Human Biochemistry Option B

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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
  respiration
► Glucose + oxygen →
► CO2 + H2O
► Other sources of energy
► Glycogen in the cells
► Starch
► Fats and oils
► proteins
► Women   need 9,200 KJ per day
► Men 12,600 KJ
► If we take in too much we get fat
           Bomb calorimeter




► Heat = mass x 4.18 J g-1K-1 x Δ T
► Energy absorbed by water = energy released
►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
► Animation
► Do   question 1
              B.2 Proteins
► Functions
► Stucture- hair, nails, connective tissue,
  muscles examples keratin, collagen, myosin
► Enzymes example lactase
► Protective example antibodies
► Transport example haemoglobin
► Storage
                  structure
        of the monomer amino acid
► Polymer
► 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
► Abbreviate   amino acids with the first 3
  letters
► Alanine
► Ala
► Glycine
► Gly
► What are the R groups?
► Do   questions 2 and 3
                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
              More properties
► Buffers
► MaintainspH 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
           Isoelectric point
► Gly 6.0
► Ala 6.0
► Lysine 9.7
► Aspartic acid 2.8
► Does the R group contain and acid or base?
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
► 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
            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)
► β-pleated  sheet
► Side by side inter-chain H bonds
► Inelastic ie silk, claws, beaks
► Tough, insoluble in water
            Tertiary structure
► Overall shape due to the R groups
► Conformation
► Intra-molecular forces disulfide bridge,
  ionic bond, H bonds, van der Waals forces
            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
                 Perming
► Break disulfide bridges in cysteine use a
  reducing agent
► Reoxidize around rollers form new disulfide
  bridges
                 Denature
► Messing with the tertiary structure
► With temperature and pH
► Eggs
► Make them biologically active
         Quaternary structure
► More  than one polypeptide chain
► Association between chains
► Collagen in skin and tendons is a triple helix
  with rope like structure
► animation
              Hemoglobin
►4  polypeptides
► 2 alpha 2 beta
► Do   question 4
                 Analysis
► What is its amino acids composition?
Reverse the condensation reaction with acid
 and water to break apart the chain
              chromatography
► Lab   activity
              electrophoresis
► Animation
► Lab activity
► Do question 1 page 496 and 2-4 page 497
         B.3 Carbohydrates
►C  compounds with H2O 1:2:1 rate
► Simple sugars (monosaccharides)
► polysaccharides
                Functions
► Source  of energy
► Precursors to other molecules
► Storage
► Cellulose in plants
             monosaccharides
► Trioses,pentoses, hexoses
► Very soluble
► 2 or more hydroxyl and a carbonyl group
► Form rings when dissolved in water
                   aldoses
► Carbonyl   on the end of the dry crystal
► Glucose
► Know   straight and ring
                   ring
► In water =O breaks and attaches to the 5
  carbon
► draw                        ???
                 ketoses
► Ketone   on the 2nd carbon
► in the ring =O and attaches to the 5 carbon
          Alpha and beta forms
► Alpha OH below the plane on carbon 1
► Beta OH above the plane
             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
            polysaccharides
► Starch polymer of alpha glucose 1-4 linkage
► Plant storage energy molecule
► 2 forms amylose straight chain
► Amylopectin  side group off every other
  glucose 6-1 linkage
► Both are a compact spiral structure
                glycogen
► Animal starch
► Stored in the liver and muscles
► Polymer of alpha glucose
► Like amylopectin but more side linkages
                  cellulose
► Plantstructure
► Polymer of β-glucose
► Uncoiled allowing H bonding
► Forms microfibrils with parallel chains
► Woody type structure
               Dietary fiber
► Doesn’t digest
► Abrade the digestive tract lining making it
  produce mucous
► Whole grains
► Doquestion 5 and 6
► Question 5 page 501
                 B.3 Lipids
► Insoluble  in water
► Oily nonpolar molecules
► Less oxidized molecules
► Oils, steroids, fats, phospholipids
                functions
► Variety of roles
► Storage of energy- they release more
  energy because they can be oxidized more
► 2x per gram of carbohydrate
► Hormones
► Cellmembranes
► insulation
                    problems
► Obesity
► Atherosclerosis   fats, cholesterol
               Cholesterol
► LDL  Low density lipoprotein (bad?)
► Lots of this means it gets deposited on the
  walls of arteries
► Sources are saturated and trans fats
► HDL high density lipoprotein (good?)
► Seem to protect against heart disease
► Tends to carry LDL away from arteries
                     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
      Structure of triglycerides
► Glycerol   and 3 fatty acids
             Essential fatty acids
► Linoleicacid (omega-6-fatty acid)
  CH3(CH2)4(CH=CHCH2)2(CH2)6COOH
► Linolenic acid (omega-3-fatty acid)
  CH3CH2(CH=CHCH2)3(CH2)6COOH
► Number refers to position of the first double
  bond omega distance from the first C
► Cannot be made in the human body
► Involved in lowering blood pressure by
  synthesizing postaglandins
► Lower LDL cholesterol
       Determining unsaturation
► I2 breaks the double bond
► Iodine number grams of Iodine that reacts
  with 100 g of fat
► Linoleic acid has the formula C18H32O2
  Determine the iodine number of linoleic
  acid.
►2  C=C bonds
► Mm Linoleic acid 280 g mol-1 mm I2 254
► 280 g reacts with 508 g I2
► Iodine number is 181
         Partially hydrogenated fat
► Oilsmore solid by adding H2 to C=C
► More convenient packing
► Break down less
► Remaining C=C go to trans forms (trans fat)
► Trans fat = decreased HDL increased LDL
             Digestion of fats
► Lipases
► Slow   to digest
              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
                 steroids
► Four fused rings
► Pg 509 in your textbook
► LDL transports cholesterol
► Do questions 7 and 8
► Do question 6 page 509
► Web quiz

				
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