BiochemistryBiochemistry

Biology 20Biology 20

Chemistry of LifeChemistry of Life

• 98% to 99% of living matter is made up of 6 98% to 99% of living matter is made up of 6 atomsatoms– Carbon, Oxygen, Hydrogen, Nitrogen, Phosphorus Carbon, Oxygen, Hydrogen, Nitrogen, Phosphorus

and Sulphurand Sulphur

• Metabolism is the sum of all chemical Metabolism is the sum of all chemical reactions that take place within the cellreactions that take place within the cell

• The four most important organic compounds The four most important organic compounds are:are:– Proteins, Carbohydrates, Lipids and Nucleic AcidsProteins, Carbohydrates, Lipids and Nucleic Acids

Types of ProteinsTypes of Proteins

• Proteins function in the growth, repair and Proteins function in the growth, repair and protection of living tissueprotection of living tissue

• Special Proteins in the human body include:Special Proteins in the human body include:

NameName FunctionFunction ExampleExample

AntibodiesAntibodies Immune Immune ResponseResponse

Antibody AAntibody A

EnzymesEnzymes Catalyse Catalyse ReactionReaction

SucraseSucrase

HormonesHormones Chemical Chemical MessengersMessengers

InsulinInsulin

Protein StructureProtein Structure

• Proteins are built from 20 Proteins are built from 20 different types of amino acidsdifferent types of amino acids– 8 essential amino acids 8 essential amino acids

(obtained from food)(obtained from food)

• AA AA joined by joined by peptide peptide bondsbonds Polypeptide Chains Polypeptide Chains Proteins Proteins

• Proteins can be almost any Proteins can be almost any 3D shape, therefore the often 3D shape, therefore the often work by using a work by using a lock and lock and key fitkey fit

Chemistry of ProteinsChemistry of Proteins

• Chemically composed of C, H, O and Chemically composed of C, H, O and NN• Broke down for energy after carbohydrates and Broke down for energy after carbohydrates and

lipids (Anorexia)lipids (Anorexia)• Deamination – breakdown of proteins into amino Deamination – breakdown of proteins into amino

acidsacids– Proteins Proteins Ammonia Ammonia Urea Urea Urine Urine

(Poisonous) (Safe)(Poisonous) (Safe)

• Denaturation – a temporary change in the shape of Denaturation – a temporary change in the shape of protein do to expose to extreme heat, acidity or protein do to expose to extreme heat, acidity or radiationradiation

• Coagulation – permanent change in the shape of a Coagulation – permanent change in the shape of a protein.protein.

Leucine

Formation and Breaking of Formation and Breaking of Chemical BondsChemical Bonds

• Dehydration Synthesis – Dehydration Synthesis – removing water in order removing water in order to form a new bondto form a new bond

• Hydrolysis – using water Hydrolysis – using water to aid in the breaking of a to aid in the breaking of a bondbond

• Dehydration Synthesis Dehydration Synthesis and Hydrolysis are used and Hydrolysis are used to join or break apart to join or break apart proteins, carbohydrates proteins, carbohydrates and lipidsand lipids

Characteristics of a Characteristics of a CarbohydrateCarbohydrate

• Function: The most readily available Function: The most readily available source of energy for our body.source of energy for our body.

• Chemically composed of Carbon, Chemically composed of Carbon, Hydrogen and Oxygen in 1:2:1 ratio. Hydrogen and Oxygen in 1:2:1 ratio. CC66hh1212OO66 - glucose - glucose

Types of CarbohydratesTypes of Carbohydrates

• MonosaccharideMonosaccharide– Simple sugarsSimple sugars– Glucose (fuel for the human body), fructose, riboseGlucose (fuel for the human body), fructose, ribose

• DisaccharidesDisaccharides– Combination of two monosaccharides.Combination of two monosaccharides.– Sucrose (table sugar) – glucose and fructoseSucrose (table sugar) – glucose and fructose

• PolysaccharidesPolysaccharides– Formed from long chains of monosaccharides (joined by Formed from long chains of monosaccharides (joined by

dehydration synthesis)dehydration synthesis)– Stored form of glucose in plants and animalsStored form of glucose in plants and animals

• Starch – stored form of glucose in plantsStarch – stored form of glucose in plants• Cellulose – component of the cell wall, cannot be digested in Cellulose – component of the cell wall, cannot be digested in

humans.humans.• Glycogen – stored for of glucose in humansGlycogen – stored for of glucose in humans

Characteristics of LipidsCharacteristics of Lipids

• Lipids are used for energy, Lipids are used for energy, storage and cushioning.storage and cushioning.

• Lipids compose the cell Lipids compose the cell membrane, help with the membrane, help with the absorption of vitamins and absorption of vitamins and help build hormones.help build hormones.

• Chemically composed of Chemically composed of carbon, hydrogen and oxygen carbon, hydrogen and oxygen but in no fixed ratio.but in no fixed ratio.

• Composed of glycerol and fatty Composed of glycerol and fatty acids (joined by dehydration acids (joined by dehydration synthesis)synthesis)

Types of LipidsTypes of Lipids

• MonoglyceridesMonoglycerides– Composed of 1 glycerol and 1 Composed of 1 glycerol and 1

fatty acidfatty acid• DiglyceridesDiglycerides

– Composed of 1 glycerol and 2 Composed of 1 glycerol and 2 fatty acidsfatty acids

• TriglyceridesTriglycerides– Composed of 1 glycerol and 3 Composed of 1 glycerol and 3

fatty acidsfatty acids

Case Study – Fats and Health Pg 248Case Study – Fats and Health Pg 248

Nucleic AcidsNucleic Acids

• Building blocks of the genetic codeBuilding blocks of the genetic code• Forms the DNA which in turn is the Forms the DNA which in turn is the

molecule that makes up your molecule that makes up your chromosome (DNA – deoxyribose chromosome (DNA – deoxyribose nucleic acid)nucleic acid)

• Composed of 4 nitrogen basesComposed of 4 nitrogen bases– Adenine Adenine Thymine Thymine– Cytosine Cytosine Guanine Guanine

• NucleotideNucleotide– Sugar/Phosphate backbone and Sugar/Phosphate backbone and

nitrogen basenitrogen base

Test SubstancesTest Substances

• Benedict’s Solution – tests Benedict’s Solution – tests for monosaccharidesfor monosaccharides– Blue Blue Orange/Red Orange/Red

• Iodine – tests for starchesIodine – tests for starches– Amber Amber Blue/Black Blue/Black

• Beuret’s Reagent – tests for Beuret’s Reagent – tests for peptide bonds (proteins)peptide bonds (proteins)– Blue Blue Pink/Purple Pink/Purple

• Sudan IV Solution – tests for Sudan IV Solution – tests for lipidslipids– Clear Clear Pink/Red Pink/Red

• Translucence test (brown Translucence test (brown bag) – tests for lipidsbag) – tests for lipids– Bag becomes transparentBag becomes transparent

The Importance of WaterThe Importance of Water

• Absorbs and releases energy (moderates temperature) Absorbs and releases energy (moderates temperature) • Is the medium in which metabolic reactions take place in Is the medium in which metabolic reactions take place in

organisms organisms • Is an excellent solvent Is an excellent solvent • Composes about 60% of the cells mass Composes about 60% of the cells mass • Cushions the body organsCushions the body organs• Lubricates body parts – jointsLubricates body parts – joints• Cleaning – tears and salivaCleaning – tears and saliva• Important for the breakdown of chemicals – hydrolysis and Important for the breakdown of chemicals – hydrolysis and

dehydration synthesisdehydration synthesis• Dissolves particles for transportationDissolves particles for transportation• Provides H+ and OH- for acid-base reactionsProvides H+ and OH- for acid-base reactions• It comprises 70% of the human body It comprises 70% of the human body • Covers two-thirds of out planet ( 97% salt water, 3% fresh Covers two-thirds of out planet ( 97% salt water, 3% fresh

water)water)

Characteristics of WaterCharacteristics of Water

• Occurs in all there Occurs in all there statesstates: liquid, gas, solid : liquid, gas, solid • High freezing pointHigh freezing point (o (o degree Celsiusdegree Celsius) and high boiling ) and high boiling

point (100 point (100 degree Celsiusdegree Celsius) ) • High heat of vaporizationHigh heat of vaporization – amount of energy – amount of energy

needed to turn liquid into gas (cools our body – needed to turn liquid into gas (cools our body – sweat)sweat)

• High heat of fusionHigh heat of fusion – amount of energy needed to – amount of energy needed to turn a solid into a liquid.turn a solid into a liquid.

• CohesionCohesion – tendency of like molecules to cling – tendency of like molecules to cling together together

• AdhesionAdhesion – tendency of unlike molecules to cling – tendency of unlike molecules to cling together (capillary action)together (capillary action)

• Surface tensionSurface tension

Acids and BasesAcids and Bases

• H2O H2O H H++ + OH + OH--

• Producing acids and basesProducing acids and bases– Neutral substances HNeutral substances H++ = OH = OH--

– Acidic substances HAcidic substances H++ > OH > OH--

– Basic substances HBasic substances H++ < OH < OH--

• The pH scaleThe pH scale

• BuffersBuffers– Absorb excess fluctuations in the levels of acids and bases. Maintain a Absorb excess fluctuations in the levels of acids and bases. Maintain a

substance at a specific pH.substance at a specific pH.• NeutralizersNeutralizers

– Maintains the pH at 7.Maintains the pH at 7.• ExamplesExamples

– Stomach ph 2.4Stomach ph 2.4– Blood pH 7Blood pH 7– Vagina ph 4.5Vagina ph 4.5

EnzymesEnzymes

• Enzymes are special Enzymes are special proteins that proteins that increase the speed increase the speed (catalyze) of (catalyze) of chemical reactionschemical reactions

• Enzymes are not Enzymes are not used up in the used up in the chemical reaction.chemical reaction.

• Examples of Examples of enzymesenzymes

EnzymeEnzyme SubstrateSubstrate LocationLocation

AmylaseAmylase StarchStarch MouthMouth

ATPaseATPase ADPADP MitochondriaMitochondria

LactaseLactase LactoseLactose Sm. Sm. IntestineIntestine

LipaseLipase LipidsLipids Sm. Sm. IntestineIntestine

MaltaseMaltase MaltoseMaltose Sm. Sm. IntestineIntestine

PepsinPepsin ProteinsProteins StomachStomach

Enzyme - Lock and Key FitEnzyme - Lock and Key Fit

• Substrate – the molecule Substrate – the molecule that fits with the enzymethat fits with the enzyme

• Enzyme-Substrate Enzyme-Substrate complex – when a complex – when a molecule and enzyme molecule and enzyme become locked togetherbecome locked together

• Product – end result of the Product – end result of the reactionreaction

• Active Site – the area on Active Site – the area on the enzyme in which the the enzyme in which the substrate attaches.substrate attaches.

Rate of Enzyme ActivityRate of Enzyme Activity

• Factors that affect the rate of enzyme activity:Factors that affect the rate of enzyme activity:– TemperatureTemperature

• 37 C is optimal37 C is optimal• Colder or warmer they slow downColder or warmer they slow down• Denaturation at 45 CDenaturation at 45 C

– AcidityAcidity• pH sensitive. Designed to function of specific pHpH sensitive. Designed to function of specific pH

– Substrate ConcentrationSubstrate Concentration• Decrease substrate concentration, decrease enzyme Decrease substrate concentration, decrease enzyme

activity and visa versaactivity and visa versa– End Product ConcentrationEnd Product Concentration

• As end product concentration increases enzyme activity will As end product concentration increases enzyme activity will decreasedecrease

• Some end product are poisonous in high concentrationSome end product are poisonous in high concentration

Coenzymes and CofactorsCoenzymes and Cofactors

• Alter the active site so the enzyme Alter the active site so the enzyme will fit a new substrate. will fit a new substrate.

• Normally vitaminsNormally vitamins

Competitive InhibitorsCompetitive Inhibitors

• Block the active site of an Block the active site of an enzyme. Therefore prevents enzyme. Therefore prevents contact from the substratecontact from the substrate

• Most competitive inhibitors are Most competitive inhibitors are reversible and only temporarily reversible and only temporarily block the active site.block the active site.

• Cyanide – irreversible inhibitor. Cyanide – irreversible inhibitor. Prevents to production of ATP Prevents to production of ATP by the mitochondria.by the mitochondria.