BIOCHEMISTRY – BIOCHEMISTRY – Part IPart I

The highest courage is to The highest courage is to dare to appear to be what dare to appear to be what

one is.one is.

John SpaldingJohn Spalding

Hydrogen BondHydrogen Bond

A type of Van der Waals forceA type of Van der Waals forceAttractive force BETWEEN Attractive force BETWEEN

moleculesmoleculesNOT a true chemical bondNOT a true chemical bondLinks two Links two polar moleculespolar molecules

together.(not atoms)together.(not atoms)

Hydrogen BondHydrogen Bond

Hydrogen bonds are Hydrogen bonds are individually very individually very weakweak..

Hydrogen bonds only form Hydrogen bonds only form when molecules are very when molecules are very close close togethertogether..

Hydrogen bonds determine the Hydrogen bonds determine the shapes of shapes of DNA and proteins.DNA and proteins.

Hydrogen BondingHydrogen Bonding

Properties of Water to DiscussProperties of Water to DiscussCohesionCohesionSurface TensionSurface TensionAdhesionAdhesionImbibitionImbibitionHigh Specific HeatHigh Specific HeatHigh Heat of VaporizationHigh Heat of VaporizationExpansion upon FreezingExpansion upon FreezingVersatile SolventVersatile Solvent

Polar vs.Nonpolar MoleculePolar vs.Nonpolar Molecule

Nonpolar molecule – a Nonpolar molecule – a molecule with equal areas of molecule with equal areas of chargecharge

Polar molecule - A molecule Polar molecule - A molecule with unequal areas of with unequal areas of chargecharge

Polar MoleculePolar MoleculeExample: In water, electrons Example: In water, electrons

are shared are shared unequallyunequally, so , so different parts of the different parts of the molecule have different molecule have different charges.charges.

Polar MoleculePolar MoleculeAny molecules with charges Any molecules with charges

like to STICK to other like to STICK to other molecules with charges molecules with charges (opposites attract !!!)(opposites attract !!!)

CohesionCohesion

Attraction between Attraction between water moleculeswater molecules that that creates surface tension..creates surface tension..

Water sticks to water Water sticks to water due to Hydrogen due to Hydrogen BondingBonding

Hydrogen BondingHydrogen Bonding

Hydrogen Hydrogen BondingBonding

Surface Surface TensionTension

AdhesionAdhesion

Attraction of water to Attraction of water to other other polarpolar molecules molecules. .

Water sticks (adheres) to Water sticks (adheres) to other things.other things.

Capillary action: allows water Capillary action: allows water to move up small tubes to move up small tubes against gravityagainst gravity– Example: helps plants “drink”Example: helps plants “drink”

Solvent PropertiesSolvent PropertiesWater is called the Water is called the universal universal

solventsolvent; many things can dissolve ; many things can dissolve in water because it is a polar in water because it is a polar molecule.molecule.

HydrationHydration

SOLUTIONS & SUSPENSIONSSOLUTIONS & SUSPENSIONS

Examples to discuss: Don’t have to Examples to discuss: Don’t have to memorizememorize

Solutions:Solutions:– Very evenly dispersed small particlesVery evenly dispersed small particles– SOLUTE is dissolved into the SOLVENTSOLUTE is dissolved into the SOLVENT

Example: salt into water, fluids around your cellsExample: salt into water, fluids around your cells

Suspensions:Suspensions:– Larger particlesLarger particles– Will settle out if let to sitWill settle out if let to sit

Example: bloodExample: blood

Solvent properties allow transport of many Solvent properties allow transport of many substances in our bodiessubstances in our bodies

Density of WaterDensity of Water

Water is unique because its solid Water is unique because its solid form (ice) is form (ice) is lessless dense than the dense than the liquid form due to expansion.liquid form due to expansion.

Question: Why is this property Question: Why is this property important to aquatic plant and important to aquatic plant and animal life?animal life?– Discuss the answerDiscuss the answer

Hydrogen Bonding (ICE)Hydrogen Bonding (ICE)

Notice the “hole” Notice the “hole” in the hexagonal in the hexagonal structure and all structure and all the H-Bondsthe H-Bonds

The “hole” is why The “hole” is why the ice floats – it the ice floats – it makes it less makes it less dense than waterdense than water

ImbibitionImbibition

Water will Water will soak into a soak into a hydrophilic hydrophilic substance.substance.

High Specific HeatHigh Specific Heat

Water can absorb Water can absorb a lot of energy a lot of energy before its before its temperature temperature changes.changes.

This helps us to This helps us to maintain our body maintain our body temperaturetemperature

High Heat of Vaporization High Heat of Vaporization Water absorbs a Water absorbs a

lot of energy (576 lot of energy (576 cal/g) to change cal/g) to change states-our sweat states-our sweat carries away that carries away that energy when it energy when it evaporates!!!evaporates!!!

ACIDS, BASES, AND ACIDS, BASES, AND pHpH

pH ScalepH Scale

pH of Common SubstancespH of Common SubstancespH of Common SubstancespH of Common Substances

pH ScalepH Scale

Indicates concentration of H+ ions in Indicates concentration of H+ ions in a solutiona solution

Neutral = 7 = concentrations of H+ Neutral = 7 = concentrations of H+ and OH- are equaland OH- are equal

Acids are below 7 = higher H+ Acids are below 7 = higher H+ concentrationsconcentrations

Bases are above 7 = lower H+ Bases are above 7 = lower H+ concentrationsconcentrations

BuffersBuffers BUFFERS ARE VERY IMPORTANT!!!BUFFERS ARE VERY IMPORTANT!!! EVERYTIME YOU EAT, DRINK, OR BREATHE EVERYTIME YOU EAT, DRINK, OR BREATHE

YOU CHANGE YOUR pH YOU CHANGE YOUR pH Buffers help maintain your pH homeostasis Buffers help maintain your pH homeostasis

by resisting large, abrupt changes in the by resisting large, abrupt changes in the pHpH

This is important because all chemical This is important because all chemical reactions are affected by pH (we will reactions are affected by pH (we will discuss this with proteins)discuss this with proteins)

Buffers are a combo of a weak acid and a Buffers are a combo of a weak acid and a weak baseweak base

Pre AP Biology Pre AP Biology Biochemistry Part II - Biochemistry Part II -

MacromoleculesMacromolecules

The molecules that make up and The molecules that make up and run your bodyrun your body

4 Types of Macromolecules4 Types of Macromolecules

REVIEW CONCEPTSREVIEW CONCEPTS

ALL of these Macromolecules are ALL of these Macromolecules are Organic moleculesOrganic molecules

What does that mean?What does that mean? It means they have carbon in the It means they have carbon in the

presence of hydrogenpresence of hydrogen

MacromoleculesMacromolecules

ORGANICORGANIC molecules that weigh molecules that weigh more than more than 100,000100,000 Daltons are Daltons are referred to as macromoleculesreferred to as macromolecules

Macromolecules are constructed of Macromolecules are constructed of smaller units called smaller units called POLYMERSPOLYMERS

Polymers are subdivided into their Polymers are subdivided into their basic units called basic units called MONOMERS.MONOMERS.

MacromoleculesMacromolecules

Polymers account for the molecular Polymers account for the molecular uniqueness of organisms. uniqueness of organisms.

FOR EXAMPLE: ~20 amino acids are FOR EXAMPLE: ~20 amino acids are responsible for all forms of life. responsible for all forms of life. These amino acids form every These amino acids form every conceivable protein known to man.conceivable protein known to man.

Making & Breaking of Making & Breaking of PolymersPolymers

MakingMaking of Polymers of Polymers

Dehydration Synthesis – is Dehydration Synthesis – is an an anabolicanabolic process by process by which two molecules are which two molecules are chemically joined through chemically joined through the use of enzymes and a the use of enzymes and a lossloss of water of water

AKA: PolymerizationAKA: Polymerization

Dehydration Synthesis Dehydration Synthesis Example: Example:

Glucose + Fructose = SucroseGlucose + Fructose = Sucrose

Making & Making & BreakingBreaking of Polymers of Polymers

HydrolysisHydrolysis – is a – is a cataboliccatabolic process by process by which the bonds which the bonds between monomers are between monomers are broken by the enzyme broken by the enzyme and the and the additionaddition of of water.water.

Hydrolysis Example: Hydrolysis Example: Sucrose = Glucose + FructoseSucrose = Glucose + Fructose

(just reverse dehydration synthesis) (just reverse dehydration synthesis)

MacromoleculesMacromolecules

CarbohydratesCarbohydrates

CarbohydratesCarbohydrates

Molecules made of C,H,and OMolecules made of C,H,and OMonosaccharides = monomerMonosaccharides = monomerDisaccharide = polymerDisaccharide = polymerPolysaccharide = Polysaccharide =

macromoleculemacromolecule

MonosaccharidesMonosaccharides

Single Single SugarsSugars

MonosaccharidesMonosaccharides

Basic Formula: Basic Formula: CCnnHH2n2nOOn

examples: – CC66HH1212OO6

– CC55HH1010OO5

– 1:2:1 ratioFunction: To supply Function: To supply IMMEDIATEIMMEDIATE

energy for all cell activitiesenergy for all cell activities

Monosaccharide ExamplesMonosaccharide Examples

Triose sugarsTriose sugars– 3 carbons3 carbons– Glyceraldehyde & dihydroxyacetoneGlyceraldehyde & dihydroxyacetone

Pentose sugarsPentose sugars– 5 carbons5 carbons– Ribose, deoxyribose, and ribuloseRibose, deoxyribose, and ribulose

Hexose sugarsHexose sugars– 6 carbons6 carbons– Glucose, galactose, fructoseGlucose, galactose, fructose

Glucose: Your brain’s favorite foodGlucose: Your brain’s favorite food

Glucose MetabolismGlucose Metabolism

DisaccharidesDisaccharides DoubleDouble sugars sugars Basic Formula: Basic Formula: CC12HH2222OO1111

Same formula but different structural Same formula but different structural arrangementsarrangements

Notice that one molecule of Notice that one molecule of waterwater is is missing from the formulamissing from the formula

2 x2 x CC66HH1212OO6 = = CC12HH2222OO11 11 + H + H22OO

Making a DisaccharideMaking a Disaccharide

Dehydration SynthesisDehydration Synthesis

DisaccharidesDisaccharides Bond holding monomers together is Bond holding monomers together is

called a 1-4 or 1-2 called a 1-4 or 1-2 glycosideglycoside linkage linkage (the #s refer to the position of the (the #s refer to the position of the carbons that are bonded)carbons that are bonded)

Examples:Examples:– SucroseSucrose– MaltoseMaltose– LactoseLactose– NOTICE: Mono & Disaccharides end in NOTICE: Mono & Disaccharides end in

the suffix the suffix -ose-ose

PolysaccharidesPolysaccharides

ManyMany sugars sugarsBasic FormulaBasic Formula: : ( C( C66HH1010OO55))nn

Act as structural or Act as structural or storage moleculesstorage molecules

Storage PolysaccharidesStorage Polysaccharides

These are our “complex These are our “complex carbohydrates” (carbohydrates” (ENERGY ENERGY STORAGESTORAGE))

STARCH is a PLANT storage STARCH is a PLANT storage polysaccharide that is composed polysaccharide that is composed entirely of glucose joined by 1-4 entirely of glucose joined by 1-4 glycoside linkagesglycoside linkages

Amylose is the simplest form of Amylose is the simplest form of starchstarch

Amylopectin is more complex with a Amylopectin is more complex with a branched structurebranched structure

Storage PolysaccharidesStorage Polysaccharides

Glycogen is an animal starch stored Glycogen is an animal starch stored in the liver and skeletal muscles of in the liver and skeletal muscles of vertebrates.vertebrates.

It is more highly branched than It is more highly branched than amylopectin.amylopectin.

PLANTS make their own PLANTS make their own carbohydrates carbohydrates

ANIMALS eat the plantsANIMALS eat the plants FOOD/ENERGY WEB IN ACTION!!FOOD/ENERGY WEB IN ACTION!!

Glycogen StorageGlycogen Storage

Using GlycogenUsing Glycogen

If your blood sugar (glucose) gets too If your blood sugar (glucose) gets too high:high:– Your body stores it in your liver and Your body stores it in your liver and

skeletal muscles as glycogenskeletal muscles as glycogen If your blood sugar gets too low:If your blood sugar gets too low:

– Your body breaks down the glycogen Your body breaks down the glycogen and releases glucose to your bloodand releases glucose to your blood

Structural PolysaccharidesStructural Polysaccharides

Cellulose and chitin are examples of Cellulose and chitin are examples of structural polysaccharidesstructural polysaccharides

Cellulose is the most abundant Cellulose is the most abundant organic compound on earth.organic compound on earth.

Chitin is found in arthropod Chitin is found in arthropod exoskeletons and the cell walls of exoskeletons and the cell walls of fungi (absorbs fat – remember fungi (absorbs fat – remember commercials for the fat absorbing commercials for the fat absorbing pill? It was chitin. It works but you pill? It was chitin. It works but you couldn’t eat enough of it to really couldn’t eat enough of it to really help lose weight!)help lose weight!)

Structural PolysaccharidesStructural Polysaccharides CelluloseCellulose

– Primarily found in cell walls of plantsPrimarily found in cell walls of plants– Must be broken down into glucose Must be broken down into glucose

before cells can use it for energybefore cells can use it for energy– Cows, termites, and roaches have Cows, termites, and roaches have

microbes in their digestive tracts that do microbes in their digestive tracts that do this for themthis for them

– WE DON’T – that is why we can’t graze WE DON’T – that is why we can’t graze on grass for lunch!!on grass for lunch!!

– However, we do need cellulose although However, we do need cellulose although we just call it FIBER in our diet: It scrubs we just call it FIBER in our diet: It scrubs out our intestines!out our intestines!

LIPIDSLIPIDS

Or fat fat fat fat fatOr fat fat fat fat fat

WARNING!!!!!WARNING!!!!!

YOU WILL HAVE TO CHOOSE ONE YOU WILL HAVE TO CHOOSE ONE DISCUSSION QUESTION ON YOUR DISCUSSION QUESTION ON YOUR TEST ABOUT THE FYI INFORMATION TEST ABOUT THE FYI INFORMATION CONTAINED IN THE REST OF THESE CONTAINED IN THE REST OF THESE NOTES NOTES

LipidsLipids

Contain C, H, and O but with a lower Contain C, H, and O but with a lower proportion of Oproportion of O

Do not mix with waterDo not mix with water They are HYDROPHOBIC because They are HYDROPHOBIC because

they are non polar.they are non polar. Examples: neutral fats, Examples: neutral fats,

phospholipids, and steroidsphospholipids, and steroids

LipidsLipids

KNOW THIS FACT: KNOW THIS FACT: Lipids are not Lipids are not solublesoluble in water. This is in water. This is

because water is polar and most lipids because water is polar and most lipids are nonpoloar.are nonpoloar.

Why are nonpolar substances unable Why are nonpolar substances unable to dissolve in a polar substance such to dissolve in a polar substance such as water?as water?

(can’t form hydrogen bonds)(can’t form hydrogen bonds)

Neutral Fats aka. TriglyceridesNeutral Fats aka. Triglycerides

Monomers:Monomers:–Glycerol: an alcohol Glycerol: an alcohol containing 3 Carbonscontaining 3 Carbons

–3 fatty acids3 fatty acidsAn ESTER bond connects An ESTER bond connects

the fatty acids with the the fatty acids with the glycerol.glycerol.

Neutral Fats:Neutral Fats:

Dehydration SynthesisDehydration Synthesis

Saturated Fats vs. UnsaturatedSaturated Fats vs. Unsaturated

Saturated Fats - all SINGLE C-C bondsSaturated Fats - all SINGLE C-C bonds Unsaturated Fats - have one or more Unsaturated Fats - have one or more

double C=C bonddouble C=C bond– The double bonds cut down on the # of The double bonds cut down on the # of

H atoms that can be attached. This H atoms that can be attached. This causes the molecule to bend at each of causes the molecule to bend at each of the double bond sites. the double bond sites.

Saturated Fats vs. UnsaturatedSaturated Fats vs. Unsaturated

WRITE THESE FACTS IN THE CHART WRITE THESE FACTS IN THE CHART ON YOUR NOTESON YOUR NOTES

Saturated Fats – Saturated Fats – – SINGLE BONDS, straight, pack SINGLE BONDS, straight, pack

closely together closely together – SOLID at room temp.SOLID at room temp.– ANIMAL FATSANIMAL FATS

Saturated Fats vs. UnsaturatedSaturated Fats vs. Unsaturated

WRITE THESE FACTS IN THE CHART WRITE THESE FACTS IN THE CHART ON YOUR NOTESON YOUR NOTES

Unsaturated Fats –Unsaturated Fats –– DOUBLE BONDS, Bent, can’t pack DOUBLE BONDS, Bent, can’t pack

closely togetherclosely together– LIQUID at room tempLIQUID at room temp– PLANT FATSPLANT FATS

Saturated vs. Unsaturated BondsSaturated vs. Unsaturated Bonds

http://biology.clc.uc.edu/courses/bio104/lipids.htm

Function of Neutral FatsFunction of Neutral Fats

INSULATION (subcutaneous fat)INSULATION (subcutaneous fat) ENERGY STORAGEENERGY STORAGE

– Very energy denseVery energy dense– Fat: 9 kcal of energy per gramFat: 9 kcal of energy per gram

Carbs & proteins 4 kcal of energy per gramCarbs & proteins 4 kcal of energy per gram

CUSHIONING FOR INTERNAL ORGANSCUSHIONING FOR INTERNAL ORGANS ABSORPTION OF FAT SOLUBLE VITAMINS:ABSORPTION OF FAT SOLUBLE VITAMINS:

– ADEKADEK– THESE VITAMINS CANNOT BE ABSORBED THESE VITAMINS CANNOT BE ABSORBED

UNLESS THEY ARE DISSOLVED IN FATUNLESS THEY ARE DISSOLVED IN FAT

FYI: CIS vs. TRANS ISOMERSFYI: CIS vs. TRANS ISOMERS

http://biology.clc.uc.edu/courses/bio104/lipids.htm

FYI: Trans FatsFYI: Trans Fats

Produced when cis vegetable oils are Produced when cis vegetable oils are heated.heated.

Multiple heatings, such as a fast food Multiple heatings, such as a fast food fryer, converts large quantities of cis fryer, converts large quantities of cis to trans bondsto trans bonds

Concern: trans fatty acids are Concern: trans fatty acids are carcinogeniccarcinogenic

PhospholipidsPhospholipids

Monomers are:Monomers are:– 2 fatty acids2 fatty acids– 1 phosphate1 phosphate

Both polar and non polar Both polar and non polar qualitiesqualities– Phosphate head is polarPhosphate head is polar– Fatty acid tail is non polarFatty acid tail is non polar

Function of PhospholipidsFunction of Phospholipids

Form cell membraneForm cell membrane–Phospholipid bilayerPhospholipid bilayer

Component of Nervous Component of Nervous TissueTissue

Phospholipid BilayerPhospholipid Bilayer

Myelin Sheath: Insulates NerveMyelin Sheath: Insulates Nerve

SteroidsSteroids

Monomers are carbon skeleton of 4 Monomers are carbon skeleton of 4 fused ringsfused rings

SteroidsSteroids Steroids are FAT SOLUBLE and Steroids are FAT SOLUBLE and

contain little oxygencontain little oxygen THE FOLLOWING ARE EXAMPLES:THE FOLLOWING ARE EXAMPLES: Cholesterol is found in all ANIMAL Cholesterol is found in all ANIMAL

tissue. Plants do NOT contain tissue. Plants do NOT contain cholesterolcholesterol– Cholesterol is the MOST IMPORTANT Cholesterol is the MOST IMPORTANT

steroid since it is essential for the steroid since it is essential for the manufacture of ALL other steroidsmanufacture of ALL other steroids

– It also helps to STABILIZE your cell It also helps to STABILIZE your cell membranes.membranes.

ExamplesExamples

Sex hormones: estrogen, Sex hormones: estrogen, testosterone, progesteronetestosterone, progesterone

Insulin: blood glucose regulationInsulin: blood glucose regulation Aldosterone: maintains water Aldosterone: maintains water

balancebalance Bile salts: digestion & absorption of Bile salts: digestion & absorption of

FATSFATS

FYI: HDL vs. LDLFYI: HDL vs. LDL LIPOPROTEINS are molecules that help LIPOPROTEINS are molecules that help

transport lipids in the blood (since lipids transport lipids in the blood (since lipids are NOT water soluble, they cannot are NOT water soluble, they cannot circulate by themselves)circulate by themselves)

HIGH DENSITY LIPOPROTEINSHIGH DENSITY LIPOPROTEINS– Transport excess cholesterol to liver for Transport excess cholesterol to liver for

breakdownbreakdown LOW DENSITY LIPOPROTEINSLOW DENSITY LIPOPROTEINS

– Transport excess cholesterol to cells for Transport excess cholesterol to cells for storage (can clog artery walls, etc.)storage (can clog artery walls, etc.)

YOU WANT YOUR HDL LEVEL TO BE YOU WANT YOUR HDL LEVEL TO BE HIGHER THAN YOUR LDL LEVELHIGHER THAN YOUR LDL LEVEL

PreLab RemarksPreLab Remarks Learn how to test for macromoleculesLearn how to test for macromolecules

– 1 Glucose—Benedicts test1 Glucose—Benedicts testTest tubes will be hot, handle carefullyTest tubes will be hot, handle carefully

– 2 Starch—iodine turns blue/black on 2 Starch—iodine turns blue/black on starchstarch

– 3 Proteins—Biuret’s test turns purple 3 Proteins—Biuret’s test turns purple on proteinon protein

– 4 Lipids---Sudan III stains fats pink4 Lipids---Sudan III stains fats pinkSuit up—goggles & apronsSuit up—goggles & aprons

Each group member performs a different test and shares results with group

ClosureClosureWhat test can be used to detect What test can be used to detect

the presence of starch? glucose? the presence of starch? glucose? protein?protein?

What elements do glucose, What elements do glucose, starch, and proteins have in starch, and proteins have in common?common?

Don’t forget the homework Don’t forget the homework assignment.assignment.

NUCLEIC ACIDSNUCLEIC ACIDS

GENETIC MATERIALGENETIC MATERIAL

Nucleic AcidsNucleic Acids

NUCLEOTIDESNUCLEOTIDES (monomers) (monomers) consist of:consist of:– 5-C ribose or 5-C ribose or

deoxyribose deoxyribose sugar (ribose sugar (ribose has one more has one more oxygen in its oxygen in its molecule)molecule)

Nucleic AcidsNucleic Acids Nucleotides con’t:Nucleotides con’t:

– PhosphatePhosphate– Nitrogenous baseNitrogenous base

Double ring purines: guanine (G) or Double ring purines: guanine (G) or adenine (A)adenine (A)

Single ring pyrimidine: Cytosine (C), Single ring pyrimidine: Cytosine (C), thymine (T), or uracil (U)thymine (T), or uracil (U)

Nucleotides are joined together by Nucleotides are joined together by phosphodiester bondsphosphodiester bonds

Nucleic acids contain (CHONP)Nucleic acids contain (CHONP)

NucleotidesNucleotides

DNA & RNA

DNA CHART INFODNA CHART INFO

Cellular site = nucleusCellular site = nucleus Function = Directs protein synthesis Function = Directs protein synthesis

(contains all the instructions)(contains all the instructions) Sugar = deoxyriboseSugar = deoxyribose Nitrogenous bases = A T C GNitrogenous bases = A T C G Structure = double helixStructure = double helix

RNA CHART INFORNA CHART INFO

Cellular site = in & out of nucleus Cellular site = in & out of nucleus (can travel)(can travel)

Function = Carries out protein Function = Carries out protein synthesis (makes it happen)synthesis (makes it happen)

Sugar = riboseSugar = ribose Nitrogenous bases = A U C GNitrogenous bases = A U C G Structure = single strandStructure = single strand

PROTEINSPROTEINS

In charge of all your body In charge of all your body functionsfunctions

ProteinsProteins

Monomer: Amino AcidsMonomer: Amino Acids– Each amino acid consists of a Each amino acid consists of a

central carbon bonded to:central carbon bonded to:Amino group (-NHAmino group (-NH22) ) HydrogenHydrogenR group – this is a functional group that R group – this is a functional group that

makes each amino acid unique in makes each amino acid unique in function and actionfunction and action

Carboxyl group (-COOH): an acid groupCarboxyl group (-COOH): an acid group

Basic amino acid structureBasic amino acid structure

20 main 20 main amino acidsamino acids

General structure Alanine Serine

Section 2-3

Figure 2-16 Amino Acids

Amino group Carboxyl group

Protein formationProtein formation

Dehydration synthesisDehydration synthesis joins the joins the amino acid monomers together by amino acid monomers together by use of a use of a peptidepeptide bond bond– Hydrolysis breaks them apartHydrolysis breaks them apart

You will sometimes hear proteins You will sometimes hear proteins called “polypeptides” for this reason.called “polypeptides” for this reason.

Proteins make up ~50% of dry Proteins make up ~50% of dry weight of most cells and contain the weight of most cells and contain the elements elements CHONCHON..

Functions of ProteinsFunctions of Proteins

Proteins have a wide variety of Proteins have a wide variety of functions. These functions can be functions. These functions can be divided into 2 categories:divided into 2 categories:– STRUCTURAL: support and strengthenSTRUCTURAL: support and strengthen– FUNCTIONAL: crucial roles in biological FUNCTIONAL: crucial roles in biological

processesprocesses

– Let’s take a look at a few of the Let’s take a look at a few of the examples in your notes: You do need to examples in your notes: You do need to memorize these examples. Proteins are memorize these examples. Proteins are VERY IMPORTANT!!!VERY IMPORTANT!!!

Structural ProteinsStructural Proteins

Functional Functional

Proteins Proteins

Cell Membrane Proteins Cell Membrane Proteins

Protein HormonesProtein Hormones

Functional ProteinsFunctional Proteins

Let’s take a look at the rest of the Let’s take a look at the rest of the examples in your notesexamples in your notes

Enzyme actionEnzyme action

Enzymes can act as a catalystEnzymes can act as a catalyst– A molecule that lowers A molecule that lowers ACTIVATION ACTIVATION

ENERGYENERGY– This can increase a reaction’s speed This can increase a reaction’s speed

(rate) up to 10(rate) up to 101010 times!! times!!– The enzyme is The enzyme is not changed at allnot changed at all by by

the chemical reaction so can be reused the chemical reaction so can be reused over and overover and over

Enzyme SpecificityEnzyme Specificity

SubstrateSubstrate: the molecule that is : the molecule that is affected by the enzymeaffected by the enzyme

Active siteActive site: place on the enzyme : place on the enzyme where the reaction occurswhere the reaction occurs

ONE ENZYME ACTS ON ONLY ONE ONE ENZYME ACTS ON ONLY ONE SUBSTRATE: VERY SPECIFIC !SUBSTRATE: VERY SPECIFIC !

AmylAmylasease breaks down amyl breaks down amyloseose LactLactasease breaks down lact breaks down lactoseose

Enzyme ActionEnzyme Action

Lock and key fitLock and key fit: active site and : active site and substrate fit exactlysubstrate fit exactly

Induced fitInduced fit: active site can adjust to : active site can adjust to “wrap around” substrate to get “wrap around” substrate to get optimum fitoptimum fit

Protein DenaturationProtein Denaturation

Functional Proteins depend on their Functional Proteins depend on their structurestructure to do their job to do their job

STRUCTURE DETERMINES FUNCTIONSTRUCTURE DETERMINES FUNCTION Active siteActive site must be the correct must be the correct

shape for the substrateshape for the substrate H-bondsH-bonds hold these proteins hold these proteins

together in their correct shapetogether in their correct shape

Protein DenaturationProtein Denaturation

Extremes (too high or too low) in Extremes (too high or too low) in TEMPERATURETEMPERATURE and and pHpH can disrupt can disrupt the the H-bondsH-bonds causing the causing the active siteactive site to be destroyed.to be destroyed.

Then the enzyme CANNOT do its Then the enzyme CANNOT do its function! Thus it is said to be function! Thus it is said to be denatured (Not the same nature as denatured (Not the same nature as before)before)

Glucose

Substrates

ATP

Substratesbind toenzyme

Substratesare convertedinto products

Enzyme-substratecomplex

Enzyme(hexokinase)

ADPProducts

Glucose-6-phosphate

Productsare released

Section 2-4

Figure 2-21 Enzyme Action

Active site

FACT REVIEWFACT REVIEW

Put the info from the Put the info from the following charts into your following charts into your

notes chartsnotes charts

Elements in MacromoleculesElements in Macromolecules

CarbohydrateCarbohydrate C,H,OC,H,O

LipidsLipids C,H,O,(P)C,H,O,(P)

ProteinsProteins C,H,O,NC,H,O,N

NucleicNucleic

AcidsAcidsC,H,O,N,PC,H,O,N,P

MonomersMonomersCarbohydratesCarbohydrates Mono-Mono-

saccharidessaccharides

Lipids (neutral Lipids (neutral fats)fats)

Glycerol & Glycerol & fatty acidsfatty acids

ProteinsProteins AminoAmino

AcidsAcids

NucleicNucleic

AcidsAcidsNucleotidesNucleotides

BondsBonds

CarbohydratesCarbohydrates Glycoside Glycoside linkagelinkage

LipidsLipids Ester Ester linkageslinkages

ProteinsProteins Peptide Peptide

NucleicNucleic

AcidsAcidsPhospho-Phospho-diesterdiester

Major functionMajor functionCarbohydratesCarbohydrates Immediate Immediate

energy & storageenergy & storage

LipidsLipids Energy storageEnergy storage

Cell componentsCell components

Form steroidsForm steroids

ProteinsProteins FunctionalFunctional

Structural Structural

NucleicNucleic

AcidsAcidsGenetic infoGenetic info

NUTRITIONNUTRITION

LET’S TAKE A LOOK AT THE LET’S TAKE A LOOK AT THE NUTRITION NOTES NUTRITION NOTES

WORKSHEETWORKSHEET

Nutrition LabelNutrition Label

What are the labels valuable?What are the labels valuable? Consider the label in your notes:Consider the label in your notes:

– How many servings?How many servings?– What is a serving?What is a serving?– How much fat if I ate the whole How much fat if I ate the whole

package?package?