BIOLOGICAL MOLECULES 1

Transcription

1 Name: Option Group: BIOLOGICAL MOLECULES 1 GENERAL CHEMISTRY, CARBOHYDRATES, MATHS AND PRAC WORKBOOK

2 You realise when you know how to think, because it empowers you far beyond those who know only what to think. Neil degrasse Tyson. Tyrone R.L. John, Chartered Biologist 2

3 Instructions REVISION CHECKLIST AND ASSESSMENT OBJECTIVES Regular revision throughout the year is essential. It s vital you keep a track of what you understand and what you don t understand. This booklet is designed to help you do this. Use the following key to note how well you understand the work after your revision. Put the letter R, A or G in the table. If you place an R or an A then you should make a note of what you are struggling with and the end of this book under the relevant section and seek help with this. Key R = Red. I am not confident about my knowledge and understanding A = Amber. I am fairly confident about my knowledge and understanding G = green. I am very confident about my knowledge and understanding AO1 Demonstrate knowledge and understanding of scientific ideas, processes, techniques and procedures. AO2 Apply knowledge and understanding of scientific ideas, processes, techniques and procedures: In a theoretical context In a practical context Tyrone R.L. John, Chartered Biologist 3

4 When handling qualitative data When handling quantitative data AO3 Analyse, interpret and evaluate scientific information, ideas and evidence, including in relation to issues, to: Make judgments and reach conclusions Develop and refine practical design and procedures The ability to select, organise and communicate information and ideas coherently using appropriate scientific conventions and vocabulary will be tested across the AO. Tyrone R.L. John, Chartered Biologist 4

5 The following points are what you need to know, revise and answer questions on. Biological Molecules General Chemistry 1. Can you distinguish between the terms: atom, molecule, element, compound, organic and inorganic? 2. Can you describe the role of magnesium, iron, phosphate and calcium ions in cell metabolism? Carbohydrates 3. Can you name at least 4 Monosaccharides? Can you classify these monosaccharides based on their: number of carbon atoms and functional group? 4. Can you recognise the structure of these monosaccharides? 5. Can you state the functions, chemical and physical properties of these monosaccharides? 6. Can you state the general formula of a monosaccharide? 7. Can you define what an isomer is using glucose as an example. 8. Can you identify α and β glucose from molecular structure diagrams. 9. Do you know what elements make up a carbohydrate? 10. Monosaccharides have both a structural formula that can be a ring or a straight chain structure. 11. Two monosaccharides can join together to form disaccharides. Can you name three disaccharides? 12. Can you name the two monosaccharides that make up each disaccharide? 13. Can you name the bond that joins the two monosaccharides together? 14. Can you name the reaction that occurs when monosaccharides join together to form disaccharides and polysaccharides? Can you state the products of this reaction? Can you describe this reaction with the aid of annotated diagrams? 15. Can you state the function of the three disaccharides and where each is found? 16. Can you state the names of 5 polysaccharides? 17. Can you describe the structure and function of these 5 polysaccharides? 18. Do you know the role of hydrogen bonds in polysaccharides? Place an R, A or G when you have revised and make notes of what you do not understand in the relevant section at the back of this booklet. Tyrone R.L. John, Chartered Biologist 5

6 19. Can you describe the biological test for a reducing and non-reducing sugar and for starch? 20. Do you understand the quantitative benedict s test and the use of standard solutions to calibrate a colorimeter? 21. Can you determine the concentration of an unknown glucose solution from a calibration curve? 22. Do you understand why when measuring the percentage transmission of blue light through reduced benedict s reagent produces a negative correlation on a graph of percentage transmission of blue light against glucose concentration. 23. Do you know the name of the reaction that can break the bond between monosaccharides in disaccharides and polysaccharides? Can you describe this reaction and show it occurring with an annotated diagram? Application of Knowledge 24. Can you apply your knowledge of carbohydrates to unfamiliar scenarios? Tyrone R.L. John, Chartered Biologist 6

7 WORD BANK Below is a list of some key words and phrases you will need to learn and understand in this carbohydrate and general chemistry section 1. 1,4 glycosidic bond 2. 1,6 glycosidic bond 3. Aldehyde 4. Alpha glucose 5. Atom 6. Beta glucose 7. Cellulose 8. Chitin 9. Condensation reaction 10. Disaccharide 11. Element 12. Fructose 13. Galactose 14. Glucose 15. Glycosidic bond 16. Hexose 17. Hydrogen bond 18. Hydrolysis reaction 19. Inorganic 20. Isomer 21. Ketone 22. Lactose 23. Macrofibril 24. Maltose 25. Microfibril 26. Molecule 27. Monomer 28. Monosaccharide 29. Organic 30. Pentose 31. Polymer 32. Polysaccharide 33. Saccharide 34. Sucrose 35. Triose Tyrone R.L. John, Chartered Biologist 7

8 GENERAL CHEMISTRY Self-study exercises Instructions Read the following pages on general chemistry and then answer the questions that follow Completion date: Important Definitions An element is a substance which cannot be split into simpler substances. Examples of elements would be sodium (Na) and calcium (Ca). An element is made up of atoms. So, an atom is the smallest particles of element. In some elements atoms are joined together by a chemical bond to form larger particles called molecules. Examples of molecules would be: hydrogen (H 2 ) oxygen (O 2 ) and Nitrogen (N 2 ). A compound contains two or more different elements chemically bonded together. Examples of compounds would be: sodium chloride (NaCl), glucose (C 6 H 12 O 6 ) and hydrochloric acid (HCl). Tyrone R.L. John, Chartered Biologist 8

9 An organic compound is one that contains carbon while an inorganic compound is that does not contain carbon. Examples of organic compounds would be: glucose, fats and proteins. Examples of inorganic compounds would be: sodium carbonate, methane and carbon dioxide. The Importance of Carbon to Life Unique feature 1 Carbon atoms can bond together by single or double bonds Carbon atoms can form 4 covalent bonds as shown below. In this case, I have shown the carbon being covalent bound to hydrogen. This gives carbon the unique ability to form chain and ring structures as shown below A chain A ring Tyrone R.L. John, Chartered Biologist 9

10 As well as there being a single covalent bond between the carbon atoms, form double bonds can form between carbon atoms as shown below. Unique feature 2 Carbon atoms can bond to different elements to form function groups Functional groups give specific chemical properties to compounds that contain them. There are too many functional groups to mention them all here so I will stick to those that will be covered in your biological molecules sections 1. The aldehyde and ketone functional groups These functional groups are shown below: Aldehyde Ketone An Aldehyde functional group is located at the end of a chain, while a ketone is located within the chain of carbons. Despite the location both have a carbon double bonded to an oxygen. The letter R is a standard way of representing a chain of carbons and will be used again in the biological molecules chapters. 2. The amino group and carboxyl group Tyrone R.L. John, Chartered Biologist 10

11 These functional groups are shown below: Amino Carboxyl An amino group is a nitrogen atom bonded to two hydrogen atoms. A carboxyl group is a carbon atom double bonded to an oxygen and also single bonded to an hydroxyl group. 3. The hydroxyl group This function group is shown below: Tyrone R.L. John, Chartered Biologist 11

12 The role of 4 important inorganic ions to organisms Magnesium (Mg 2+ ) The magnesium ion is required for the production of chlorophyll in plants and so form a component of chlorophyll. Calcium (Ca 2+ ) Calcium ions form a component of teeth and bone. They are also important for the normal functioning of nerves and muscles. Iron (Fe 2+ ) Iron is a component of haemoglobin which is the protein in red blood cell that binds to oxygen. Phosphate (PO 4 3- ) The phosphate ion is a component of many molecules, for example: ATP, DNA, Phospholipids and bone. Tyrone R.L. John, Chartered Biologist 12

13 COMPLETE THE FOLLOWING ACTIVITIES 1. Complete the following table by placing a tick in the correct box. Glucose Water Protein phosphate Na + Hydrogen Na Oxygen Haemoglobin NaHCO3 Atom Molecule Ion Compound Organic Inorganic Element 2. Identify the functional group(s) in the following structures by circling them and write the name of the function group on the line. 1 2 Tyrone R.L. John, Chartered Biologist 13

14 Which of the structures from question 2 have the following features? (i) (ii) Has all single carbon-carbon bonds? Is inorganic. (iii) Is organic. (iv) Can form ring structures. (v) Has only acidic properties. (vi) Has two different properties. Tyrone R.L. John, Chartered Biologist 14

15 4. State how many covalent bonds a carbon atom can form with neighbouring atoms. 5. During the first few years of the menopause women are at increased risk of developing osteopenia. What is the cause of osteopenia? 6. The leaves below have been taken from a plant suffering from a deficiency disease. Suggest a name for this deficiency disease and what the plant may be deficient in. 7. Anaemia can be caused by a loss of erythrocytes. What mineral is needed to synthesis more erythrocytes? 8. An investigation into the rate of binary fission in bacteria resulted in all the bacteria dying. Suggest what could have caused the death of the bacteria. Tyrone R.L. John, Chartered Biologist 15

16 CARBOHYDRATES MONOSACCHARIDES COMPLETE THE FOLLOWING ACTIVITIES Instructions Read the following texts on carbohydrates and monosaccharides and complete the exercises that follow. Completion date: Text 1. Taken from Biological Science 1 and 2, p 82-85, Tayler et al Tyrone R.L. John, Chartered Biologist 16

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20 Text 2. Taken from Advanced Biology, Third Edition, p16 18, J Simpkins and J I Williams. Tyrone R.L. John, Chartered Biologist 20

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23 1. Make some summary notes from the text in the template below. TOPIC NOTES Questions/Main Ideas SUMMARY Tyrone R.L. John, Chartered Biologist 23

24 2. Thinking about and organising the new information from the text. i. Classify carbohydrates into monosaccharides, disaccharides and polysaccharide using the family tree below. Carbohydrates Monosaccharide Polysaccharides Disaccharides ii. Classify monosaccharides based on their number of carbons Three carbons Five carbons Six carbons iii. What are the prefixes for: three: Five: Six: Tyrone R.L. John, Chartered Biologist 24

25 iv Which carbohydrate(s) is/are the odd one(s) out. Give a reason for your answer. Glucose Galactose Ribose Tyrone R.L. John, Chartered Biologist 25

26 v. Complete the diagram below. Write similarities between the monosaccharides in the explosions and differences in the call outs. α-glucose β-glucose Galactose Tyrone R.L. John, Chartered Biologist 26

27 Complete the diagram below. This time you choose the combination of monosaccharides you want to compare. Tyrone R.L. John, Chartered Biologist 27

28 vi. Classify the following monosaccharides based on their functional groups. Monosaccharide Name of Functional Group Glucose Fructose Glyceraldehyde ribose Name of monosaccharide based on functional group and number of carbons vii What is the definition of an isomer? viii Are glucose, fructose and galactose isomers of each other? Explain your answer. ix Explain the action of a reducing sugar on copper (ii) ions. x What is the general formula for a carbohydrate and a monosaccharide. xi What is the meaning of the term carbohydrate? Tyrone R.L. John, Chartered Biologist 28

29 xii What elements are in all monosaccharides, and what ratio are they in. xiii Describe the difference between α and β glucose. ix An experiment was carried out to determine the concentration of reducing sugars in different energy drinks. Benedict s reagent was used and the colour chart below was used to determine the concentration of the reducing sugar. (a) State the name given to the type of data generated during this experiment. (b) What are the disadvantages of generating data in this way and what would be a suitable improvement to obtaining the data. Tyrone R.L. John, Chartered Biologist 29

30 i ii Question Number 2 iii iv v vi vii viii iv x xi xii xiii ix Which AO is being Tested AO1, AO2, AO3 Which number from the revision checklist is being tested Tyrone R.L. John, Chartered Biologist 30

31 A maths and prac break You will need the following books: Maths for AS Biology: Making Solutions. Prac for AS Biology. Tyrone R.L. John, Chartered Biologist 31

32 Disaccharides Complete the following activities Instructions Read the following texts on Disaccharides and complete the exercises that follow. Completion date: Text 1. Taken from Biological Science 1 and 2, p 85, Tayler et al 2001 Tyrone R.L. John, Chartered Biologist 32

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34 Text 2. Taken from Advanced Biology, Third Edition, p18 19, J Simpkins and J I Williams. Tyrone R.L. John, Chartered Biologist 34

35 1. Make some summary notes from the text. TOPIC NOTES Questions/Main Ideas SUMMARY Tyrone R.L. John, Chartered Biologist 35

36 2. Thinking about and organising the new information from the text. i. Write the molecular formulas for Maltose Lactose ii. Complete the following table. Disaccharide Monomers Function/where found Maltose Sucrose Glucose iii. Describe what a hydrolysis reaction is. Give examples of hydrolysis reactions along with the products of this reaction. Tyrone R.L. John, Chartered Biologist 36

37 iv Sucrose, maltose and lactose were tested using benedict s reagent. All three sugars caused a colour change from blue to brick red. Is this correct? Explain your answer. v In sucrose the bond between the glucose and fructose is an α1, 4 glyosidic bond. Is this correct? Explain your answer. vi Complete the passage below by inserting the correct terms. Glyceraldehyde is the monosaccharide having carbons so is a. Glucose has two called. Lactose is a disaccharide made from and. The only carbohydrate that is not a reducing sugar is. Tyrone R.L. John, Chartered Biologist 37

38 i ii Question Number 2 iii iv v vi Which AO is being Tested AO1, AO2, AO3 Which number from the revision checklist is being tested Tyrone R.L. John, Chartered Biologist 38

39 Polysaccharides Instructions Read the following texts on polysaccharides and complete the exercises that follow. Completion date: Text 1. Taken from Biological Science 1 and 2, p 86-89, Tayler et al Tyrone R.L. John, Chartered Biologist 39

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43 Text 2. Taken from Advanced Biology, Third Edition, p20 22, J Simpkins and J I Williams. Tyrone R.L. John, Chartered Biologist 43

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46 TOPIC NOTES Questions/Main Ideas SUMMARY Tyrone R.L. John, Chartered Biologist 46

47 2. Thinking about and organising the new information from the video(s). i. Glycogen and starch can be hydrolysed by enzymes. Which row shows the correct features of the structure of glycogen. 1,4-glycosidic bonds only Branched 1,6-glycosydic bonds only Unbranched 1,4-glycosidic bonds and branched 1,6-glycosidic bonds 1,4-glycosidic bonds and unbranched 1,6-glycosidic bonds Place a tick in the correct row ii. Starch contains two different molecules amylose and amylopectin. The percentage of each molecule found in starch depends on its source. The effect of amylose content on the hydrolysis of starch from different sources by enzymes was investigated. Source of starch Amylose content (%) Percentage of starch hydrolysed after 4 hours (%) Cassava Peruvian carrot Potato Yellow maize Calculate the ratio of amylose to amylopectin in cassava. Give your answer in simplest form. Answer Tyrone R.L. John, Chartered Biologist 47

48 3. (i) Below are images of wires. Place a tick so to correctly identify the wire that represent the structure in cellulose. Wire Microfibril Macrofibril Chain of β-glucose (ii) The image below is a cross section of a wire. Label this image to identify the following structure in cellulose: chain of β-glucose, microfibril and macrofibril. Tyrone R.L. John, Chartered Biologist 48

49 4. This question is a comprehension activity. In the biological molecules reading booklet read the following article: Glucose and glucose containing carbohydrates. Use some appropriate reading strategies to help you understand the article see the getting started with A-Biology booklet and answer the following questions. a. Why is glucose soluble in water and why is its solubility in water important? b. How many α1-6 branches are there per 30 α1-4 links in amylopectin? c. What is the most abundant organic compound in the biosphere? d. Name the different structures that make up a cellulose fibre. e. What are the functions of cellulose? f. Is cellulose a source of glucose for humans? Explain your answer. Tyrone R.L. John, Chartered Biologist 49

50 5. Compare the structure of cellulose and starch. 6. Describe how cellulose and glycogen perform their functions. Tyrone R.L. John, Chartered Biologist 50

51 1. Complete the crossword. PUTTING IT ALL TOGETHER Tyrone R.L. John, Chartered Biologist 51

52 2. Complete the following multiple-choice questions. (a) Which statement about atoms and ions is correct. (i) Atoms are charged ions. (ii) Ions are atoms or groups of atoms that are charged. (iii) Neither atoms or ions are charged. (iv) Atoms can only be made from ions. (b) Which of the following are reducing sugars? (i) Fructose (ii) Glucose (iii) Sucrose (iv) Cellulose (c) Lactose is a disaccharide consisting of. (i) Glucose and fructose (ii) Glucose and galactose (iii) Glucose and glucose (iv) β glucose and galactose (d) Starch consists of. (i) Unbranched amylose and branched amylopectin. (ii) Branched amylose and branched amylopectin. (iii) Unbranched amylose and unbranched amylopectin. (iv) None of these. Tyrone R.L. John, Chartered Biologist 52

53 (e) The simplest carbohydrate is. (i) Glucose (ii) Ribose (iii) Glyceraldehyde (iv) Fructose (f) Which of the following gives a blue/black colour on reaction with iodine? (i) Starch (ii) Glycogen (iii) Cellulose (iv) Chitin (g) Which out of the following is a carbohydrate with 6 carbon atoms and a keto functional group? (i) Glyceraldehyde (ii) Fructose (iii) Galactose (iv) Sucrose (h) A positive benedict s test is not given by. (i) Sucrose (ii) Lactose (iii) Maltose (iv) Glucose Tyrone R.L. John, Chartered Biologist 53

54 3. There are two passages below, mistake 1 and mistake 2, that contain incorrect information. Read the passages underlining the mistakes and write the correction above the mistake. MISTAKE 1 Carbohydrates contain carbon, hydrogen and oxygen in the ratio of 1:2:2. Carbohydrates can be grouped into monosaccharides, disaccharides and polysaccharides. Monosaccharides include glucose, sucrose and galactose. Glucose is an example of a triose sugar and a reducing sugar. Glucose can form 2 different isomers called alpha and beta glucose. Beta glucose has the OH group pointing down on carbon number 2. 2 Alpha glucose molecules can join together by a condensation reaction to form the polysaccharide maltose. The bond that is formed is an alpha 1,6 glycosidic bond. Glycogen is a storage of energy found in plants. Glucose molecules can be easily removed from glycogen by a condensation reaction so the glucose can be used in respiration to produce ATP. Glycogen is less branched than amylopectin but does have alpha 1,4 and alpha 1,6 glycosidic bonds. Cellulose is a straight chain of beta glucose molecules where every other beta glucose is rotated by 90 o. These beta glucose chains join together to form macrofibrils. Tyrone R.L. John, Chartered Biologist 54

55 MISTAKE 2 Carbohydrates contain carbon, hydrogen and oxygen in the ratio of 1:2:2. Carbohydrates can be grouped into trisaccharides, disaccharides and polysaccharides. trisaccharides include glucose, sucrose and galactose. Glucose is an example of a triose sugar and a reducing sugar. Glucose can form 2 different isomers called alpha and gamma glucose. Gamma glucose has the OH group pointing down on carbon number 1. 2 Alpha glucose molecules can join together by a condensation reaction to form the polysaccharide maltose. The bond that is formed is an alpha 1,2 glycosidic bond. Glycogen is a storage of energy found in plants. Glucose molecules can be easily removed from glycogen by a condensation reaction so the glucose can be used in respiration to produce ATP. Sucrose is made up of galactose and glucose and is the sugar that is transported in the xylem vessel of plants. Glycogen is less branched than amylopectin but does have alpha 1,4 and alpha 1,2 glycosidic bonds. Cellulose is a curved chain of gamma glucose molecules where every other gamma glucose is rotated by 90 o. These gamma glucose chains join together to form macrofibrils. Starch is made up of amylose and glycogen, with amylose being a coiled structure that is compact and forms starch granules in liver cells. Tyrone R.L. John, Chartered Biologist 55

56 LONG ANSWER QUESTIONS WITH QER The long answer question requires you to write at length about a topic. The quality of your extended responses (QER) will also be assessed. The mark scheme will have the following areas: 1. Indicative Content this is the biological concepts and terminology you are expected to use in your answer marks to gain these top marks your answer will show: The candidate constructs an articulate, integrated account correctly linking relevant points, such as those in the indicative content, which shows sequential reasoning. The answer fully address the question with no irrelevant inclusions or significant omissions. The candidate uses scientific conventions and vocabulary appropriately and accurately marks to gain these marks your answer will show: The candidate constructs an account correctly linking some relevant points, such as those in the indicative content showing some reasoning. The answer addresses the question with some omissions. The candidate uses scientific conventions and vocabulary appropriately and accurately marks to gain these marks your answer will show: The candidate makes some relevant points, such as those in the indicative content, showing limited reasoning. The answer addresses the question with significant omissions. The candidate has limited use of scientific conventions and vocabulary. Tyrone R.L. John, Chartered Biologist 56

57 Complete the QER questions number 4 below. 4. Carbohydrates are a large group of biological molecules with diverse structures and functions. Plants and animals can use different carbohydrates to perform a common function. In addition to this, plants and animals can use carbohydrates that are unique to them and for unique functions. The microscope images below show carbohydrates that fit the description stated in this question. Image A Image B State the names of the carbohydrates shown in image A and Image B. Describe the structure of these carbohydrates and explain how this structure permits their function. [9] Tyrone R.L. John, Chartered Biologist 57

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60 APPLICATION AND EXTENSION 1. Rare sugar syrup containing D -Allulose but not high-fructose corn syrup maintains glucose tolerance and insulin sensitivity partly via hepatic glucokinase translocation in Wistar rats. The above title is from a scientific paper published in the journal of agricultural and food chemistry (2017, 64, , Shintani et al). Below are extracts taken from this paper (some slightly modified). Using information in these extracts and your own knowledge answer the questions that follow. High-fructose corn syrup (HFCS) is commercially produced by isomerizing glucose to fructose. The taste of HFCS is similar to that of sucrose, and its price is affordable. Thus, HFCS has been used in various foods, such as beverages, desserts and confectionary and bakery products. However, the consumption of HFCS has been reported to be one of the risk factors for developing diabetes and obesity. From a preventative point of view it is advisable to reduce sugar intake or replace sugar with other low-calorie sweeteners. Thus, the development of new types of sweeteners is awaiting. D-Allulose is a C 3 epimer of D -fructose and is one of the rare sugars that are present in a limited quantity in nature. Studies have shown that D -allulose has various functions, such as reducing postprandial glucose elevation this has been confirmed in a number of studies and there have been two mechanisms proposed for the glucose lowering effect of D -allulose. These are: 1. The inhibition of α-glucosidase resulting in the decreased absorption of glucose. 2. The effect on the glycaemic response in the liver. D -Allulose promotes the conversion of blood glucose to glycogen in the liver via the use of Tyrone R.L. John, Chartered Biologist 60

61 glucokinase. When glucose enters the hepatocytes, it is phosphorylated to glucose-phosphate by glucokinase which is a key step to forming glycogen. Thus, glucokinase increases the amount of glycogen in the liver, suppressing postprandial blood glucose elevation. D -Allulose has the effect of activating the glucokinase, causing its transport out of the nucleus and into the cytoplasm where it will then increase the amount of glycogen and thus lower the blood glucose level. Rare sugar syrup (RSS) is a mixture of 45% glucose, 29% fructose, 5% D - allulose and a number of other carbohydrates. Therefore, RSS containing D-allulose may activate glucokinase and lead to improved glycaemic control. The anti-obesity effect of RSS has been confirmed in both humans and animals in a clinical trial the results of which showed that the intake of 40g of RSS for 3 months lead to a 1.8Kg reduction in body weight compared to that observed after HFCS intake. It is of interest to assess whether RSS, a new sweetener derived from HFCS, maintains glucose tolerance and insulin sensitivity and, if so, whether anti-hyperglycaemic action of RSS is mediated by exporting glucokinase from the nucleus to the cytoplasm. To this end, glucose tolerance and the degree of glucokinase translocation in rats administered water, HFCS or RSS in drinking water were investigated. (a). State three controlled variables for this investigation. Tyrone R.L. John, Chartered Biologist 61

62 (b). Which of the following molecules are mentioned in the passage? A B C D E F (c). What are the ethical issues of this investigation. (d). Explain why the statement glucokinase increases the amount of glycogen in the liver is scientifically inaccurate. Tyrone R.L. John, Chartered Biologist 62

63 (e). Below is some selective data from this investigation (the data has been significantly modified for the purposes of this question). Figure 1. Effects of water, HFCS and RSS on glucose levels expressed as a percentage ± range. Figure 2. Effects of water, HFCS and RSS on Plasma glucose levels ± range. Tyrone R.L. John, Chartered Biologist 63

64 Figure 3. Effects of water, HFCS and RSS on Plasma insulin levels ± range. Figure 4. Effects of water, HFCS and RSS on cytoplasmic glucokinase levels ± range. (i) Using figure 1 describe the trend for the effect of HFCS on glucose levels. Tyrone R.L. John, Chartered Biologist 64

65 (ii) Explain which set of data: water, RSS or HFCS from figure 1 has the greatest consistency. (iii) Insulin sensitivity is a measure of how sensitive the body is to the effects of insulin. Glucose tolerance is a measure of glucose levels in the blood. Using both figure 2 and figure 3 explain whether water, HFCS or RSS shows the greatest glucose tolerance and greatest insulin sensitivity. (iv) It has been suggested that the polymerisation of glucose to glycogen is achieved by the action of glucokinase in the cytoplasm of hepatic cells and that the glucokinase levels in the cytoplasm are greatest with d -allulose present. Does the data presented in this question fully confirm this suggestion? Explain your answer. Tyrone R.L. John, Chartered Biologist 65

66 (v) Compare the structure of glycogen and starch. (vi) Does the data disprove the prediction stated at the start of this question? Explain your answer. Tyrone R.L. John, Chartered Biologist 66

67 Q2. Below is the structure of a carbohydrate called raffinose. Raffinose can be found in beans, cabbage, Brussel sprouts and other vegetables. Study this structure carefully and answer the following questions. (a) (i) What type of carbohydrate is raffinose? (ii) State the names of the two bonds in raffinose including carbon numbers. (b) The enzyme α-galactosidase can breakdown raffinose but is not found in the human digestive tract. (i) What is the name of the reaction catalysed by α-galactosidase? (ii) Place an arrow on the diagram of raffinose to show the site of action of α-galactosidase and state the names of the products of this reaction. Tyrone R.L. John, Chartered Biologist 67

68 (c) The molar mass for raffinose is g/mol. You need to make up 5 standard solutions of concentration: 0.60 moldm -3, 0.45 moldm -3, 0.25 moldm -3, 0.15 moldm -3, 0.08 moldm -3. (i) Describe and calculate how you would make up the above 5 standard solutions. Each standard solution must be in a total volume of 100cm 3. Tyrone R.L. John, Chartered Biologist 68

69 (ii) Explain why you would need to make up standard solutions. Tyrone R.L. John, Chartered Biologist 69

70 Notes Tyrone R.L. John, Chartered Biologist 70

71 TOPIC NOTES Questions/Main Ideas SUMMARY Tyrone R.L. John, Chartered Biologist 71

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