2 Organic ~ once alive or part of a living thing, carbon containing. Biosynthesis ~ the putting together of substances by living things.
3 Carbon is EssentialSymbolElementAbundance in human body (% weightOOxygen65CCarbon18HHydrogen10NNitrogen3CaCalcium2Carbon has 4 valence electrons, so it can form bonds with up to 4 other atoms.Often a carbon atom will form rings or chains with other carbon atoms, which form the backbone of most organic molecules.A Carbon atom can form double or even triple bonds with another carbon atom.
5 Functions of organic compounds: Structural ~ building blocks of a cellular or extracellular structureEnzymatic ~ are enzymes or help enzymes perform their functions.Storage ~ Can store:EnergySubstancesInformation for future use*Many organic compounds perform combinations of these functions.Four Main Groups of Organic Compounds:1. Carbohydrates2. Lipids3. Proteins4. Nucleic acids*They are often called macromolecules because of their large size
6 The building blocks are called monomers Monomers and PolymersThey are also called polymers because each class is made from identical building blocks strung togetherThe building blocks are called monomersMonosaccharides - CarbohydratesAmino Acids - ProteinsNucleotides - Nucleic Acids
7 Synthesis ~ process that forms a new substance Dehydration/Condensation and Hydrolysis Reactions(Making and Breaking Polymers)Monomers are linked together to form polymers through dehydration synthesis aka condensation reactions, which remove waterSynthesis ~ process that forms a new substancePolymers are broken apart by hydrolysis, the addition of water
8 Unlinked monomer Short polymer Figure 3.3A_s1 Figure 3.3A_s1 Dehydration reaction building a polymer chain (step 1)8
9 Dehydration reaction forms a new bond Figure 3.3A_s2Unlinked monomerShort polymerDehydration reaction forms a new bondFigure 3.3A_s2 Dehydration reaction building a polymer chain (step 2)Longer polymer9
10 Figure 3.3B_s1Figure 3.3B_s1 Hydrolysis breaking down a polymer (step 1)10
11 Hydrolysis breaks a bond Figure 3.3B_s2Hydrolysis breaks a bondFigure 3.3B_s2 Hydrolysis breaking down a polymer (step 2)11
12 Glucose Glucose Figure 3.5_s1 Figure 3.5_s1 Disaccharide formation by a dehydration reaction (step 1)12
13 Glucose Glucose Maltose Figure 3.5_s2GlucoseGlucoseFigure 3.5_s2 Disaccharide formation by a dehydration reaction (step 2)Maltose13
15 CarbohydratesOrganic compounds that only contain Carbon, Hydrogen and Oxygen.Carbohydrates are structural and energy storage compoundsTypes of Carbohydrates1) Monosaccharides ~ simple sugars that are the basic units of carbohydrates. May contain as few as 3 carbons, but the 5 or 6 carbon monosaccharides are important building blocks of other organic compounds.Monosaccharides have a 1 carbon : 2 hydrogen : 1 oxygen ratio.Ribose ~ common 5 carbon monosaccharideGlucose, galactose and fructose ~ common 6 carbon monosaccharides
16 Carbohydrates2. Disaccharide ~ two monosaccharides joined together by enzymesSucrose, maltose, and lactose ~ common disaccharides.Sucrose is table sugar.Many people are lactose intolerant because their bodies don’t produce lactase, which is an enzyme needed to break down lactose.3. Polysaccharide ~ large molecule made of many monosaccharides.Four Important Polysaccharides:Starch ~ used for energy storage for plants; major source of energy for animals.Glycogen ~ starches from plants are broken down and made into glycogen for temporary storage in animalsCellulose ~ chains of glucose molecules found in plant cell walls; structural; large molecules that most animals can’t digest.Chitin ~ strong, insoluble yet very flexible, similar to cellulose. One of the most abundant polysaccharides in nature, makes up the exoskeletons of arthropods (insects, crustaceans, spiders); structural
17 Starch granules in potato tuber cells Starch Figure 3.7Starch granules in potato tuber cellsStarchGlucose monomerGlycogen granules in muscle tissueGlycogenCellulose microfibrils in a plant cell wallCelluloseFigure 3.7 PolysaccharidesHydrogen bondsCellulose molecules17
19 LipidsGroup of organic substances which are only slightly soluble in water but are very soluble in organic solvents.Lipids function in structure and energy storage (just like carbohydrates).A gram of lipid contains much more potential energy than does a gram of carbohydrates.1. Fatty acids ~ the most abundant lipids, are unbranched chains of 14 to 28 carbon atoms that have a carboxyl group (COOH) added to one end.Hydrophilic ~ attracted to water (ex: carboxyl end of fatty acid)Hydrophobic ~ repelled by water (the opposite end of a fatty acid)*Fatty acids can be broken into many 2-carbon molecules pieces, which may release useable energy, which makes them a good energy source.
20 Lipids 2) Triglycerides Triglycerides ~ the body’s most abundant type of lipidTriglycerides are formed by 3 fatty acid molecules bonded to 3 carbons in a molecule of glycerol. (dehydration synthesis)Glycerol (glycerin) is a 3 carbon alcohol.
22 Saturated or Unsaturated Fats with the maximum number of hydrogens are called saturated fatty acids.Butter and lard are saturated fatsStudent Misconceptions and Concerns1. Students may struggle with the concept that a pound of fat contains more than twice the calories of a pound of sugar. It might seem that a pound of food would potentially add on a pound of weight. Other students may have never understood the concept of calories in the diet, simply following general guidelines of avoiding fatty foods. Furthermore, fiber and water have no caloric value but add to the weight of food. Consider class discussions that explore student misconceptions about calories, body weight, and healthy diets.2. Students might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on our heads remains flexible because of oils produced in our scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world.Teaching Tips1. The text in Module 3.8 notes the common observation that vinegar and oil do not mix in this type of salad dressing. A simple demonstration can help make this point. In front of the class, mix together colored water and a yellow oil (corn or canola oil work well). Shake up the mixture and then watch as the two separate. (You may have a mixture already made ahead of time that remains separated; however, the dye may bleed between the oil and the water.) Placing the mixture on an overhead projector or other well-illuminated imaging device makes for a dramatic display of hydrophobic activity!2. The text notes that a gram of fat stores more than twice the energy of a gram of polysaccharide, such as starch. You might elaborate with a simple calculation to demonstrate how a person’s body weight would vary if the energy stored in body fat were stored in carbohydrates instead. If a 100-kg man carried 25% body fat, he would have 25 kg of fat in his body. Fat stores about 2.25 times more energy per gram than carbohydrate. What would be the weight of the man if he stored the energy in the fat in the form of carbohydrate? (2.25 x 25 = kg of carbohydrate + 75kg (nonfat body weight) = kg, an increase of 31.25%)3. Margarine in stores commonly comes in liquid squeeze containers, in tubs, and in sticks. These forms reflect increasing amounts of hydrogenation, gradually increasing the stiffness from a liquid, to a firmer spread, to a firm stick of margarine. As noted in the text, recent studies have suggested that unsaturated oils become increasingly unhealthy as they are hydrogenated. Students might therefore remember that as margarine products increase in stiffness, they generally become less healthy. Public attention to hydrogenation and the health risks of the resulting trans fats are causing changes in the use of products containing trans fats.22
25 Lipids 3) Phospholipids structurally similar to fats Fats contain three fatty acids attached to glycerol.Phospholipids contain two fatty acids attached to glycerol and a phosphate attached to the other side of the glycerol.the major component of all cell membranes.Student Misconceptions and ConcernsStudents might struggle to extrapolate the properties of lipids to their roles in an organism. Ducks float because their feathers repel water instead of attracting it. Hair on our heads remains flexible because of oils produced in our scalp. Examples such as these help connect the abstract properties of lipids to concrete examples in our world.Teaching TipsBefore explaining the properties of a polar molecule such as a phospholipid, have students predict the consequences of adding phospholipids to water. See if the class can generate the two most common configurations: (1) a lipid bilayer encircling water (water surrounding the bilayer and water contained internally) and (2) a micelle (polar heads in contact with water and hydrophobic tails clustered centrally).25
26 Symbol for phospholipid Figure 3.9A-BPhosphate groupGlycerolWaterHydrophilic headsHydrophobic tailsSymbol for phospholipidWaterFigure 3.9A-B Detail of a phospholipid membrane26
27 Phosphate group Glycerol Hydrophilic head Hydrophobic tail Figure 3.9A Figure 3.9A Chemical structure of a phospholipid molecule27
29 Symbol for phospholipid Figure 3.9BWaterHydrophilic headHydrophobic tailSymbol for phospholipidFigure 3.9B Section of a phospholipid membraneWater29
30 Lipids4. Sterols ~ a lipid composed of four different carbon rings for its backbone and a side chain of carbons. They often combine with other substances to form hormones and other compounds.Ex: Cholesterol ~ found in the membranes of human and animal cells.