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BIOCHEMISTRYBIOCHEMISTRY

The chemical The chemical

basis of lifebasis of life

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ATOMSATOMS Basic unit of matterBasic unit of matter Two regionsTwo regions

NucleusNucleus Electron cloudElectron cloud

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Subatomic ParticlesSubatomic Particles

• Protons Protons • Positively charged particles Positively charged particles • Located in the nucleusLocated in the nucleus

• Neutrons Neutrons • Neutral particlesNeutral particles• Located in the nucleus Located in the nucleus

• Electrons Electrons • Negatively charged particlesNegatively charged particles• Located in the electron cloudLocated in the electron cloud• These are the particles involved These are the particles involved

when atoms bond with other when atoms bond with other atomsatoms

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Electrons orbit the Electrons orbit the nucleus.nucleus.

An atom is only about An atom is only about 0.0000000001 meters big. 0.0000000001 meters big. It would take 10 BILLIONS It would take 10 BILLIONS atoms lying side by side to atoms lying side by side to equal 1 meter! equal 1 meter!

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Atomic Atomic NumberNumber

The number of The number of protons protons distinguishes an atom of one type distinguishes an atom of one type from another.from another.

All atoms of the same element All atoms of the same element have the same number of protons.have the same number of protons.

This unique number is This unique number is

called thecalled the atomic numberatomic number..

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Atomic MassAtomic Mass

The atomic mass is equal to The atomic mass is equal to the total number of protons the total number of protons plus neutrons in an atom.plus neutrons in an atom.

Atomic Mass = P + NAtomic Mass = P + N

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Mass NumberMass Number The mass number can be The mass number can be

written as a superscript written as a superscript above the symbol and the above the symbol and the atomic number as a atomic number as a subscript below the symbol.subscript below the symbol.

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Elements & IsotopesElements & Isotopes Elements: Simplest Pure Elements: Simplest Pure

SubstanceSubstance Elements of LifeElements of Life

• 96% 96% Carbon (C), Hydrogen (H), Oxygen Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N)(O), and Nitrogen (N)

• 3% 3% P, S, Ca, K, Na, Mg, Fe, Cl P, S, Ca, K, Na, Mg, Fe, Cl • 1% 1% other trace elements other trace elements

IsotopesIsotopes• Atoms of the same element that contain Atoms of the same element that contain

a different number of neutronsa different number of neutrons• Radioactive isotopes will breakdown at a Radioactive isotopes will breakdown at a

specific rate and are used in determining specific rate and are used in determining the age of various things (i.e. fossils & the age of various things (i.e. fossils & rocks)rocks)

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IsotopesIsotopes Atoms of the same element can Atoms of the same element can

have different numbers of have different numbers of neutrons. neutrons.

These different forms of the same These different forms of the same element are called isotopes.element are called isotopes.

The atomic mass is the average The atomic mass is the average mass of all the known isotopes of mass of all the known isotopes of the element.the element.

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AtomsAtoms All atoms are neutral; they have the All atoms are neutral; they have the

same number of electrons as protons. same number of electrons as protons.

Example: An atom of Example: An atom of 4422He has an atomic He has an atomic

number of 2 and a mass of 4. number of 2 and a mass of 4.

Therefore, it has 2 protons and 2 Therefore, it has 2 protons and 2 neutrons in its nucleus.neutrons in its nucleus.

Since it has 2 positive protons (neutrons Since it has 2 positive protons (neutrons are neutral) it must have 2 negative are neutral) it must have 2 negative electrons to make the total charge electrons to make the total charge neutral.neutral.

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How are electrons How are electrons arranged?arranged? Electrons are located in different Electrons are located in different

energy levels.energy levels. The farther away from the nucleus The farther away from the nucleus

the electron is found, the higher the the electron is found, the higher the energy.energy.

As electrons move from a lower level As electrons move from a lower level to a higher level energy is absorbed.to a higher level energy is absorbed.

As electrons move from a higher As electrons move from a higher level to a lower level energy is level to a lower level energy is release in the form of light.release in the form of light.

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Periodic TablePeriodic Table

The elements are listed in order of increasing The elements are listed in order of increasing atomic number.atomic number.

By looking at the row (period) number you can By looking at the row (period) number you can determined how many energy levels an atom determined how many energy levels an atom has. has.

By looking at the column (group) number you By looking at the column (group) number you can determine how many electrons are in the can determine how many electrons are in the outermost level.outermost level.

Period

Group

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Comparing AtomsComparing Atoms

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How does one kind of How does one kind of atom differ from atom differ from another?another?

Number of Number of protonsprotons determines an element.determines an element.

Even if atoms bond or Even if atoms bond or break apart, the number break apart, the number of protons will of protons will alwaysalways be be the same.the same.

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Chemical CompoundChemical Compound Pure substance formed by two Pure substance formed by two

or more elements chemically or more elements chemically combined. combined.

Ex: water: HEx: water: H22O, sodium chloride O, sodium chloride NaClNaCl

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Types of BondsTypes of Bonds Ionic: Ionic: The TRANSFER of electrons The TRANSFER of electrons

between a metal and a nonmetalbetween a metal and a nonmetal CovalentCovalent: The SHARRING of : The SHARRING of

electrons between two or more electrons between two or more nonmetalsnonmetals Two Types: Two Types: PolarPolar and and NonpolarNonpolar

MetallicMetallic: A “sea of electrons” : A “sea of electrons” around two or more metalsaround two or more metals

Animations: Animations: http://ithacasciencezone.com/chemzone/lessons/03bonding/http://ithacasciencezone.com/chemzone/lessons/03bonding/mleebonding/covalent_bonds.htmmleebonding/covalent_bonds.htm

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Bonding by AnalogyBonding by Analogy Sometimes it helps to Sometimes it helps to

think of bonds (which think of bonds (which you can't see) in you can't see) in terms of familiar terms of familiar things you can see.  things you can see.  This is called an This is called an analogy.  Let's use the analogy.  Let's use the natural attraction natural attraction between dogs and between dogs and bones as an analogy bones as an analogy to the attraction to the attraction between opposite between opposite charges and atomic or charges and atomic or intramolecular bonds.intramolecular bonds.http://ithacasciencezone.com/chemzone/lessons/03bondin

g/dogbonds.htm#Ionic%20Bonding

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A neutral atom contains an equal A neutral atom contains an equal number of positive and negative number of positive and negative charges.  charges. 

In a sense, the atoms fight over the In a sense, the atoms fight over the available electrons in much the same available electrons in much the same way two or more dogs will fight over way two or more dogs will fight over bones.  bones.  The bone and the electron are very similar.  The bone and the electron are very similar. 

The Dog - Bone analogy works quite The Dog - Bone analogy works quite well for three of the four types of well for three of the four types of atomic bonds.  (van der Waal's forces atomic bonds.  (van der Waal's forces are the only one which cannot be are the only one which cannot be represented with this analogy)represented with this analogy)

http://ithacasciencezone.com/chemzone/lessons/03bonding/doghttp://ithacasciencezone.com/chemzone/lessons/03bonding/dogbonds.htm#Ionic%20Bondingbonds.htm#Ionic%20Bonding

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Ionic bondsIonic bonds: One big greedy : One big greedy thief dog! thief dog!

Covalent bondsCovalent bonds:  Dogs of equal :  Dogs of equal strength. strength.

Polar Covalent bondsPolar Covalent bonds: Unevenly : Unevenly matched but willing to share. matched but willing to share.

Metallic bondsMetallic bonds:  Mellow dogs :  Mellow dogs with plenty of bones to go with plenty of bones to go around. around.

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Ionic BondsIonic Bonds

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Covalent BondsCovalent Bonds Sharing of electronsSharing of electrons These are stronger These are stronger

bonds than either of the bonds than either of the other two types other two types because the electrons because the electrons are shared.are shared.

Your body is based Your body is based upon carbon bonding. upon carbon bonding. So the covalent bond is So the covalent bond is

considered the most considered the most important bond with important bond with regards to life. regards to life.

Interestingly, Si, just Interestingly, Si, just above C in the periodic above C in the periodic table, with its covalent table, with its covalent bonding, is the basis for bonding, is the basis for the computer industry. the computer industry.

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Metallic BondsMetallic Bonds

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Van der Waals BondsVan der Waals Bonds When molecules When molecules

are close are close together an together an attraction can attraction can develop between develop between oppositely oppositely charged regions charged regions of nearby of nearby molecules molecules Example: water Example: water

molecules molecules

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Geckos and Van der Geckos and Van der Waals Waals

Geckos can stick to so many Geckos can stick to so many surfaces in a seemingly surfaces in a seemingly impossible manner. impossible manner.

Specifically, the tiny hairs on Specifically, the tiny hairs on the gecko's feet (called the gecko's feet (called setaesetae) ) are split at the microscopic are split at the microscopic level into as many as 1,000 level into as many as 1,000 branches. branches. As a result, even though the Van der Waals As a result, even though the Van der Waals

forces acting on an individual tip is small, the forces acting on an individual tip is small, the adhesion of a billion or so tips adhesion of a billion or so tips adds up to enough force to let adds up to enough force to let the gecko stick to basically the gecko stick to basically anything.anything.

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Water (HWater (H22O)O) Most abundant compound Most abundant compound

in organisms in organisms Water is polar Water is polar

Unequally shares electrons Unequally shares electrons between hydrogen & oxygen between hydrogen & oxygen atomsatoms•Makes it possible for Makes it possible for other compounds to other compounds to dissolve in water dissolve in water

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Water has Hydrogen Water has Hydrogen BondsBonds

Adhesion – Adhesion – the attraction of unlike the attraction of unlike molecules to one anothermolecules to one another

Cohesion – Cohesion – the attraction of the attraction of like molecules to one another like molecules to one another

Cohesion causes water to form drops, surface tension causes them to be nearly spherical, and adhesion keeps the drops in place.

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ProperPropertyty

MeaningMeaning ImportanceImportance

1. 1. TransparencyTransparency

Light passes through Light passes through waterwater

Light reaches chloroplast in Light reaches chloroplast in cells and aquatic plantscells and aquatic plants

2. Universal 2. Universal SolventSolvent

Many compounds Many compounds dissolve in waterdissolve in water

Dissolved compounds can be Dissolved compounds can be brought to cells (via sap or brought to cells (via sap or blood) or move about cell blood) or move about cell cytoplasm. cytoplasm.

3. Cohesion3. Cohesion

4. Adhesion4. AdhesionWater molecules stick Water molecules stick together due to H together due to H bonds.bonds.

Water molecules stick Water molecules stick to other moleculesto other molecules

Small animals may walk on Small animals may walk on water.water.

Capillary action. Water pulled Capillary action. Water pulled to top of treesto top of trees

5. Heat 5. Heat CapacityCapacity

Large amounts of Large amounts of energy are needed to energy are needed to raise temp of water raise temp of water

Water bodies have stable Water bodies have stable temperatures. Body temps can temperatures. Body temps can be maintained. Transfer of be maintained. Transfer of heat from warm to cool body heat from warm to cool body partsparts

6. Heat Point 6. Heat Point CapacityCapacity

7. Density of 7. Density of IceIce

Much energy needed to Much energy needed to pull water molecules pull water molecules apart. apart.

Ice is less dense than Ice is less dense than water so it floatswater so it floats

In nature, water rarely boils so In nature, water rarely boils so life is spared.life is spared.

Ice insulates organisms living Ice insulates organisms living beneathbeneath

8.Evaporation8.Evaporation Evaporation (boiling) Evaporation (boiling) requires much energy.requires much energy.

Evaporation can cool warm Evaporation can cool warm cells cells

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Properties of WaterProperties of Water Solutions and suspensionsSolutions and suspensions

Mixtures are composed of 2 or Mixtures are composed of 2 or more elements or compounds more elements or compounds that are physically mixed, but that are physically mixed, but not chemically combinednot chemically combined

There are two types of mixtures There are two types of mixtures that can be made with waterthat can be made with water•SolutionsSolutions•suspensionssuspensions

Solutions – made of a solute Solutions – made of a solute and a solventand a solvent

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Properties of WaterProperties of Water SolutionsSolutions

Made of a solute and a solventMade of a solute and a solvent Usually water acts as a solventUsually water acts as a solvent

•Polar water molecules are able to pull Polar water molecules are able to pull apart the solute to form a solutionapart the solute to form a solution

•Water is known as the “universal Water is known as the “universal solvent”solvent”

Many biological fluids are Many biological fluids are solutionssolutions

Solutions are also known as Solutions are also known as homogeneous mixtureshomogeneous mixtures

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Properties of WaterProperties of Water SuspensionsSuspensions

Particles do not dissolve in HParticles do not dissolve in H22O O and remain suspendedand remain suspended

Colloids are a type of suspensionColloids are a type of suspension Examples of suspensions: smoke, Examples of suspensions: smoke,

fog, jello, bloodfog, jello, blood

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pH scale and pH scale and buffersbuffers

The pH of substances ranges The pH of substances ranges from 0-14 from 0-14 7 = neutral7 = neutral 0 - 6.9 = acid0 - 6.9 = acid 7.1 - 14 = base7.1 - 14 = base

BuffersBuffers Prevent sharp, sudden changes in Prevent sharp, sudden changes in

pH so that the body can maintain pH so that the body can maintain homeostasishomeostasis

pH of most fluids in the body = 6.5 - pH of most fluids in the body = 6.5 - 7.57.5

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NeutralBasic (base)

7 - 14

Acidic (acid)0 - 7

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Acids, Bases and the pH Acids, Bases and the pH scalescale

[H+] = concentration of hydrogen ions

[OH-] = concentration of hydroxide ions

The pH scale measures the concentration of H+ ions (how acidic something is)

Ranges from 0-14

At 7: H+ ions and OH- ions are equal so it is neutral

0-7: acidic, has more H+ ions

7-14: basic, has more OH- ions

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ACIDS: release H+ when mixed with water

Sour, corrosive

Ex: HCl, H2SO4

Always have H at front of formula

BASES: release OH- when mixed with water

Bitter, slippery, usually in cleaners

NaOH, CaOH

Always have OH at end of formula

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What is a buffer?What is a buffer? Buffers are weak acids or bases that react with strong acids and bases to prevent sharp changes in pH

Helps to neutralize

Help to control pH in blood, digestive tract, etc. to maintain homeostasis

Ex: Antacids buffer the stomach from the Hydrochloric Acid (HCl)

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Organic vs. InorganicOrganic vs. Inorganic All compounds can be separated All compounds can be separated

into two groups: into two groups: InorganicInorganic

• Does not contain carbonDoes not contain carbon• Non-living (never alive)Non-living (never alive)• Examples: Oxygen gas, metals, rocks, Examples: Oxygen gas, metals, rocks,

water water OrganicOrganic

• Contains carbonContains carbon• Living (or dead – once was alive)Living (or dead – once was alive)• Examples: wood, grass, diamonds, Examples: wood, grass, diamonds,

petroleumpetroleum

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Inorganic CompoundsInorganic Compounds

Usually do not contain Usually do not contain CARBON (except good old CARBON (except good old COCO22))

WATER-- a very curious WATER-- a very curious materialmaterial

salts, compounds in our salts, compounds in our bones, etc. but none as bones, etc. but none as numerous as the ORGANIC numerous as the ORGANIC compounds in living thingscompounds in living things

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Why Carbon Why Carbon Compounds?Compounds?

Carbon (C) forms strong, stable Carbon (C) forms strong, stable COVALENTCOVALENT bonds bonds

Carbon forms almost infinite Carbon forms almost infinite chains when bonded to other C chains when bonded to other C atomsatoms

Chains may form as ring Chains may form as ring structures with single or double structures with single or double bondsbonds Ex: PolymerizationEx: Polymerization

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We eat polymers!We eat polymers! Hey, come on over here and Hey, come on over here and

have a big slice of POLYMER have a big slice of POLYMER pizza. It's not as strange as it pizza. It's not as strange as it sounds. French fries are loaded sounds. French fries are loaded with a polymer called with a polymer called starch, which your body starch, which your body digests into sugar to digests into sugar to use as fuel. use as fuel.

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PolymerizationPolymerization

Monomers (small)Monomers (small) One unit of a compoundOne unit of a compound

PolymersPolymers Many monomers combine Many monomers combine

to make a polymerto make a polymer Macromolecules (huge)Macromolecules (huge)

Many large molecules Many large molecules combined combined

Polymers are everywhere: Polymers are everywhere: http://pslc.ws/macrog/paul/http://pslc.ws/macrog/paul/

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ContainersContainers Fast food often comes in Fast food often comes in

boxes made of boxes made of polystyrenepolystyrene foam. foam. Cup lids are made of Cup lids are made of polystyrenepolystyrene, but in , but in

plastic form instead of foam.plastic form instead of foam. Napkins are made of paper, which is Napkins are made of paper, which is

made from wood pulp, and that wood made from wood pulp, and that wood pulp has an awful lot of the polymer pulp has an awful lot of the polymer cellulosecellulose. .

The trays are made of The trays are made of polyethylenepolyethylene. . Most of the prizes in the kids' meals are Most of the prizes in the kids' meals are made from polystyrene and polyethylene made from polystyrene and polyethylene or or polyvinyl chloridepolyvinyl chloride..

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ClothingClothing

The polymers in clothes can be The polymers in clothes can be everything from everything from plant materialsplant materials, to , to syntheticssynthetics, to , to proteinsproteins like silk and wool. like silk and wool.

Sweaters are also made out of acrylics, Sweaters are also made out of acrylics, like like polyacrylonitrilepolyacrylonitrile. .

SpandexSpandex is a special kind of is a special kind of polyurethanepolyurethane that's that's veryvery stretchy. stretchy. Spandex is also used in bicycle pants, Spandex is also used in bicycle pants, swim suits, and other items of swim suits, and other items of stretchwear. stretchwear.

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CarbohydratesCarbohydrates Made of C, H, & OMade of C, H, & O FunctionsFunctions

Main energy source in organismsMain energy source in organisms Structural component in plantsStructural component in plants

TypesTypes Sugars Sugars

• gives off energy when broken downgives off energy when broken down• Cellulose Cellulose twisted chain of sugars, not twisted chain of sugars, not

digestible by humansdigestible by humans• Chitin Chitin hard cellulose found in the hard cellulose found in the

exoskeletons of invertebratesexoskeletons of invertebrates• Ex. SucroseEx. Sucrose, fructose, glucose, fructose, glucose

Starches Starches • used as a storage molecule for sugarsused as a storage molecule for sugars

• Many athletes eat these before eventsMany athletes eat these before events• Ex. Bread, rice, pasta, cornEx. Bread, rice, pasta, corn

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LipidsLipids Made of C, H, O Made of C, H, O

in the form of glycerol and fatty acid in the form of glycerol and fatty acid chainschains

Commonly called fats, oils, & waxesCommonly called fats, oils, & waxes FunctionsFunctions

Storage of energyStorage of energy Parts of biological membranesParts of biological membranes Water proof coveringsWater proof coverings Chemical messengers (steroids)Chemical messengers (steroids)

Insoluble in waterInsoluble in water Ex. Lard, butter, oil, hormones, Ex. Lard, butter, oil, hormones,

steroids steroids

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SteriodsSteriods Steroids occur in animals in something Steroids occur in animals in something

called hormones. The basis of a steroid called hormones. The basis of a steroid molecule is a four-ring structure, one with molecule is a four-ring structure, one with five carbons and three with six carbons in five carbons and three with six carbons in the rings.the rings. Many body builders and athletes use anabolic Many body builders and athletes use anabolic

steroids to build muscle mass. The steroids steroids to build muscle mass. The steroids make their body want to add more muscle than make their body want to add more muscle than they normally would be able to. they normally would be able to. • The body builders wind up stronger and bulkier (but The body builders wind up stronger and bulkier (but

not faster). not faster).

Never take drugs to enhance your body. Those body Never take drugs to enhance your body. Those body builders are actually hurting their bodies. They can't builders are actually hurting their bodies. They can't see it because it is slowly destroying their internal see it because it is slowly destroying their internal organs and not the muscles. When they get older, organs and not the muscles. When they get older, they can have kidney and liver problems. Some even they can have kidney and liver problems. Some even die!die!

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Lipids...Lipids... Saturated fatsSaturated fats

all Carbons attached by single bonds with all Carbons attached by single bonds with the maximum H atomsthe maximum H atoms

meats, dairymeats, dairy Unsaturated fatsUnsaturated fats

C atoms joined by double bond, not with C atoms joined by double bond, not with the maximum H atoms (more double the maximum H atoms (more double bonds=polyunsaturated)bonds=polyunsaturated)

liquid fats at room temp.--sesame, liquid fats at room temp.--sesame, peanut, canola oilspeanut, canola oils

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FatsFats There are two kinds of fats, saturated and There are two kinds of fats, saturated and

unsaturated. unsaturated. Unsaturated fats have at least one double bond Unsaturated fats have at least one double bond

in one of the fatty acids. in one of the fatty acids. A double bond happens when two electrons are A double bond happens when two electrons are

shared or exchanged in a bond. They are much shared or exchanged in a bond. They are much stronger than single bonds. stronger than single bonds.

Saturated fats have no double bonds. Saturated fats have no double bonds.

Fats have a lot of energy stored up in their Fats have a lot of energy stored up in their molecular bonds. That's why the human body molecular bonds. That's why the human body stores fat as an energy source. When it needs stores fat as an energy source. When it needs extra fuel, your body breaks down the fat and extra fuel, your body breaks down the fat and uses the energy. uses the energy.

One molecule of sugar only gives a small One molecule of sugar only gives a small amount of energy, a fat molecule gives off amount of energy, a fat molecule gives off many times more. many times more.

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Trans FatsTrans Fats Trans fats are Trans fats are unsaturated fatsunsaturated fats Found in Found in partially hydrogenatedpartially hydrogenated

oilsoils Have recently been removed from Have recently been removed from

many foods due to health concernsmany foods due to health concerns N.Y restaurantsN.Y restaurants Frito LayFrito Lay Krispy KremeKrispy Kreme Girl Scout CookiesGirl Scout Cookies Wendy’s Wendy’s etc…etc…

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and more fats…and more fats…

SterolsSterols cholesterol (HDL, LDL)cholesterol (HDL, LDL) build cells, chemical build cells, chemical

messengersmessengers PhospholipidsPhospholipids

molecules that have parts that molecules that have parts that dissolve in water and parts dissolve in water and parts that do notthat do not

cell membrane structure--cell membrane structure--bilayersbilayers

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Nucleic acidsNucleic acids Made of C, H, O, N, & PMade of C, H, O, N, & P Monomers are called nucleotidesMonomers are called nucleotides

Nucleotides are made up of a 5-Nucleotides are made up of a 5-carbon sugar, phosphate group and carbon sugar, phosphate group and a nitrogen basea nitrogen base

FunctionsFunctions Store hereditary informationStore hereditary information Transmit hereditary informationTransmit hereditary information

Two typesTwo types RNA (ribonucleic acid)RNA (ribonucleic acid) DNA (deoxyribonucleic acid)DNA (deoxyribonucleic acid)

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ProteinsProteins Made of C, H, O, & NMade of C, H, O, & N Monomers of proteins are amino acidsMonomers of proteins are amino acids

There are 20 different amino acids that There are 20 different amino acids that combine in different ways to make combine in different ways to make millions of proteinsmillions of proteins

The most diverse macromoleculesThe most diverse macromolecules FunctionsFunctions

Control the rates of chemical reactions Control the rates of chemical reactions (enzymes)(enzymes)

Regulate cell processesRegulate cell processes Used to form bone & musclesUsed to form bone & muscles Transport substances into or out of cellsTransport substances into or out of cells Help fight diseaseHelp fight disease

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ProteinProtein Burgers are full of Burgers are full of proteinsproteins, ,

which your body uses to which your body uses to

build and repair itself. build and repair itself. The pepperoni and the cheese on this The pepperoni and the cheese on this

pizza are also loaded with pizza are also loaded with proteinsproteins. . And popcorn is formed from starch, while a hot And popcorn is formed from starch, while a hot

dog is yet another source of protein. (Of course, dog is yet another source of protein. (Of course, buttery popcorn and hot dogs also contain a lot of buttery popcorn and hot dogs also contain a lot of fat. Fat molecules are big, but they're not fat. Fat molecules are big, but they're not polymers.)polymers.)

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Proteins & DigestionProteins & Digestion

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Polymer OR ProteinPolymer OR Protein As we discussed As we discussed

earlier, sweaters earlier, sweaters can be made from can be made from polymerspolymers..

Sweaters can also Sweaters can also be made from wool, be made from wool, which is a which is a proteinprotein called called keratinkeratin. . So is your hair and So is your hair and

fingernails, by the fingernails, by the way.way.

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Those fabulous Those fabulous proteins...proteins... Organics of Organics of C-H-O-NC-H-O-N Build structures, carry out Build structures, carry out

metabolismmetabolism made up of made up of AMINO ACIDSAMINO ACIDS

20 common amino acids20 common amino acids• an an aminoamino group (NH group (NH22) on one end) on one end

• an acid or carboxyl group (-COOH) on the otheran acid or carboxyl group (-COOH) on the other• a Hydrogen (H) atoma Hydrogen (H) atom• a fourth compound - which determines the a fourth compound - which determines the

nature of the amino-acidnature of the amino-acid

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Amino AcidAmino Acid

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Amino Amino Acids form Acids form covalent covalent bondsbonds ((PEPTIDE PEPTIDE BONDSBONDS) ) and may and may form form EXTREMELEXTREMELY long Y long chainschains

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Protein structureProtein structure One or more One or more polypeptidepolypeptide

chainschains enzymesenzymes

CatalystsCatalysts: decrease start up energy : decrease start up energy of RXNof RXN

may accelerate RXN by 10may accelerate RXN by 1010 10 timestimes regulate chemical pathways, regulate chemical pathways,

release energy, transfer info release energy, transfer info involved in all life processes, involved in all life processes,

even in enzyme production!even in enzyme production!

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EnzymesEnzymes They usually speed up the rate of They usually speed up the rate of

a reaction by lowering the a reaction by lowering the amount of activation amount of activation energy needed to energy needed to start the start the reaction.reaction.

end with -ase.end with -ase. Ex. lactaseEx. lactase

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Chemical reactionsChemical reactions Chemical Chemical

reactions reactions involve the involve the making and making and breaking of breaking of chemical bonds.chemical bonds.

Chemical bonds Chemical bonds “store” energy.“store” energy.

When a bond is When a bond is broken, energy broken, energy is released is released (heat, light, (heat, light, sound)sound)

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Exothermic ReactionExothermic Reaction Energy is Energy is

ReleasedReleased Ex. Fireworks, Ex. Fireworks,

cellular cellular respiration, respiration, digestiondigestion

These reactions These reactions involve the involve the breaking of breaking of polymers into polymers into monomers monomers

http://www2.uni-siegen.de/~pci/versuche/english/v41-1.html

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Endothermic ReactionEndothermic Reaction is one in is one in

which energy is absorbed (stored in which energy is absorbed (stored in bonds)bonds)

The joining of monomers into The joining of monomers into polymers.polymers.

Ex. Photosynthesis, making Ex. Photosynthesis, making proteins, etc.proteins, etc.

http://www.chemistry-videos.org.uk/chem%20clips/KS3%20Endothermic/enothermic.html

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Exothermic = ExergonicExothermic = ExergonicEndothermic = Endothermic = EndergonicEndergonic

http://www2.uni-siegen.de/~pci/versuche/english/kapitel4.html

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SummarySummary