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IB Biology

IB Biology. Joni Rogan Escuela de Lancaster A.C. Course outline - Theory. 1: The chemistry of life Statistical analysis 2: Cells 3: Genetics 4: 5: Ecology and evolution 6: Human health and physiology. Theory Assessment. Makes up 76% of final grade 3 exam papers: Paper 1- 30 MCQ

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IB Biology

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  1. IB Biology Joni Rogan Escuela de Lancaster A.C.

  2. Course outline - Theory • 1: The chemistry of life • Statistical analysis • 2: Cells • 3: Genetics • 4: 5: Ecology and evolution • 6: Human health and physiology

  3. Theory Assessment • Makes up 76% of final grade • 3 exam papers: • Paper 1- 30 MCQ • Paper 2- data based Qs, Extended response • Paper 3- short answer questions

  4. Course Outline- Practical • Practicals make up 24% of final grade. • The marks are in 2 parts: • Investigations • Group 4 projects

  5. Investigations • Throughout course as fits with theory • You are assessed on 2 examples of each of the following: • Design • Data collection • Concluding • Evaluating

  6. Group 4 Projects • Cross-curricular Science project in small groups (with Chemistry and Physics) • You design and carry out an investigation on a theme • You are marked on: • Manipulative skills • Personal skills

  7. To do well in IB Biology..... • Work hard and learn at home throughout the year • Use the rubrics • Learn the command terms • Take the practical work seriously

  8. Biological MoleculesTopic 1

  9. What are living things made of? • 4 most commonly occuring elements? • Other elements?

  10. What are elements are made of? • Chemistry revision!

  11. What are we made of? Richmond upon Thames College

  12. Introduction • For each of the following you should be able to: • Describe the properties • Know the general formulae & structure • Understand the role in animals & plants • Water • Carbohydrates • Lipids • Proteins • Nucleic acids

  13. Water • What is it made of? • How is it chemically arranged and held together? • What does this mean for how it behaves? • How is this useful for life?

  14. Water H + O - H + • Water is a polar molecule • It forms weak hydrogen bonds • It remains a liquid over a wide temperature range • Water molecules stick to one another = cohesion (surface tension) • Water molecules stick to other substances = adhesion (capillarity)

  15. Water • It has a high specific heat capacity – so water can maintain a reasonably constant temperature (homeostasis) • It has a high latent heat of vaporisation – so animals use water to cool themselves • It is less dense as a solid (ice)… • … and ice is a poor conductor • Water is a good solvent

  16. Carbohydrates • Contain the elements Carbon Hydrogen & Oxygen • There are 3 types: • Monosaccharides • Disaccharides • Polysaccharides

  17. C C O C C C C Monosacharides • (CH2O)n • If n=3, triose (glyceraldehyde) • If n=5, pentose (fructose, ribose) • If n=6, hexose (glucose, galactose) • Monosaccharides are used for • Energy • Building blocks

  18. Isomerism • They can exist as isomers:  &  glucose OH   OH

  19. Disaccharides • Formed from two monosaccharides • Joined by a glycosidic bond • A condensation reaction: • glucose + glucose  maltose • glucose + galactose  lactose • glucose + fructose  sucrose

  20. C C C C O O C C C C C C C C Condensation reaction OH OH

  21. C C C C O O C C C C C C C C Condensation reaction OH OH

  22. C C C C O O C C C C C C C C Condensation reaction O H2O

  23. C C C C O O C C C C C C C C Condensation reaction 1 4 O A disaccharide 1,4 glycosidic bond

  24. Polysaccharides • Polymers formed from many monosaccharides • Three important examples: • Starch • Glycogen • Cellulose

  25. Amylose -glucose 1,4 glycosidic bonds Spiral structure Amylopectin -glucose 1,4 and some 1,6 glycosidic bonds Branched structure Starch Insoluble store of glucose in plantsformed from two glucose polymers:

  26. Glycogen • Insoluble compact store of glucose in animals • -glucose units • 1,4 and 1,6 glycosidic bonds • Branched structure

  27. O O O O O Cellulose • Structural polysaccharide in plants • -glucose • 1,4 glycosidic bonds • H-bonds link adjacent chains

  28. Lipids • Made up of C, H and O • Can exist as fats, oils and waxes • They are insoluble in water • They are a good source of energy (38kJ/g) • They are poor conductors of heat • Most fats & oils are triglycerides

  29. C O H H C O H H C O H H Triglycerides • Formed by esterification… • …a condensation reaction between 3 fatty acids and glycerol: Glycerol

  30. H H H H H H H C C C C C C C O C H H H H H H H O H Fatty acids • Carboxyl group (-COOH) • attached to a long non-polar hydrocarbon chain (hydrophobic): H A saturated fatty acid (no double bonds)

  31. H H H H H H H H C C C C C C C C H H H H H H H H H O C H C C O H H A monounsaturated fatty acid H H O C C H C C C O H H H A polyunsaturated fatty acid

  32. H H H H C C C C O C O H H C H H H H O C O H H H C O H H Esterification Fatty acid Glycerol

  33. H H H H C C C C O C O H H C H H H H O C O H H H C O H H Esterification Fatty acid Glycerol

  34. H H H H C C C C H H H H Esterification C O H H C O H H O C C O H O H H Fatty acid Glycerol

  35. H H H H C C C C H H H H Esterification C O H H C O H H O C C O H Ester bond O H H water

  36. Esterification • This happens three times to form a triglyceride: glycerol fatty acids

  37. Phospholipids • One fatty acid can be replaced by a polar phosphate group: hydrophilic phosphate glycerol Hydrophobic fatty acids

  38. Functions of lipids • Protection of vital organs • To prevent evaporation in plants & animals • To insulate the body • They form the myelin sheath around some neurones • As a water source (respiration of lipids) • As a component of cell membranes

  39. Research Topics • Hydrogenated fats What are they? What foods are they in? How do your bodies deal with them? Why do some people want them banned? 2) Atkins Diet Why does the diet get people to lose weight? What is the difference between how carbohydrates and fats are stored and metabolised? Why are Doctors worried about people on the diet?

  40. R O H N C C H O H H Proteins • Made from C H O N & sometimes S • Long chains of amino acids • Properties determined by the aa sequence Amino acids • ~20 aa • Glycine R=H • Alanine R=CH3 amine carboxyl

  41. R R O O H H N N C C C C H H O O H H H H Peptide bonding

  42. R R O O H H N N C C C C H H O O H H H H Peptide bonding

  43. Peptide bonding R R O O H H N C C N C C H O H H H H H O

  44. H H O Peptide bonding R R O O H H N C C N C C H O H H H Peptide bond A condensation reaction water

  45. R O H N C C H H Peptide bonding R O N C C O H H H A dipeptide

  46. Primary structure • The sequence of aas is known as the primary structure • The aa chain is a polypeptide Secondary structure • H-bonding forms between adjacent aa R groups • This results in the chains folding:

  47. Secondary structure -helix -pleated sheet

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