03 Lecture Presentation-Spring 2010

7/25/2019 03 Lecture Presentation-Spring 2010

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INTRODUCTION TOORGANIC COMPOUNDS

Copyright 2009 Pearson Education, Inc.

Chapter 3: The Molecules of Cells


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3.1 Lifes molecular diversity is based on the

properties of carbon

Diverse molecules found in cells are composed

of carbon bonded to oter elements

! Carbon"based molecules are called organic

compounds

! #$ sarin% electrons& carbon can bond to four oter

atoms

! #$ doin% so& it can branc in up to four directions



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3.1 Lifes molecular diversity is based on the

properties of carbon

Metane 'C()

* is one of te simplest or%anic compounds! +our covalent bonds lin, four $dro%en atoms to te carbon atom'sarin% a pair of electrons*

compounds composed of onl$ carbon and $dro%en are calledhydrocarbons


Structural

formulaBall-and-stick

model

Methane

The four single bonds of carbon point to the

Corners of a tetrahedron.

Space-fillingmodel


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Carbon skeletons vary in length.

Branching. Skeletons may be unbranched or branched.

Butane Isobutane

Propanethane

!ouble bonds.

"-Butene

Skeletons may have double bonds#$hich can vary in location.

Cyclohe%ane

&ength.

'-Butene

Ben(ene

Skeletons may be arranged in rings.)ings.

A cain of carbon

atoms is called a carbon

skeleton!Carbon s,eletons can be

brancedor unbranced

!Terefore& different

compounds -it te samemolecular formula can be

produced

!Tese structures are

called isomers


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3.2 Characteristic chemical groups help determine

the properties of organic compounds

An or%anic compound as uni.ue properties tatdepend upon

! Te si/e and sape of te molecule and! Te %roups of atoms 'functional %roups* attaced to it

A functional groupaffects a biolo%ical molecule0sfunction in a caracteristic -a$

Compounds containin% functional %roups are hydrophilic'-ater"lovin%*



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!Hydroxylgroup1 a $dro%enbonded to an o2$%en

!Carbonylgroup1 a carbonlin,ed b$ a double bond to ano2$%en atom

!Carboxylgroup1 a carbon

double"bonded to bot an o2$%enand a $dro2$l %roup

!Aminogroup1 a nitro%enbonded to t-o $dro%en atoms

and te carbon s,eleton!Phosphategroup1 a posporusatom bonded to four o2$%en atoms

!Methyl group1 a carbon bonded

to tree $dro%ens


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stradiol

Male lionTestosterone

*emale lion

Similar compounds

differ onl$ in functional

%roups3 se2 permones


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3.3 Cells make a huge number of large molecules

from a small set of small moleculesTere are four classes of biolo%ical molecules

! Carbo$drates

! Proteins

! 4ipids

!Nucleic acids


!Te$ are often calledmacromoleculesbecause of teir

lar%e si/e

!Te$ are also called polymersbecause te$ are madefrom identical buildin% bloc,s

!Te buildin% bloc,s are called monomers


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3.3 Cells make a huge number of large molecules

from a small set of small molecules

Monomers are lin,ed to%eter to form pol$mers

trou% dehydration reactions& -ic remove

-ater

Pol$mers are bro,en apart b$ hydrolysis& te

addition of -ater

All biolo%ical reactions of tis sort are mediated b$

enzymes& -ic speed up cemical reactions in cells



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+nlinkedmonomer

Short polymer


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+nlinkedmonomer

Short polymer

&onger polymer

!ehydrationreaction


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,ydrolysis


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CARBOHYDRATES

Carbo$drates ran%e from small su%armolecules'monomers* to lar%e pol$saccarides! Su%ar monomers are monosaccharides& suc as

%lucose and fructose


3 4 h id h i l


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3.4 Monosaccharides are the simplest

carbohydrates

Te carbon s,eletonsof monosaccaridesvar$ in len%t! Glucose and fructose

are si2 carbons lon%! Oters ave tree to

seven carbon atoms

Monosaccharidesare the main fuelsfor cellular ork


lucose

an aldose/*ructose

a ketose/


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Structuralformula

0bbreviatedstructure

Simplifiedstructure


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lucose lucose

Maltose

T-o mono"

saccarides

'monomers*can bond to

form a

disaccharidein a

de$dration

reaction

lucose 1 *ructose2

Sucrose


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!tarchis a stora%e pol$saccaride composed of

%lucose monomers and found in plants

"lycogenis a stora%e pol$saccaride composed

of %lucose& -ic is $drol$/ed b$ animals-en %lucose is needed

Celluloseis a pol$mer of %lucose tat forms

plant cell -alls

Chitinis a pol$saccaride used b$ insects and

crustaceans to build an e2os,eleton


olysaccharides are polymers of

monosaccharides


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Starch granules inpotato tuber cells

lycogengranules

in muscletissue

Cellulose fibrils ina plant cell $all

Cellulosemolecules

lucosemonomer

&3C45

C&&+&4S

,ydrogen bonds

ST0)C,

Pol$saccarides are $dropilic'-ater"lovin%*!Cotton fibers& suc as tose in bat to-els& are -ater absorbent

3 ! " t li id th t tl


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3.! "ats are lipids that are mostly energy#

storage molecules

#ipidsare -ater insoluble 'hydrophobic& or -aterfearin%* compounds tat are important in ener%$

stora%e

! Te$ contain t-ice as muc ener%$ as a pol$saccaride

$atsare lipids made from %l$cerol and fatt$ acids



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storage molecules

+att$ acids lin, to %l$cerolb$ a de$drationreaction

! A fat contains one %l$cerol

lin,ed to tree fatt$ acids! +ats are often called

tri%l$ceridesbecause of

teir structure


*atty acid

lycerol


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storage molecules

Some fatt$ acids contain double bonds! Tis causes bends in te carbon cain

! Tese compounds are called unsaturatedfats!because te$ ave fe-er tan te ma2imum number of

$dro%ens

!+ats -it te ma2imum number of $dro%ens are calledsaturated fats



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3.$ hospholipids and steroids are important

lipids %ith a variety of functionsPhospholipidsare structurall$ similar to fats and are an

important component of all cells! +or e2ample& te$ are a ma5or part of cell membranes

! Te $dropilic eads are in contact -it te -ater of te environment

and te internal part of te cell

! Te $dropobic tails band in te center of te bila$er


6ater

,ydrophobictails

,ydrophilicheads

6ater

3 $ h h li id d t id i t t


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3.$ hospholipids and steroids are important

lipids %ith a variety of functions

!teroidsare lipids composed of fused rin%structures

! Cholesterolis an e2ample of a steroid tat pla$s a

si%nificant role in te structure of te cell membrane



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3.1& C'(()C*+'(,-nabolic steroids

pose health risks

Anabolic steroidsare s$ntetic variants oftestosterone tat can cause a buildup of muscleand bone mass! Te$ can be sold as prescription dru%s and used to

treat certain diseases 'anemia& bod$ muscle*! Te$ ma$ also be abused -it serious conse.uences&

suc as liver dama%e tat can lead to cancer



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3.11 '*)+(/ are essential to the structures

and functions of life

A proteinis a pol$mer built from various

combinations of 67 amino acid monomers

! Proteins ave uni.ue structures tat are directl$

related to teir functions

! %nzymes& proteins tat serve as metabolic catal$sts&

re%ulate te cemical reactions -itin cells



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3.11 roteins are essential to the structures

and functions of life

!tructuralproteins provide associationsbet-een bod$ parts and contractileproteins arefound -itin muscle

&efensi'eproteins include antibodies of teimmune s$stem& and signalproteins are beste2emplified b$ te ormones

(eceptorproteins serve as antenna for outsidesi%nals& and transportproteins carr$ o2$%en



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3.12 roteins are made from amino acids

linked by peptide bonds

Amino acids& te buildin% bloc,s of proteins& ave anamino %roup and a carbo2$l %roup

! #ot of tese are covalentl$ bonded to a central carbon atom

! Also bonded to te central carbon is a $dro%en atom and

some oter cemical %roup s$mboli/ed b$ R


Carbo%ylgroup

0minogroup

0mino acids are

classified as

hydrophobic orhydrophilic


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&eucine &eu/

,ydrophobic

Serine Ser/

,ydrophilic

0spartic acid 0sp/


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Carbo%ylgroup

0mino acid

0minogroup

0mino acid

Peptidebond

!ipeptide

!ehydrationreaction

0mino acid monomers are linked together to

form polymeric proteins

The covalent linkage resulting is called apeptide bond

0 polypeptide chain contains hundreds or

thousands of amino acids linked by peptide bonds


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roove


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roove


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3.13 - proteins specific shape determines

its function

If for some reason a protein0s sape is altered& itcan no lon%er function

! &enaturation-ill cause pol$peptide cains to

unravel and lose teir sape and& tus& teir function!Proteins can be denatured by changes in saltconcentration and pH


0 protein can have four levels

of structurePrimary structureSecondary structureTertiary structure

7uaternary structure

*our &evels of Protein Structure


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0mino acids

Primary structure



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0mino acids

Primary structure

0lpha heli%

,ydrogenbond

Secondary structure

Pleated sheet



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0mino acids

Primary structure

0lpha heli%

,ydrogenbond

Secondary structure

Pleated sheet

Polypeptidesingle subunit

of transthyretin/

Tertiary structure

4verall 8-!

structure



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0mino acids

Primary structure

0lpha heli%

,ydrogenbond

Secondary structure

Pleated sheet

Polypeptidesingle subunit

of transthyretin/

Tertiary structure

Transthyretin# $ithfour identicalpolypeptide subunits

7uaternary structure

T$o or more

polypeptides


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3.10 (ucleic acids are information#rich

polymers of nucleotides

&)A'deoxyribonucleic acid* and ()A'ribonucleic acid* are composed of monomers

called nucleotides

!Nucleotides ave tree parts!A five"carbon su%ar called ribose in RNA and deo2$ribose

in DNA

!A pospate %roup

!A nitro%enous base


5itrogenousbase

adenine/

Sugar

Phosphategroup


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Sugar-phosphate

backbone

5ucleotide

0 nucleic acid polymer# apolynucleotide# forms from

the nucleotide monomers$hen the phosphate of one

nucleotide bonds to the sugarof the ne%t nucleotide

!50 nitrogenous bases areadenine 0/# thymine T/#

cytosine C/# and guanine /)50 also has 0# C# and #

but instead of T# it hasuracil +/


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Basepair

T$o polynucleotide strands

form a !50 double heli%The t$o strands are

associated because

particular bases al$ays

hydrogen bond to one

another0 pairs $ith T# and C

pairs $ith # producing

base pairs

)50 is usually a singlepolynucleotide strand


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3.10 (ucleic acids are information#rich

polymers of nucleotides

A particular nucleotide se.uence tat can instruct te

formation of a pol$peptide is called a gene

! Most DNA molecules consist of millions of base pairs and&

conse.uentl$& many genes! Tese %enes& man$ of -ic are uni.ue to te species&

determine te structure of proteins and& tus& life0s structures

and functions



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You should now be able to

89 Discuss te importance of carbon to lifesmolecular diversit$

69 Describe te cemical %roups tat areimportant to life

:9 ;2plain o- a cell can ma,e a variet$ of lar%emolecules from a small set of molecules

)9 Define monosaccarides& disaccarides& andpol$saccarides and e2plain teir functions


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You should now be able to

=9 Describe te cemical structure of proteins andteir importance to cells

>9 Describe te cemical structure of nucleic acidsand o- te$ relate to ineritance

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03 Lecture Presentation-Spring 2010