Section 6.3 – Life Section 6.3 – Life SubstancesSubstances

p.157-163p.157-163

Role of Carbon in OrganismsRole of Carbon in Organisms Carbon (C) has 4 electrons available Carbon (C) has 4 electrons available

for bondingfor bonding C bonds to form single, double, or C bonds to form single, double, or

triple bonds with other atomstriple bonds with other atoms

Role of Carbon in OrganismsRole of Carbon in Organisms

When C-C atoms, can form straight When C-C atoms, can form straight or branched chains, or ringsor branched chains, or rings

Role of Carbon in OrganismsRole of Carbon in Organisms IsomerIsomer

Compounds that have the chemical Compounds that have the chemical formula but different 3-D structuresformula but different 3-D structures

Examples:Examples: CC66HH1212OO66

Glucose, Fructose, GalactoseGlucose, Fructose, Galactose

Role of Carbon in OrganismsRole of Carbon in Organisms

BiomoleculesBiomolecules Large organic compoundsLarge organic compounds

May consist of 100s or 1000s of C atomsMay consist of 100s or 1000s of C atoms Example:Example:

ProteinProtein

Role of Carbon in OrganismsRole of Carbon in Organisms

PolymerPolymer Large molecule formed when many Large molecule formed when many

smaller molecules bond togethersmaller molecules bond together Condensation ReactionCondensation Reaction

monomer + monomer = polymer + Hmonomer + monomer = polymer + H22OO

HydrolysisHydrolysis polymer + Hpolymer + H22O = monomer + monomerO = monomer + monomer

CondensatiCondensationon

HydrolysisHydrolysis

CarbohydratesCarbohydrates Used to provide cells with energyUsed to provide cells with energy Biomolecule composed of Carbon, Biomolecule composed of Carbon,

Hydrogen, + OxygenHydrogen, + Oxygen Found in ratios of 2 H: 1O; the # of C Found in ratios of 2 H: 1O; the # of C

atoms variesatoms varies

CarbohydratesCarbohydrates MonosaccharidesMonosaccharides

A building block of a A building block of a carbohydratecarbohydrate

A simple sugarA simple sugar Most common types:Most common types:

Glucose – used in cellsGlucose – used in cells Fructose – found in Fructose – found in

fruitsfruits Galactose – found in Galactose – found in

milkmilk

CarbohydratesCarbohydrates DisaccharideDisaccharide

““double sugar”double sugar” Combination of 2 monosaccharides from Combination of 2 monosaccharides from

a condensation reactiona condensation reaction Example:Example:

SucroseSucrose

CarbohydratesCarbohydrates PolysaccharidesPolysaccharides

Composed of many monosaccharidesComposed of many monosaccharides Examples:Examples:

StarchStarch Stored as branched chain of glucoseStored as branched chain of glucose Used as energy storage for plant cellsUsed as energy storage for plant cells

GlycogenGlycogen Stored as highly branched chain of glucoseStored as highly branched chain of glucose Used as energy storage for animal cellsUsed as energy storage for animal cells

CelluloseCellulose Stored as chain-linked branches of glucoseStored as chain-linked branches of glucose Makes up plant cell wallsMakes up plant cell walls

Polysaccharides ExamplesPolysaccharides Examples

LipidsLipids Biomolecule composed of C, H, + few Biomolecule composed of C, H, + few

OO Examples:Examples:

FatsFats OilsOils WaxesWaxes SteroidsSteroids

LipidsLipids Lipids are insoluble in water because Lipids are insoluble in water because

molecules are nonpolarmolecules are nonpolar Not attracted by waterNot attracted by water

LipidsLipids Fatty AcidFatty Acid

Long chain of Long chain of carbon + hydrogencarbon + hydrogen

Building block of Building block of lipidslipids

SaturatedSaturated C-C (single bonds)C-C (single bonds)

UnsaturatedUnsaturated C-C (double bond)C-C (double bond)

PolyunsaturatedPolyunsaturated C-C (many double C-C (many double

bonds)bonds)

LipidsLipids Functions of lipids:Functions of lipids:

Energy storageEnergy storage InsulationInsulation Protective Protective

coveringscoverings Cell membraneCell membrane

ProteinsProteins Functions:Functions:

Provide structure for tissues + organsProvide structure for tissues + organs Carries out cell metabolismCarries out cell metabolism

Large, complex polymer composed of Large, complex polymer composed of C, H, O, Nitrogen (N), + Sulfur (S)C, H, O, Nitrogen (N), + Sulfur (S)

ProteinsProteins Amino Acid (AAs)Amino Acid (AAs)

A building block of proteinsA building block of proteins 20 common AAs20 common AAs Linked by condensation reaction – forms Linked by condensation reaction – forms

a peptide bonda peptide bond

ProteinsProteins Proteins come in a Proteins come in a

large variety of large variety of shapes + sizesshapes + sizes

The number + The number + sequence of AAs sequence of AAs determines its determines its shapeshape

ProteinsProteins EnzymeEnzyme

Protein that changes the rate of the chemical Protein that changes the rate of the chemical reactionreaction

May increase or decrease activityMay increase or decrease activity Activity of enzyme depends upon:Activity of enzyme depends upon:

TemperatureTemperature Ionic conditionsIonic conditions pHpH

Works like a “lock + key”Works like a “lock + key” Example (p. 162)Example (p. 162)

Nucleic AcidsNucleic Acids

Are necessary for lifeAre necessary for life Complex Complex

biomolecule that biomolecule that stores cellular stores cellular information in the information in the form of a codeform of a code

Nucleic AcidsNucleic Acids NucleotideNucleotide

A building block of nucleic acidsA building block of nucleic acids Composed of C, H, O, N, + Phosphorus Composed of C, H, O, N, + Phosphorus

(P)(P) Arranged in 3 groups:Arranged in 3 groups:

Nitrogenous baseNitrogenous base Simple sugarSimple sugar Phosphate groupPhosphate group

Nucleic AcidsNucleic Acids Types of Nucleic AcidsTypes of Nucleic Acids

DNADNA Deoxyribonucleic acidDeoxyribonucleic acid Master copy of organism’s information Master copy of organism’s information

(appearance + behavior)(appearance + behavior) Contains the instructions to be used by cellContains the instructions to be used by cell Passed down as cell dividesPassed down as cell divides

RNARNA Ribonucleic acidRibonucleic acid Formed from DNA to make proteinsFormed from DNA to make proteins