i. chapter 5 summarysci.sdsu.edu/tfrey/biology203/ch5ch2onucleotideslipids.pdfi. chapter 5 summary...
TRANSCRIPT
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I. Chapter 5 Summary
A. Simple Sugars (CH2O)n:
1. One C contains a carbonyl (C=O) rest contain -OH
2. Classification by functional group: aldoses & ketoses
3. Classification by number of C's: trioses, pentoses, hexoses
4. Stereochemistry: all sugars have D conformation
5. Cyclic structure: -OH bonds to carbonyl carbon ==> 5- or 6-member ring
B. Disaccharides: 2 simple sugars joined by "glycosidic" bond between -OH of one and carbonyl of another
1. Table sugar 2 . M a l t o s e 3. Lactose
C. Polysaccharides
1. Food Storage: starch and glycogen are polymers of glucose
2. Structural: cellulose is polymer of glucose
3. Differ in conformation of carbonyl C where sugars are joined
II. Nucleotides & Nucleic Acids
A. Nucleotides: Base-sugar-phosphate
B. Nucleic Acids
1. Nucleotide polymer connected by phosphodiester bonds
2. RNA (RiboNucleic Acid)-nucleotides contain ribose sugar
3. DNA (DeoxyriboNucleic Acid)-nucleotides contain 2!-deoxy-ribose sugar
III. Lipids
A. Glycerides
1. Triglycerides: 3 fatty acids bonded to 3 -OH's of glycerol by ester bonds
2. Phospholipids: Diglycerides and Amphipathic (have polar and nonpolar groups)
3. Phospholipid bilayer
B. Cholesterol-sterol lipid
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Figure 4-02
In 1953 Stanley Miller simulated what were thought to be environmental conditions in the prebiotic earth.
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Water vapor
“Atmosphere”
Electrode
Condenser
Cold water
Cooled water
containing organic
molecules
Sample for chemical analysis
H2O “sea”
EXPERIMENT
CH4
Fig. 4-2: He created Building Block Molecules
Simple compounds: Formaldehyde & Hydrogen Cyanide More Complex Molecules: Amino Acids & Hydrocarbons
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Fig. 5.2a: Common Features of Macromolecules (a) Dehydration reaction: synthesizing a polymer
Short polymer Unlinked monomer
Dehydration removes a water molecule, forming a new bond.
Longer polymer
1 2 3 4
1 2 3
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(b) Hydrolysis: breaking down a polymer
1 2 3 4
1 2 3
Fig. 5.2b: Common Features of Macromolecules
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Monomer Simple Polymer Complex Polymer (Macromolecule)
Monosaccharide (Simple Sugar)
Oligosaccharide Polysaccharide
(Complex Carbohydrate)
Nucleotide Oligonucleotide Nucleic Acid
Amino Acid Peptide Polypeptide
Protein
Chapter 5: Biological Building Block Molecules are the units (Monomers) of Macromolecules
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What do Macromolecules Do?
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Common Features of Macromolecules - Shape
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Common Features of Macromolecules
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Fig. 2.18: Important Concept The Function of a macromolecule is determined by its
Molecular Shape (conformation) & Composition
Macromolecules such as proteins work by interacting with other molecules. These interactions depend on the molecules having complementary shapes that fit together (like a lock and key)
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Monomer Simple Polymer Complex Polymer (Macromolecule)
Monosaccharide (Simple Sugar)
Oligosaccharide Polysaccharide
(Complex Carbohydrate )
Nucleotide Oligonucleotide Nucleic Acid
Amino Acid Peptide Polypeptide
Protein
Chapter 5: Biological Building Block Molecules are the units (Monomers) of Macromolecules
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Number of Carbon atoms:
3 C’s Triose
4 C’s Tetrose
5 C’s Pentose
6 C’s Hexose
Note: suffix …ose indicates a sugar
R-C-R
O
R-C-H
O
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Aldose (Aldehyde Sugar) Ketose (Ketone Sugar)
D - Glyceraldehyde
Trioses: 3-carbon sugars (C3H6O3)
Dihydroxyacetone
Fig. 5.3a: Trioses
Chiral Carbon
D- because –OH is on the right
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L-Glyceraldehyde D-Glyceraldehyde
–OH is on the right D
–OH is on the left L
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4 Chiral Carbons
3 Chiral Carbons
3 Chiral Carbons
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Linear and ring forms
Pentoses and Hexoses form ring structures in water when one of the –OH groups forms a bond to the carbonyl group
Fig. 5.4a: Linear and ring forms of glucose
OH
CH2OH
O
OH OH
OH
OH
CH2OH
O
OH OH
OH
OH
OH-CH2
OH
OH
CH2OH
O
OH
OH-CH2
OH
OH O Assume C’s at vertices and H’s at ends of lines
α-D-Glucose β-D-Glucose β-D-Fructose β-D-Ribose
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Maltose Glucose Glucose
1–4 glycosidic
linkage
Figure 5.5a: Disaccharides
Table Sugar Glucose-Fructose
Milk Sugar Galactose-Glucose
Malt Sugar Glucose-Glucose
OH
CH2OH
O
OH OH
O OH
OH-CH2
OH
CH2OH
O
OH
CH2OH
O HO
OH
OH
CH2OH
O
OH OH
O O
OH
CH2OH
O
OH OH
OH
CH2OH
O
OH OH
O
O
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(a) α and β glucose ring structures
α Glucose β Glucose
(b) Starch: 1–4 linkage of α glucose monomers (b) Cellulose: 1–4 linkage of β glucose monomers
Figure 5.7: Polysaccharides – Starch & Cellulose
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Fig. 5.6: Starch & Glycogen – Food Storage Polysaccharides.
(a) Starch: a plant polysaccharide
(b) Glycogen: an animal polysaccharide
Chloroplast Starch granules
Mitochondria Glycogen granules
Amylopectin
Amylose
Glycogen
1 µm
0.5 µm
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LE 5-8
Cellulose molecules
Cellulose microfibrils in a plant cell wall
Cell walls Microfibril
Plant cells
0.5 µm
β Glucose monomer
Fig. 5.8: Structural Polysaccharides - Cellulose
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Chitin forms the hard exterior exoskeleton of insects
It is also used to make biodegradable surgical threads
β (14) Glycosidic Bond – similar to cellulose
Structural Polysaccharides - Chitin
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Lipids
Lipids are a diverse group of molecules that are primarily water-insoluble and include:
Fats Oils
Waxes Phospholipids
Steroids Carotenoids
Triglycerides
Biological Membranes
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Fatty Acids
Acyl chain (16 – 18 carbons)
Straight conformation Bent (kinked) conformation
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Fig 5.10: Triglycerides Triglycerides consist of 3 fatty acids bonded to the three
hydroxyl (-O-H) groups of a molecule of glycerol (ester bonds)
Dehydration (condensation) Reaction
Acyl chains can be saturated or unsaturated
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Structural formula of a saturated fat
molecule
Stearic acid, a saturated fatty acid
(a) Saturated fat
Structural formula of an unsaturated
fat molecule
Oleic acid, an unsaturated
fatty acid
(b) Unsaturated fat
cis double bond causes
bending
Fig 5.12: Triglycerides
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Fig 5.12: Phospholipids
Hydrophobic tails
Hydrophilic head
Fatty acids
Choline
Phosphate
Glycerol
Hyd
roph
obic
tails
H
ydro
phili
c he
ad
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Fig 5.13 / 7.2: Phospholipids Assemble to Form Membrane Bilayers
Fig 7.2
Phospholipid bilayers form impermeable membranes
that enclose and compartmentalize cells
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Fig 5.14: Steroids are lipid molecules (water insoluble) based on a hydrocarbon structure with four fused rings
The Polar -OH group makes this molecule amphipathic
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Monomer Simple Polymer Complex Polymer (Macromolecule)
Monosaccharide (Simple Sugar)
Oligosaccharide Polysaccharide
(Complex Carbohydrate)
Nucleotide Oligonucleotide Nucleic Acid
Amino Acid Peptid e Polypeptide
Protein
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Adenine
Phosphate
Adenosine 5’-monophosphate (AMP)
N-Glycosidic Bond
Phosphoester Bond
RNA RiboNucleic Acid
DNA DeoxyriboNucleic Acid
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Sugar-phosphate backbone 5′ end
5′C
3′C
5′C
3′C
3′ end
(a) Polynucleotide, or nucleic acid
(b) Nucleotide
Phosphate group Sugar
(pentose)
Nucleoside
Nitrogenous base
5′C
3′C
1′C
Nitrogenous bases
Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA)
Adenine (A) Guanine (G)
Sugars
Deoxyribose (in DNA) Ribose (in RNA)
(c) Nucleoside components
Pyrimidines
Purines
Fig. 5.26: The components of Nucleic Acids
Phosphodiester Bond
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Fig. 5.28: The DNA double helix and its replication.
Sugar-phosphate backbone
3′ end 5′ end
Base pair (joined by hydrogen bonding)
Old strands
Nucleotide about to be added to a new strand
5′ end
New strands
3′ end
5′ end 3′ end
5′ end