1. Biology Sylvia S. Mader Michael Windelspecht
Chapter 3
The Chemistry of Organic Molecules
Part 2
Mills Biology 2012
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2. Lipids Phospholipids Important in animal cell walls
Water soluble because of hydrophillic phosphate group
Molecule has a hydrophillic and a hydrophobic end
Amphipathic – has both polar and nonpolar regions
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3. Lipids Phospholipids
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4. Fig. 3.11 Phospholipids Form Membranes outside cell inside cell
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Fig. 3.11
Phospholipids Form Membranes
glycerol O
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
Polar
Head
CH2
CH2
CH2
CH3 1
CH2 C O
fatty acids 2 O
CH2 O R O P O 3
CH2 C
CH2
CH2
CH2
CH2
CH2
CH2
CH2 CH CH O
CH2
Nonpolar Tails
CH2
phosphate
CH2
CH2 a.
Phospholipid structure
CH2
CH2
CH2
CH3
inside cell
outside cell
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b. Plasma membrane of a cell .

5. Lipids Steroids Have a different structure than other lipids
Backbone is made of four carbon rings
Cholesterol, vit D, and many hormones (testosterone, estrogen)
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6. © Ernest A. Janes/Bruce Coleman/Photoshot
Steroid Diversity
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. OH
CH3
CH3 O b . T e s t o s t e r o n e
CH3 HC
CH3
(CH2)3 OH HC
CH3
CH3
CH3
CH3 HO HO c.
Estrogen a.
Cholesterol
© Ernest A. Janes/Bruce Coleman/Photoshot
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7. 3.4 Proteins Proteins perform many functions Support
Enzymes/Metabolism
Transport
Defense
Hormones/Regulation
Motion
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8. Proteins Contain C,H,O,N +\- S and P
Structural, hormones, enzymes, receptors, antibodies
Made up of amino acids (20 different amino acids)
Amino acids joined by peptide bonds
Length can vary from 100 a.a. to thousands
Have primary, secondary and tertiary shape (structure)
Denaturing can change structure back to primary
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9. Proteins show great variety
Some structural proteins: hair, horn and spider web silk.
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10. How many different proteins could be formed from 20 amino acids?
Proteins – amino acids
COOH = carboxyl group
How many different proteins could be formed from 20 amino acids?
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11. Proteins – peptide bond
Dipeptide vs polypeptide?
What is the name of this synthesis process?
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12. Insulin is composed of an A chain of 21 amino acids and a B chain of 30 amino acids, the chains being held together by two disulfide bonds. A third disulfide bond is present within the A chain.
Insulin is an anabolic signal. The binding of the hormone to its receptor initiates a series of events within the cells that results in the increased uptake of glucose into the cells, where it is converted into metabolic energy or stored as glycogen and fat.
What was the first protein to have it’s primary structure mapped?
How long did it take?
The hormone, insulin, in It took Frederick Sanger(won Nobel Prize in Chemistry in 1958 AND 1980) 10 years to determine the sequence!
Proteins – structure
                                           
Thank You Fred!
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13. Proteins – Structure Primary – order of a.a.
Secondary – 3 dimensional shape that results from H bonds
Alpha helix
Pleats
Tertiary structure – 3 dimensional shape
Globular proteins
H bonding
Hydrophobic effect
Ionic bonding
Disulfide bonds
Quaternary structure – made of 2 or more peptide chains
Example – hemoglobin made from 4 globular proteins
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14. Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H3N+
Primary Structure
This level of structure
is determined by the
sequence of amino
acids coded by a
gene that joins to
form a polypeptide.
amino acid
peptide bond
COO– C O CH C
hydrogen bond O C N O CH R C C C N H N C CH R
hydrogen bond R H O H O C C O C H R R C C N O C O H R H N C CH H N N C N H C C CH R C O O O R O H C C N N H R R O C N H R H N H C
Secondary Structure O C O R CH C C O C N R
Hydrogen bonding
between amino acids
causes the polypeptide
to form an alpha helix
or a pleated sheet. CH R C C N C O N H H R N N C R CH C C O O H N
α alpha) helix
Β (beta) sheet = pleated sheet
Tertiary Structure
Interactions of amino
acid side chains with
water, covalent bonding
between R groups, and
other chemical interactions
determine the folded
three-dimensional shape
of a protein.
disulfide bond
Quaternary Structure
This level of structure
occurs when two or more
folded polypeptides interact
to perform a biological function.

15. Protein-Folding Diseases
Biology, 9th ed,Sylvia Mader
Chapter 03
Slide #15
Protein-Folding Diseases
Organic Chemistry
Chaperone proteins help proteins fold into their normal shape.
Defects in chaperone proteins may play a role in several human diseases such as Alzheimer disease and cystic fibrosis.
Prions are misfolded proteins that have been implicated in a group of fatal brain diseases known as TSEs.
Mad cow disease is one example of a TSE disease. 15

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17. Proteins – Structure - denaturing
When get perm-breaks disulfide bonds and then makes new ones that are not aligned.
The amino acid cysteine has an “R” group that ends with a sulfhydryl (-SH). Often form disulfa bonds between amino acid chains.
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19. Proteins – simple mistake-big problem
Glutamic acid and Valine are amino acids.
Can you identify the disease?
Sickle Cell Disease
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For more info:

20. Sample Amino Acids with Nonpolar (Hydrophobic) R Groups
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Sample Amino Acids with Nonpolar (Hydrophobic) R Groups H O H H O O H
H3N+ O C C
H3N+ C C
H3N+ C C H O O O
H3N+ O
CH2
H2N+ C C
(CH2)2
CH2 C C O O CH CH S
H2C
CH2
CH3
CH3
CH3
H3C
CH2
CH3
valine (Val)
methionine (Met)
phenylalanine (Phe)
leucine (Leu)
proline (Pro)
Sample Amino Acids with Polar (Hydrophilic) R Groups H O H O H O H O
H3N+ C C
H3N+ C C
H3N+ C C
H3N+ C C O O
CH2 O O CH
CH2
(CH2)2 SH OH C
cysteine (Cys)
serine (Ser) H O
NH2 O OH
glutamine (Gln)
H3N+ C C H O
tyrosine (Tyr) O
H3N+ C C
CH2 O CH C
NH2 O OH
CH3
asparagine (Asn)
threonine (Thr)
Sample Amino Acids with Ionized R Groups H O H O H O
H3N+ C C
H3N+ C C H H O O O
H3N+ C C
CH2
(CH2)3 O
H3N+ C C
H3N+ C C O O
CH2
CH2 O
CH2 NH
CH2 NH
CH2
CH2 C C
N+H2
COO-
N+H3 O O
NH2
N+H
glutamicacid (Glu)
lysine (Lys)
aspartic acid (Asp)
arginine (Arg)
histidine (His)