Chemical Basis of Life. Outline: The Chemical Basis of Life 1.Chemistry of Carbon 2.Polymers & Monomers 3.Biologically Important Compounds Carbohydrates

Chemical Basis of Life

Outline: The Chemical Basis of Life

1. Chemistry of Carbon

2. Polymers & Monomers

3. Biologically Important Compounds Carbohydrates Lipids Proteins Nucleic Acids

ProtonsNeutronsElectrons

1. Carbon has 4 valence electrons

2. Each carbon atom four covalent bonds

Carbon Chemistry

Electron PairCovalent Bond

Covalent Bonds in Carbon

Carbon ChemistryMolecular Formula

CH4

C2H6

Carbon Chemistry

C4H10C4H10

C4H8 C4H8

Carbon Chemistry

Structuralformula

Methane

H H

H

H H H

H

H

Ball-and-stickmodel

Space-fillingmodel

C

C

The 4 single bonds of carbon point to the corners of a tetrahedron.

H H

HH

H H

Ethane Propane

HH

H H

H

H

H

H

H

H

Carbon skeletons vary in length.

H

H

H

H

H H

H H

H H

H H

H H

H H

H

H

H

H

H

H H H H

H

H

C

HH H

H H

H H

H

H

H

H H

H

H

HH

H

H

H H

H

H

Butane Isobutane

Skeletons may be unbranched or branched.

1-Butene 2-Butene

Skeletons may have double bonds, which can vary in location.

CC C

C

CC

H

CC

C

CC

C

Cyclohexane Benzene

Skeletons may be arranged in rings.

C C C C C

C C C C

C

C CC

CCC C CCCH H

Summary: Carbon Chemistry

4 Covalent Bonds

Variable Length

Unbranched or Branched

Single or Double Bonds

Rings

Functional Group

StructuralFormula

HS

P

O–

O

O

HC

H

H

OH

O

OHC

H

HN

CO

C

H

H

CH

H

H

OH

CH

H

HC

O

OH

H

CH3

OH

CCHO NH

CH

H

HHC

O

CHOH

H HS HC

H

CH

OH

HC

OH

H HOC

H

P

O

C

O

C

O

HHC

H

O–

O–

O–

O–

FUNCTIONAL GROUPS Hydroxyl

Carbonyl

Carboxyl

Amino

Sulfhydryl

Phosphate

Methyl

HYDROXYL

Carboxyl

Melting Point (C)

C2H6O -114

C2H5O2 17

C2H6O 78

Boiling Point (C)

C2H5O2 118

Figure 3. Functional groups of male and female sex hormones

Male lion

Female lion

Estradiol

HO

OH

OH

OTestosterone

H

OH HOH

H OH

Unlinked monomer

Dehydration reaction

Longer polymer

Short polymer

H2O

Dehydration synthesis isPolymer Building

H

H2O

OH

H OHOH H

Hydrolysis

Hydrolysis is Polymer Breaking

Classes of Biologically Important Compounds

CarbohydratesLipidsProteinsNucleic Acids

Carbohydrates

Monosaccharides

Disaccharides

Polysaccharides

Figure 3.4B Structure of Monosaccharides

C

C

C

C

C

C

C

C

C

C

H

H

H

H

H

H

H H

H

H

H

HO

H

H

H

C

O

HO

OH

OH

OH

OH OH

OH

OH

C O

OH

Glucose Fructose

C6H12O6

CarbonylGroup

CarboxylGroups

Three representations of glucose

H

H

H

H

H

H H

H

H HO

C

C

C C

O

OHOH HO OH

OH

CH2OHCH2OH

C

OH

OH

O

OH

Structural formula

Abbreviated structure

Simplified structure

6

5

4

3 2

1

6

5

4

3 2

1

Figure 3.5 Disaccharide formation

H

HH

H

H HO

H

H

H

H

H

H

H

H

H HH

H

H

H

OH OH

OHOHOH

HO

O O

O

OH

OH

OH

CH2OH CH2OH

CH2OH CH2OH

H2O

OH

HO

O

OH

H

Glucose Glucose

Maltose

O

OH

Lactose – A Disaccharide

OH

OH

H

H

H

HH

OH

OH

OH

O

H

H

O

H

H

H

OH

O

Galactose

Glucose

CH2OH

CH2OH

Starch

Glycogen

Cellulose

Starch in potato cells

Glycogen in muscle tissue

plant cell wall

Glucose monomer

Cellulose molecules

STARCH

GLYCOGEN

CELLULOSE

O O

OOOOOO

O O O

O

OO

OO

OO

OOOO

OO

OOO

OO

OOOO O

OOOOOO

OOOOOO

O

OH

OH

Figure 3.7

Polysaccharides – Complex Carbohydrates

Functions of Carbohydrates

1. Energy Source e.g. blood sugar

2. Energy Storage e.g. starch

3. Structural Material e.g. cellulose

End Carbohydrates

Start Fri 9/15/06



Lipids

Properties

Non-polar molecules

Not Water soluble

Dissolve in nonpolar solvents

1. Fatty acids

2. Triglycerides or neutral fats

3. Phospholipids

4. Steroids, prostaglandins and waxes

Types of Lipids

Fatty Acid Structure

Hydrocarbon chain CarboxylGroup

Saturated & Unsaturated Fatty Acids

Cis & Trans Unsaturated Fatty Acids

Increase LDL levels (bad cholesterol)

Decrease HDL levels (good cholesterol)

Increase heart attack risk

Trans Fatty Acids

Omega Numbering System for Fatty Acids

Linoleic Acid

An omega-6 fatty acid

Unsaturated Fatty Acids

1. Monounsaturated and Polyunsaturated fatty acidsMONO ONE double bondPOLY more than one double bond

2. Essential fatty acids – All unsaturatedA. linoleic acid… Omega-6 fatty acid

sources: canola, soybean, corn, flaxseed1. heart protective

B. alpha linolenic acid … Omega-3 fatty acidsources: canola, olive oil, flax seed oil1. heart protective2. Reduce triglycerides

Beneficial Fatty Acids

1. Saturated

2. UnsaturatedA. monounsaturatedB. polyunsaturated

Types of polyunsaturated fatty acids1. omega-3 alpha linolenic acid2. omega-6 linoleic acid

3. Trans fatty acids...products of food processing

Fatty Acids - Summary

Triglyceride Synthesis

Triglyceride or Neutral Fat

Structure of a Triglyceride

C

C

C

Fatty acid

Fatty acid

Fatty acid

H

H

H

H

H

Hydrophilic Polar Head

HydrophobicNonpolar Tails

Phospholipid Structure

Phospholipid bilayer Water

Membrane Structure

Steroids

HydrocortisoneCholesterol

Digitoxin

Steroids

Other Lipids

Waxes

Citronellol Taxol

Terpenes

Prostaglandins

Waxes, Sperm Whales & Jojoba oil

Examples of Waxes, Terpenes and Prostaglandins

WaxesJojoba oilBeeswaxCarnauba wax

TerpenesCitronellolTaxolMentholCamphor oil

ProstaglandinsThromboxane – stimulates blood clottingPGE2 – stimulates uterine contractions/laborInflammation/painControl of blood pressure

Lipid Functions

1. Long term energy storageTriglycerides

1. ProtectionFat deposits around kidneysProstaglandin thromboxane induces clottingWaxes on leaf surface

2. Synthesis: hormonesCholesterol



Fig. 3.4

H

N

C

O

OH

Aminogroup

Carboxyl group

Protein Structure

CR

H H

Protein = chain of amino acids

Amino acid

H

H N C OH

H

H

H2O

H C OH

O

C

Amino acidAmino acid

H

H N C

H

H

C OH

O

C

Polypeptide chain

R R

R

O

C N

H

O

C N

H

R

Peptide Bond

Nonpolar Amino Acids

Amino Acid Structure


Polar Charged



Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Proline(Pro)

CH C

NH2+ O

Methionine(Met)

CH2

C C O–

H O

CH2

S

CH3

Cysteine(Cys)

H3N+ C C O–

H O

SH

Special Function Amino Acids

CH2

CH2CH2

CH2

H3N+

O–

Types of Amino Acid Side Groups - Summary

1. Non-Polar

2. Polar – Uncharged

3. Polar – Charged

4. Aromatic

5. Special Function

Four Levels of Protein Structure

Primary

Secondary

Tertiary

Quaternary

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

Protein StructureLevels of Protein Structure

Primary structureGly

ThrGly Glu

Ser Lys

Cys

ProLeu Met

Val

Lys

ValLeu Asp Ala Val Arg Gly Ser

Pro

Ala

Ile

Asn ValAla

ValHis Val

Secondary structureC

N

O C

C

N H

O C

C

HC

N HC

CO

N H

O C

C

N H

C

N

O C

C

N HO C

C

N H

CO

C

H

N H

CO

H C R

HN

Alpha helix

Amino acids

CN

H

C C

H HO

NR C C

ON

H

O

C C N

H

C C

O

N

H

O

C C NH

C

O

C N

H

O

C C N

H

C

O

O

CC

N

H

C C

O

N

H

C C

O

N

H

CC

O

N

H

CC

O

N

H

C C

O

N

H

CC

O

N

H

CC

O

H

N

C

Pleated sheet

Tertiary structure

Quaternary structure

PheArg

Animation07F1005ProteinPrimaryStructureCampbelletal.swf

Animation08F1005ProteinSecondaryStructureCampbelletal.swf

Animation09F1005ProteinTertiaryStructureCampbelletal.swf

Animation10F1005ProteinQuaternaryStructureCampbelletal.swf.swf

Domains

Two or morePolypeptides

What is it?

Humans: Creutzfeldt Jacob Disease

Cattle: Bovine Spongiform encephalopathy(Mad cow disease)

Deer: Chronic Wasting Disease

Normal (Good) PrPC43% -helix

Prion (Bad) PrPSc30% -helix43% -sheet

Normal Protein Folding is Critical to Function

Protein Functions

Function Class Examples Use

Enzyme catalysis

Enzymes ProteasesBreak down

protein

Defense Immunoglobulins AntibodiesMark foreign substances

TransportLong distance transporters

HemoglobinTransport O2

and CO2

TransportShort distance transporters

Proton pumpTransports

protons across membranes

Function Class Examples Use

Support Fibers CollagenForms

cartilage

Motion MuscleActin & Myosin

Muscle Contraction

Regulation

Hormones InsulinGlucose

Transport

Storage Ion BindingFerritin

Calmodulin

Stores IronBinds

Calcium

Protein Functions



Nucleic Acids

Deoxyribonucleic Acid = DNA

Genetic Material

Ribonucleic Acid = RNA

Protein Synthesis

Fig. 3.14(TE Art)

Phosphate group

Sugar

Nitrogenous base

N

N

O

P CH2

O

–O

O–

OH ROH in RNA

H in DNA

O

N

NH2

N


A Nucleotide is a monomer of a nucleic acid

Adenine

Guanine

CC

NN

N

C

HN

CCH

O

H

Cytosine(both DNAand RNA)

Thymine(DNA only)

Uracil(RNA only)

HCC

NC

HN

C

NH2

N

NCH

OCC

NC

HN

CH

H

OCC

NC

HN

C

O

HH3CH

OCC

NC

H

N

C

O

HHH

PURINES

PYRIMIDINES

NH2

NH2

Fig. 3.16(TE Art)

Sugar-phosphate "backbone"

Hydrogen bonds betweennitrogenous bases

Phosphodiesterbond

P

P

P

P

P

P

P

P

C

C

G

G

A

A

T

T

P

O

O

O

O

O

O

O

O

O

OO

C G

5’ end

3’ endOH

P


DNA Structure

Fig. 3.17b(TE Art)

RNA Structure

Ribose-phosphatebackbone

Bases

G

G

C

A

A

U

U

P

P

PP

P

P

P


Nucleic Acid Functions

DNA – Genetic material

RNA – Protein synthesis

END

Fig. 3.13

END

Carbohydrates

Lipids

Proteins

Nucleic Acids

Documents

Chemical Basis of Life. Outline: The Chemical Basis of Life 1.Chemistry of Carbon 2.Polymers & Monomers 3.Biologically Important Compounds Carbohydrates