The Chemistry of Life Elements C – carbon H – hydrogen O – oxygen 30/09/99 The Chemistry of Life Elements C – carbon H – hydrogen O – oxygen N – nitrogen P – phosphorus S – sulfur With T/F questions, these two PowerPoint files take full 2-hour period. Save other worksheet for tomorrow.

30/09/99 Major Macromolecules Macromolecules are large organic (carbon- containing) molecules. We will look at 4 kinds: Carbohydrates Lipids Proteins Nucleic Acids monomers formation (dehydration synthesis) breakdown (hydrolysis) monosaccharides fatty acids and glycerol amino acids nucleotides Many macro-molecules start as small monomers that grow into large polymers Point out unique properties of carbon that makes it ideal for macromolecules and therefore life. Biologically, any complex life form must be carbon based due to the need for complexity. H2O H2O polymer polysaccharides triglycerides polypeptides (proteins) nucleic acids (DNA, RNA)

Carbohydrates Elements Carbon (C), hydrogen (H), oxygen (O) Types 30/09/99 Carbohydrates Elements Carbon (C), hydrogen (H), oxygen (O) Types Monosaccharides (e.g. glucose, fructose) Disaccharides (e.g. sucrose) Polysaccharides: starch, glycogen, cellulose, chitin Functions Energy supply (not cellulose or chitin) & storage (glycogen in animals, starch in plants) Structural support in plant cell walls (cellulose) and other organisms, such as lobsters (chitin) Provides dietary fibre for humans Deoxyribose and ribose in DNA and RNA chitin is pronouncedˈkī-tən\. It is found in fungal cell walls and arthropod shells (crab, lobster). Maltose is two glucose molecules; lactose is a glucose and galactose Trivia The average Canadian consumes 57 kg of sugar every year. Inexpensive high-fructose corn syrup has replaced sucrose as a sweetener by some companies like Coke and Pepsi, adversely affecting the economy of Caribbean countries that produce sucrose from sugar cane. In its unmodified form, chitin is translucent, pliable, resilient and quite tough. In arthropods, however, it is often modified, becoming embedded in a hardened proteinaceous matrix, which forms much of the exoskeleton. In its pure form it is leathery, but when encrusted in calcium carbonate it becomes much harder.[1] The difference between the unmodified and modified forms can be seen by comparing the body wall of a caterpillar (unmodified) to a beetle (modified). Chitin digestion by humans has generally been questioned or denied. Only recently chitinases have been found in several human tissues and their role has been associated with defense against parasite infections and to some allergic conditions. In this pilot study we tested the gastric juices of 25 Italian subjects to demonstrate the presence of a chitinase activity. Since this chitinase activity was demonstrated at acidic pH, it is currently referred to acidic mammalian chitinase (AMCase). AMCase activity was present in gastric juices of twenty of 25 Italian patients in a range of activity from 0.21 to 36.27 nmol/ml/h and from 8,881 to 1,254,782 fluorescence emission (CPS), according to the used methods. In the remaining five of 25 gastric juices, AMCase activity was almost absent in both assay methods. The absence of activity in 20% of the gastric juices may be a consequence of virtual absence of chitinous food in the Western diet.

dehydration synthesis 30/09/99 Carbohydrates Monomer glucose Polymer Monosaccharides are added together via dehydration synthesis (a condensation reaction). glucose fructose sucrose water + monosaccharide disaccharide dehydration synthesis hydrolysis + H2O O OH HO Note that carbon appears at each corner, bend, or end when an element is not labelled. Polysaccharides form when this process is repeated. For example, with glucose…

30/09/99

Starch Glycogen Cellulose bonds connect long glucose chains 30/09/99 Starch bonds connect long glucose chains Glycogen bonds link glucose molecules Cellulose bonds in cellulose are hard to break

Lipids Elements C and H, some O (P, N in phospholipids) Types 30/09/99 Lipids Elements C and H, some O (P, N in phospholipids) Types Phospholipids Triglycerides Waxes Steroids Functions Long-term energy supply and storage Main structural component of cell membranes (as phospholipids and cholesterol) Hormones such as testosterone and estradiol Hydrophobic tails (nonpolar) Polar group Phosphate Glycerol Fatty acid chain Hydrophilic head (polar) Trivia Stored fat helps cushion and protect organs. Fat is the most concentrated form of energy. Unsaturated fatty acids tend to be liquid at room temperature because double bonds bend the molecule, preventing neighboring molecules from getting close and attracting. Fat cells have almost unlimited growth potential.

Fat molecule (triglyceride) 30/09/99 Lipids Monomer The closest thing to a monomer is a fatty acid: Fatty acid Glycerol Polymer Lipids do not form polymers in the same way that carbohydrates, proteins, and nucleic acids do. The largest lipids are triglycerides: Fat molecule (triglyceride) Note: fatty acids are different lengths and have different positions for double bonds. Note: some fatty acids (and some amino acids) are essential.

30/09/99 Lipids Fatty acids can be saturated with H (all single bonds) or unsaturated (some double bonds) A double bond introduces an inflexible kink to a molecule, preventing these molecules from getting close and making them more fluid above: saturated fatty acids, as in butter (all C–C bonds) right: unsaturated fatty acids, as in corn oil (some C=C bonds)

True or False Answers: 1 – 10 30/09/99 True or False Answers: 1 – 10 T – “organic” = “carbon-containing” (slide 2) F – monomers join via dehydration synthesis (2) F – cellulose is indigestible by humans (3) T – indigestible cellulose provides fibre (3) F – two monosaccharides together is a disaccharide; “poly” means three or more (4) T – types of macromolecules include proteins, carbohydrates, lipids, nucleic acids (2) F – only C, H, and O are present (3) T – types of polysaccharides include starch, glycogen, and cellulose (3) F – Cholesterol is a lipid (6) F – Fructose is a monosaccharide (4)

True or False Answers: 11 – 20 30/09/99 True or False Answers: 11 – 20 F – Phospholipids have two fatty acids (6) T – Both provide energy (3,6) T – DNA has deoxyribose, RNA has ribose (3) F – Triglycerides have 3 fatty acids. Note: “tri” = 3 and triglyceride = triacylglycerol (7) T – Listed as the second function of lipids (6) T – Look at the structure of glycerol; it has 3 carbons, 8 hydrogens, and 3 oxygens (7) F – Saturated fatty acids have all single bond (8) T – E.g., butter contains saturated fatty acids (8) F – Amino acids are monomers (2) T – Most bonds in unsaturated fatty acids are single, but the double bonds cause bends (8)

Elements in the Human Body 30/09/99 Elements in the Human Body Oxygen (65%), Carbon (18%), Hydrogen (10%) Nitrogen (3%) Calcium (1.5%) Phosphorus (1.0%) Potassium (0.35%) Sulfur (0.25%) Sodium (0.15%) Magnesium (0.05%) Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%) Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)

Elements in the Body Oxygen (65%) Carbon (18%) Hydrogen (10%) Nitrogen (3%) Calcium (1.5%) Phosphorus (1.0%) Potassium (0.35%) Sulfur (0.25%) Sodium (0.15%) Magnesium (0.05%) Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.7%) Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts) 30/09/99 Elements in the Body

30/09/99

30/09/99