1. 12 C What information is this giving us?

1. QUIZ 1. 12C What information is this giving us? That it is a carbon atom with a mass of 12 amu. What 3 properties allow water to be able to stabilise cell temperature? Its heat capacity, latent heat of evaporation and latent heat of fusion 3. What is the pH scale? A logarithmic scale showing the concentration of H+ ions in solution 4. Name 4 types of chemical bonds. Covalent bonds, Ionic bonds, Hydrogen bonds, Van der Waals interactions

2. Lesson 3 – Carbohydrates

3. Monosaccharides All carbohydrates are made up of carbon hydrogen and oxygen in a ratio of 1:2:1. Monosaccharides are simple or ‘single’ sugars. The most important monosaccharide is glucose. C6H12O6 Glucose is a hexose sugar. Meaning 6 carbons Meaning sugar

4. Glucose – Straight Chain Form Distinguishing features of glucose: Six carbons Carbonyl group at the terminus (C=O)

5. Isomers An isomeris a molecule that has the same chemical formula but a different structural formula. In biological systems glucose is usually in the D form with the C5,4 and 2 OH groups projecting to the right.

6. Cyclical Glucose In solution glucose tends to adopt a cyclical form with the C1 and C5 being linked through an O atom. β-D-glucose

7. 4 main types of glucose Use your monograph to complete the table to show the different forms of glucose. Include details of distinguishing features as well as abundance as given in the monograph. To remember which is alpha and which is beta… ABBAAlpha Below Beta Above (OH on Carbon 1)

8. Making Sense of Glucose Now use the molymod kits to make the different glucose types.

9. The Glycosidic Bond The bond that links 2 monosaccharides together is called a glycosidic bond. The product is a disaccharide. If the bond is created between 2 α-glucose molecules maltose is produced. If the bond is between 2 β-glucose molecules cellobiose is produced.

10. Dehydration Synthesis The reaction between 2 monosaccharides involves carbon 1 on one glucose and carbon 4 on the other. An –OH group from one joins with an –H from the other resulting in the removal of one molecule of water (hence dehydration). The glycosidic bond is created through a dehydration synthesis reaction.

11. Other Disaccharides glucose + fructose → sucrose galactose + glucose →lactose glucose + glucose →maltose

12. Polysaccharides Monosaccharides can be joined together into larger molecules called polysaccarides. If the repeating units are the same it is a homopolymer (like starch, glycogen and cellulose) and if they are different it is called a heteropolymer (like chitin and glycosaminoglycans).

13. Making and Breaking Bonds Recall that making bonds requires energy. Creating polymers from monomers therefore also requires energy. These reactions are described as anabolic or biosynthesis reactions. Breaking bonds releases energy. These reactions are described as catabolic reactions. Where the energy of these reactions is small the reactions are said to be reversible.

14. Types of Polysaccharides Use your monograph to complete the table.

15. Your Task Past Paper Questions You will need to access these in the department. Please DO NOT TAKE past papers home – we have limited numbers. 2001 MC Q1 2002 MC 3 2006 MC Q3 Section B Q2 2008 MC 3,4 2009 ER8A 2010 Section BQ2 2011 MC 1