THE CHEMISTRY OF THE CHEMISTRY OF LIFELIFE

CHAPTER 2CHAPTER 2

BEWARE!

SECTION 2-1: THE NATURE OF SECTION 2-1: THE NATURE OF MATTERMATTER• REMEMBER from a long, long REMEMBER from a long, long

time ago…time ago…• Atoms are made up of electrons Atoms are made up of electrons

(-), neutrons (neutral), and (-), neutrons (neutral), and protons (+)protons (+)

• If the number of +s in the If the number of +s in the nucleus = the number of –s in nucleus = the number of –s in the electron shells the atom is the electron shells the atom is stable.stable.

• If not the atom wants to bond.If not the atom wants to bond.

BondsBonds

• Ionic bondIonic bond – when electrons – when electrons are transferred from one are transferred from one atom to anotheratom to another– Example NaClExample NaCl

• Covalent bondCovalent bond – electrons – electrons are shared between atomsare shared between atoms

– Example HExample H22OO

Bonds• All of what we do in this unit will

focus on different types of COVALENT BONDS

• Now let’s look at the difference between Polar and NON-Polar Covalent bonds.

BEWARE!

SECTION 2-2: PROPERTIES OF SECTION 2-2: PROPERTIES OF WATERWATER• PolarityPolarity – uneven distribution of – uneven distribution of

electrons between the electrons between the hydrogen and oxygen atoms hydrogen and oxygen atoms – Oxygen is bigger and Oxygen is bigger and

attracts the electrons more attracts the electrons more than hydrogenthan hydrogen

• Hydrogen bondsHydrogen bonds – slightly – slightly positive, polar H atoms are positive, polar H atoms are attracted to polar negative attracted to polar negative atoms like Oatoms like O

• CohesionCohesion – attraction between – attraction between molecules of same substancemolecules of same substance– Water has high surface Water has high surface

tension (allows some bugs tension (allows some bugs to walk on water)to walk on water)

• AdhesionAdhesion - attraction between - attraction between molecules of different molecules of different substancessubstances– Capillary action (water Capillary action (water

moves up a straw along the moves up a straw along the sides)sides)

Acids, Bases, and pHAcids, Bases, and pH

HH22O HO H++ + OH + OH--

Water Water Proton Proton + + HydroxideHydroxide

IonIon

• pH scalepH scale – indicates the – indicates the concentration of Hconcentration of H+ +

• pH = 7 = neutral (HpH = 7 = neutral (H++ = OH = OH--))• BaseBase = pH above 7 (lower H = pH above 7 (lower H+ +

than pure water)than pure water)• AcidAcid = pH below 7 (higher H = pH below 7 (higher H+ +

than pure water)than pure water)• BufferBuffer – weak acids or bases – weak acids or bases

that can prevent sharp, that can prevent sharp, sudden changes in pHsudden changes in pH– Example: bicarbonateExample: bicarbonate

http://www.epa.gov/acidrain/education/site_students/phscale.html

LIFE’S BACKBONELIFE’S BACKBONE

• Most of the compounds that Most of the compounds that make up living things contain make up living things contain carbon. carbon.

• Carbon makes up the basic Carbon makes up the basic structure, or “backbone,” of structure, or “backbone,” of these compounds. these compounds.

• Each atom of carbon has four Each atom of carbon has four electrons in its outer energy electrons in its outer energy level, which makes it possible for level, which makes it possible for each carbon atom to form four each carbon atom to form four bonds with other atoms. bonds with other atoms.

Carbon Backbone

From this guy!!!

And why is he called the cigarette snail?

SECTION 2-3: CARBON SECTION 2-3: CARBON COMPOUNDSCOMPOUNDS• Organic compoundsOrganic compounds- those - those

compounds that contain carbon compounds that contain carbon • Chemical FormulasChemical Formulas - show how - show how

many and which atoms are in a many and which atoms are in a compound compound

• Structural FormulasStructural Formulas - show the - show the arrangement of the atoms in a arrangement of the atoms in a compoundcompound

• IsomersIsomers - compounds with - compounds with the same chemical formula, the same chemical formula, but different structure (ex. but different structure (ex. propanol and isopropanol)propanol and isopropanol)

COVALENT BOND #’SCOVALENT BOND #’S

•Atoms want to fill their Atoms want to fill their electron shells. An atom electron shells. An atom wants to make just wants to make just enough bonds to fill its enough bonds to fill its shells.shells.

•H (white) makes one bondH (white) makes one bond•O (red) makes two bondsO (red) makes two bonds•C (black) makes four bondsC (black) makes four bonds

Important Biological MoleculesImportant Biological Molecules

•What are they?What are they?– Carbohydrates Carbohydrates – LLipidsipids– Proteins Proteins – Nucleic acidsNucleic acids

•We’ll learn about them We’ll learn about them one at a time.one at a time.

CARBOHYDRATESCARBOHYDRATES

•Organic Organic compounds compounds composed of carbon, composed of carbon, hydrogen and oxygen with a hydrogen and oxygen with a ratio of two hydrogen atoms ratio of two hydrogen atoms to every one oxygen atomto every one oxygen atom

• Made up of smaller units Made up of smaller units called simple sugars called simple sugars (monosaccharides)(monosaccharides)

USE OF CARBOHYDRATESUSE OF CARBOHYDRATES

• Source of energy for Source of energy for many living things many living things

• Also used to build body Also used to build body structuresstructures

• Examples: sugar and Examples: sugar and starch, cellulose and starch, cellulose and chitinchitin

Chitin!

TYPES OF CARBOHYDRATESTYPES OF CARBOHYDRATES

• MonosaccharidesMonosaccharides

• DisaccharidesDisaccharides

• PolysaccharidesPolysaccharides

MONOSACCHARIDESMONOSACCHARIDES

• Only one sugar moleculeOnly one sugar molecule

• Examples -Examples -glucoseglucose, fructose, , fructose, andand galactose galactose

• All three are All three are CC66HH1212OO66, but , but

they are isomersthey are isomers

• Draw GlucoseDraw Glucose

DISACCHARIDESDISACCHARIDES

• Double sugars (two Double sugars (two monosaccharides combined) monosaccharides combined)

• Examples: sucrose, lactose, and Examples: sucrose, lactose, and maltose maltose

• All are isomers with the chemical All are isomers with the chemical formula formula CC1212HH2222OO1111

POLYSACCHARIDESPOLYSACCHARIDES• Long chains of Long chains of

monosaccharides joined monosaccharides joined together together

• Examples: Examples: starchstarch, , glycogenglycogen, , and and cellulosecellulose

• PlantsPlants store excess sugar store excess sugar as as starchstarch, and break it down , and break it down for energyfor energy

Representation of a Polysaccharide

• HumansHumans store excess store excess sugar as sugar as glycogenglycogen, & , & break it down for energy break it down for energy

• CelluloseCellulose used by used by plants plants for structural purposes.for structural purposes.

DEHYDRATION SYNTHESISDEHYDRATION SYNTHESIS

• Two molecules join together Two molecules join together by losing a molecule of by losing a molecule of water water

HYDROLYSIS REACTIONHYDROLYSIS REACTION

• Larger molecules broken Larger molecules broken down into smaller molecules down into smaller molecules by the addition of water by the addition of water

Lipids

Aka The Fat Cat Sat on a

Flat Mat Section

LIPIDSLIPIDS

• Include Include fatsfats, , oilsoils, , steroidssteroids & & waxeswaxes

• Composed of carbon, Composed of carbon, hydrogen and oxygen, but hydrogen and oxygen, but the # of H atoms per the # of H atoms per molecule is much greater molecule is much greater than the # of O atoms than the # of O atoms

• An example, An example, CC5757HH110110OO66

Other examples

USES OF LIPIDSUSES OF LIPIDS• Stored for energy Stored for energy • Form basic structure of cell Form basic structure of cell

membranesmembranes• Protection Protection • Insulation Insulation • Waterproof coveringsWaterproof coverings

THE STRUCTURE OF SOME IMPORTANT THE STRUCTURE OF SOME IMPORTANT FATSFATS

• Built from 2 basic molecules: Built from 2 basic molecules:

–GlycerolGlycerol - an alcohol - an alcohol –Fatty AcidsFatty Acids - a long carbon - a long carbon

chain with a -COOH chain with a -COOH (carboxyl group) at one end(carboxyl group) at one end

Triglyceride StructureTriglyceride Structure

Phospholipid StructurePhospholipid Structure•

http://library.tedankara.k12.tr/chemistry/vol5/polarity%20and%20activity/z247.htm

• Different types of fatty acids: Different types of fatty acids: –SaturatedSaturated - all single, covalent - all single, covalent

bonds in between carbons in bonds in between carbons in chain chain

–UnsaturatedUnsaturated - one double bond - one double bond between carbons in chainbetween carbons in chain

–PolyunsaturatedPolyunsaturated - many - many double bonds between double bonds between carbons in chaincarbons in chain

• CholesterolCholesterol - another lipid, - another lipid, made by animals, both made by animals, both helpful & harmful helpful & harmful

Proteins

Yaw dis is aboout da Proteens !

PROTEINPROTEIN

• Made up of amino acids Made up of amino acids linked togetherlinked together

• Composed of C, H, & O as Composed of C, H, & O as well as nitrogen, N, and well as nitrogen, N, and possibly sulfurpossibly sulfur

USES OF PROTEINSUSES OF PROTEINS

• build living materials like build living materials like musclemuscle

• act as enzymes to help carry act as enzymes to help carry out chemical reactionsout chemical reactions

• fight diseasefight disease• transport particles into or out transport particles into or out

of cellsof cells• act as markers on cells act as markers on cells

Alanine Serine

General Structure

• Each has same basic structure Each has same basic structure with the only difference being with the only difference being the “R” group the “R” group

• Amino acids are linked by Amino acids are linked by peptide bonds (formed by peptide bonds (formed by dehydration synthesis) dehydration synthesis)

Essential Amino Acids

There are 20 main amino acids

• Peptide bondPeptide bond is between two is between two amino acids amino acids

• PolypeptidePolypeptide – (a protein) – (a protein) many amino acids joined many amino acids joined

Aminoacids

Nucleic Acids

Nucleic AcidsNucleic Acids• Nucleic Acids are molecules that Nucleic Acids are molecules that

are used for the storage of energy are used for the storage of energy or information.or information.

• Some examples of Nucleic Acids Some examples of Nucleic Acids are DNA (deoxyribonucleic acid), are DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and ATP RNA (ribonucleic acid), and ATP (adenosine triphosphate)(adenosine triphosphate)

• Nucleic Acids are made of Nucleic Acids are made of monomers called NUCLEOTIDES.monomers called NUCLEOTIDES.

NucleotidesNucleotides

http://dnatesting.biz/nucleotides.png

• DNA 3DDNA 3D

MATTER AND ENERGYMATTER AND ENERGY

SECTION 2-4: CHEMICAL REACTIONSSECTION 2-4: CHEMICAL REACTIONS

• Chemical reactions always Chemical reactions always involve breaking bonds in involve breaking bonds in reactants and making bonds in reactants and making bonds in productsproducts

• Some reactions release energy Some reactions release energy and therefore usually occur and therefore usually occur spontaneouslyspontaneously

• Other reactions need energy to Other reactions need energy to happenhappen

• Activation energyActivation energy – the – the minimum amount of energy minimum amount of energy needed to start a reactionneeded to start a reaction

• Enzymes Enzymes are catalysts which are catalysts which speed up chemical reactionsspeed up chemical reactions

• EnzymesEnzymes are are proteinsproteins that that lowerlower activation energyactivation energy and and allow reactions to occur at allow reactions to occur at normal temperatures normal temperatures

Reaction pathwaywith enzyme

Reaction pathwaywithout enzyme

Activation energywithout enzyme

Activation energywith enzyme

• Each enzyme is specific and Each enzyme is specific and has a specific shape has a specific shape

• Enzymes are not Enzymes are not permanently changed and permanently changed and are not used up in the are not used up in the reactionreaction

• They are continuously They are continuously recycled! recycled!

• Most enzymes end in Most enzymes end in --asease

• Reactants are called Reactants are called substratessubstrates

EnzymesEnzymes

•The area where the enzyme The area where the enzyme interacts is called the interacts is called the active siteactive site•Think of the substrate as a flexible Think of the substrate as a flexible key that must fit into the active sitekey that must fit into the active site

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Enzyme

Substrates

Active site

Products

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