2. Proteins Using the text book, you have 5 minutes to find and write down notes on: What elements are present in proteins? Which element is ESSENTIAL to build proteins Where do (i) plants (ii) animals get this element from? What are the main uses of proteins?

3. Proteins Facts about Proteins: Proteins are an important part of a balanced diet for body-building and repair Animals take in proteins when they eat plants or other animals Proteins are the major structural material in tissue and are involved in many human biological processes Plants and animals need a supply of NITROGEN to build proteins

4. Structure of Protein Molecules H NH H R OC O Carboxyl group CH Amine group Proteins are natural polymers, made by joining up many AMINO ACID monomers (where R changes for each amino acid) AMINO ACIDS contain both an ACID GROUP and an AMINE GROUP Amino Acids

5. Glycine Alanine In PAIRS: Build these amino acids using Molymods In PAIRS: Proteins are formed by CONDENSATION reactions, join your two amino acids together to form part of a protein polymer

6. Condensation Polymerisation N H H O Amino Acid Monomer O HHN O HHNHH Protein Water Molecule H HH C O

7. N H H O H C O N H H O H C O Condensation Polymerisation HO N H C O N H C O N H C O Removing a H 2 O

8. N H H O H C O N H H O H C O Protein Hydrolysis Adding H 2 O in presence of enzyme N H C O N H C O N H C O

9. Reactions in the Body Proteins in food (Insoluble) Hydrolysis Proteins needed by body Condensation Amino Acids (Soluble)

10. Breaking down proteins in the lab 1.Add 2cm-depth of a cloudy suspension of egg white to each of two test-tubes 2.Add 3 drops of dilute hydrochloric acid (1M) to each test-tube 3.Add 1ml of pepsin solution to one test-tube, leave for 10 mins Questions: Describe how proteins can be broken down in the lab What are formed when proteins are broken down? What type of reaction takes place?

12. Fats & Oils Facts: Fats and oils are examples of esters Their main function is to provide energy They are a more concentrated source of energy than carbohydrates Fats and oils come from three sources – animal, vegetable or marine

13. Fats & Oils Using the displays, copy and complete the tables:

14. Fats & Oils Facts: Fats and oils are mixtures of both saturated and unsaturated molecules Fats have higher melting points – they have more SATURATED molecules These can pack more closely together, and as a result they have large forces of attraction, giving them high melting points

15. Structure of Fats & Oils All fats and oils are formed when 3 molecules of fatty acids combine with 1 molecule of GLYCEROL (propan-1,2,3-triol) via a condensation reaction (esterification)condensation reaction

16. Structure of Fats & Oils Similar to other condensation reactions, the reaction can be reversed by HYDROLYSIS:

17. The Difference Between Fats & Oils FATS – the R chains of the fatty acids has less C=C bonds (this makes the structure more rigid) OILS – the R chains have more C=C bonds, which makes the molecule less rigid, and unable to pack tightly

18. Converting Oils to Fats Oils can be converted to fats by Hydrogenation i.e. the addition of hydrogen across the C=C to make it saturated. Industrially this is known as the Hardening of Oils and is used regularly to make spreadable margarines from vegetable oil.

19. Answer these questions in your class-work jotter You have until 8:50 to complete them! 1.What is the process of BREAKING DOWN a carbohydrate? 2.Proteins break down into which type of monomers? 3.What is the essential element in Proteins 4.What part of the structure gives oils a lower melting point than fats? 5.Which sugar does not give a positive test with Benedict’s?