Human Biochemistry Option B

1. Human Biochemistry Option B

2. B.1 energy • Calculate the energy value of a food from enthalpy of combustion data • Energy is made available by cellular respiration • Glucose + oxygen → • CO2 + H2O

3. Other sources of energy • Glycogen in the cells • Starch • Fats and oils • proteins

4. Women need 9,200 KJ per day • Men 12,600 KJ • If we take in too much we get fat

5. Bomb calorimeter • Heat = mass x 4.18 J g-1K-1 x Δ T • Energy absorbed by water = energy released

6. A 0.78 g sample of a food substance was combusted in a bomb calorimeter and raised the temperature of 105.10 g of water from 15.4 oC to 30.6 oC. Calculate the energy value of the food in kJ g-1 • 8.56 kJ g-1

7. Animation • Do question 1

8. B.2 Proteins • Functions • Stucture- hair, nails, connective tissue, muscles examples keratin, collagen, myosin • Enzymes example lactase • Protective example antibodies • Transport example haemoglobin • Storage

9. structure • Polymer of the monomer amino acid • NH2CHRCOOH • Called 2-amino acids because the carbon of the acid is 1 carbon • The difference in amino acids is the R group • Look in your data booklet table 19 for the common human amino acids

10. Abbreviate amino acids with the first 3 letters • Alanine • Ala • Glycine • Gly • What are the R groups?

11. Do questions 2 and 3

12. properties • Crystalline solids • Mp above 200 oC • More soluble than non-polar compounds • Typical of ionic compounds • Dipolar ions = zwitterions • Amphoteric = both acid (COOH) and base(NH3) H+ can move from acid to base

13. More properties • Buffers • Maintains pH in the body cells • Must be about 7.4 • <6.9 can be deadly • Each one has an isoelectric point where it is neutral • Lower pH +ion H on the NH3<isoelectric point<higher pH – ion lose H off the COOH

14. Isoelectric point • Gly 6.0 • Ala 6.0 • Lysine 9.7 • Aspartic acid 2.8 • Does the R group contain and acid or base?

15. Condensation reactions form peptide bonds • Show how the tripeptide Cys-Val-Asn forms • OH comes off the acid H off the amine • What other tripeptides can form from this? They are different because of the sequence. This is the primary structure

16. 20 amino acids can form 8000 tripeptides 20 x 20 x 20 • Proteins are at least 50 amino acids 2050 types • Change one and the function changes ie sickle cell anaemia 146 amino acids • Made by DNA, RNA in the ribosomes

17. Secondary structure • Folding of the chain due to the H bonding on the peptide groups • Influenced by R groups • Α-helix 4 amino acids apart • Like a spiral staircase • Flexible and elastic like hair,skin, nails (keratin)

18. β-pleated sheet • Side by side inter-chain H bonds • Inelastic ie silk, claws, beaks • Tough, insoluble in water

19. Tertiary structure • Overall shape due to the R groups • Conformation • Intra-molecular forces disulfide bridge, ionic bond, H bonds, van der Waals forces

20. Globular proteins • enzymes and hormones • Water soluble –polar R groups on outside • Insoluble on the inside • Forces Hydrophobic interactions, H bonding, Ionic bonding, Disulfide bridges

21. Perming • Break disulfide bridges in cysteine use a reducing agent • Reoxidize around rollers form new disulfide bridges

22. Denature • Messing with the tertiary structure • With temperature and pH • Eggs • Make them biologically active

23. Quaternary structure • More than one polypeptide chain • Association between chains • Collagen in skin and tendons is a triple helix with rope like structure • animation

24. Hemoglobin • 4 polypeptides • 2 alpha 2 beta

25. Do question 4

26. Analysis • What is its amino acids composition? Reverse the condensation reaction with acid and water to break apart the chain

27. chromatography • Lab activity

28. electrophoresis • Animation • Lab activity • Do question 1 page 496 and 2-4 page 497

29. B.3 Carbohydrates • C compounds with H2O 1:2:1 rate • Simple sugars (monosaccharides) • polysaccharides

30. Functions • Source of energy • Precursors to other molecules • Storage • Cellulose in plants

31. monosaccharides • Trioses, pentoses, hexoses • Very soluble • 2 or more hydroxyl and a carbonyl group • Form rings when dissolved in water

32. aldoses • Carbonyl on the end of the dry crystal • Glucose • Know straight and ring

33. ring • In water =O breaks and attaches to the 5 carbon • draw ???

34. ketoses • Ketone on the 2nd carbon • in the ring =O and attaches to the 5 carbon

35. Alpha and beta forms • Alpha OH below the plane on carbon 1 • Beta OH above the plane

36. Disaccharides • Maltose 2 alpha glucose • Lactose β-glucose and β-galactose found in milk • Sucrose α-glucose and β-fructose (table sugar) • Attaches from the 1 and 4 carbon

37. polysaccharides • Starch polymer of alpha glucose 1-4 linkage • Plant storage energy molecule • 2 forms amylose straight chain

38. Amylopectin side group off every other glucose 6-1 linkage • Both are a compact spiral structure

39. glycogen • Animal starch • Stored in the liver and muscles • Polymer of alpha glucose • Like amylopectin but more side linkages

40. cellulose • Plant structure • Polymer of β-glucose • Uncoiled allowing H bonding • Forms microfibrils with parallel chains • Woody type structure

41. Dietary fiber • Doesn’t digest • Abrade the digestive tract lining making it produce mucous • Whole grains

42. Do question 5 and 6 • Question 5 page 501

43. B.3 Lipids • Insoluble in water • Oily nonpolar molecules • Less oxidized molecules • Oils, steroids, fats, phospholipids

44. functions • Variety of roles • Storage of energy- they release more energy because they can be oxidized more • 2x per gram of carbohydrate

45. Hormones • Cell membranes • insulation

46. problems • Obesity • Atherosclerosis fats, cholesterol

47. Cholesterol • LDL Low density lipoprotein (bad?) • Lots of this means it gets deposited on the walls of arteries • Sources are saturated and trans fats

48. HDL high density lipoprotein (good?) • Seem to protect against heart disease • Tends to carry LDL away from arteries

49. Diet • Decrease saturated and trans fats (tend to be solid) • Increase polyunsaturated (fish, nuts, corn oil) • Essential fatty acids (cannot be manufactured by body) omega-3-polyunsaturated fatty acid

50. Structure of triglycerides • Glycerol and 3 fatty acids