CARBOHYDRATESCARBOHYDRATES

• Living things use carbohydrates as a key source Living things use carbohydrates as a key source of of ENERGYENERGY! !

• include sugars and complex carbohydrates include sugars and complex carbohydrates (starches) (starches)

• contain the elements contain the elements carbon, hydrogen, and carbon, hydrogen, and oxygenoxygen in a in a 1:2:1 ratio 1:2:1 ratio

• 4 calories per gram4 calories per gram

Monosaccharides (simple sugars) Monosaccharides (simple sugars)

• all have the formula Call have the formula C66HH1212OO66 • all have a single ring structure all have a single ring structure

– (glucose is an example) (glucose is an example)

Disaccharides (double sugars) Disaccharides (double sugars)

• all have the formula Call have the formula C1212HH2222OO1111 • sucrose (table sugar) is an example sucrose (table sugar) is an example

Polysaccharides Polysaccharides

• Formed of three or more simple sugar units Formed of three or more simple sugar units • GlycogenGlycogen - animal starch stored in liver & muscles - animal starch stored in liver & muscles • CelluloseCellulose – plant starch - indigestible in humans - – plant starch - indigestible in humans -

forms cell walls forms cell walls • Starches - used as energy storage Starches - used as energy storage

Lipids (Fats)Lipids (Fats)• Fats, oils, waxes, steroids Fats, oils, waxes, steroids • Chiefly function in Chiefly function in energy storage, protection, energy storage, protection,

and insulation and insulation • Contain Contain carbon, hydrogen, and oxygen carbon, hydrogen, and oxygen but they but they

are not in a 1:2:1 ratio are not in a 1:2:1 ratio • Tend to be Tend to be largelarge molecules -- an example of a molecules -- an example of a

neutral lipid is belowneutral lipid is below• 9 calories per gram 9 calories per gram

Lipids - What are they good for?

• Fats -- found chiefly in Fats -- found chiefly in animalsanimals • Oils and waxes -- found chiefly in Oils and waxes -- found chiefly in plantsplants • Oils are liquid at room temperature, waxes are Oils are liquid at room temperature, waxes are

solids solids • Lipids along with proteins are key components Lipids along with proteins are key components

of of cell membranescell membranes • Steroids are special lipids used to build many Steroids are special lipids used to build many

reproductive hormones and cholesterolreproductive hormones and cholesterol

PROTEINSPROTEINS• Contain the elements carbon, hydrogen, oxygen,Contain the elements carbon, hydrogen, oxygen, and nitrogen and nitrogen • 4 calories per gram4 calories per gram• Build & repair tissue• Movement (actin,myosin)• Structure (collagen)• Transport (hemoglobin)• Defense (antibodies)• Regulation (enzymes)

NUCLEIC ACIDS aka the building NUCLEIC ACIDS aka the building blocks of DNA and RNAblocks of DNA and RNA

• composed of composed of NUCLEOTIDESNUCLEOTIDES• store & transmit store & transmit heredity/geneticheredity/genetic information information• a 5- carbon sugar + a nitrogenous base + a phosphate

group• Contain C, H, N, O, & P• We’ll talk about these later

Enzymes and Enzyme Action Enzymes and Enzyme Action • catalystcatalyst: inorganic or organic substance which : inorganic or organic substance which

speeds up the ratespeeds up the rate of a chemical reaction without of a chemical reaction without changing the reaction changing the reaction

• enzymesenzymes: organic catalysts made of protein: organic catalysts made of protein– most enzyme names end in -ase most enzyme names end in -ase – Enzymes lower the energy needed to start a chemical Enzymes lower the energy needed to start a chemical

reaction. (reaction. (activation energyactivation energy))• SubstrateSubstrate = reactant = reactant

– reactant + reactant = products reactant + reactant = products

"Lock and Key Theory"

• each enzyme is specific for each enzyme is specific for one and ONLY one one and ONLY one substratesubstrate (one lock - one key) (one lock - one key)

• this theory has some weaknesses, but it this theory has some weaknesses, but it explains some basic things about enzyme explains some basic things about enzyme functionfunction

Factors Influencing Rate of Enzyme Factors Influencing Rate of Enzyme Action Action

1.1. pHpH - the optimum (best) in most living things is - the optimum (best) in most living things is close to 7 (neutral)close to 7 (neutral)

2.2. TemperatureTemperature - strongly influences enzyme - strongly influences enzyme activity activity

3.3. ConcentrationsConcentrations of Enzyme and Substrate of Enzyme and Substrate

The Extraordinary The Extraordinary Properties of WaterProperties of Water

Hydrolysis • Hydro = water• Lysis = break apart• Chemical process in which a water molecule is

added to a substance resulting in the split of that substance into two parts

Dehydration • Chemical process involving the removal of

water to join molecules• (it’s the opposite of hydrolysis)

WaterWater

•A water molecule (H2O), is made up of threethree atoms --- one oxygen and two hydrogen.

H

HO

Water is PolarWater is Polar

• In each water molecule, the oxygen atom attracts moreoxygen atom attracts more than its "fair share" of electronselectrons

• The oxygenoxygen end “acts” negativenegative• The hydrogenhydrogen end “acts” positivepositive• Causes the water to be POLARPOLAR• However, Water is neutralneutral (equal

number of e- and p+) --- Zero Net Zero Net ChargeCharge

Hydrogen Bonds Exist Hydrogen Bonds Exist Between Water MoleculesBetween Water Molecules

• Formed between a Formed between a highly highly Electronegative atom Electronegative atom of a polar molecule of a polar molecule and a and a HydrogenHydrogen

• OneOne hydrogen bond hydrogen bond is is weakweak , but , but manymany hydrogen bonds are hydrogen bonds are strongstrong

Interaction Between Interaction Between Water MoleculesWater Molecules

Negative Oxygen Negative Oxygen end of one water molecule is attracted to the end of one water molecule is attracted to the Positive Hydrogen Positive Hydrogen end of another water molecule to form a end of another water molecule to form a

HYDROGEN BONDHYDROGEN BOND

What are What are the the

PropertieProperties of s of

Water?Water?

Properties of WaterProperties of Water• At sea level, pure water At sea level, pure water boils at boils at

100 °C100 °C and and freezes at 0 °Cfreezes at 0 °C. .

• The The boiling temperature of water boiling temperature of water decreases at higher elevations decreases at higher elevations (lower atmospheric pressure). (lower atmospheric pressure).

• For this reason, an For this reason, an eggegg will take will take longer to boil longer to boil at higher altitudesat higher altitudes

Properties of WaterProperties of Water

•CohesionCohesion•AdhesionAdhesion•High Specific HeatHigh Specific Heat•High Heat of VaporizationHigh Heat of Vaporization•Less Dense as a SolidLess Dense as a Solid

Property 1: CohesionProperty 1: Cohesion• Attraction between particles of Attraction between particles of

the same substance the same substance (( why water why water is attracted to itself)is attracted to itself)

• Results in Results in Surface tensionSurface tension (a (a measure of the strength of measure of the strength of water’s surface)water’s surface)

• Produces a Produces a surface film surface film on water on water that that allows insects to walk on allows insects to walk on the surfacethe surface of water of water

Cohesion …Cohesion …

Helps insects walk across water

Property 2: AdhesionProperty 2: Adhesion

• Attraction between two different Attraction between two different substancessubstances..

• Water will make Water will make hydrogen bonds with hydrogen bonds with other surfacesother surfaces such as glass, soil, plant such as glass, soil, plant tissues, and cotton. tissues, and cotton.

• CapillaryCapillary actionaction-water molecules will -water molecules will “tow” each other along when in a thin “tow” each other along when in a thin glass tube.glass tube.

• Example: Example: transpirationtranspiration process which process which plants and trees remove water from plants and trees remove water from the soil, and paper towels soak up the soil, and paper towels soak up water.water.

Adhesion Causes Adhesion Causes Capillary ActionCapillary Action

Which gives water the ability to “climb”

structures

Capillary Action• aka – capillarity• The ability of a liquid to flow against gravity • Liquid spontaneously rises in a narrow space

such as a thin tube or paper

Capillary Action

• It happens because: the inter-molecular attractive forces between the liquid and solid surrounding surfaces

• The combination of surface tension (which is caused by cohesion within the liquid) and forces of adhesion between the liquid and container act to lift the liquid

Adhesion Also Causes Adhesion Also Causes Water to …Water to …

Form spheres & hold onto

plant leaves

Attach to a silken spider

web

Property 3: High Specific Property 3: High Specific HeatHeat• Amount of heatAmount of heat needed to raise needed to raise

or lower or lower 1g1g of a substance of a substance 1° C1° C..

• Water Water resistsresists temperature temperature changechange, both for heating and , both for heating and cooling.cooling.

• Water can absorb or release large Water can absorb or release large amounts of heat energy with little amounts of heat energy with little change in actual temperature.change in actual temperature.

Property 4: High Heat of Property 4: High Heat of VaporizationVaporization

• Amount of energy to convert 1g Amount of energy to convert 1g or a substance from a or a substance from a liquid to a liquid to a gasgas

• In order for water to evaporate, In order for water to evaporate, hydrogen bonds must be brokenhydrogen bonds must be broken..

• As water evaporatesAs water evaporates, it removes , it removes a lot of a lot of heatheat with it. with it.

High Heat of VaporizationHigh Heat of Vaporization

• Water's heat of vaporization is 540 cal/g.540 cal/g.

• In order for water to In order for water to evaporateevaporate, , each gram must each gram must GAIN 540 GAIN 540 calories (temperature doesn’t calories (temperature doesn’t change --- 100change --- 100ooC).C).

• As water evaporatesAs water evaporates, it removes , it removes a lot of a lot of heatheat with it with it (cooling (cooling effect)effect)..

• Water vapor Water vapor forms a kind of global ‘‘blanket” which helps to keep the Earth warm.

• Heat radiated from the sun Heat radiated from the sun warmed surface of the earth is

absorbed and held absorbed and held

by the vaporby the vapor.

Property 5: Water is Less Property 5: Water is Less Dense as a SolidDense as a Solid

• Ice is less denseIce is less dense as a solid than as a liquid (ice floats)

• Liquid water has hydrogen hydrogen

bonds bonds that are constantly being constantly being

broken and reformed.broken and reformed.

• Frozen waterFrozen water forms a crystal-like crystal-like

latticelattice whereby molecules are set at fixed distances.

Water is Less Dense as a Water is Less Dense as a SolidSolid

•Which is ice and which is water?Which is ice and which is water?

Water is Less Dense as a Water is Less Dense as a SolidSolid

WaterWater IceIce

Property 6: Property 6: HomeostasisHomeostasis

• Ability to maintain a Ability to maintain a steady state steady state despite changing conditionsdespite changing conditions

• Water is important to this process Water is important to this process because:because:a. Makes a a. Makes a good insulatorgood insulatorb. Resists temperature changeb. Resists temperature changec. c. Universal solventUniversal solventd. Coolantd. Coolante. Ice protects against temperature e. Ice protects against temperature

extremes ( extremes (insulatesinsulates frozen frozen lakes)lakes)

Solutions & Solutions & SuspensionsSuspensions

• Water is usually part of a Water is usually part of a mixture.mixture.

• There are two types of There are two types of mixtures:mixtures:– SolutionsSolutions– SuspensionsSuspensions

SolutionSolution

• Ionic compounds disperse as Ionic compounds disperse as ionsions in waterin water

• Evenly distributedEvenly distributed• SOLUTESOLUTE

– Substance that is being Substance that is being dissolveddissolved

• SOLVENTSOLVENT– Substance into which the solute Substance into which the solute

dissolvesdissolves

SolutionSolution

SuspensionsSuspensions

• Substances that don’t dissolve don’t dissolve but separate but separate into tiny pieces.

• Water keeps Water keeps the pieces the pieces suspended suspended so they don’t settle out.

Acids, Bases and pHAcids, Bases and pHOne water molecule One water molecule in 550 million in 550 million

naturally naturally dissociatesdissociates into a into a Hydrogen Ion Hydrogen Ion (H+) (H+) and a Hydroxide and a Hydroxide Ion Ion (OH-)(OH-)

Hydrogen Ion Hydroxide IonHydrogen Ion Hydroxide Ion Acid Acid BaseBase

H2O H+ + OH-

The pH ScaleThe pH Scale• Indicates the concentration of Hconcentration of H++

ionsions• Ranges from 0 – 140 – 14• pH of 7 is neutral7 is neutral• pH 0 up to 7 is acid 0 up to 7 is acid … H+ • pH above 7 – 14 is babove 7 – 14 is basic… OH- • Each pH unit represents a factor of

10X 10X change in concentration• pH 3 is 10 x 10 x 10 (1000) pH 3 is 10 x 10 x 10 (1000)

stronger than a pH of 6stronger than a pH of 6

AcidsAcids

• StrongStrong Acids Acids have a have a pH of pH of 1-31-3

• Produce Produce lots of lots of H H+ + ionsions

BasesBases

• Strong Strong Bases Bases have a pH of 11 to 14 11 to 14

• Contain lots of OHlots of OH--

ions ions and fewer H+ ions

BuffersBuffers• Weak acids or bases that react Weak acids or bases that react

with strong acids or bases to with strong acids or bases to prevent sharp, sudden changes prevent sharp, sudden changes in pH in pH (neutralization).(neutralization).

• Produced naturally by the body Produced naturally by the body to maintain homeostasisto maintain homeostasis

Weak AcidWeak Acid Weak BaseWeak Base