Download Ch.05The Structure and Function of Large Biological Molecules

1
2
3
H
Short polymer
HO
Dehydration removes a water
molecule, forming a new bond
HO
2
1
H
Trioses (C3H6O3)
Pentoses (C5H10O5)
Hexoses (C6H12O6)
Unlinked monomer
3
H 2O
4
Aldoses
HO
H
Glyceraldehyde
Longer polymer
(a) Dehydration reaction in the synthesis of a polymer
Ribose
Glucose
1
2
3
4
Hydrolysis adds a water
molecule, breaking a bond
HO
1
2
3
H
H 2O
HO
Galactose
H
Ketoses
HO
Dihydroxyacetone
H
Ribulose
Fructose
(b) Hydrolysis of a polymer
1
2
1–4
glycosidic
linkage
Glucose
Glucose
Maltose
(a) Dehydration reaction in the synthesis of maltose
1–2
glycosidic
linkage
(a) Linear and ring forms
(b) Abbreviated ring structure
Glucose
Fructose
Sucrose
(b) Dehydration reaction in the synthesis of sucrose
3
Chloroplast
4
Mitochondria Glycogen granules
Starch
(a) α and β glucose
ring structures
0.5 µm
α Glucose
β Glucose
1 µm
(b) Starch: 1–4 linkage of α glucose monomers
Glycogen
Amylose
(b) Cellulose: 1–4 linkage of β glucose monomers
Amylopectin
(a) Starch: a plant polysaccharide
(b) Glycogen: an animal polysaccharide
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6
Cell walls
Cellulose
microfibrils
in a plant
cell wall
Microfibril
10 µm
0.5 µm
Cellulose
molecules
β  Glucose
monomer
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8
Fatty acid
(palmitic acid)
Glycerol
(a) Dehydration reaction in the synthesis of a fat
Ester linkage
(b) Chitin forms the
exoskeleton of
arthropods.
(c) Chitin is used to make
a strong and flexible
surgical thread.
(b) Fat molecule (triacylglycerol)
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Hydrophilic head
Structural
formula of a
saturated fat
molecule
10
Stearic acid, a
saturated fatty
acid
(a) Saturated fat
Structural formula
of an unsaturated
fat molecule
Hydrophobic tails
(a) The structure
of the chitin
monomer.
Oleic acid, an
unsaturated
fatty acid
(a) Structural formula
Choline
Phosphate
Glycerol
Fatty acids
Hydrophilic
head
Hydrophobic
tails
(b) Space-filling model
(c) Phospholipid symbol
cis double
bond causes
(b) Unsaturated fat
bending
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12
Hydrophilic
head
Hydrophobic
tail
WATER
WATER
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Substrate
(sucrose)
Glucose
Enzyme
(sucrase)
OH
H2O
Fructose
H
O
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Nonpolar
α carbon
Glycine
(Gly or G)
Valine
(Val or V)
Alanine
(Ala or A)
Methionine
(Met or M)
Leucine
(Leu or L)
Trypotphan
(Trp or W)
Phenylalanine
(Phe or F)
Isoleucine
(Ile or I)
Proline
(Pro or P)
Polar
Serine
(Ser or S)
Threonine
(Thr or T)
Cysteine
(Cys or C)
Tyrosine
(Tyr or Y)
Asparagine Glutamine
(Asn or N) (Gln or Q)
Electrically
charged
Amino
group
Acidic
Carboxyl
group
Aspartic acid Glutamic acid
(Glu or E)
(Asp or D)
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Basic
Lysine
(Lys or K)
Arginine
(Arg or R)
Histidine
(His or H)
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Peptide
bond
(a)
Groove
Groove
Side chains
Peptide
bond
(a)
A ribbon model of lysozyme
(b)
A space-filling model of lysozyme
Backbone
(b)
Amino end
(N-terminus)
Carboxyl end
(C-terminus)
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Antibody protein
20
Protein from flu virus
Primary
Structure
Secondary
Structure
Tertiary
Structure
Quaternary
Structure
β pleated sheet
+H N
3
Amino end
Examples of
amino acid
subunits
α helix
21
Hydrophobic
interactions and
van der Waals
interactions
22
Polypeptide
chain
β Chains
Polypeptide
backbone
Hydrogen
bond
Disulfide bridge
Iron
Heme
α Chains
Hemoglobin
Ionic bond
Collagen
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Normal hemoglobin
Primary
structure
1
2
3
4
5
6
7
Secondary
and tertiary
structures
Sickle-cell hemoglobin
Primary
structure
Val
His
Leu
Thr
Pro
Glu
Glu
β subunit
Val
His
Leu
Thr
Pro
Val
Glu
1
2
3
4
5
6
7
Secondary
and tertiary
structures
Exposed
hydrophobic
region
β subunit
Denaturation
Normal
hemoglobin
(top view)
Quaternary
structure
β
Function
α
β
α
Quaternary
structure
β
Sickle-cell
hemoglobin
α
β
α
Function
Molecules do
not associate
with one
another; each
carries oxygen.
Molecules
interact with
one another and
crystallize into
a fiber; capacity
to carry oxygen
is greatly reduced.
Normal protein
10 µm
Red blood
cell shape
Normal red blood
cells are full of
individual
hemoglobin
moledules, each
carrying oxygen.
Denatured protein
Renaturation
10 µm
Red blood
cell shape
Fibers of abnormal
hemoglobin deform
red blood cell into
sickle shape.
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DNA
1
Synthesis of
mRNA in the
nucleus
Correctly
folded
protein
Polypeptide
mRNA
Cap
NUCLEUS
CYTOPLASM
Hollow
cylinder
mRNA
Chaperonin
(fully assembled)
Steps of Chaperonin 2
The cap attaches, causing the 3
Action:
cylinder to change shape in
such a way that it creates a
1
An unfolded polyhydrophilic environment for
peptide enters the
cylinder from one end.
the folding of the polypeptide.
2
Movement of
mRNA into cytoplasm
via nuclear pore
The cap comes
off, and the properly
folded protein is
released.
Ribosome
3
Synthesis
of protein
Amino
acids
Polypeptide
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5' end
5ʹ′ end
Nitrogenous bases
Pyrimidines
5ʹ′C
Sugar-phosphate
backbones
3ʹ′C
Base pair (joined by
hydrogen bonding)
Nucleoside
Nitrogenous
base
Cytosine (C)
Thymine (T, in DNA)
Uracil (U, in RNA)
Old strands
Purines
Phosphate
group
5ʹ′C
(b) Nucleotide
3ʹ′C
3' end
Nucleotide
about to be
added to a
new strand
Sugar
(pentose)
3' end
Adenine (A)
Guanine (G)
Sugars
3ʹ′ end
5' end
(a) Polynucleotide, or nucleic acid
New
strands
Deoxyribose (in DNA)
Ribose (in RNA)
5' end
3' end
(c) Nucleoside components: sugars
5' end
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3' end
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