11

The Chemical ElementsThe Chemical Elements

Element = simplest form of matter with Element = simplest form of matter with unique chemical propertiesunique chemical properties

Atomic number = # of protons in nucleusAtomic number = # of protons in nucleus periodic table periodic table

• elements arranged by atomic numberelements arranged by atomic number 24 elements have biological role24 elements have biological role

• 6 elements = 98.5% of body weight 6 elements = 98.5% of body weight • Carbon, Hydrogen, Oxygen, NitrogenCarbon, Hydrogen, Oxygen, Nitrogen• trace elements in minute amountstrace elements in minute amounts

22

Terms to knowTerms to know ElementElement

matter composed of atoms that all have the same atomic number (protons). matter composed of atoms that all have the same atomic number (protons). AtomAtom

the smallest component of an element that still has properties of the element, the smallest component of an element that still has properties of the element, consisting of a positively charged nucleus surrounded by a charged cloud of consisting of a positively charged nucleus surrounded by a charged cloud of electrons. electrons.

"+" and "-" charges strongly attract. "+" and "-" charges strongly attract. ProtonProton

particle in the nucleus with a positive charge of +1 and an atomic mass number particle in the nucleus with a positive charge of +1 and an atomic mass number of 1 Dalton. of 1 Dalton.

NeutronNeutron a non-charged nuclear particle with the same mass as the proton. a non-charged nuclear particle with the same mass as the proton.

ElectronElectron negatively charged particle (-1) with a mass 1/1837 of that of a proton. negatively charged particle (-1) with a mass 1/1837 of that of a proton.

IsotopeIsotope atoms with the same number of protons and electrons, but different numbers of atoms with the same number of protons and electrons, but different numbers of

neutrons. neutrons.

33

Structure of an AtomStructure of an Atom Nucleus = center of atomNucleus = center of atom

protonsprotons neutronsneutrons

Electron shells surround the nucleusElectron shells surround the nucleus electrons: single negative charge, little masselectrons: single negative charge, little mass valence electrons in the outermost shellvalence electrons in the outermost shell

• interact with other atomsinteract with other atoms• determine chemical behaviordetermine chemical behavior

44

ElectrolytesElectrolytes

Salts that ionize in water to form body Salts that ionize in water to form body fluidsfluids capable of conducting electricitycapable of conducting electricity

Electrolyte importanceElectrolyte importance chemical reactivitychemical reactivity osmotic effects (influence water movement)osmotic effects (influence water movement) electrical effects on nerve and muscle tissueelectrical effects on nerve and muscle tissue

Imbalances cause muscle cramps, brittle Imbalances cause muscle cramps, brittle bones, coma and deathbones, coma and death

55

Free RadicalsFree Radicals Particle with an odd number of electronsParticle with an odd number of electrons Produced by Produced by

normal metabolic reactions, radiation, normal metabolic reactions, radiation, chemicals chemicals

Causes tissue damageCauses tissue damage reactions that destroy moleculesreactions that destroy molecules causes cancer, death of heart tissue and causes cancer, death of heart tissue and

agingaging

AntioxidantsAntioxidants neutralize free radicalsneutralize free radicals in diet (vitamin E, carotenoids, vitamin C)in diet (vitamin E, carotenoids, vitamin C)

66

Molecules and Chemical BondsMolecules and Chemical Bonds

MoleculesMolecules two or more atoms covalently bondedtwo or more atoms covalently bonded

CompoundsCompounds two or more atoms of different elements two or more atoms of different elements

covalently bondedcovalently bonded

Molecular formula Molecular formula elements and how many atoms of eachelements and how many atoms of each

Structural formulaStructural formula location of each atomlocation of each atom structural isomers revealedstructural isomers revealed

77

Chemical BondsChemical Bonds

Ionic bondsIonic bonds Covalent bondsCovalent bonds Hydrogen bondsHydrogen bonds Van der Waals forceVan der Waals force

88

Ionic BondsIonic Bonds

Attraction of oppositely charged ions Attraction of oppositely charged ions No sharing of electronsNo sharing of electrons Weak bond (easily dissociates in water)Weak bond (easily dissociates in water)

99

Covalent BondsCovalent Bonds Formed by sharing of valence electronsFormed by sharing of valence electrons Types of covalent bondsTypes of covalent bonds

single = sharing of single pair electronssingle = sharing of single pair electrons double = sharing of 2 pairsdouble = sharing of 2 pairs nonpolarnonpolar

• shared electrons (equal time around each nucleus)shared electrons (equal time around each nucleus)• strongest of all bondsstrongest of all bonds

polarpolar• negative charge where electrons spend most timenegative charge where electrons spend most time

1010

Properties of waterProperties of water

Terms we should knowTerms we should know Hydrophilic (charged substances) dissolve Hydrophilic (charged substances) dissolve

easily in watereasily in water Hydrophobic (neutral substances) do not Hydrophobic (neutral substances) do not

easily dissolve in watereasily dissolve in water Water = universal solventWater = universal solvent

metabolic reactions and transport of metabolic reactions and transport of substancessubstances

1111

Water as a SolventWater as a Solvent

Polar water molecules overpower the ionic Polar water molecules overpower the ionic bond in Nabond in Na++ClCl- -

forming hydration spheres around each ion forming hydration spheres around each ion

1212

Cohesiveness of waterCohesiveness of water

Cohesion – tendency of like molecules Cohesion – tendency of like molecules to cling to each otherto cling to each other water is very cohesive due to its hydrogen water is very cohesive due to its hydrogen

bondsbonds surface film on water formed by surface surface film on water formed by surface

tensiontension

1313

Chemical Reactivity of WaterChemical Reactivity of Water

Participation in chemical reactionsParticipation in chemical reactions water ionizes into Hwater ionizes into H++ and OH and OH--

water ionizes other chemicals (acids and water ionizes other chemicals (acids and salts)salts)

water involved in hydrolysis and water involved in hydrolysis and dehydration synthesis reactionsdehydration synthesis reactions

1414

Thermal Stability of WaterThermal Stability of Water

Water stabilizes internal temperature Water stabilizes internal temperature has high heat capacityhas high heat capacity

• hydrogen bonds inhibit temperature increases hydrogen bonds inhibit temperature increases by inhibiting molecular motionby inhibiting molecular motion

effective coolanteffective coolant• 1 ml of perspiration removes 500 calories1 ml of perspiration removes 500 calories

calorie: amount of heat required to raise temperature calorie: amount of heat required to raise temperature of 1g of water by 1°Cof 1g of water by 1°C

1515

SolutionsSolutions

Mixture of a solute Mixture of a solute into a solventinto a solvent

Small solute Small solute particles particles Can pass through Can pass through

cell membranescell membranes

1616

ColloidsColloids Mixture of protein Mixture of protein

and waterand water change from liquid change from liquid

to gel state within to gel state within and between cellsand between cells

Particles too large Particles too large to pass through cell to pass through cell membranesmembranes

CloudyCloudy Remains mixedRemains mixed

1717

MolarityMolarity

Molecular weight in grams = 1 mole of Molecular weight in grams = 1 mole of moleculesmolecules

1 mole = Avogadro’s number of 1 mole = Avogadro’s number of moleculesmolecules

Molarity is the number of moles of Molarity is the number of moles of solute/ liter of solutionsolute/ liter of solution MW of glucose is 180MW of glucose is 180 one-molar (1.0M) glucose solution one-molar (1.0M) glucose solution

contains 180g/L contains 180g/L

1818

Electrolyte ConcentrationsElectrolyte Concentrations

Effect the body chemically, physically and Effect the body chemically, physically and electricallyelectrically depends on charge and concentrationdepends on charge and concentration

Measured in equivalentsMeasured in equivalents 1 Eq will electrically neutralize 1 mole of H1 Eq will electrically neutralize 1 mole of H++ or OH or OH--

ionsions multiply molar concentration x valence of the ionmultiply molar concentration x valence of the ion 1 M Na1 M Na++ = 1 Eq/L = 1 Eq/L 1 M Ca1 M Ca2+2+ = 2 Eq/L = 2 Eq/L

1919

Acids, Bases and pHAcids, Bases and pH

An acid is proton donor (releases HAn acid is proton donor (releases H++ ions) ions) A base is proton acceptor (accepts HA base is proton acceptor (accepts H++ ions) ions) pH = the concentration of HpH = the concentration of H++ ions in ions in

solutionsolution a pH of less than 7 is acidic solutiona pH of less than 7 is acidic solution a pH of greater than 7 is basic solutiona pH of greater than 7 is basic solution a pH of 7.0 is neutral pHa pH of 7.0 is neutral pH

2020

pHpH

Our body uses buffers to prevent changeOur body uses buffers to prevent change pH of blood ranges from 7.35 to 7.45pH of blood ranges from 7.35 to 7.45 tremors, paralysis or even deathtremors, paralysis or even death

2121

pH ScalepH Scale

2222

Work and EnergyWork and Energy

Energy - capacity to do workEnergy - capacity to do work Kinetic energy - energy of motion Kinetic energy - energy of motion

heat is kinetic energy of molecular heat is kinetic energy of molecular motionmotion

Potential energy- energy due to Potential energy- energy due to object’s position (ions on one side object’s position (ions on one side only of cell membrane)only of cell membrane) chemical energy - potential energy chemical energy - potential energy

stored in the molecular bondsstored in the molecular bonds

2323

Chemical ReactionChemical Reaction Process that forms or breaks an Process that forms or breaks an

ionic or covalent bondionic or covalent bond Symbolized by chemical equationSymbolized by chemical equation

reactants reactants products products

Classes of reactionsClasses of reactions Decomposition reactionsDecomposition reactions Synthesis reactionsSynthesis reactions Exchange reactionsExchange reactions

2424

Decomposition Decomposition ReactionsReactions

Large molecules Large molecules broken down into broken down into smaller onessmaller ones

AB AB A + B A + B

2525

Synthesis Synthesis ReactionsReactions

Two or more small Two or more small molecules combine to molecules combine to form a larger oneform a larger one

A + B A + B AB AB

2626

Exchange ReactionsExchange Reactions Two molecules collide and exchange Two molecules collide and exchange

atoms or group of atomsatoms or group of atoms AB+CD AB+CD ABCD ABCD AC + BD AC + BD

2727

Reversible ReactionsReversible Reactions

Go in either direction (symbolized with Go in either direction (symbolized with double-headed arrow)double-headed arrow)

COCO22 + H + H22O HO H22COCO33 HCO HCO3-3- + H + H++

most common equation discussed in this most common equation discussed in this bookbook

Law of mass action determines Law of mass action determines directiondirection side of equation with greater quantity of side of equation with greater quantity of

reactants dominates reactants dominates

2828

Chemical BookkeepingChemical Bookkeeping

Chemical equation shows reactionChemical equation shows reaction

Reactants ---> ProductsReactants ---> Products Equation for photosynthesis:Equation for photosynthesis:

REACTANTS PRODUCTS

6CO2

CARBONDIOXIDE

12H2O

WATER

+ C6H12O6

GLUCOSE

6H2O

WATER

+

6 carbons12 oxygens

24 hydrogens12 oxygens

6 carbons12 hydrogens

6 oxygens

12 hydrogens6 oxygens

6O2

OXYGEN

+

12 oxygens

sunlightenergy

2929

Reaction RatesReaction Rates Basis for reactions is molecular motion and Basis for reactions is molecular motion and

collisionscollisions reactions occur when molecules collide with enough reactions occur when molecules collide with enough

force and the correct orientationforce and the correct orientation

Reaction Rates affected by:Reaction Rates affected by: concentrationconcentration

• more concentrated, more collisions, faster ratemore concentrated, more collisions, faster rate temperaturetemperature

• higher temperature, greater collision force, faster ratehigher temperature, greater collision force, faster rate Catalysts (enzymes)Catalysts (enzymes)

• speed up reactions without permanent change to itselfspeed up reactions without permanent change to itself• holds reactant molecules in correct orientationholds reactant molecules in correct orientation

3030

MetabolismMetabolism

All the chemical reactions of the bodyAll the chemical reactions of the body CatabolismCatabolism

energy releasing (exergonic) decomposition energy releasing (exergonic) decomposition reactionsreactions

• breaks covalent bonds, produces smaller molecules, breaks covalent bonds, produces smaller molecules, releases useful energyreleases useful energy

AnabolismAnabolism energy storing (endergonic) synthesis reactionsenergy storing (endergonic) synthesis reactions

• requires energy inputrequires energy input

3131

Oxidation-Reduction Oxidation-Reduction ReactionsReactions

Oxidation (LEO)Oxidation (LEO) molecule gives up electrons and releases energymolecule gives up electrons and releases energy accepting molecule is the oxidizing agentaccepting molecule is the oxidizing agent

• oxygen is often the electron acceptoroxygen is often the electron acceptor

Reduction (GER)Reduction (GER) molecule gains electrons and energymolecule gains electrons and energy donating molecule is the reducing agentdonating molecule is the reducing agent

Oxidation-reduction (redox) reactionsOxidation-reduction (redox) reactions Electrons are often transferred as hydrogen atomsElectrons are often transferred as hydrogen atoms

3232

Organic ChemistryOrganic Chemistry

Study of compounds containing carbonStudy of compounds containing carbon 4 categories of carbon compounds4 categories of carbon compounds

carbohydratescarbohydrates lipidslipids proteinsproteins nucleotides and nucleic acidsnucleotides and nucleic acids

3333

Organic Molecules and Organic Molecules and CarbonCarbon

Only 4 valence electronsOnly 4 valence electrons bonds readily to gain more valence bonds readily to gain more valence

electronselectrons Forms long chains, branched molecules Forms long chains, branched molecules

and ringsand rings serve as the backbone for organic serve as the backbone for organic

molecules molecules Carries a variety of functional groupsCarries a variety of functional groups

3434

Atoms attached to Atoms attached to carbon backbonecarbon backbone

Determines chemical Determines chemical propertiesproperties

Functional Groups Functional Groups

3535

Monomers and PolymersMonomers and Polymers

Macromolecules = very large moleculesMacromolecules = very large molecules Polymers = macromolecules formed Polymers = macromolecules formed

from monomers bonded together from monomers bonded together Monomers = an identical or similar Monomers = an identical or similar

subunitsubunit

3636

PolymerizationPolymerization

Bonding of monomers together to form Bonding of monomers together to form a polymera polymer

Formed by dehydration synthesisFormed by dehydration synthesis starch molecules are a polymer of 3000 starch molecules are a polymer of 3000

glucose monomersglucose monomers protein molecules are a polymer of amino protein molecules are a polymer of amino

acidsacids

3737

Dehydration SynthesisDehydration Synthesis Monomers covalently bond together to form a Monomers covalently bond together to form a

polymer with the removal of a water moleculepolymer with the removal of a water molecule A hydroxyl group is removed from one monomer A hydroxyl group is removed from one monomer

and a hydrogen from the nextand a hydrogen from the next

3838

HydrolysisHydrolysis Splitting a polymer (lysis) by the addition of a water Splitting a polymer (lysis) by the addition of a water

molecule (hydro)molecule (hydro) a covalent bond is brokena covalent bond is broken

All digestion reactions consists of hydrolysis All digestion reactions consists of hydrolysis reactionsreactions

3939

Organic Molecules: Organic Molecules: CarbohydratesCarbohydrates

Hydrophilic organic moleculeHydrophilic organic molecule General formula General formula

(CH(CH22O)O)n n n = number of carbon atoms n = number of carbon atoms

2:1 ratio of hydrogen to oxygen2:1 ratio of hydrogen to oxygen

Names of carbohydratesNames of carbohydrates word root word root saccharsacchar- or the suffix -- or the suffix -ose ose often often

usedused• monosaccharide or glucosemonosaccharide or glucose

4040

MonosaccharidesMonosaccharides

Simple sugarsSimple sugars

General formula is CGeneral formula is C66HH1212OO66

structural isomersstructural isomers

Major monosaccharidesMajor monosaccharides glucose, galactose and glucose, galactose and

fructosefructose produced by digestion of produced by digestion of

complex carbohydratescomplex carbohydrates• glucose is blood sugar glucose is blood sugar

4141

DisaccharidesDisaccharides Sugar molecule Sugar molecule

composed of 2 composed of 2 monosaccharidesmonosaccharides

Major disaccharidesMajor disaccharides sucrose = table sugarsucrose = table sugar

• glucose + fructoseglucose + fructose Lactose = sugar in milkLactose = sugar in milk

• glucose + galactoseglucose + galactose Maltose = grain productsMaltose = grain products

• glucose + glucoseglucose + glucose

4242

PolysaccharidesPolysaccharides Chains of glucose subunitsChains of glucose subunits Starch: energy storage in plantsStarch: energy storage in plants

digestible by humans for energydigestible by humans for energy

Cellulose: structural molecule of plant cell Cellulose: structural molecule of plant cell wallswalls fiber in our dietfiber in our diet

Glycogen: energy storage in animalsGlycogen: energy storage in animals liver synthesizes after a meal and breaks down liver synthesizes after a meal and breaks down

between mealsbetween meals

4343

Cellulose and StarchCellulose and Starch

Fig. 3-8, p.38

4444

Carbohydrate FunctionsCarbohydrate Functions All digested carbohydrates converted to glucose All digested carbohydrates converted to glucose

and oxidized to make ATPand oxidized to make ATP Conjugated carbohydrate = bound to lipid or Conjugated carbohydrate = bound to lipid or

proteinprotein glycolipids glycolipids

• external surface of cell membraneexternal surface of cell membrane glycoproteinsglycoproteins

• external surface of cell membraneexternal surface of cell membrane• mucus of respiratory and digestive tractsmucus of respiratory and digestive tracts

proteoglycansproteoglycans• gels that hold cells and tissues togethergels that hold cells and tissues together• joint lubricationjoint lubrication• rubbery texture of cartilagerubbery texture of cartilage

4545

Organic Molecules: LipidsOrganic Molecules: Lipids Hydrophobic organic moleculeHydrophobic organic molecule

composed of carbon, hydrogen and oxygencomposed of carbon, hydrogen and oxygen Less oxidized and thus has more Less oxidized and thus has more

calories/gramcalories/gram Five primary types in humansFive primary types in humans

fatty acidsfatty acids triglyceridestriglycerides phospholipidsphospholipids eicosanoidseicosanoids steroidssteroids

4646

Fatty AcidsFatty Acids Chain of 4 to 24 carbon atomsChain of 4 to 24 carbon atoms

carboxyl (acid) group on one end, methyl group on the other carboxyl (acid) group on one end, methyl group on the other and hydrogen bonded along the sidesand hydrogen bonded along the sides

Classified Classified saturated - carbon atoms saturated with hydrogen saturated - carbon atoms saturated with hydrogen unsaturated - contains C=C bonds without hydrogenunsaturated - contains C=C bonds without hydrogen

4747

Triglycerides (Neutral Fats)Triglycerides (Neutral Fats)

3 fatty acids bonded to glycerol molecule 3 fatty acids bonded to glycerol molecule (dehydration synthesis)(dehydration synthesis)

At room temperatureAt room temperature when liquid called oilswhen liquid called oils

• often polyunsaturated fats from plantsoften polyunsaturated fats from plants when solid called fatwhen solid called fat

• saturated fats from animalssaturated fats from animals

Function - energy storage, insulation and Function - energy storage, insulation and shock absorptionshock absorption

4848

PhospholipidsPhospholipids Triglyceride with one fatty acid replaced by a Triglyceride with one fatty acid replaced by a

phosphate groupphosphate group Amphiphilic characterAmphiphilic character

fatty acid “tails” are hydrophobicfatty acid “tails” are hydrophobic Phosphate “head” is hydrophilicPhosphate “head” is hydrophilic

4949

EicosanoidsEicosanoids

Derived from arachidonic acid (a fatty acid)Derived from arachidonic acid (a fatty acid) Hormone-like chemical signals between cellsHormone-like chemical signals between cells Includes prostaglandins – produced in all Includes prostaglandins – produced in all

tissuestissues role in inflammation, blood clotting, hormone role in inflammation, blood clotting, hormone

action, labor contractions, blood vessel diameteraction, labor contractions, blood vessel diameter

5050

Steroids and CholesterolSteroids and Cholesterol

Steroid = lipid with carbon atoms in Steroid = lipid with carbon atoms in four ringsfour rings all steroids are derived from cholesterolall steroids are derived from cholesterol

• cortisol, progesterone, estrogens, testosterone cortisol, progesterone, estrogens, testosterone and bile acidsand bile acids

Cholesterol Cholesterol important component of cell membranes important component of cell membranes produced only in animal liver cellsproduced only in animal liver cells

• naturally produced by our body naturally produced by our body

5151

Organic Molecules: ProteinsOrganic Molecules: Proteins Protein = polymer of amino acidsProtein = polymer of amino acids Combination determines structure and Combination determines structure and

functionfunction Amino acid = carbon with 3 attachmentsAmino acid = carbon with 3 attachments

Amino (NH2), carboxy (COOH) and radical Amino (NH2), carboxy (COOH) and radical group (R group)group (R group)

20 unique amino acids20 unique amino acids -R groups differ-R groups differ properties determined by -R groupproperties determined by -R group

5252

Naming of PeptidesNaming of Peptides Peptide = polymer of 2 or more amino Peptide = polymer of 2 or more amino

acidsacids Named for the number of amino acidsNamed for the number of amino acids

dipeptides have 2, tripeptides have 3dipeptides have 2, tripeptides have 3 oligopeptides have fewer than 10 to 15 oligopeptides have fewer than 10 to 15 polypeptides have more than 15polypeptides have more than 15 proteins have more than 100proteins have more than 100

5353

Dipeptide SynthesisDipeptide Synthesis

•Dehydration synthesis creates a peptide bond that joins amino acids

5454

Protein Structure and ShapeProtein Structure and Shape Primary structure Primary structure

amino acid sequenceamino acid sequence

Secondary structureSecondary structure coiled or folded shapecoiled or folded shape hydrogen bonds between negative C=O and positive hydrogen bonds between negative C=O and positive

N-H groupsN-H groups

Tertiary structure Tertiary structure further folding and bending into globular and fibrous further folding and bending into globular and fibrous

shapesshapes

Quaternary structureQuaternary structure associations of two or more separate polypeptide associations of two or more separate polypeptide

chainschains

5555

5656

Contain a non-amino acid moietyContain a non-amino acid moiety Hemoglobin contains complex iron Hemoglobin contains complex iron

containing ring called a containing ring called a hemeheme moiety moiety

Conjugated ProteinsConjugated Proteins

5757

Protein Conformation and Protein Conformation and DenaturationDenaturation

Conformation – unique 3-D shape crucial Conformation – unique 3-D shape crucial to functionto function ability to reversibly change their conformationability to reversibly change their conformation

• opening and closing of cell membrane poresopening and closing of cell membrane pores

DenaturationDenaturation conformational change that destroys functionconformational change that destroys function

• extreme heat, pH or saltsextreme heat, pH or salts

5858

Protein FunctionsProtein Functions StructureStructure

collagen, keratincollagen, keratin CommunicationCommunication

some hormones, cell receptorssome hormones, cell receptors Membrane TransportMembrane Transport

channels, carriers channels, carriers CatalysisCatalysis

enzymesenzymes

5959

Protein Functions 2Protein Functions 2

Recognition and protectionRecognition and protection antigens, antibodies and clotting proteinsantigens, antibodies and clotting proteins

MovementMovement molecular motor = molecules that can change molecular motor = molecules that can change

shape repeatedlyshape repeatedly Cell adhesionCell adhesion

proteins bind cells togetherproteins bind cells together

6060

EnzymesEnzymes Proteins as biological catalysts Proteins as biological catalysts

promote rapid reaction ratespromote rapid reaction rates Substrate - substance an enzyme acts Substrate - substance an enzyme acts

uponupon Naming ConventionNaming Convention

named for substrate with -ase as the suffixnamed for substrate with -ase as the suffix• amylase enzyme digests starch (amylose)amylase enzyme digests starch (amylose)

Lowers activation energy = energy needed Lowers activation energy = energy needed to get reaction startedto get reaction started enzymes facilitate molecular interactionenzymes facilitate molecular interaction

6161

Enzymes and Activation EnergyEnzymes and Activation Energy

6262

Steps of an Enzyme ReactionSteps of an Enzyme Reaction Substrate approaches enzyme moleculeSubstrate approaches enzyme molecule Substrate binds to active site forming Substrate binds to active site forming

enzyme-substrate complexenzyme-substrate complex highly specifichighly specific

Enzyme breaks bonds in substrateEnzyme breaks bonds in substrate Reaction products releasedReaction products released Enzyme repeats process over and overEnzyme repeats process over and over

6363

Enzymatic Reaction Enzymatic Reaction StepsSteps

6464

Reusability of enzymesReusability of enzymes enzymes are unchanged by the reactionsenzymes are unchanged by the reactions

Astonishing speedAstonishing speed millions of molecules per minutemillions of molecules per minute

Temperature and pHTemperature and pH change shape of enzyme and alter its ability to change shape of enzyme and alter its ability to

bindbind enzymes vary in optimum pHenzymes vary in optimum pH

• salivary amylase works best at pH 7.0salivary amylase works best at pH 7.0• pepsin works best at pH 2.0pepsin works best at pH 2.0

temperature optimum for human enzymes = body temperature optimum for human enzymes = body temperaturetemperature

Enzymatic ActionEnzymatic Action

6565

Cofactors and CoenzymesCofactors and Coenzymes

CofactorsCofactors nonprotein partners (iron, copper, zinc, nonprotein partners (iron, copper, zinc,

magnesium or calcium ions) magnesium or calcium ions) bind to enzyme and change its shapebind to enzyme and change its shape essential to function essential to function

CoenzymesCoenzymes organic cofactors derived from water-soluble organic cofactors derived from water-soluble

vitamins (niacin, riboflavin)vitamins (niacin, riboflavin) transfer electrons between enzymestransfer electrons between enzymes

6666

Coenzyme NADCoenzyme NAD++

NADNAD++ transports electrons from one transports electrons from one metabolic pathway to anothermetabolic pathway to another

6767

Metabolic PathwaysMetabolic Pathways Chain of reactions, each catalyzed by an Chain of reactions, each catalyzed by an

enzymeenzyme A A B B C C D D A is initial reactant, B+C are intermediates A is initial reactant, B+C are intermediates

and D is the end productand D is the end product Regulation of metabolic pathways Regulation of metabolic pathways

activation or deactivation of the enzymes activation or deactivation of the enzymes cells can turn on or off pathwayscells can turn on or off pathways

6868

Organic Molecules: Organic Molecules: NucleotidesNucleotides

3 components3 components nitrogenous basenitrogenous base sugar (monosaccharide)sugar (monosaccharide) one or more phosphate groupsone or more phosphate groups

Physiological important nucleotides Physiological important nucleotides ATP = energy carrying moleculeATP = energy carrying molecule cAMP = activates metabolic pathwayscAMP = activates metabolic pathways DNA = carries genetic code DNA = carries genetic code RNA = assists with protein synthesisRNA = assists with protein synthesis

6969

ATP (Adenosine Triphosphate)ATP (Adenosine Triphosphate)

ATP contains adenine, ribose and 3 phosphate groups

7070

ATPATP Holds energy in covalent bonds Holds energy in covalent bonds

2nd and 3rd phosphate groups have high 2nd and 3rd phosphate groups have high energy bonds ~energy bonds ~

ATPases hydrolyze the 3ATPases hydrolyze the 3rdrd high energy high energy phosphate bondphosphate bond separates into ADP + Pseparates into ADP + Pii + energy + energy

PhosphorylationPhosphorylation addition of free phosphate group to another addition of free phosphate group to another

moleculemolecule

7171

Overview of ATP ProductionOverview of ATP Production

ATP consumed within 60 secondsATP consumed within 60 seconds Continually replenishedContinually replenished

7272

Other NucleotidesOther Nucleotides

Cyclic adenosine monophosphate (cAMP)Cyclic adenosine monophosphate (cAMP) formed by removal of both high energy Pformed by removal of both high energy P ii’s ’s

from ATPfrom ATP formation triggered by hormone binding to cell formation triggered by hormone binding to cell

surfacesurface cAMP becomes “second messenger” within cAMP becomes “second messenger” within

cellcell activates effects inside cellactivates effects inside cell

7373

Nucleic AcidsNucleic Acids

DNA (deoxyribonucleic acid)DNA (deoxyribonucleic acid) 100 million to 1 billion nucleotides long100 million to 1 billion nucleotides long contains genetic codecontains genetic code

• cell division, sexual reproduction, protein synthesis cell division, sexual reproduction, protein synthesis

RNA (ribonucleic acid) – 3 typesRNA (ribonucleic acid) – 3 types transfer RNA, messenger RNA, ribosomal RNAtransfer RNA, messenger RNA, ribosomal RNA 70 to 10,000 nucleotides long70 to 10,000 nucleotides long involved in protein synthesis coded for by involved in protein synthesis coded for by

DNADNA