AP Biology

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AP Biology

• Biochemistry Macromolecules
• Part 2

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Proteins
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LE 5-UN78
a carbon
Amino group
Carboxyl group
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Fig 5.17a
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Fig 5.17b
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Dehydration and HydrolysisReactions again
Short polymer
Unlinked monomer
Dehydration removes a water molecule, forming a
new bond
Longer polymer
Dehydration reaction in the synthesis of a polymer
Hydrolysis adds a water molecule, breaking a bond
Hydrolysis of a polymer
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Peptide Bonding
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Primary (1) sequence
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Primary Structure is IMPORTANT
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Sickle Cell and Oxygen transport
Normal hemoglobin
Sickle-cell hemoglobin
Primary structure
Primary structure
Val
His
Val
Leu
Thr
Pro
Glu
Glu
His
Leu
Thr
Pro
Val
Glu
1
2
3
4
5
6
7
1
2
3
4
5
6
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Exposed hydrophobic region
Secondary and tertiary structures
Secondary and tertiary structures
b subunit
b subunit
a
?
a
?
Quaternary structure
Normal hemoglobin (top view)
Quaternary structure
Sickle-cell hemoglobin
a
?
?
a
Function
Molecules do not associate with one another
each carries oxygen.
Function
Molecules interact with one another
to crystallize into a fiber capacity to carry
oxygen is greatly reduced.
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2 structure
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3 Structure
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4 Structure
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Proteins Natural Form
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Denaturation of a protein
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Chaperonin
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Nitrogen Cycle and Proteins
N2 in atmosphere
Assimilation
Denitrifying bacteria
NO3
Nitrogen-fixing bacteria in root nodules of
legumes
Decomposers
Nitrifying bacteria
Ammonification
Nitrification
NO2
NH4
NH3
Nitrogen-fixing soil bacteria
Nitrifying bacteria