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Macromolecules carbohydrates, lipids, proteins, nucleic acids
• Monomers and Polymers – dehydration reactions
• Carbohydrates – Sugars and starches
• Lipids – Fats and oils – Phospholipids – How soap works
• Start proteins, if time 10 Sept. 2021
Carbohydrates
Sugars Aldoses
(Aldehyde Sugars) Ketoses
(Ketone Sugars) Trioses: three-carbon sugars (C3H6O3)
Glyceraldehyde Dihydroxyacetone
Pentoses: five-carbon sugars (C5H10O5)
Ribose Ribulose
Hexoses: six-carbon sugars (C6H12O6)
Glucose Galactose Fructose
(Understand, but don�t memorize structures)
Monosaccharides
Glucose
Ribose
Figure 5.2 (a) Dehydration reaction: synthesizing a polymer
1 2 3
Dehydration removes a water molecule, forming a new bond.
1 2 3 4
H2O
(b) Hydrolysis: breaking down a polymer
1 2 3 4
H2O Hydrolysis adds a water molecule, breaking a bond.
1 2 3 H
Glucose
CH2OH H
2 1 2 1
Fructose
CH2OH
CH2OH
CH2OH CH2OH
CH2OH
Sucrose
OH
H
HO
H O O O
O
O
H2O
Simple sugars can be linked by Dehydration reactions
Sucrose is a common disaccharide:
Glucose+Fructose
2
Other common disaccharides
Do not memorize
Fig. 5-8 β Glucose monomer
Cellulose molecules
0.5 µm
10 µm
Cellulose
Small difference in structure, big difference in function.
Starch:
Cellulose:
Lipids (fats and oils)
http://www.johnnyjet.com/images/PicForNewsletterItalyMarch2005FRIEDDOUGHnLARD.JPG
Fried dough with lard . . . .
Fats or triglycerides (glycerol + 3 fatty acids)
Fat molecule
H H H H
H H H
H H
H H
H H
H H
H O
H O H C
C
C
H
H OH
OH
H
H H
H H
H H
H H
H H
H H
H H
H
H C C C
C C
C C
C C
C C
C C
C C C
Glycerol + Fatty acid
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 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 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 H
H H H H H H
H H H H H
H H
HO
O
O
O
O C
C
C C C C C C C C C C C C C C C C C
C
C C C C C C C
C C C C C C C C C
C C C C C C C C
C C C C
C C
C
O
O
Dehydration reaction
Figure 5.11 hydrophilic or hydrophobic?
FATS OILS Solid Liquid
WHY?
Saturated Unsaturated or
Polyunsaturated Like Fig 5-12
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What are trans fats? Polar (charged) Head
Very Hydrophobic Tail In water
they can form a “micelle” -- why?
“Amphipathic”
Fatty Acids
Why soap works
• Grease is attracted to the interior of the micele
Soap micele
Hydrophilic heads
Hydrophobic tails
Greasy mess on plate
• Phospholipids – Glycerol + 2 fatty acids + phosphate
CH2
O P O O O
CH2 CH CH2 O O
C O C O
Phosphate
Glycerol
(a) Structural formula
Fatty acids
Hyd
roph
obic
tails
–
Hyd
roph
ilic
head
CH2 Choline +
Figure 5.13
N(CH3)3
Hydrophilic �head� Hydrophobic �tails�
How will phospholipids behave in water?
Form Boundaries
Phospholipid Bilayer Proteins
What are some of the functions of proteins?
4
Can Keep adding to the end
R5 Oil OH Duracell
SH
Nonpolar Polar Charged
Polymers of Amino Acids • Amino Acids differ only by their �R� group • 20 kinds of amino acids
– Same chasis, different cargo
Nonpolar Side Chains
Glycine (Gly or G)
Alanine (Ala or A)
Valine (Val or V)
Leucine (Leu or L)
Isoleucine (Ile or I)
Methionine (Met or M)
Phenylalanine (Phe or F)
Tryptophan (Trp or W)
Proline (Pro or P)
Polar Side Chains
Serine (Ser or S)
Threonine (Thr or T)
Cysteine (Cys or C)
Tyrosine (Tyr or Y)
Asparagine (Asn or N)
Glutamine (Gln or Q)
Charged Side Chains
Basic (positively charged)
Acidic (negatively charged)
Aspartic acid (Asp or D)
Glutamic acid (Glu or E)
Lysine (Lys or K)
Arginine (Arg or R)
Histidine (His or H)
The amino and acid groups couple the monomers together
• Can make polymers that are 100s or 1000s of amino acids long
Can Keep adding to the end
R1 R2 R3 R4 R5
4 Levels of Structure
Secondary Structure: Local folding α helix and β sheet
Primary Structure: Amino acid sequence
Tertiary Structure: 3-D shape of one polypeptide Quaternary Structure:
Assembly of several polypeptides to form one functional protein
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Stopped here Nucleic Acids
ATP
Nucleotides have three components
• Sugar • Base • Phosphate
Use dehydration reactions to connect these molecules
Carbons in the sugar are numbered with primes
3� 2�
Nucleotides
Purines Pyrimidines
A, G C, T, U
The bases each have a polar edge for
hydrogen bonding
Thymine
Cytosine
Adenine
Guanine
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The nucleotide ATP is a common energy carrier
Also GTP, CTP, etc.
These are high-energy phosphate bonds
Polynucleotide (DNA, RNA) chains are assembled by yet another type of dehydration reaction
• Link the -OH on the 3� carbon of one nucleotide
• to the phosphate on the 5� carbon of the next.
5� end
3� end
RNA DNA DNA copying is the basis of heredity
The sequences of bases is the hereditary information
Flow of information
DNA --> RNA --> Protein
Stopped here
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