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 Fig. 4.2: In 1953 Stanley Miller simulated what were thought to be Figure 4-02 environmental conditions in the prebiotic earth. 1 Chapter 5: Biological Building Block Molecules (Monomers) and Macromolecules Complex Polymer Monomer Simple Polymer (Macromolecule) Monosaccharide Polysaccharide Oligosaccharide (Simple Sugar) (Complex Carbohydrate) Nucleotide Oligonucleotide Nucleic Acid Polypeptide Amino Acid Peptide Protein What do Macromolecules Do? Carbohydrates & Lipids: Important Functions fuel molecules for energy structural roles Nucleic Acids: Store, Transmit, and Decode Hereditary Information (also some structural roles) Proteins: Perform an incredible number of functions! structural proteins transport proteins enzymes hormones & signaling molecules storage proteins receptor proteins contractile & motor proteins defense proteins 2 Fig. 5.2: Common Features of Macromolecules 1. Proteins, carbohydrates and nucleic acids are complex polymer molecules created by joining together building blocks called monomers 5 6 7 Monomers are linked by a condensation reaction (a dehydration reaction that produces H2O) Fig. 5.2 Common Features of Macromolecules 2. Protein, carbohydrate and nucleic acid polymer molecules are broken down into monomers by hydrolysis of the bonds between monomers Hydrolysis adds a water molecule, breaking a bond 3 Common Features of Macromolecules 3. Protein, carbohydrate and nucleic acid polymer molecules can fold into complex 3-dimensional shapes (specific shape depends on sequence of monomers) Ionic bonds, Hydrogen bonds and Van der Waal’s interactions are important in specifying and maintaining shape Common Features of Macromolecules 4. Protein, carbohydrate, lipids and nucleic acids can associate with each other and with other types of molecules via specific intermolecular interactions Molecular shape, Ionic bonds, Hydrogen bonds and Van der Waal’s interactions are important to determine strength and specificity of interactions 4 Fig. 2.17: 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) Chapter 5: Biological Building Block Molecules (Monomers) and Macromolecules Complex Polymer Monomer Simple Polymer (Macromolecule) Monosaccharide Polysaccharide Oligosaccharide (Simple Sugar) (Complex Carbohydrate ) Nucleotide Oligonucleotide Nucleic Acid Polypeptide Amino Acid Peptide Protein 5 Carbohydrates: Contain Carbon, Hydrogen and Oxygen in the ratio CH2O Monomers: The simplest Carbohydrates are the Simple Sugars, these are classified by: O Type of Carbonyl group Ketone Ketose R-C-R O Aldehyde Aldose or by R-C-H 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 Trioses Aldose Ketose All sugars, except Di-hydroxy acetone, can have D or L optical isomers, although only the D isomers exist naturally. L-Glyceraldehyde D-Glyceraldehyde 6 Common Simple Sugars Trioses Pentoses Hexoses Fig. 5.4a: Linear and ring forms of glucose Pentoses and Hexoses form ring structures in water when one of the –OH groups forms a bond to the carbonyl group Linear and 2 forms, β and α ring forms 7 Figure 5.5a: Disaccharides 1–4 glycosidic linkage Glucose Glucose Maltose Disaccharides contain two simple sugars joined by a Glycosidic Bond Common Disaccharides Malt Sugar Milk Sugar Table Sugar Glucose-Glucose Galactose-Glucose Glucose-Fructose Polysaccharides (Glycans): Starch and Glycogen: Fuel storage polysaccharides α (14) Glycosidic Bond Cellulose: Structural polysaccharide β (14) Glycosidic Bond 8 FLEig 5-6. 5.6: Food Storage Polysaccharides - Starch and Glycogen Chloroplast Starch Mitochondria Glycogen granules 0.5 µm 1 µm Amylose Amylopectin Glycogen Starch: a plant polysaccharide Glycogen: an animal polysaccharide LE 5-8 Fig. 5.8: Structural Polysaccharides - Cellulose Cellulose microfibrils in a plant cell wall Cell walls Microfibril 0.5 µm Plant cells Cellulose molecules β Glucose monomer 9 Structural Polysaccharides - Chitin β (14) Glycosidic Bond Chitin forms the hard exterior exoskeleton of insects It is also used to make biodegradable surgical threads Nucleotides / Nucleic Acids Complex Polymer Monomer Simple Polymer (Macromolecule) Monosaccharide Polysaccharide Oligosaccharide (Simple Sugar) (Complex Carbohydrate) Nucleotide Oligonucleotide Nucleic Acid Polypeptide Amino Acid Peptid e Protein 10 Nucleotides: Adenine consists of three components: •Nitrogenous base, Adenine in this example Phosphate •A sugar: ribose or 2’-deoxyribose •Phosphate N-Glycosidic Bond Adenosine 5’-monophosphate (AMP) Phosphoester Bond RNA DNA Fig. 5.26a: The components of Nucleic Acids 5′ end Nucleoside Nitrogenous base Phosphodiester Bond Phosphate group Pentose sugar Nucleotide 3′ end Polynucleotide, or Nucleic Acid 11 Fig. 5.26b: Nucleoside Components Nitrogenous bases Pyrimidines Cytosine Thymine (in DNA) Uracil (in RNA) C T U Purines Adenine Guanine A G Pentose sugars Deoxyribose (in DNA) Ribose (in RNA) Nucleoside components Fig. 5.27: The DNA double helix and its replication. 5′ end 3′ end Sugar-phosphate backbone 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 5′ end 3′ end 12 Lipids Lipids are a diverse group of molecules which are primarily water-insoluble and include: Fats triglycerides Oils Waxes Phospholipids Biological Steroids Membranes Carotenoids Fatty acids are the building blocks of lipids Fatty Acids Saturated fatty acids: Unsaturated fatty acids: No double bonds between One or more double bonds adjacent carbon atoms between adjacent carbon atoms Acyl chain (16 – 18 carbons) Straight Bent (kinked) conformation conformation 13 Fig 5.11 & 5.12: Triglycerides Triglycerides consist of 3 fatty acids bonded to the three hydroxyl (-O-H) groups of a molecule of glycerol (ester bonds) Fats = triglycerides from animals with mostly saturated fatty acids (condensation reaction) Oils = triglycerides from Acyl chains can be saturated plants with mostly unsaturated or unsaturated fatty acids Fig 5.13: Phospholipids Hydrophilic head 2 Hydrophobic tails Phospholipds are amphipathic molecules (contain both hydrophilic and hydrophobic parts) 14 Fig 5.14 / 7.2: Phospholipids Assemble to Form Membrane Bilayers Fig 7.2 Phospholipid bilayers form impermeable membranes that enclose and compartmentalize cells Steroids are lipid molecules (water insoluble) based on a hydrocarbon structure with four fused rings Cholesterol is the most common steroid and is found in membranes Cortisol, Estrogen and Testosterone are steroid The Polar -OH group makes hormones this molecule amphipathic 15.