THE CHEMISTRY OF LIFE
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Transcript of THE CHEMISTRY OF LIFE
THE CHEMISTRY THE CHEMISTRY OF LIFEOF LIFE
CHAPTER 2CHAPTER 2
Honors NotesHonors Notes
SECTION 2-1: THE SECTION 2-1: THE NATURE OF MATTERNATURE OF MATTER
REMEMBER…REMEMBER… Atoms are made up of electrons (-), Atoms are made up of electrons (-),
neutrons (neutral), and protons (+)neutrons (neutral), and protons (+) Proton number = atomic number = Proton number = atomic number =
type of elementtype of element IsotopeIsotope – atoms of same element, – atoms of same element,
but with a different number of but with a different number of neutronsneutrons
BondsBonds
Ionic bondIonic bond – when – when electrons are transferred electrons are transferred from one atom to anotherfrom one atom to anotherExample NaClExample NaCl
Covalent bondCovalent bond – electrons – electrons are shared between atomsare shared between atomsExample HExample H22OO
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 enough wants to make just enough bonds to fill its shells.bonds to fill its shells.
H makes one bondH makes one bondO makes two bondsO makes two bondsC makes four bondsC makes four bonds
Protons +11Electrons -11Charge 0
Protons +17Electrons -17Charge 0
Protons +11Electrons -10Charge +1
Protons +17Electrons -18Charge -1
Sodium atom (Na)
Chlorine atom (Cl)
Chloride ion (Cl-)
Sodium ion (Na+)
SECTION 2-2: PROPERTIES SECTION 2-2: PROPERTIES OF WATEROF WATER PolarityPolarity – uneven distribution of – uneven distribution of
electrons between the hydrogen and electrons between the hydrogen and oxygen atoms oxygen atoms Oxygen is bigger and attracts the Oxygen is bigger and attracts the
electrons more than hydrogenelectrons more than hydrogen Hydrogen bondsHydrogen bonds – slightly positive, – slightly positive,
polar H atoms are attracted to polar polar H atoms are attracted to polar negative atoms like Onegative atoms like O
CohesionCohesion – attraction between – attraction between molecules of same substancemolecules of same substanceWater has high surface tension Water has high surface tension
(allows some bugs to walk on (allows some bugs to walk on water)water)
AdhesionAdhesion - attraction between - attraction between molecules of different substancesmolecules of different substancesCapillary action (water moves up a Capillary action (water moves up a
straw along the sides)straw along the sides)
Acids, Bases, and pHAcids, Bases, and pH
HH22O HO H++ + OH + OH--
Water Water Proton Proton ++ hydroxide hydroxide 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 than
pure water)pure water) AcidAcid = pH below 7 (higher H = pH below 7 (higher H+ + than than
pure water)pure water) BufferBuffer – weak acids or bases that – weak acids or bases that
can prevent sharp, sudden changes can prevent sharp, sudden changes in pHin pHExample: bicarbonateExample: bicarbonate
http://www.epa.gov/acidrain/education/site_students/phscale.html
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 many - show how many and which atoms are in a compound and which atoms are in a compound
Structural FormulasStructural Formulas - show the - show the arrangement of the atoms in a arrangement of the atoms in a compoundcompound
LIFE’S BACKBONELIFE’S BACKBONE
Most of the compounds that make Most of the compounds that make up living things contain carbon. In up living things contain carbon. In fact, carbon makes up the basic fact, carbon makes up the basic structure, or “backbone,” of these structure, or “backbone,” of these compounds. Each atom of carbon compounds. Each atom of carbon has four electrons in its outer has four electrons in its outer energy level, which makes it energy level, which makes it possible for each carbon atom to possible for each carbon atom to form four covalent bonds with form four covalent bonds with other atoms. other atoms.
Carbon’s tetrahedral Carbon’s tetrahedral shapeshape
http://www.chem.uic.edu/web1/OCOL-II/WIN/STRUCT/SB/14.HTM
Carbon-Carbon bonds can be single, Carbon-Carbon bonds can be single, double, or even triple. This bonding double, or even triple. This bonding characteristic allows for a virtually limitless characteristic allows for a virtually limitless number of different carbon compounds. number of different carbon compounds. Each carbon compound has a different Each carbon compound has a different structure. For example, carbon atoms can structure. For example, carbon atoms can bond together to form chains that can be bond together to form chains that can be straight or branching. They can bond to straight or branching. They can bond to form single or multiple ring structures. form single or multiple ring structures. They can even bond to form crystalline or They can even bond to form crystalline or hollow polyhedrons—multi-sided 3 hollow polyhedrons—multi-sided 3 dimentional molecules. dimentional molecules.
DiamondDiamond
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C-60 “Buckey Ball”C-60 “Buckey Ball”
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Other PolyhedronsOther Polyhedrons
A*
C
D*
G*
H*
E
F
B*
Organic molecules are named using Organic molecules are named using an internationally recognized an internationally recognized (IUPAC) system of naming Also, (IUPAC) system of naming Also, other kinds of atoms can be attached other kinds of atoms can be attached to the carbon chain. to the carbon chain.
IsomersIsomers - compounds with the - compounds with the same chemical formula, but same chemical formula, but different structure (ex. different structure (ex. propanol and isopropanol)propanol and isopropanol)
Functional GroupsFunctional Groups
Functional groups are like power Functional groups are like power attachments that change the job attachments that change the job (chemical and physical properties) that a (chemical and physical properties) that a molecule does.molecule does.
We’ve already looked at the hydroxyl –We’ve already looked at the hydroxyl –OH group. Now let’s look at some others:OH group. Now let’s look at some others:
Chemical Compound Formula Name of Compound Chemical Compound Formula Name of Compound ExampleExample
Esters Esters Esters EstersMethyl salicylate
Biology text reference
MACROMOLECULESMACROMOLECULES
Monomers (smaller units) Monomers (smaller units) join to make polymers or join to make polymers or macromoleculesmacromoleculesCarbohydrates Carbohydrates LLipidsipidsProteins Proteins Nucleic acidsNucleic acids
CARBOHYDRATESCARBOHYDRATES
Organic Organic compounds composed compounds composed of carbon, hydrogen and oxygen of carbon, hydrogen and oxygen with a ratio of two hydrogen with a ratio of two hydrogen atoms to every one oxygen atomatoms to every one oxygen atom
Made up of sugars Made up of sugars
USE OF CARBOHYDRATESUSE OF CARBOHYDRATES
Source of energy for many Source of energy for many living things living things
Examples: sugar and starch Examples: sugar and starch
TYPES OF TYPES OF CARBOHYDRATESCARBOHYDRATES
MonosaccharidesMonosaccharidesDisaccharidesDisaccharidesPolysaccharidesPolysaccharides
MONOSACCHARIDESMONOSACCHARIDES
Only one sugar moleculeOnly one sugar moleculeExamples -Examples -glucoseglucose, fructose, , fructose,
andand galactose galactose All three are All three are CC66HH1212OO66, but they , but they
are isomersare isomersDraw 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 monosaccharides Long chains of monosaccharides joined together joined together
Examples: Examples: starchstarch, , glycogenglycogen, , and and cellulosecellulose
PlantsPlants store excess sugar as store excess sugar as starchstarch, and break it down for , and break it down for energyenergy
Representation of a Polysaccharide
HumansHumans store excess sugar store excess sugar as as glycogenglycogen, & break it , & break it down for energy down for energy
CelluloseCellulose used by used by plants plants for for structural purposes.structural purposes.
DEHYDRATION SYNTHESISDEHYDRATION SYNTHESIS
Two molecules join together Two molecules join together by losing a molecule of water by losing a molecule of water
HYDROLYSIS REACTIONHYDROLYSIS REACTION
Larger molecules broken down Larger molecules broken down into smaller molecules by the into smaller molecules by the addition of water addition of water
LIPIDSLIPIDS
Include Include fatsfats, , oilsoils, , steroidssteroids & & waxeswaxes
Composed of carbon, hydrogen Composed of carbon, hydrogen and oxygen, but the # of H atoms and oxygen, but the # of H atoms per molecule is much greater per molecule is much greater then the # of O atoms then the # of O atoms
An example, An example, CC5757HH110110OO66
USES OF LIPIDSUSES OF LIPIDS
Stored for energy Stored for energy Form basic structure of cell Form basic structure of cell
membranesmembranesProtection Protection Insulation Insulation Waterproof coveringsWaterproof coverings
THE STRUCTURE OF SOME FATSTHE STRUCTURE OF SOME FATS
Built from 2 basic molecules: Built from 2 basic molecules: GlycerolGlycerol - an alcohol - an alcohol Fatty AcidsFatty Acids - a long - a long
carbon chain with a -COOH carbon chain with a -COOH (carboxyl group) at one end(carboxyl group) at one end
Triglyceride StructureTriglyceride Structure
http://library.tedankara.k12.tr/chemistry/vol5/Proteins%20peptides%20fats%20structure%20heme%20proteins/z245.htm
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 helpful made by animals, both helpful & harmful & harmful
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 musclebuild living materials like muscle act as enzymes to help carry out act as enzymes to help carry out
chemical reactionschemical reactions fight diseasefight disease transport particles into or out of transport particles into or out of
cellscells 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 AcidsNucleic Acids
Nucleic Acids are molecules that are Nucleic Acids are molecules that are used for the storage of energy or used for the storage of energy or information.information.
Some examples of Nucleic Acids are Some examples of Nucleic Acids are DNA (deoxyribonucleic acid), RNA DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and ATP (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 Have you ever sat around a campfire or Have you ever sat around a campfire or
watched flames flicker in a fireplace? The watched flames flicker in a fireplace? The burning of wood is a chemical reaction—a burning of wood is a chemical reaction—a process that changes one set of chemicals process that changes one set of chemicals into another set of chemicals. A chemical into another set of chemicals. A chemical reaction always involves changes in chemical reaction always involves changes in chemical bonds that join atoms in compounds. The bonds that join atoms in compounds. The elements or compounds that enter into a elements or compounds that enter into a chemical reaction are called reactants. The chemical reaction are called reactants. The elements or compounds produced by a elements or compounds produced by a chemical reaction are called products. As chemical reaction are called products. As wood burns, molecules of cellulose are wood burns, molecules of cellulose are broken down and combine with oxygen to broken down and combine with oxygen to form carbon dioxide and water vapor, and form carbon dioxide and water vapor, and energy is released.energy is released.
QUESTIONSQUESTIONS
1.1. What are the reactants when wood What are the reactants when wood burns?burns?
2.2. What are the products when wood What are the products when wood burns?burns?
3.3. What kinds of energy are given off What kinds of energy are given off when wood burns?when wood burns?
4.4. Wood doesn’t burn all by itself. Wood doesn’t burn all by itself. What must you do to start a fire? What must you do to start a fire? What does this mean in terms of What does this mean in terms of energy?energy?
5.5. Once the fire gets started, it keeps Once the fire gets started, it keeps burning. Why don’t you need to burning. Why don’t you need to keep restarting the fire?keep restarting the fire?
SECTION 2-4: CHEMICAL SECTION 2-4: CHEMICAL REACTIONSREACTIONS
Chemical reactions always involve Chemical reactions always involve breaking bonds in reactants and breaking bonds in reactants and making bonds in productsmaking bonds in products
Some reactions release energy and Some reactions release energy and therefore usually occur 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 permanently Enzymes are not permanently changed and are not used up changed and are not used up in the reactionin the reaction
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 Think of the substrate as a flexible key that must fit into the flexible key that must fit into the active siteactive site
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Example LysozymeExample Lysozyme
Q: What is it?Q: What is it? A:A: Q: How does it work?Q: How does it work? A:A: TutorialTutorial Animation without tutorialAnimation without tutorial
Enzyme
Substrates
Active site
Products
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