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Moleculesof life
- 1. Chapter 3: The Molecules of Life 0
- 5. Would it be possible for ME to have lactose intolerance ?
- 9. Structural formula Ball-and-stick model Space-filling model Methane The four single bonds of carbon point to the corners of a tetrahedron.
- 11. SREMOSI!!
- 13. Carbon skeletons vary in length. Branching. Skeletons may be unbranched or branched. Butane Isobutane Propane Ethane Double bonds. 2-Butene Skeletons may have double bonds, which can vary in location. Cyclohexane Length. 1-Butene Benzene Skeletons may be arranged in rings. Rings.
- 14. Carbon skeletons vary in length. Propane Ethane Length.
- 15. Skeletons may be unbranched or branched. Butane Isobutane Branching.
- 16. Double bonds. 2-Butene Skeletons may have double bonds, which can vary in location. 1-Butene
- 17. Cyclohexane Benzene Skeletons may be arranged in rings. Rings.
- 21. You MUST know EVERYTHING on THIS slide!! This slide WILL be on the test… BTW… TEST on 12/14!!
- 25. Estradiol Male lion Testosterone Female lion
- 32. Unlinked monomer Short polymer
- 33. Unlinked monomer Short polymer Longer polymer Dehydration reaction
- 35. Hydrolysis A more betterer vid: http://www.youtube.com/watch?v=k_6bRcEVlcA
- 39. Glucose (an aldose) Fructose (a ketose)
- 40. Structural formula Abbreviated structure Simplified structure
- 42. Glucose Glucose
- 49. Starch granules in potato tuber cells Glycogen granules in muscle tissue Cellulose fibrils in a plant cell wall Cellulose molecules Glucose monomer GLYCOGEN CELLULOSE Hydrogen bonds STARCH This is Mr. Edgar.
- 50. Starch granules in potato tuber cells Glucose monomer STARCH
- 51. Glycogen granules in muscle tissue GLYCOGEN
- 52. Cellulose fibrils in a plant cell wall Cellulose molecules CELLULOSE Hydrogen bonds
- 61. Water Hydrophobic tails Hydrophilic heads Water
- 68. Carboxyl group Amino group
- 70. Leucine (Leu) Hydrophobic Serine (Ser) Hydrophilic Aspartic acid (Asp)
- 72. Carboxyl group Amino acid Amino group Amino acid
- 73. Carboxyl group Amino acid Amino group Amino acid Peptide bond Dipeptide Dehydration reaction
- 75. Groove
- 84. Four Levels of Protein Structure Amino acids Primary structure
- 85. Four Levels of Protein Structure Amino acids Primary structure Alpha helix Hydrogen bond Secondary structure Pleated sheet
- 86. Four Levels of Protein Structure Amino acids Primary structure Alpha helix Hydrogen bond Secondary structure Pleated sheet Polypeptide (single subunit of transthyretin) Tertiary structure
- 87. Four Levels of Protein Structure Amino acids Primary structure Alpha helix Hydrogen bond Secondary structure Pleated sheet Polypeptide (single subunit of transthyretin) Tertiary structure Transthyretin, with four identical polypeptide subunits Quaternary structure
- 88. Amino acids Primary structure
- 89. Amino acids Alpha helix Hydrogen bond Secondary structure Pleated sheet
- 90. Polypeptide (single subunit of transthyretin) Tertiary structure
- 91. Transthyretin, with four identical polypeptide subunits Quaternary structure
- 93. Phosphate group Nitrogenous base (adenine) Sugar
- 98. Base pair
- 101. Short polymer Monomer Hydrolysis Dehydration Longer polymer
- 106. Sucrose
- 108. Temperature (°C) 0 20 Rate of reaction Enzyme A 100 Enzyme B 40 60 80
Notas do Editor
- General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension.
- When a lactose-intolerant person ingests milk-based foods, the person will experience nausea, cramps, and bloating.
- The ability to bond in four directions is called tetravalence. This is one facet of carbon’s versatility that makes large, complex molecules possible. One of the great advantages of life based on carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.1 can thus easily be demonstrated (and consumed!).
- Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.1 can thus easily be demonstrated (and consumed!).
- Figure 3.1A Three representations of methane (CH 4 ). Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.1 can thus easily be demonstrated (and consumed!).
- Hydrocarbons are the major components of petroleum. Hydrocarbons consist of the partially decomposed remains of organisms that lived millions of years ago. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.1 can thus easily be demonstrated (and consumed!).
- You may want to give an example of an isomer. Students can relate to the isomers glucose and galactose, because both are energy sources for organisms. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. 2. Students might need to be reminded about the levels of biological organization. The relationship between atoms, monomers, and polymers can be confusing as each is discussed. Consider noting these relationships somewhere in the classroom (such as on the board) where students can quickly glance for reassurance. Teaching Tips 1. One of the great advantages of carbon is its ability to form up to four bonds, permitting the assembly of diverse components and branching configurations. Challenge your students to find another element that might also permit this sort of adaptability. (Like carbon, silicon has four electrons in its outer shell.) 2. Toothpicks and gumdrops (or any other pliable small candy) permit the quick construction of chemical models. Different candy colors can represent certain atoms. The model of the methane molecule in Figure 3.1 can thus easily be demonstrated (and consumed!).
- Figure 3.1B Variations in carbon skeletons.
- Figure 3.1B Variations in carbon skeletons.
- Figure 3.1B Variations in carbon skeletons.
- Figure 3.1B Variations in carbon skeletons.
- Figure 3.1B Variations in carbon skeletons.
- Functional groups may participate in chemical reactions or may contribute to function indirectly by their effects on molecular shape. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy relates the role of different functions with different structures. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy relates the role of different functions to different structures.
- Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy relates the role of different functions to different structures.
- You may want to add the methyl group as a functional group because of its importance in methylating certain compounds. For example, a methyl group on DNA may affect expression of genes. Another example is the arrangement of methyl groups in male and female sex hormones to affect their shape and function. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy relates the role of different functions to different structures.
- Table 3.2 Functional Groups of Organic Compounds.
- Table 3.2 Functional Groups of Organic Compounds.
- Table 3.2 Functional Groups of Organic Compounds.
- Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. A drill with interchangeable drill bits is a nice analogy to carbon skeletons with different functional groups. The analogy relates the role of different functions to different structures.
- Figure 3.2 Differences in the chemical groups of sex hormones.
- Figure 3.2 Differences in the chemical groups of sex hormones.
- Figure 3.2 Differences in the chemical groups of sex hormones.
- Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. Train cars linking together to form a train is a nice analogy to linking monomers to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus the reference to water production and a dehydration reaction when linking molecular monomers.
- Macromolecules are large and complex. A protein may consist of thousands of atoms that form a molecular colossus with a mass well over 100,000 daltons. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. Train cars linking together to form a train is a nice analogy to linking monomers to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus the reference to water production and a dehydration reaction when linking molecular monomers.
- As an example of the universality of monomers, the amino acids in your student’s proteins are the same ones found in a bacterium’s or plant’s proteins. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. Train cars linking together to form a train is a nice analogy to linking monomers to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus the reference to water production and a dehydration reaction when linking molecular monomers.
- The bulk of the organic material we ingest is in the form of polymers that are much too large to enter our cells. Within our digestive tract, various enzymes attack the polymers, speeding up hydrolysis. Student Misconceptions and Concerns 1. General biology students might not have previously taken a chemistry course. The concept of molecular building blocks that cannot be seen can be abstract and difficult to comprehend for such students. Concrete examples from our diets and good images will increase comprehension. Teaching Tips 1. Train cars linking together to form a train is a nice analogy to linking monomers to form polymers. Consider adding that as the train cars are joined, a puff of steam appears—thus the reference to water production and a dehydration reaction when linking molecular monomers.
- Figure 3.3A Dehydration reactions build a polymer chain.
- Figure 3.3A Dehydration reactions build a polymer chain.
- Figure 3.3B Hydrolysis breaks a polymer chain.
- Figure 3.3B Hydrolysis breaks a polymer chain.
- Monosaccharides have molecular formulae that are multiples of CH 2 O. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful, as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references. For example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). Teaching Tips 1. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen -> water + usable energy (used to build ATP) + heat + exhaling CO 2 .
- Figure 3.4A Bees with honey, a mixture of two monosaccharides.
- Monosaccharides, particularly glucose, are major nutrients for cells. Glucose is the starting compound for an important metabolic pathway called cellular respiration. If your lectures will eventually include details of cellular respiration (glycolysis or aerobic respiration), this is a good point to introduce the basic concepts of glucose as fuel. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful, as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references. For example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). Teaching Tips 1. If your lectures will eventually include details of glycolysis and aerobic respiration, this is a good point to introduce the basic concepts of glucose as fuel. Just introducing this conceptual formula might help: eating glucose + breathing in oxygen -> water + usable energy (used to build ATP) + heat + exhaling CO 2 .
- Figure 3.4B Structures of glucose and fructose.
- Figure 3.4C Three representations of the ring form of glucose.
- Sucrose is the sugar (disaccharide) we keep around the kitchen to sweeten coffee or use for dozens of other things. Student Misconceptions and Concerns 1. The abstract nature of chemistry can be discouraging to many students. Consider starting out this section of the lecture by examining the chemical groups on a food nutrition label. Candy bars with peanuts are particularly useful, as they contain significant amounts of all three sources of calories (carbohydrates, proteins, and lipids). 2. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references. For example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). Teaching Tips 1. Learning the definitions of word roots is invaluable when learning science. Learning the meaning of the prefix word roots “mono” (one), “di” (two), and “poly” (many) helps to distinguish the structures of various carbohydrates.
- Figure 3.5 Disaccharide formation by a dehydration reaction.
- Figure 3.5 Disaccharide formation by a dehydration reaction.
- The population of the United States eats more sweetener made from corn than from sugarcane or beets, gulping it down in drinks as well as in frozen food and baked goods. Even ketchup is laced with it. Student Misconceptions and Concerns 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references. For example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). Teaching Tips 1. The widespread use of high-fructose corn syrup can be surprising to students. Consider asking each student to bring to class a product label that indicates the use of high-fructose corn syrup (HFCS) as an ingredient. 2. Consider an assignment for students to access the Internet and find reliable sources that discuss high rates of sugar consumption in the modern diet. The key, of course, is in the quality of the resource. Consider limiting their search to established nonprofit organizations (American Cancer Society, American Heart Association, etc.) and peer-reviewed journals.
- Figure 3.6 HFCS, a main ingredient of soft drinks and processed foods.
- Animals and plants store sugars for later use. Plants store starch while animals store glycogen. Student Misconceptions and Concerns 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references. For example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). Teaching Tips 1. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 2. The text notes that cellulose is the most abundant organic molecule on Earth. Ask your students why this is true. 3. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper.) 4. An adult human may store about a half kilogram of glycogen in the liver and muscles of the body, depending upon recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors).
- Most mammals, including humans, do not have enzymes necessary to digest cellulose. Thus the energy in the glucose monomers is not available. Cows have solved this problem by harboring prokaryotes (bacteria) in their rumen that hydrolyze the cellulose of grass and hay to glucose monomers. The glucose can be used for energy as well as building blocks for other nutrients that nourish the cow. Likewise, termites cannot digest cellulose in wood, but the bacteria in their guts can, and so provide a meal for themselves as well as the termites The text notes that cellulose is the most abundant organic molecule on Earth. Ask your students why this is true. Student Misconceptions and Concerns 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references. For example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). Teaching Tips 1. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 2. The text notes that cellulose is the most abundant organic molecule on Earth. Ask your students why this is true. 3. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper.) 4. An adult human may store about a half kilogram of glycogen in the liver and muscles of the body, depending upon recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors).
- Student Misconceptions and Concerns 1. Consider reinforcing the three main sources of calories with food items that clearly represent each group. Bring clear examples to class as visual references. For example, a can of Coke or a bag of sugar for carbohydrates, a tub of margarine for lipids, and some beef jerky for protein (although some fat and carbohydrates might also be included). Teaching Tips 1. A simple exercise demonstrates the enzymatic breakdown of starches into sugars. If students place an unsalted cracker in their mouths, holding it in their mouths while it mixes well with saliva, they might soon notice that a sweeter taste begins to emerge. The salivary enzyme amylase begins the digestion of starches into disaccharides, which may be degraded further by other enzymes. These disaccharides are the source of the sweet taste. 2. The text notes that cellulose is the most abundant organic molecule on Earth. Ask your students why this is true. 3. The cellophane wrap often used to package foods is a biodegradable material derived from cellulose. Consider challenging students to create a list of other cellulose-derived products (such as paper.) 4. An adult human may store about a half kilogram of glycogen in the liver and muscles of the body, depending upon recent dietary habits. A person who begins dieting might soon notice an immediate weight loss of 2–4 pounds (1–2 kilograms) over several days, reflecting reductions in stored glycogen, water, and intestinal contents (among other factors).
- Figure 3.7 Polysaccharides
- Figure 3.7 Polysaccharides
- Figure 3.7 Polysaccharides
- Figure 3.7 Polysaccharides
- Lipids are generally not big enough to be macromolecules. They are grouped together because they mix poorly, if at all, with water. Student Misconceptions and Concerns 1. 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 Tips 1. 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 25 56.25 kg of carbohydrate 75 kg 131.25 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. Public attention to hydrogenation and the health risks of the resulting trans fats are causing changes in the use of products containing trans fats.
- Figure 3.8A Water beading on the only coating of feathers.
- Student Misconceptions and Concerns 1. 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 Tips 1. 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 25 56.25 kg of carbohydrate 75 kg 131.25 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. Public attention to hydrogenation and the health risks of the resulting trans fats are causing changes in the use of products containing trans fats.
- Figure 3.8B A dehydration reaction linking a fatty acid to glycerol.
- Figure 3.8C A fat molecule made from glycerol and three fatty acids.
- Most animal fat is saturated fat. Saturated fats, such as butter and lard, will pack tightly together and will be solid at room temperature. Plant and fish fats are usually unsaturated fats. They are usually liquid at room temperature. Olive oil and cod liver oil are examples. Peanut butter, margarine, and many other products are hydrogenated to prevent lipids from separating out in liquid (oil) form. Student Misconceptions and Concerns 1. 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 Tips 1. 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 25 56.25 kg of carbohydrate 75 kg 131.25 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. Public attention to hydrogenation and the health risks of the resulting trans fats are causing changes in the use of products containing trans fats.
- The phospholipid bilayer provides the cell with a structure that separates the outside from the inside of the cell. The integrity of the membrane is necessary for life functions. Because of the nature of the phospholipid, many molecules cannot move across the membrane without help. Student Misconceptions and Concerns 1. 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 Tips 1. Before 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 contained internally) and (2) a micelle (polar heads in contact with water and hydrophobic tails clustered centrally). 2. The consequences of steroid abuse will likely be of great interest to your students. However, the reasons for the damaging consequences might not be immediately clear. As time permits, consider noting the diverse homeostatic mechanisms that normally regulate the traits affected by steroid abuse.
- Figure 3.9A Section of a phospholipid membrane.
- Unfortunately, a high level of cholesterol in the blood can lead to atherosclerosis. This is a heart disease that results when deposits form in the arteries that supply the heart muscle with oxygen. The deposits block blood flow, and a heart attack results. Both saturated fats and trans fats promote higher levels of cholesterol. Student Misconceptions and Concerns 1. 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 Tips 1. Before 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 contained internally) and (2) a micelle (polar heads in contact with water and hydrophobic tails clustered centrally). 2. The consequences of steroid abuse will likely be of great interest to your students. However, the reasons for the damaging consequences might not be immediately clear. As time permits, consider noting the diverse homeostatic mechanisms that normally regulate the traits affected by steroid abuse.
- Figure 3.9B Cholesterol, a steroid.
- There are several important adverse consequences to steroid use to gain an athletic edge. Sports organizations and the public have come out against their use as a means to enhance performance. Athletic governing bodies prohibit their use. The consequences of steroid abuse will likely be of great interest to your students. However, the reasons for the damaging consequences might not be immediately clear. As time permits, consider noting the diverse homeostatic mechanisms that normally regulate the traits affected by steroid abuse.
- Figure 3.10UN Flexed biceps.
- Proteins account for more than 50% of the dry mass of cells. Teaching Tips 1. Many analogies help students appreciate the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words,” creating even more diversity. Another analogy is to trains. This builds upon the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20 100 , a number beyond imagination.
- Teaching Tips 1. Many analogies help students appreciate the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words,” creating even more diversity. Another analogy is to trains. This builds upon the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20 100 , a number beyond imagination. 2. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex!
- Figure 3.12A General structure of an amino acid.
- Teaching Tips 1. Many analogies help students appreciate the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words,” creating even more diversity. Another analogy is to trains. This builds upon the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20 100 , a number beyond imagination. 2. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex!
- Figure 3.12B Examples of amino acids with hydrophobic and hydrophilic R groups.
- Teaching Tips 1. Many analogies help students appreciate the diversity of proteins that can be made from just 20 amino acids. The authors note that our language uses combinations of 26 letters to form words. Proteins are much longer “words,” creating even more diversity. Another analogy is to trains. This builds upon the earlier analogy when polymers were introduced. Imagine making different trains about 100 cars long, using any combination of 20 types of railroad cars. Mathematically, the number of possible trains is 20 100 , a number beyond imagination. 2. The authors note that the difference between a polypeptide and a protein is analogous to the relationship between a long strand of yarn and a sweater knitted from yarn. Proteins are clearly more complex!
- Figure 3.12C Peptide bond formation. As more and more amino acids are added, a chain of amino acids called a polypeptide results. The combination of amino acids is determined by expression of genes on DNA. Although there seems to be an unlimited number of combinations of 20 amino acids, the combinations are limited in an individual because of inheritance.
- Figure 3.12C Peptide bond formation. As more and more amino acids are added, a chain of amino acids called a polypeptide results. The combination of amino acids is determined by expression of genes on DNA. Although there seems to be an unlimited number of combinations of 20 amino acids, the combinations are limited in an individual because of inheritance.
- Because of the molecular structure of specific proteins on brain cells, endorphins bind to them. This gives us a feeling of euphoria and pain relief. Morphine, heroin, and other opiate drugs are able to mimic endorphins and bind to the endorphin receptors in the brain. Because of the euphoria that results, we become addicted. Student Misconceptions and Concerns 1. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. Teaching Tips 1. Most cooking results in changes in the texture and color of food. The brown color of a cooked steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked.
- Figure 3.13B Space-filling model of lysozyme.
- Excessive heat can also denature a protein. A good example is frying or boiling an egg. The proteins in the egg “white” become solid, white, and opaque upon denaturation. Student Misconceptions and Concerns 1. The functional significance of protein shape is an abstract molecular example of form and function relationships, which might be new to some students. The binding of an enzyme to its substrate is a type of molecular handshake, which permits specific interactions. To help students think about form and function relationships, share some concrete analogies in their lives—perhaps flathead and Phillips screwdrivers that match the proper type of screws or the fit of a hand into a glove. Teaching Tips 1. Most cooking results in changes in the texture and color of food. The brown color of a cooked steak is the product of the denaturation of proteins. Fixatives such as formalin also denature proteins and cause color changes. Students who have dissected vertebrates will realize that the brown color of the muscles makes it look as if the animal has been cooked.
- For the BLAST Animation Alpha Helix, go to Animation and Video Files. Teaching Tips 1. Consider this assignment to review the organic molecules in our diets. Have students, working individually or in small groups, analyze a food label listing the components of a McDonalds’ Big Mac or other fast-food sandwich. Note the most abundant organic molecule class (perhaps by weight) found in each component.
- Sickle cell disease is manifested by an inability of hemoglobin in red blood cells to carry oxygen, the primary function of hemoglobin. This blood disorder is the result of change in a single amino acid. Teaching Tips 1. Consider this assignment to review the organic molecules in our diets. Have students, working individually or in small groups, analyze a food label listing the components of a McDonalds’ Big Mac or other fast-food sandwich. Note the most abundant organic molecule class (perhaps by weight) found in each component.
- Hydrogen bonding is an important component of the silk protein of a spider’s web. The many hydrogen bonds makes the web as strong as steel. Teaching Tips 1. Consider this assignment to review the organic molecules in our diets. Have students, working individually or in small groups, analyze a food label listing the components of a McDonalds’ Big Mac or other fast-food sandwich. Note the most abundant organic molecule class (perhaps by weight) found in each component.
- Figure 3.14UN01 Spider in web.
- Figure 3.14UN02 Collagen.
- Teaching Tips 1. Consider this assignment to review the organic molecules in our diets. Have students, working individually or in small groups, analyze a food label listing the components of a McDonalds’ Big Mac or other fast-food sandwich. Note the most abundant organic molecule class (perhaps by weight) found in each component.
- Misfolding of proteins cause diseases, such as Alzheimer’s and Parkinson’s. Both are manifested by accumulations of misfolded proteins. Consider an assignment to review the organic molecules in our diets. Have students, working individually or in small groups, analyze a food label listing the components of a McDonald’s Big Mac or other fast food sandwich. Note the most abundant organic molecule class (perhaps by weight) found in each component. For the BLAST Animation Protein Primary Structure, go to Animation and Video Files. For the BLAST Animation Protein Secondary Structure, go to Animation and Video Files. For the BLAST Animation Protein Tertiary Structure, go to Animation and Video Files. For the BLAST Animation Protein Quaternary Structure, go to Animation and Video Files. Teaching Tips 1. Consider this assignment to review the organic molecules in our diets. Have students, working individually or in small groups, analyze a food label listing the components of a McDonalds’ Big Mac or other fast-food sandwich. Note the most abundant organic molecule class (perhaps by weight) found in each component.
- Figure 3.14A Primary structure.
- Figure 3.14A Primary structure. Figure 3.14B Secondary structure.
- Figure 3.14A Primary structure. Figure 3.14B Secondary structure. Figure 3.14C Tertiary structure.
- Figure 3.14A Primary structure. Figure 3.14B Secondary structure. Figure 3.14C Tertiary structure. Figure 3.14D Quaternary structure.
- Figure 3.14A Primary structure.
- Figure 3.14B Secondary structure.
- Figure 3.14C Tertiary structure.
- Figure 3.14D Quaternary structure.
- Student Misconceptions and Concerns 1. Module 3.16 is the first time the authors present the concept of transcription and translation, discussed extensively in later chapters. The basic conceptual flow of information from DNA to RNA to proteins is essential to these later discussions. Teaching Tips 1. The “NA” in the acronyms DNA and RNA stands for “nucleic acid.” Students often do not make this association without assistance.
- Figure 3.16A A nucleotide, consisting of a phosphate group, sugar, and a nitrogenous base. Student Misconceptions and Concerns 1. Module 3.16 is the first time the authors present the concept of transcription and translation, discussed extensively in later chapters. The basic conceptual flow of information from DNA to RNA to proteins is essential to these later discussions. Teaching Tips 1. The “NA” in the acronyms DNA and RNA stands for “nucleic acid.” Students often do not make this association without assistance.
- Student Misconceptions and Concerns 1. Module 3.16 is the first time the authors present the concept of transcription and translation, discussed extensively in later chapters. The basic conceptual flow of information from DNA to RNA to proteins is essential to these later discussions. Teaching Tips 1. The “NA” in the acronyms DNA and RNA stands for “nucleic acid.” Students often do not make this association without assistance.
- Student Misconceptions and Concerns 1. Module 3.16 is the first time the authors present the concept of transcription and translation, discussed extensively in later chapters. The basic conceptual flow of information from DNA to RNA to proteins is essential to these later discussions. Teaching Tips 1. The “NA” in the acronyms DNA and RNA stands for “nucleic acid.” Students often do not make this association without assistance.
- Figure 3.16B Part of a nucleotide.
- Student Misconceptions and Concerns 1. Module 3.16 is the first time the authors present the concept of transcription and translation, discussed extensively in later chapters. The basic conceptual flow of information from DNA to RNA to proteins is essential to these later discussions. Teaching Tips 1. The “NA” in the acronyms DNA and RNA stands for “nucleic acid.” Students often do not make this association without assistance.
- Figure 3.16C DNA double helix.
- Student Misconceptions and Concerns 1. Module 3.16 is the first time the authors present the concept of transcription and translation, discussed extensively in later chapters. The basic conceptual flow of information from DNA to RNA to proteins is essential to these later discussions. Teaching Tips 1. The “NA” in the acronyms DNA and RNA stands for “nucleic acid.” Students often do not make this association without assistance.
- Mutations that lead to lactose tolerance are relativity recent events. The mutation was useful because it allowed people to drink milk when other foods were unavailable. In other words, it provided a survival advantage. Student Misconceptions and Concerns 1. The evolution of lactose tolerance within human groups in East Africa does not represent a deliberate decision, yet this evolutionary change appears logical. Many students perceive adaptations as deliberate events with purpose. As students develop a better understanding of the mechanisms of evolution, it will be important to point out that mutations arise by chance, with the culling hand of natural selection favoring traits that convey advantage. Organisms cannot plan evolutionary change. Teaching Tips 1. When discussing the sequence of nucleotides in DNA and RNA, consider challenging your students with the following questions based upon prior analogies. If the 20 possible amino acids in a polypeptide represent “words” in a long polypeptide sentence, how many possible words are in the language of a DNA molecule? (Four nucleotides, GCAT, are possible). Are these the same “words” used in RNA? (Answer: No. Uracil substitutes for thymine.)