'
DNA
The End
?
G
?
C
?
T
?
RNA