Macromolecules 1 Carbohydrates, Lipids & Nucleic Acids

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1 VEA Bringing Learning to Life Program Support Notes Macromolecules 1 Carbohydrates, Lipids & Nucleic Acids Grades 10 - College 25mins Teacher Notes by Sue Wright, B. Sc., Dip. Ed. Produced by VEA Pty Ltd Commissioning Editor Christine Henderson B.Sc. Ph.D. Dip.Ed. Executive Producer Mark McAuliffe Dip.Art (Film & TV) Dip.Ed. B.Ed. Ph.D. Video Education America To order or inquire please contact VEA: America Phone: Facsimile: Website WARNING This program is protected by copyright laws worldwide. Unauthorized copying, in whole or part, in any format, can result in substantial penalties for both individuals and institutions. These notes can be freely copied for classroom use only.

2 For Teachers: Brief Summary of Program This is the first of a two part series dealing with the biological macromolecules for senior secondary Biology students. It covers carbohydrates, lipids and nucleic acids. The second program in the series deals with proteins and Proteomics. In this program the structure and biological roles of each type of macromolecule are examined. Similarities and differences between the macromolecules are covered. There are many biological examples and graphics are used extensively to assist understanding. DVD Timeline 00:00:00 Introduction 00:01:34 The Macromolecules Carbohydrates 00:02:33 Carbohydrates Monosaccharides 00:05:08 Carbohydrates Disaccharides 00:10:59 Summary 00:11:35 The Macromolecules Lipids 00:19:06 Summary 00:19:48 The Macromolecules Nucleic Acids 00:22:53 Summary 00:23:29 Conclusion 00:24:22 Credits 00:25:10 Program end Other Relevant Programs Available from VEA Macromolecules 2 - Proteins & Proteomics Cellular Signaling Please visit our website for many more relevant programs VEA Bringing Learning to Life

3 For Students: Before Viewing the Program 1. Carbohydrates and lipids are essential parts of our diet. What are the sources of each group? Why do we need to eat them? 2. Follow the pathway of a peanut butter sandwich from your mouth to its final destination. 3. What is digestion? What is assimilation? 4. There is much concern in the community about genetically modified foods, but we consume the DNA of other organisms with every bite we take. What happens to foreign DNA in our digestive system? Why do anti-gmo campaigners think that food from GMOs is a problem? 5. What do the following terms mean? a) macromolecule b) polymer c) synthetic polymer d) biological polymer e) monomer f) anabolic g) catabolic h) hydrophilic i) hydrophobic 6. What is ATP? What role does it play in the cell? 7. As a class or in groups, brainstorm what you know about the structure and composition of cell membranes. What other terms are used for the cell membrane? What is a micelle?

4 While Viewing the Program 1. What elements make up 99% of cells? What percentage of water does an average cell have? 2. There is a pool of small organic molecules that is found in cells. About how many carbon atoms per molecule would be the maximum for these molecules? 3. What is it about Carbon s electronic configuration that allows Carbon to bond in a huge array of shapes? Give 3 examples of these shapes. 4. What are the four main groups of macromolecules? 5. What are four characteristics of carbohydrates? What is the general formula of a carbohydrate? 6. What is another term for a simple sugar? How do simple sugars taste? What is the most common simple sugar? What is its chemical formula?

5 7. What three important macromolecules are built up from D-glucose subunits? 8. Complete the following table Number of carbon atoms General name of monosaccharide 9. What are the chemical similarities of all monosaccharides? What part of their chemical structure makes them hydrophilic? What does hydrophilic mean? What is the sweetest monosaccharide and where is it found? 10. What happens to the shape of the D-glucose molecule when it dissolves in water? What is the difference between the alpha and beta forms of D-glucose? 11. Define disaccharides. Give two examples. What are the names of the monosaccharides that make up sucrose? 12. What kind of chemical reaction occurs when a disaccharide forms? What are the monosaccharides now called?

6 13. What is a polysaccharide? Give three characteristics of polysaccharides. 14. The reactions that occur between the monomers that make up the biological polymers have at least two things in common. They are the source of energy for the reaction and the type of reaction. What are they? 15. What two reasons are given for the huge diversity of polysaccharides? 16. What characteristics do starch and glycogen have that make them suitable for energy storage? 17. What is an isomer? 18. Why is starch digestible by animals but not cellulose? 19. Name three other structural polysaccharides and say where at least one of them would be found.

7 20. Why is the identification of polysaccharides difficult and time consuming? What are glycoproteins? Glycolipids? 21. What are 6 functions of lipids in cells? 22. How are the elements that make up carbohydrates similar to lipids? What differences are there? 23. Why do lipids have 2-3 times more energy per gram than carbohydrates? 24. Describe the structure of a fat molecule. What is the difference between a saturated fat and an unsaturated fat? What does polyunsaturated mean? 25. Why are polyunsaturated fats considered healthier?

8 26. Where would waxes be found in plants and animals? Explain their function. 27. What is the difference in chemical structure between lipids and phospholipids? How does a phospholipid bilayer form? 28. What is a glycolipid? Where are they found in membranes and what function is suggested for them? 29. Why are steroids included with lipids? What functions do steroids have in animals? 30. High blood cholesterol can be a serious health problem. Why? Cholesterol is also important in a positive way. What is it? What is the human body s major source of cholesterol? 31. What subunits make up nucleic acids? What kind of bonds joins the subunits together?

9 32. What is the difference between purines and pyrimidines? Which bases belong to each group? 33. What kind of bonds joins the two strands of DNA? 34. What are the three types of RNA? 35. What is the function of nucleic acids? How do DNA and RNA differ? 36. What is transcription? What is translation? 37. What do the three types of Macromolecules in the program have in common?

10 After Viewing the Program 1. Make some models of the general structures of the biological macromolecules. There are many materials you can choose. Cardboard, pasta, pipe cleaners, straws, beads and plasticine are only a few of the possibilities. Hang them up as mobiles in your classroom so you become familiar with the structures. 2. Make a summary, (a table would work well) where you look for similarities, then differences between the biological macromolecules. Include proteins either by watching the second program in the series or by using reference books. 3. The program refers to a pool of small organic molecules in the cell. Where would these molecules come from? What kind of molecules would you expect to find? 4. The program refers to D-glucose in alpha and beta forms. What other kinds of glucose are there? 5. Is all starch the same? 6. Find out some more about the micro-organisms that digest cellulose. There are 2 main types. What are they? It is possible to observe some of them if you can find some large white ants and have your teacher show you how to examine the gut contents between a slide and a cover slip. 7. What are anabolic steroids? Why are they so dangerous? 8. Some cholesterol is called good cholesterol and other types are considered bad. Find out why. Find out some more about arteriosclerosis. Is diet the only cause? 9. Make a poster that explains the roles of the different nucleic acids in the cell.

11 Suggested Student Responses 1. What elements make up 99% of cells? What percentage of water is an average cell? Carbon, Hydrogen, Oxygen and Nitrogen. 70% water. 2. There is a pool of small organic molecules that is found in cells. About how many carbon atoms per molecule would be the maximum for these molecules? What is it about Carbon s electronic configuration that allows Carbon to bond in a huge array of shapes? Give three examples of these shapes. 4 outer shell electrons which can be shared with other atoms in single, double and even triple covalent bonds. This means shapes such as long chains, rings and branched shapes are possible. 4. What are the four main groups of macromolecules? Carbohydrates, Lipids. Nucleic acids and Proteins 5. What are four characteristics of carbohydrates? What is the general formula of a carbohydrate? They are the most abundant of the organic compounds and are a source of energy, structural elements and components of glycolipids with lipids and glycoproteins with proteins. General formula (CH 2O) n 6. What is another term for a simple sugar? How do simple sugars taste? What is the most common simple sugar? What is its chemical formula? Monosaccharides, which taste sweet. Glucose is the most common. Its formula is C 6H 12O 6 7. What 3 important macromolecules are built up from D-glucose subunits? Starch, glycogen and cellulose 8. Complete the following table Number of carbon atoms General name of monosaccharide 3 Trioses 5 Pentoses 6 Hexoses 9. What are the chemical similarities of all monosaccharides? What part of their chemical structure makes them hydrophilic? What does hydrophilic mean? What is the sweetest monosaccharide and where is it found? All contain a carbon atom bonded to an oxygen atom with a double bond and other carbon atoms bonded with a hydrogen and a hydroxyl or OH group. Hydrophilic means water loving. Fructose is the sweetest monosaccharide and is found in fruit, nectar and in human and bull semen. 10. What happens to the shape of the D=glucose molecule when it dissolves in water? What is the difference between the alpha and beta forms of D-glucose? It looses its straight chain form and becomes a ring. The carbon that is bonded to the oxygen in the ring form is also bonded to a hydrogen and a hydroxyl group. The arrangement of these 2 groups is opposite in the alpha and beta forms of glucose. 11. Define disaccharides. Give 2 examples. What are the names of the monosaccharides that make up sucrose? Two monosaccharides joined with a glycosidic bond. Examples are sucrose, maltose and lactose. Sucrose is a glucose plus a fructose.

12 12. What kind of chemical reaction occurs when a disaccharide forms? What are the monosaccharides now called? A dehydration reaction. They are now called monosaccharide residues. 13. What is a polysaccharide? Give three characteristics of polysaccharides. Many monosaccharide residues joined in linear or branched chains. They are tasteless, insoluble and have high molecular weight. 14. The reactions that occur between the monomers that make up the biological polymers have at least two things in common. They are the source of energy for the reaction and the type of reaction. What are they? The source of energy for the reaction is ATP breaking down to ADP and a phosphate group and the reaction is a dehydration reaction. 15. What two reasons are given for the huge diversity of polysaccharides? If you look at the ways 2 glucose molecules can join there are 11 possibilities. Some polysaccharides like amylopectin have up to i million glucose residues so the number of possible arrangements for polysaccharides is huge. 16. What characteristics do starch and glycogen have that make them suitable for energy storage? Starches are made up of different amounts of amylose and amylopectin. Amylose is long unbranched chains of D-glucose, which coil up in water making it insoluble. Amylopectin is a branched chain and its branches make it insoluble and protect it from being broken down. Glycogen is similar to amylopectin only more branched. 17. What is an isomer? Molecules with the same number of the same atoms but in different arrangements. 18. Why is starch digestible by animals but not cellulose? Animals have the necessary enzymes to break down the alpha linkages of starch but not the enzymes that break the beta linkages that join glucose residues in the cellulose molecule. 19. Name three other structural polysaccharides and say where at least one of them would be found. Pectin, hemicellulose and chitin. Chitin is found in insect skeletons and in the cell walls of fungi. 20. Why is the identification of polysaccharides difficult and time consuming? What are glycoproteins? Glycolipids? Because there are so many possible types of bonds and because carbohydrates often havea protein component and are called glycoproteins or a lipid component and are called glycolipids. 21. What are 6 functions of lipids in cells? Structural elements, membrane components, energy storage compounds, involved in transport, repelling water and acting as a protective coating or insulation and functioning as chemical messengers. 22. How are the elements that make up carbohydrates similar to lipids? What differences are there? Like carbohydrates, they are made up of Carbon, Hydrogen and Oxygen but with a smaller proportion of Oxygen and sometimes containing other elements such as Nitrogen and Phosphorus. 23. Why do lipids have 2-3 times more energy per gram than carbohydrates? Because the have a greater proportion of Carbon Hydrogen bonds than carbohydrates.

13 24. Describe the structure of a fat molecule. What is the difference between a saturated fat and an unsaturated fat? What does polyunsaturated mean? They have a glycerol backbone with 3 fatty acid chains attached to each of the carbons that make up the glycerol molecule. Saturated means the maximum number of hydrogen s attached to each carbon in the fatty acid chain, that is, there are no carbon carbon double bonds in the fatty acid chain. In an unsaturated lipid there is at least one double bond. Polyunsaturated means there is more than one double bond. 25. Why are polyunsaturated fats considered healthier? They are considered less likely to cause arteriosclerosis. 26. Where would waxes be found in plants and animals? Explain their function. Forming a protective coating on insects, birds, fruit and leaves. 27. What is the difference in chemical structure between lipids and phospholipids? How does a phospholipid bilayer form? They both have a glycerol backbone, which are 3 carbons long. In lipids there is a fatty acid chain attached to each of these carbons but phospholipids only have 2 fatty acid chains and a phosphate group attached to the third carbon. The phosphate end of the phospholipid molecule is hydrophilic and negatively charged but the fatty acid tails are hydrophobic. The hydrophobic tails form the inside of the bilayer away from water and the phosphates are the outsides of the layer. 28. What is a glycolipid? Where are they found in membranes and what function is suggested for them? Again there is a glycerol backbone with two fatty acid chains attached but this time there is a short chain of 1-15 monosaccharides attached to the third carbon. They are found in the outer layer of the phospholipid bilayer that makes up cell membranes away from the cytosol. Their function is not fully understood but they are thought to play a role in protecting the membrane and acting as receptors. 29. Why are steroids included with lipids? What functions do steroids have in animals? They have a very different structure but like lipids they are soluble in fat solvents and insoluble in water so they are often included with lipids. They are important in heart blood vessels and the livers of vertebrates. Sex hormones, both male and female, growth hormones, some adrenal hormones and vitamin and D are all steroids. 30. High blood cholesterol can be a serious health problem. Why? Cholesterol is also important in a positive way. What is it? What is the human body s major source of cholesterol? It forms plaque in arteriosclerosis and may also form gallstones. It is an important component in many eukaryotic cell membranes making those membranes with it stiffer than those without it. It is also the stating point for the synthesis of some hormones. The liver manufactures 1-3 grams of cholesterol per day while the average diet provides 300mg-1 gram per day. 31. What subunits make up nucleic acids? What kind of bonds joins the subunits together? Nucleotides linked by phosphodiester bonds. 32. What is the difference between purines and pyrimidines? Which bases belong to each group? Purines have a double ring structure and are Adenine and Guanine. Pyrimidines have a single ring structure and are Thymine, Cytosine and Uracil. 33. What kind of bonds join the two strands of DNA? Hydrogen bonds 34. What are the three types of RNA? Messenger RNA, ribosomal RNA and transfer RNA

14 35. What is the function of nucleic acids? How do DNA and RNA differ? They are information storage molecules responsible for the storage and transfer of information. DNA is self-replicating and the major component of chromosomes. Its bases are A,C,G,and T and its sugar is deoxyribose with one less Oxygen at carbon 2 than ribose. There is only one type of DNA and it its molecule is a double helix. RNA has the bases A,C,G and U and the sugar ribose. It is typically single stranded and there are 3 types m-rna, ribosomal and transfer. 36. What is transcription? What is translation? Transcription is the DNA code transcribed into m-rna. Translation occurs at the ribosome where the code carried by the m-rna is translated into protein by transfer RNA 37. What do the 3 types of Macromolecules in the program have in common? All are polymers synthesized from different monomers using energy from the breakdown of ATP to ADP and a phosphate. All these synthesis reactions are dehydration reactions. All the macromolecules contain Carbon, Hydrogen and Oxygen and sometimes other elements.

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