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

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Presentation on theme: "Chapter 4~ Carbon & The Molecular Diversity of Life Chapter 5~ The Structure & Function of Macromolecules."— 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 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 (-NH 2 ) –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 –CH 2 O (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 3 – 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 (NH 2 ), 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: –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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