1. Lecture #2 Date ______
Chapter 4~ Carbon & The Molecular Diversity of Life
Chapter 5~ The Structure & Function of Macromolecules

2. Organic chemistry
Carbon tetravalence tetrahedron shape determines function

3. Hydrocarbons Isomers! (Link)
Only carbon & hydrogen (petroleum; lipid ‘tails’)
Covalent bonding;
Essentially nonpolar
High energy storage
Isomers (same molecular formula, but different structure & properties)
3 types of Isomers are:
Structural ~ differing covalent bonding arrangement
Geometric ~ differing spatial arrangement around a double bond
Enantiomers ~ mirror images
Difference around the asymmetrical carbon
Isomers! (Link)

4. Functional Groups, I Hydroxyl Group H bonded to O
Very polar (oxygen is much more electronegative than hydrogen);
soluble in water
The main functional group of ALCOHOLS
Carbonyl Group
C double bonded to O
Also very polar/soluble
Main functional group of SUGARS
At end : aldehyde
Otherwise: ketone
Attachments that replace one or more of the hydrogen(s) bonded to the carbon skeleton of the hydrocarbon
These regions are commonly reactive.
Each has a unique property and behave consistently from one organic molecule to another.

5. Functional Groups, II Carboxyl Group Amino Group N to 2 H atoms;
Sulfhydral Group
sulfur bonded to H
Attract each other to help stabilize proteins
(disulfide bridges)
thiols
Phosphate Group phosphate ion
covalently attached:
1 of its O to the C skeleton
Polar/hydrophilic
Important in cellular energy & transfer
Carboxyl Group
O double bonded to C to hydroxyl
Main functional group of carboxylic acids
H in the OH extremely polar dissociates to form H ion
Amino Group N to 2 H atoms;
amines
acts as a base (+1)
Converts to NH3 as it
accepts protons
Functional Groups Link

6. Polymers Most Macromolecules are POLYMERS:
Large molecules consisting of many identical or similar subunits called:
Monomers (different kinds of monomers for different kinds of polymers)
Condensation reaction (dehydration reaction):One monomer provides a hydroxyl group while the other provides a hydrogen to form a water molecule
Hydrolysis: bonds between monomers are broken by adding water (digestion)
Campbell Link

7. Carbohydrates (Sugars, etc…)
Monomer = “monosaccharide”
Used for energy & structure
“-ose” ending!
-OH attached to all carbons except 1which has a carbonyl (C=O) group
Monosaccharides are 3-7 carbons in size:
Most common: Triose-3 ; Ribose-5 ; Hexose-6
Form rings in aqueous solutions
Monosaccharides link to form….

8. Disaccharides Disaccharides
glycosidic linkage:
(covalent bond) between 2 monosaccharides
covalent bond by dehydration reaction
Sucrose (table sugar) most common disaccharide
There are also “Trisaccharides”, and even “Oligosaccharides”
Once you get more than a couple dozen in a row, you then call them…..

9. Polysaccharides: 100s to 1000s of linked Monosaccharides
Polysaccharides Storage:
Plants: Starch
can be used for energy by animals
Straight chains of glucose
Animals: Glycogen
Highly branched chains of glucose
Polysaccharides Structural:
Cellulose~ what plants are mostly made of…
Earth’s most abundant organic compound!
Chitin~ exoskeletons; cell walls of fungi; surgical thread
Campbell Link

10. Lipids No long chain polymers; glycerol and fatty acid
Fats, phospholipids, steroids
Hydrophobic; H bonds in water exclude fats
Carboxyl group = fatty acid
Non-polar C-H bonds in fatty acid ‘tails’
Ester linkage: 3 fatty acids to 1 glycerol (dehydration formation)
Triacyglycerol (triglyceride)
Saturated vs. unsaturated fats; single vs. double bonds

11. Lipids, II

12. Phospholipids 2 fatty acids instead of 3 (phosphate group)
‘Tails’ hydrophobic; ‘heads’ hydrophilic
Micelle (phospholipid droplet in water)
Bilayer (double layer); cell membranes
Hydrophilic head
Considered “Amphipathic”:
One part hydrophobic, one part Hydrophilic
Hydrophobic Tail

13. Steroids Lipids with 4 fused carbon rings
Ex: cholesterol: cell membranes; precursor for other steroids (sex hormones); atherosclerosis
Campbell Link

14. Proteins
Importance: instrumental in nearly everything organisms do; 50% dry weight of cells; most structurally sophisticated molecules known
Monomer: amino acids (there are 20) ~
carboxyl (-COOH) group, amino group (NH2), H atom, variable group (R)….
Variable group characteristics: polar (hydrophilic), nonpolar (hydrophobic), acid or base
hyperlink
Three-dimensional shape (conformation)
Polypeptides (dehydration reaction): peptide bonds~ covalent bond; carboxyl group to amino group (polar)

15. Proteins: Primary Structure
Conformation: Linear structure
Molecular Biology: each type of protein has a unique primary structure of amino acids
Amino acid substitution: hemoglobin; sickle-cell anemia

16. Proteins: Secondary Structure
Conformation:
coils & folds (hydrogen bonds)
2 main types of 2ndary structures:
Alpha Helix: coiling; keratin
Pleated Sheet: parallel; silk

17. Proteins: Tertiary Structure
Conformation: irregular contortions from R group bonding √hydrophobic √disulfide bridges √hydrogen bonds √ionic bonds

18. Proteins: Quaternary Structure
Conformation:
2 or more polypeptide chains aggregated into macromolecule √collagen (connective tissue) √hemoglobin
Campbell Link

19. Nucleic Acids, I Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
DNA RNA  protein
Polymers of nucleotides (polynucleotide): nitrogenous base pentose sugar phosphate group
Nitrogenous bases: pyrimidines~cytosine, thymine, uracil purines~adenine, guanine

20. Nucleic Acids, II
Pentoses: √ribose (RNA) √deoxyribose (DNA) √nucleoside (base + sugar)
Polynucleotide: √phosphodiester linkages (covalent); phosphate + sugar

21. Nucleic Acids, III Inheritance based on DNA replication
Double helix (Watson & Crick ) H bonds~ between paired bases van der Waals~ between stacked bases
A to T; C to G pairing
Complementary
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