Molecules of Life

Organic Molecules

Biological Molecules

Organic MoleculesWhy is this important?Cells are mostly water and carbon-based

moleculesCarbon has a valence of 4 so it will form a

tremendous variety of large, complex and diverse molecules

Large variety of molecules = diversity of life

Unity in DiversityAll life is composed of carbon

compounds (UnityUnity) DiversityDiversity of life is due to various ways

carbon can be assembled Organic chemistryOrganic chemistry = study of the

compounds formed by carbon

Organic ChemistryThe four valence electrons in carboncarbon

enable it to be bonded in four different directions

Usually forms COVALENT bonds with Hydrogen

Often oxygen, nitrogenFour most common elements are: CHON

6+

1

1

1

1

C H H

H

H

C C H

H

H H

H

H

C C H

H

H H

H

C

C C C C

C C C

C

C C C C C C C C

CC C C C C C C

CC C C C C C C

C C

C C C C C C

CC C C C C C C

C CC C C C C C

CC C C C C C

C

C OH H

H

H

C OH N

H

H

H

H

C OH H

H

H

HN

Organic Chemistry

Functional groupsFunctional groups – clusters of atoms that have a specific role on the molecule

OHOH – hydroxide (polar) NHNH22 – amino (polar)

COOHCOOH – carboxyl (polar) CHCH33 – methyl (nonpolar)

Organic Chemistry

C

C

CC

C

C

Rings H

H

H HHH

H

H

HHH

H

Each carbon has 4 bonds

Organic Chemistry

C

C

CC

C

C

Rings

Sometimes the carbon atoms form double bonds with

itself

Benzene ring

Organic Chemistry

C

C

CC

C

C

Rings OH

O

Organic Chemistry

OC

CC

C

C

OH

O

C

Organic ChemistryFunctional groups change the chemical

properties of a moleculeThe great diversity of life is caused by only

a few molecules with different arrangements of FUNCTIONAL GROUPS

BiochemistryBiochemistry - chemistry of living things

Differences in functional groups The rearrangement of FUNCTIONAL GROUPS on a molecule causes major changes in its function

BiochemistryFour basic carbon molecules important

to all living things:CarbohydratesLipidsProteinsNucleic acids

BiochemistryBiochemistry

The four basic molecules are long The four basic molecules are long chains of smaller molecules linked chains of smaller molecules linked togethertogether

A train formed by various types of A train formed by various types of carscars

Biochemistry

Smaller molecules are called

MONOMERSMONOMERSLong chains are called………POLYMERSPOLYMERSPolymers are large molecules MACROMOLECULESMACROMOLECULES – large

polymer

What You Have to Know: For each of the 4 types of molecules:

1. How each molecule is formed

2. The types and names of the monomers

3. The role of each molecule in life

How Are Organic Compounds Formed?

Monomers = smaller functional molecules that can be linked together

Macromolecule = ‘large molecule’

Polymers = macromolecules formed by linking monomers together

PolymerizationPolymerization

Many monomers are linked Many monomers are linked together to form macromoleculestogether to form macromolecules

Dehydration synthesisDehydration synthesis

Monomer Monomer Monomer Monomer

How Are Organic Compounds Formed?

Dehydration synthesisDehydration synthesis; p. 41OH- combines with OH- from adjacent

monomer (molecule)OH + OH = HOH + OHOH = H2O

How Are Organic Compounds Formed?

Dehydration synthesisDehydration synthesis polymers are formed from monomers by the removal of water

All four compounds important to life are formed by dehydration synthesisdehydration synthesis

Macromolecules – dehydration synthesis

Monomers/Polymers

Dehydration synthesis: building polymers

Hydrolysis: breaking down polymers into monomers

4 Types of Macromolecules

Carbohydrates Lipids

Proteins

Nucleic acids

CarbohydratesSugars; three types:

Monosaccharides ‘one sugar’DisaccharidesDisaccharides ‘two sugar’PolysaccharidesPolysaccharides ‘many sugar’

Carbohydrates Carbon, hydrogen, oxygenC(n)H2O

C6H12O6 – glucose

C6H12O6 - fructose

C5H10O5 - ribose

C12H22O11 – sucrose

Carbohydrates – MonomersSimple sugarsMonosaccharides – ‘one sweet’

Glucose, fructose, ribose, deoxyribose, galactose

Most monosaccharides are used as a source of energyenergyRibose and deoxyribose form part of

the structure of DNA, RNA

Carbohydrates: MonomersGlucose; #1 sugar, most used sugar for

energy, all organismsFructose; very sweet; fruits

Di-saccharides Di = ‘two’Two monosaccharides joined together

by…. DEHYDRATION SYNTHESISDEHYDRATION SYNTHESISEnergy storage

DisaccharidesGlucose + glucose = maltose;

germinating seeds, malt in beerGlucose + fructose = sucrose; table

sugarGalactose + glucose = lactose; milk

Disaccharides

Sugars a Major Cause of a Tooth Decay

Feed bacteria

Polysaccharides ‘Poly’ = manyLong chain of monosaccharidesStarch GlycogenCellulose

Carbohydrates - Polysaccharides

‘poly’ – manyMany monosaccharides =

polysaccharidepolysaccharideMacromolecule

Carbohydrates - Polysaccharides

Examples:CelluloseCellulose – used to make cell walls

of plants; indigestible without bacteria in gut; fiber

StarchStarch – stored glucose in plantsGlygogen – stored glucose in

animals

Carbohydrates: FunctionsEnergy storageStructure = plant cell wallsMonosaccharidesDisaccharidesPolysaccharides

Types of Macromolecules

Carbohydrates

LipidsProteins

Nucleic acids

Lipids Three types of lipids:

TriglyceridesTriglyceridesPhospholipidsPhospholipidsSteroidsSteroids

Lipids - TriglyceridesExamples:

Fats Oils Waxes

Insoluble in water - nonpolar

Triglycerides Glycerol + three fatty acidsDehydration synthesis Lots of C-H bonds; lots of energy

Triglycerides

Triglycerides 2 types of triglycerides:

SaturatedSaturated UnsaturatedUnsaturated

Saturated fats have no double bonds; are full (saturated) with hydrogen

Saturated fat – fatty acids, full of hydrogen

Unsaturated fat – fatty acids with double bonds; less hydrogen; less energy

Saturated fatty acids

Unsaturated fatty acid

Types of FatsSaturated

No double bondsSaturated w/ HSolids @ (200)Animal fatsBacon grease,

lard, butter

Unsaturated Double bond(s)UnsaturatedLiquids @ (200)Plant fats (oil)Corn, peanut,

olive oils

Triglycerides Link (?) between saturated fats in diet

and arteriosclerosis

Fats: Functions Store energyStore energy

More energy in fats than in carbohydrates; birds eat sunflower seeds first (fats)

Padding (eye, other organs) Insulation (keep you warmer; seals,

whales)

Fats Oils: Waterproofing -

Lipids - PhospholipidsTriglyceride - One of the fatty acid ‘tails’

is replaced with a phosphate groupPhospho – lipidMajor component of cell membrane

Fatty acids

Lipids: Steroids

Sex hormonesSex hormones:

Testosterone; maleTestosterone; maleEstrogen; female

Lipids: Steroids Anabolic steroidsAnabolic steroids = artificially created

testosteroneMimics male hormone Increased muscle massDecreased sex drive, infertilityHeart, liver problems

Lipids - Steroids Insoluble in water (nonpolar)Very different from other lipids in

structure4 fused carbon rings with various

FUNCTIONAL GROUPSFUNCTIONAL GROUPSCholesterol – basic molecule used in

cell membrane; also used to make other steroids (estrogenestrogen and testosteronetestosterone)

Cholesterol

Cholesterol

Lipids - Steroids Anabolic steroidsAnabolic steroids – synthetic variations of

testosterone Builds muscle and bone mass during

puberty; maintains male characteristicsUsed in 1950’s to treat anemia and muscle

diseasesAbused by athletes; linked to liver damage,

cardiovascular, mood swings

Proteins Protein – ‘first place’Composed of AMINO ACIDSAMINO ACIDS

(monomers)20 different kinds of amino acids

Amino group

Carboxyl

COOH

Amino group

Side groupSide group

Carboxyl

COOH

Amino group

Amino AcidsDifferences between the 20 amino acids are

caused by different R (side) groupsAmino acids are linked together by

dehydration synthesisBonds formed between amino acids are

PEPTIDE BONDSPEPTIDE BONDSLong chain of peptides = = polypeptidepolypeptide

p. 72

Different amino acids caused by different side groups

Proteins Peptide bond – bond formed between

two amino acids (dehydration synthesis)Long chain of peptides = POLYPEPTIDEPolypeptides - proteins

•Amino acids are linked together in a SPECIFICSPECIFIC sequence. Conformational shape

•If the sequence gets messed up, the protein may not function. May be fatal or only cause health problems

•Denaturation

Protein’s Shape H bonding helps determine shape Breaking the H bond changes the shape of

the protein – DENATURATION; Heat - cooking changes the shape of

proteins; turn brown; eggs turn white Poisons – chemicals change shape by

interrupting bonds (acids, bases, acetone)

Proteins - Functions

1.1. StructureStructure – feathers, hair, muscle, nail, horn

2.2. EnzymesEnzymes – speed up reactions

3.3. HormonesHormones – chemical messengers

4.4. CarriersCarriers – hemoglobin carries oxygen to cells

Nucleic Acids - Monomers

Monomers – NUCLEOTIDESNUCLEOTIDESNucleotides:

A simple sugarA phosphate groupphosphate groupA NITROGENOUS BASENITROGENOUS BASE

Adenine always bonds with Thymine

Cytosine always bonds with guanine

A-T

C-G

H bonding

A T T C C G C A T G G G T C T T T T

T A A G G C G T A C C C A G A A A A

TACCATACTTTCGGCTACTTTTGGG

DNA sequence = “genetic code”

If A-T and C-G, what is the complimentary strand?

TACCATACTATAGGCTACTATTGGG

ATGGTATGATATCCGATGATAACCC

Similarities in DNA sequences indicates close evolutionary relationship