Human Biochemistry Human Biochemistry Option BOption B

B.1 energyB.1 energy

►Calculate the energy value of a food Calculate the energy value of a food from enthalpy of combustion datafrom enthalpy of combustion data

►Energy is made available by cellular Energy is made available by cellular respirationrespiration

►Glucose + oxygen Glucose + oxygen →→►COCO22 + H + H22OO

►Other sources of energyOther sources of energy►Glycogen in the cellsGlycogen in the cells►StarchStarch►Fats and oilsFats and oils►proteinsproteins

►Women need 9,200 KJ per dayWomen need 9,200 KJ per day►Men 12,600 KJMen 12,600 KJ► If we take in too much we get fatIf we take in too much we get fat

Bomb calorimeterBomb calorimeter

► Heat = mass x 4.18 J gHeat = mass x 4.18 J g-1-1KK-1 -1 x x ΔΔ T T► Energy absorbed by water = energy Energy absorbed by water = energy

releasedreleased

►A 0.78 g sample of a food substance was A 0.78 g sample of a food substance was combusted in a bomb calorimeter and combusted in a bomb calorimeter and raised the temperature of 105.10 g of raised the temperature of 105.10 g of water from 15.4 water from 15.4 ooC to 30.6 C to 30.6 ooC. Calculate C. Calculate the energy value of the food in kJ gthe energy value of the food in kJ g-1-1

►8.56 kJ g8.56 kJ g-1-1

►AnimationAnimation►Do question 1Do question 1

B.2 ProteinsB.2 Proteins

►FunctionsFunctions►Stucture- hair, nails, connective tissue, Stucture- hair, nails, connective tissue,

muscles examples keratin, collagen, muscles examples keratin, collagen, myosinmyosin

►Enzymes example lactEnzymes example lactasease►Protective example antibodiesProtective example antibodies►Transport example haemoglobinTransport example haemoglobin►Storage Storage

structurestructure

► Polymer of the monomer amino acidPolymer of the monomer amino acid► NHNH22CHRCOOHCHRCOOH

► Called 2-amino acids because the carbon of Called 2-amino acids because the carbon of the acid is 1 carbonthe acid is 1 carbon

► The difference in amino acids is the R groupThe difference in amino acids is the R group► Look in your data booklet table 19 for the Look in your data booklet table 19 for the

common human amino acidscommon human amino acids

►Abbreviate amino acids with the first 3 Abbreviate amino acids with the first 3 lettersletters

►AlanineAlanine►AlaAla►GlycineGlycine►GlyGly►What are the R groups?What are the R groups?

►Do questions 2 and 3Do questions 2 and 3

propertiesproperties

►Crystalline solidsCrystalline solids►Mp above 200 Mp above 200 ooCC►More soluble than non-polar compoundsMore soluble than non-polar compounds►Typical of ionic compoundsTypical of ionic compounds►Dipolar ions = zwitterionsDipolar ions = zwitterions►Amphoteric = both acid (COOH) and Amphoteric = both acid (COOH) and

base(NHbase(NH33) H) H++ can move from acid to base can move from acid to base

More propertiesMore properties

►BuffersBuffers►Maintains pH in the body cellsMaintains pH in the body cells►Must be about 7.4Must be about 7.4►<6.9 can be deadly<6.9 can be deadly►Each one has an isoelectric point where it Each one has an isoelectric point where it

is neutralis neutral►Lower pH +ion H on the NHLower pH +ion H on the NH33<isoelectric <isoelectric

point<higher pH – ion lose H off the COOHpoint<higher pH – ion lose H off the COOH

Isoelectric pointIsoelectric point

►Gly 6.0Gly 6.0►Ala 6.0Ala 6.0►Lysine 9.7Lysine 9.7►Aspartic acid 2.8Aspartic acid 2.8►Does the R group contain and acid or Does the R group contain and acid or

base?base?

Condensation reactions form Condensation reactions form peptide bondspeptide bonds

►Show how the tripeptide Cys-Val-Asn Show how the tripeptide Cys-Val-Asn formsforms

►OH comes off the acid H off the amineOH comes off the acid H off the amine►What other tripeptides can form from What other tripeptides can form from

this? They are different because of the this? They are different because of the sequence. This is the primary structuresequence. This is the primary structure

►20 amino acids can form 8000 20 amino acids can form 8000 tripeptides 20 x 20 x 20tripeptides 20 x 20 x 20

►Proteins are at least 50 amino acids Proteins are at least 50 amino acids 20205050 types types

►Change one and the function changes Change one and the function changes ie sickle cell anaemia 146 amino acidsie sickle cell anaemia 146 amino acids

►Made by DNA, RNA in the ribosomesMade by DNA, RNA in the ribosomes

Secondary structureSecondary structure

►Folding of the chain due to the H Folding of the chain due to the H bonding on the peptide groupsbonding on the peptide groups

► Influenced by R groupsInfluenced by R groups►ΑΑ-helix 4 amino acids apart-helix 4 amino acids apart►Like a spiral staircaseLike a spiral staircase►Flexible and elastic like hair,skin, nails Flexible and elastic like hair,skin, nails

(keratin)(keratin)

►ββ-pleated sheet-pleated sheet►Side by side inter-chain H bondsSide by side inter-chain H bonds► Inelastic ie silk, claws, beaksInelastic ie silk, claws, beaks►Tough, insoluble in waterTough, insoluble in water

Tertiary structureTertiary structure

►Overall shape due to the R groupsOverall shape due to the R groups►ConformationConformation► Intra-molecular forces disulfide Intra-molecular forces disulfide

bridge, ionic bond, H bonds, van der bridge, ionic bond, H bonds, van der Waals forcesWaals forces

Globular proteinsGlobular proteins

►enzymes and hormonesenzymes and hormones►Water soluble –polar R groups on Water soluble –polar R groups on

outsideoutside► Insoluble on the insideInsoluble on the inside►Forces Hydrophobic interactions, H Forces Hydrophobic interactions, H

bonding, Ionic bonding, Disulfide bonding, Ionic bonding, Disulfide bridgesbridges

PermingPerming

►Break disulfide bridges in cysteine use Break disulfide bridges in cysteine use a reducing agenta reducing agent

►Reoxidize around rollers form new Reoxidize around rollers form new disulfide bridgesdisulfide bridges

DenatureDenature

►Messing with the tertiary structureMessing with the tertiary structure►With temperature and pHWith temperature and pH►EggsEggs►Make them biologically activeMake them biologically active

Quaternary structureQuaternary structure

►More than one polypeptide chainMore than one polypeptide chain►Association between chainsAssociation between chains►Collagen in skin and tendons is a triple Collagen in skin and tendons is a triple

helix with rope like structurehelix with rope like structure►animationanimation

HemoglobinHemoglobin

►4 polypeptides4 polypeptides►2 alpha 2 beta2 alpha 2 beta

►Do question 4Do question 4

AnalysisAnalysis

►What is its amino acids composition?What is its amino acids composition?

Reverse the condensation reaction with Reverse the condensation reaction with acid and water to break apart the acid and water to break apart the chainchain

chromatographychromatography

►Lab activityLab activity

electrophoresiselectrophoresis

►AnimationAnimation►Lab activityLab activity►Do question 1 page 496 and 2-4 page Do question 1 page 496 and 2-4 page

497497

B.3 CarbohydratesB.3 Carbohydrates

►C compounds with HC compounds with H22O 1:2:1 rateO 1:2:1 rate

►Simple sugars (monosaccharides)Simple sugars (monosaccharides)►polysaccharidespolysaccharides

FunctionsFunctions

►Source of energySource of energy►Precursors to other moleculesPrecursors to other molecules►StorageStorage►Cellulose in plantsCellulose in plants

monosaccharidesmonosaccharides

►TriTrioses,oses, pentoses, hexoses pentoses, hexoses►Very solubleVery soluble►2 or more hydroxyl and a carbonyl 2 or more hydroxyl and a carbonyl

groupgroup►Form rings when dissolved in waterForm rings when dissolved in water

aldosesaldoses

►Carbonyl on the end of the dry crystalCarbonyl on the end of the dry crystal►GlucoseGlucose►Know straight and ringKnow straight and ring

ringring

► In water =O breaks and attaches to In water =O breaks and attaches to the 5 carbon the 5 carbon

►drawdraw ???

ketosesketoses

►Ketone on the 2Ketone on the 2ndnd carbon carbon► in the ring =O and attaches to the 5 in the ring =O and attaches to the 5

carboncarbon

Alpha and beta formsAlpha and beta forms

►Alpha OH below the plane on carbon 1Alpha OH below the plane on carbon 1►Beta OH above the planeBeta OH above the plane

DisaccharidesDisaccharides

►Maltose 2 alpha glucoseMaltose 2 alpha glucose►Lactose Lactose ββ-glucose and -glucose and ββ-galactose -galactose

found in milkfound in milk►Sucrose Sucrose αα-glucose and -glucose and ββ-fructose -fructose

(table sugar)(table sugar)►Attaches from the 1 and 4 carbonAttaches from the 1 and 4 carbon

polysaccharidespolysaccharides

►Starch polymer of alpha glucose 1-4 Starch polymer of alpha glucose 1-4 linkagelinkage

►Plant storage energy moleculePlant storage energy molecule►2 forms amylose straight chain2 forms amylose straight chain

►Amylopectin side group off every other Amylopectin side group off every other glucose 6-1 linkageglucose 6-1 linkage

►Both are a compact spiral structureBoth are a compact spiral structure

glycogenglycogen

►Animal starchAnimal starch►Stored in the liver and musclesStored in the liver and muscles►Polymer of alpha glucosePolymer of alpha glucose►Like amylopectin but more side Like amylopectin but more side

linkageslinkages

cellulosecellulose

►Plant structurePlant structure►Polymer of Polymer of ββ-glucose-glucose►Uncoiled allowing H bondingUncoiled allowing H bonding►Forms microfibrils with parallel chainsForms microfibrils with parallel chains►Woody type structureWoody type structure

Dietary fiberDietary fiber

►Doesn’t digestDoesn’t digest►Abrade the digestive tract lining Abrade the digestive tract lining

making it produce mucousmaking it produce mucous►Whole grainsWhole grains

►Do question 5 and 6Do question 5 and 6►Question 5 page 501Question 5 page 501

B.3 LipidsB.3 Lipids

► Insoluble in waterInsoluble in water►Oily nonpolar moleculesOily nonpolar molecules►Less oxidized moleculesLess oxidized molecules►Oils, steroids, fats, phospholipidsOils, steroids, fats, phospholipids

functionsfunctions

►Variety of rolesVariety of roles►Storage of energy- they release more Storage of energy- they release more

energy because they can be oxidized energy because they can be oxidized moremore

►2x per gram of carbohydrate2x per gram of carbohydrate

►HormonesHormones►Cell membranesCell membranes► insulationinsulation

problemsproblems

►ObesityObesity►Atherosclerosis fats, cholesterolAtherosclerosis fats, cholesterol

CholesterolCholesterol

►LDL Low density lipoprotein (bad?)LDL Low density lipoprotein (bad?)►Lots of this means it gets deposited on Lots of this means it gets deposited on

the walls of arteriesthe walls of arteries►Sources are saturated and trans fatsSources are saturated and trans fats

►HDL high density lipoprotein (good?)HDL high density lipoprotein (good?)►Seem to protect against heart diseaseSeem to protect against heart disease►Tends to carry LDL away from arteriesTends to carry LDL away from arteries

DietDiet

►Decrease saturated and trans fats Decrease saturated and trans fats (tend to be solid)(tend to be solid)

► Increase polyunsaturated (fish, nuts, Increase polyunsaturated (fish, nuts, corn oil)corn oil)

►Essential fatty acids (cannot be Essential fatty acids (cannot be manufactured by body) omega-3-manufactured by body) omega-3-polyunsaturated fatty acid polyunsaturated fatty acid

Structure of triglyceridesStructure of triglycerides

►Glycerol and 3 fatty acidsGlycerol and 3 fatty acids

Essential fatty acidsEssential fatty acids

►Linoleic acid (omega-6-fatty acid) Linoleic acid (omega-6-fatty acid) CHCH33(CH(CH22))44(CH=CHCH(CH=CHCH22))22(CH(CH22))66COOHCOOH

►Linolenic acid (omega-3-fatty acid) Linolenic acid (omega-3-fatty acid) CHCH33CHCH22(CH=CHCH(CH=CHCH22))33(CH(CH22))66COOH COOH

►Number refers to position of the first Number refers to position of the first double bond omega distance from the double bond omega distance from the first Cfirst C

►Cannot be made in the human bodyCannot be made in the human body

► Involved in lowering blood pressure by Involved in lowering blood pressure by synthesizing postaglandinssynthesizing postaglandins

►Lower LDL cholesterolLower LDL cholesterol

Determining unsaturationDetermining unsaturation

► II22 breaks the double bond breaks the double bond

► Iodine number grams of Iodine that Iodine number grams of Iodine that reacts with 100 g of fatreacts with 100 g of fat

►Linoleic acid has the formula CLinoleic acid has the formula C1818HH3232OO22 Determine the iodine number of Determine the iodine number of linoleic acid.linoleic acid.

►2 C=C bonds2 C=C bonds►Mm Linoleic acid 280 g molMm Linoleic acid 280 g mol-1-1 mm I mm I22

254254►280 g reacts with 508 g I280 g reacts with 508 g I22

► Iodine number is 181Iodine number is 181

Partially hydrogenated fatPartially hydrogenated fat

►Oils more solid by adding HOils more solid by adding H22 to C=C to C=C

►More convenient packingMore convenient packing►Break down lessBreak down less►Remaining C=C go to trans forms Remaining C=C go to trans forms

(trans fat)(trans fat)►Trans fat = decreased HDL increased Trans fat = decreased HDL increased

LDLLDL

Digestion of fatsDigestion of fats

►LipasesLipases►Slow to digestSlow to digest

phospholipidsphospholipids

►Glycerol and 2 fatty acids with a Glycerol and 2 fatty acids with a phosphatephosphate

►Differ in fatty acids and what is Differ in fatty acids and what is attached to the phosphateattached to the phosphate

►Hydrophilic head and hydrophobic Hydrophilic head and hydrophobic interiorinterior

steroidssteroids

►Four fused ringsFour fused rings►Pg 509 in your textbookPg 509 in your textbook►LDL transports cholesterolLDL transports cholesterol

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