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Human Biochemistry Option B. B.1 energy ► Calculate the energy value of a food from enthalpy of combustion data ► Energy is made available by cellular.

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Presentation on theme: "Human Biochemistry Option B. B.1 energy ► Calculate the energy value of a food from enthalpy of combustion data ► Energy is made available by cellular."— Presentation transcript:

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 → ► CO 2 + H 2 O

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 -1 K -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 g of water from 15.4 o C to 30.6 o C. Calculate the energy value of the food in kJ g -1 ► 8.56 kJ g -1

7 ► Animation 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 ► NH 2 CHRCOOH ► 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 o C ► More soluble than non-polar compounds ► Typical of ionic compounds ► Dipolar ions = zwitterions ► Amphoteric = both acid (COOH) and base(NH 3 ) 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 NH 3

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 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 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 Animation ► Lab activity ► Do question 1 page 496 and 2-4 page 497

29 B.3 Carbohydrates ► C compounds with H 2 O 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 2 nd 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

51

52 Essential fatty acids ► Linoleic acid (omega-6-fatty acid) CH 3 (CH 2 ) 4 (CH=CHCH 2 ) 2 (CH 2 ) 6 COOH ► Linolenic acid (omega-3-fatty acid) CH 3 CH 2 (CH=CHCH 2 ) 3 (CH 2 ) 6 COOH ► Number refers to position of the first double bond omega distance from the first C ► Cannot be made in the human body ► Cannot be made in the human body

53 ► Involved in lowering blood pressure by synthesizing postaglandins ► Lower LDL cholesterol

54 Determining unsaturation ► I 2 breaks the double bond ► Iodine number grams of Iodine that reacts with 100 g of fat ► Linoleic acid has the formula C 18 H 32 O 2 Determine the iodine number of linoleic acid.

55 ► 2 C=C bonds ► Mm Linoleic acid 280 g mol -1 mm I ► 280 g reacts with 508 g I 2 ► Iodine number is 181

56 Partially hydrogenated fat ► Oils more solid by adding H 2 to C=C ► More convenient packing ► Break down less ► Remaining C=C go to trans forms (trans fat) ► Trans fat = decreased HDL increased LDL

57 Digestion of fats ► Lipases ► Slow to digest

58 phospholipids ► Glycerol and 2 fatty acids with a phosphate ► Differ in fatty acids and what is attached to the phosphate ► Hydrophilic head and hydrophobic interior

59 steroids ► Four fused rings ► Pg 509 in your textbook ► LDL transports cholesterol

60 ► Do questions 7 and 8 ► Do question 6 page 509 ► Web quiz Web quiz Web quiz


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