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Chapter 4~ Carbon & The Molecular Diversity of Life

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Presentation on theme: "Chapter 4~ Carbon & The Molecular Diversity of Life"— Presentation transcript:

1 Chapter 4~ Carbon & The Molecular Diversity of Life
Chapter 5~ The Structure & Function of Macromolecules

2 Organic chemistry Biological thought:
Vitalism (life force outside physical & chemical laws) – organic compounds can only arise in living organisms - Berzelius Mechanism (all natural phenomena are governed by physical & chemical laws) – organic compounds may be produced in lab - Miller Carbon Ability to branch in 4 directions allows large molecules possible Tetravalence, tetrahedron Shape determines function

3 Hydrocarbons Only carbon & hydrogen (petroleum; lipid ‘tails’)
Covalent bonding; nonpolar High energy storage Isomers (same molecular formula, but different structure & properties) 1. Structural~differing covalent bonding arrangement 2. Geometric~differing spatial arrangement 3. Enantiomers~mirror images pharmacological industry (thalidomide)

4 Functional Groups, I Attachments that replace one or more of the hydrogens bonded to the carbon skeleton of the hydrocarbon Each has a unique property from one organic to another 1. Hydroxyl Group H bonded to O (-OH); alcohols; polar (oxygen); solubility in water 2. Carbonyl Group C double bond to O At end of C skeleton - aldehyde - ex. proponal Within C skeleton – ketone – ex. acetone

5 Functional Groups, II 5. Sulfhydral Group 6. Phosphate Group
3. Carboxyl Group O double bonded to C to hydroxyl carboxylic acids, organic acids covalent bond between O and H is very polar leads to dissociation, H ion 4. Amino Group N to 2 H atoms (-NH2) Amines acts as a base 5. Sulfhydral Group sulfur bonded to H thiols 6. Phosphate Group phosphate ion covalently attached by 1 of its O to the C skeleton transfer energy

6 Polymers Macromolecules – may have thousands of linked molecules
Poly = many; mers = parts Covalent monomers link to form polymers Condensation reaction (dehydration reaction): One monomer provides a hydroxyl group while the other provides a hydrogen to form a water molecule Forms polymers Hydrolysis: bonds between monomers are broken by adding water (digestion) – aided by enzymes

7 Carbohydrates, I Monosaccharides CH2O (1:2:1) formula
Multiple hydroxyl (-OH) groups and 1 carbonyl (C=O) group Location determines if aldehyde (aldose) sugar or ketone (ketose) sugar Cellular respiration breaks them down Raw material for amino acids and fatty acids Ex. Glucose, fructose

8 Carbohydrates, II Disaccharides
Glycosidic linkage (covalent bond) between 2 monosaccharides No longer have 1:2:1 multiples – water is pulled out (condensation/ dehydration reaction) Sucrose (table sugar) -most common disaccharide

9 Carbohydrates, III Polysaccharides
Storage: Starch~ glucose monomers Plants: plastids Animals: glycogen Polysaccharides Structural: Cellulose~ most abundant organic compound; Chitin~ exoskeletons; cell walls of fungi; surgical thread

10 Lipids, I Fats, phospholipids, steroids
No polymers; glycerol and fatty acid Glycerol – alcohol w/ 3C each w/ hydroxyl group Fatty acid – long C chain w/ carboxyl group Non-polar C-H bonds in fatty acid ‘tails’ Cause to be hydrophobic Ester linkage: 3 fatty acids to 1 glycerol (dehydration formation) Triacyglycerol (triglyceride) Saturated (solid) vs. unsaturated (liquid) fats; single vs. double bonds

11 Lipids, II Phospholipids
2 fatty acids instead of – replaced by a phosphate group ‘Tails’ hydrophobic; ‘heads’ hydrophilic Micelle (phospholipid droplet in water) Form a bilayer (double layer) - cell membranes

12 Lipids, III Steroids Lipids with 4 fused carbon rings Ex: cholesterol:
Cell membranes Precursor for other steroids (sex hormones – estrogen, testosterone) Too mcuh = atherosclerosis – narrowing of vessel walls

13 Proteins, I Importance - instrumental in nearly everything organisms do; 50% dry weight of cells; most structurally sophisticated molecules known – enzymes, insulin, antibodies Monomer: amino acids (there are 20) Contain a carboxyl (-COOH) group, amino group (NH2), H atom, variable group (R – aka side chain – gives each its identity and properties) Variable group characteristics: polar (hydrophilic), nonpolar (hydrophobic), acid or base Three-dimensional shape – conformation – determines function Polypeptides (dehydration reaction) Joined by peptide bonds (covalent bond); carboxyl group to amino group (polar)

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

15 Proteins, III Secondary Structure
Conformation: coils & folds (hydrogen bonds) Alpha Helix: coiling; keratin Beta Pleated Sheet: parallel; silk

16 Proteins, IV Tertiary Structure
Conformation: irregular contortions from R group bonding hydrophobic disulfide bridges hydrogen bond ionic bonds

17 Proteins, V Quaternary Structure
Conformation: 2 or more polypeptide chains aggregated into 1 macromolecule collagen (connective tissue) hemoglobin Heat, pH, other body disturbances may denature protein (becomes inactive) – loses conformation

18 Nucleic Acids, I Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
DNA>RNA>protein Polymers of nucleotides (polynucleotide): nitrogenous base pentose – 5 carbon sugar phosphate group Nitrogenous bases: Pyrimidines – single ring ~cytosine, thymine (DNA), uracil (RNA) Purines – double ring~adenine, guanine

19 Nucleic Acids, II Pentoses: Polynucleotide: ribose (RNA)
deoxyribose (DNA) nucleoside (base + sugar) Polynucleotide: phosphodiester linkages (covalent) – btw phosphate + sugar

20 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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