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5.1.2.1 Give examples of macromolecules and their monomers Explain what polymerisation means Give the chemical and structural formulae for hexose sugars.
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The building blocks of life 4 most common elements in living things 1. Hydrogen 2. Carbon 3. Oxygen 4. Nitrogen Together they make up more than 99% of atoms found in all living things Carbon is the most important as it links with itself to form long chains or rings. All organic molecules contain carbon.
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Macromolecules Macromolecule = ‘Giant molecule’ Three types of organic macromolecules – Proteins (polypeptides) – Nucleic acids – Polysaccharides For each one give an example of what it might do in the body and where it could be found.
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Polymerisation In your own words explain what polymerisation means, using the terms polymer and monomer in your explanation. PolymerMonomer Polypeptide Nucleic Acid Polysaccharide
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Natural and synthetic Group these polymers into natural and synthetic PolyesterRubberCellulose PVCNylonPolythene
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Other organic molecules The other type of organic molecule we will be looking at is lipids This is made of fatty acids and glycerol but is smaller and simpler than the others It is not a polymer
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Carbohydrates 60 – 90% of plant dry mass. General formula C n (H 2 O) m Main groups are the Simple Sugars and the Polysaccharides. Used as storage molecules, building blocks and for energy. Sugars, starch, cellulose, glycogen and lignin are well known examples.
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Monosaccharides All Monosaccharides contain Carbon, Hydrogen and Oxygen in a ring structure. They can have different numbers of Carbon atoms and different arrangements The pentose sugars have 5 carbons The hexose sugars e.g. glucose have 6 carbons Write the formulae for a pentose and a triose sugar Draw the structure and write the formulae for -glucose
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Monosaccharides cont. Monosaccharides are sweet, soluble and have a low molecular mass The two best known Hexoses are glucose and fructose Hexoses have the same chemical formula (C 6 H 12 O 6 ) but different structural formula - glucose and fructose are Isomers Draw the structural formulae for - Glucose and for Fructose
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Disaccharides Monosaccharides can join together to form disaccharides These are sugars Using diagrams and bullet points describe how a disaccharide is made from two monosaccharides Why is this called a condensation reaction? A C 1 -C 4 glycosidic bond is made
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Polysaccharides α and β glucose molecules produce different polymers Starch and glycogen (storage) are polymers of the α form Cellulose (structural) is a polymer of the β form What is the main difference between cellulose and starch structure
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Side chains In some polysaccharides side chains are made. A glycosidic bond is formed between C1 and C6 amylopectin Using diagrams and bullet points explain how side chains are made.
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Homework What is the function of – Monosaccharides – Disaccharides – Polysaccharides In living organisms? In your answer you should give at least 3 specific examples for each group and an overview of their function.
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5.1.2.2 Look in detail at the structure of sugars and polysaccharides Give the functions of these carbohydrates
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Monosaccharides Exist as straight chains when solid Hexoses and Ribose form rings in solution Names prefixed with a D or L depending on which way the crystalline form bends light. L- Laveo rotatory (Left) D- Devo rotatory (Right) Only D forms found in multicellular organisms
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Ketone and Aldehyde groups Act as reducing agents Can donate electrons to other molecules KetoneAldehyde HO COC For each monosaccharide identify whether a ketone or aldehyde group is present
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Trioses D-Glyceraldehyde Intermediate produce of Respiration AND photosynthesis Can be converted to glycerol for lipid synthesis Involved in intermediary metabolism Glycerol Used in lipid synthesis A sugar alcohol
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Pentoses D-Ribose Formation of RNA, ATP, NADP, NAD D- Deoxyribose Formation of DNA Ribulose Carbon dioxide formation (photosynthesis)
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Hexoses Glucose Energy source for respiration Makes important polymers Galactose Formation of lactose Fructose In fruits and nectar- attracts animals Show how the hexose sugars convert from chain to pyranose ring form in solution.
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Disaccharides Made by the formation of a glycosidic bond between two monosaccharides If they have a free aldehyde or ketone group they are reducing agents For each disaccharide record the monosaccharides it is made of, the bond made and whether it is a reducing agent
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Disaccharide function Maltose 1 st product of starch digestion Important in germination Lactose Energy source for new born mammals Sucrose In vacuole-helps maintain turgor Transport in phloem (non-reducing)
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Polysaccharides Amylose- a soluble helix (hydrogen bonds with water). Amylopectin- a chain with side branches every 10 th glucose Starch- amylose helix entangled in amylopectin branches. Glycogen- similar to amylopectin but with more frequent side chains Cellulose- long straight unbranched fibres. H- bonds between strands to make a regular lattice For each polysaccharide record the subunit it is made of, the type of bond and whether its plant or animal.
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Building starch and cellulose. 1. Using the sheet- what you need to do follow the instructions to build up a starch molecule. 2. make sure your work is stuck on and clearly labelled. 3. Complete the cellulose sections. You may need draw in OH and H to see where hydrogen bonds occur.
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Complex carbohydrates Monosaccharides joined to proteins/ lipids Glycolipids- myelin sheeth Glycoproteins – cell adhesion, immunological markers Chitin- exoskeleton of insects. Hexoses linked like cellulose with amino groups (NH 2 ) every 2 nd carbon added
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Homework Learn the structure of the biologically important carbohydrates. Short test next lesson.
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5.1.2.3 Carry out tests for carbohydrates Identify a mystery carbohydrate and the properties of an enzyme.
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Starch Simple test- with iodine. Blue/black= iodine present.
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Cellulose Use Shultz solution- Turns purple in the presence of cellulose.
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Reducing sugar Add an equal amount of solution to be tested and Benedict's reagent to a test tube (about 4ml) Heat in a water bath until it boils Green precipitate- a small amount of sugar Brown or red- greater amount of sugar
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Non-reducing sugar Test as for a reducing sugar first If no precipitate boil with Hydrochloric acid (CAREFUL- EYE PROTECTION) Then neutralise with alkali. Test with Benedict’s as before,
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Solutions E, F, G, H Questions 4 on the back of the sheet Carry out and write all results and answers into your book.
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Homework 1. Write up the procedure for testing for – Starch – Cellulose – Reducing sugars – Non reducing sugars 2. For each test say how it works i.e. why does starch stain blue with iodine? Etc.
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5.1.2.4 Make standard glucose solutions Use these solutions to find the reducing power invertase on sucrose
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Making standard dilutions You have 2% glucose. You need to make 0.5%, 0.1% and 0.01 %. 1. Write down how you will make these dilutions (exact quantities of glucose solution and water you will use). Make sure all calculations are clearly recorded. 2. Make up your dilutions
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Testing reducing power. 1. Using the standard test for reducing sugar test each solution for its reducing power (part a). Record all results 2. Devise a test for the two solutions J and K to find their reducing power.
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Have you? Written a method for both parts of the experiment? Recorded all results neatly? Draw a graph from your standard results? Used your graph to calculate the reducing power of invertase? Written a clear, detailed conclusion.
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Homework Qu 3- Solution M Write a Method for both parts of the experiment. Write a rational for your method in both cases.
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