Cell Biochemistry

8/9/2019 Cell Biochemistry

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< Principles of Biochemistry

The history of biochemistryspans approximately 400 years. Although the term biochemistry

seems to have been first use in !""#$ it is generally accepte that the %or &biochemistry& %asfirst propose in !'0( by Carl Neuberg$ a )erman chemist. Biochemistry is the stuy of

chemical processes in living organisms. Biochemistry governs all living organisms an livingprocesses. By controlling information flo% through biochemical signalling an the flo% of

chemical energy through metabolism$ biochemical processes give rise to the increiblycomplexity of life. *uch of biochemistry eals %ith the structures an functions of cellular

components such as proteins$ carbohyrates$ lipis$ nucleic acis an other biomolecules

although increasingly processes rather than iniviual molecules are the main focus. +ver thelast 40 years biochemistry has become so successful at explaining living processes that no%

almost all areas of the life sciences from botany to meicine are engage in biochemical

research. Toay the main focus of pure biochemistry is in unerstaning ho% biologicalmolecules give rise to the processes that occur %ithin living cells %hich in turn relates greatly to

the stuy an unerstaning of %hole organisms. Among the vast number of ifferent

biomolecules$ many are complex an large molecules ,calle polymers-$ %hich are compose ofsimilar repeating subunits ,calle monomers-. ach class of polymeric biomolecule has a

ifferent set of subunit types. /or example$ a protein is a polymer %hose subunits are selecte

from a set of #0 or more amino acis. Biochemistry stuies the chemical properties of important

biological molecules$ lie proteins$ an in particular the chemistry of en1yme2cataly1ereactions. The biochemistry of cell metabolism an the enocrine system has been extensively

escribe. +ther areas of biochemistry inclue the genetic coe ,3A$ 5A-$ protein synthesis$

cell membrane transport$ an signal transuction.6!7

Contents

! n1ymes

# *etabolism

( #0th century

4 Bioenergetics

o 4.! ntropy6#!7

o

4.# nthalpy6#47

o 4.( )ibbs free energy

o 4.4 /ree energy of reactions

o 4.8 9seful ientities
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8 :ell The basic unit of life

o 8.! Proaryotes

o 8.# uaryotic cell

o 8.( Plant cell is ifferent from animal cell

o 8.4 +rigin of uaryotic organelles an enosymbiotic theory

8.4.! uaryotic organelles

8.4.# Proaryotic organelles

;E.coli as *oel organism

=east in biological research

" 5efrences

Enzymes

uar Buchner

As early as the late !"th century an early !'th century$ the igestion of meat by stomachsecretions6#7an the conversion of starchto sugars by plant extracts an saliva%ere no%n.

>o%ever$ the mechanism by %hich this occurre ha not been ientifie.6(7

?n the !'th century$ %hen stuying the fermentationof sugar to alcohol by yeast$ @ouis Pasteurcame to the conclusion that this fermentation %as cataly1e by a vital force containe %ithin the

yeast cells calle &ferments&$ %hich %ere thought to function only %ithin living organisms. >e
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%rote that &alcoholic fermentation is an act correlate %ith the life an organi1ation of the yeast

cells$ not %ith the eath or putrefaction of the cells.&647

?n !"" )erman physiologist ilhelm Chne,!"(D!'00- coine the termenzyme$ %hichcomes from )ree &in leaven&$ to escribe this process. The %or enzyme%as use later to refer

to nonliving substances such aspepsin$ an the %orfermentuse to refer to chemical activityprouce by living organisms.

?n !"' uar Buchnerbegan to stuy the ability of yeast extracts to ferment sugar espite theabsence of living yeast cells. ?n a series of experiments at the 9niversity of Berlin$ he foun that

the sugar %as fermente even %hen there %ere no living yeast cells in the mixture.687>e name

the en1yme that brought about the fermentation of sucrose &1ymase&.6;7?n !'0 he receive theobel Pri1e in :hemistry &for his biochemical research an his iscovery of cell2free

fermentation&. /ollo%ing BuchnerEs exampleF en1ymes are usually name accoring to the

reaction they carry out. Typically the suffix -aseis ae to the name of the substrate ,e.g.$

lactase is the en1yme that cleaves lactose- or the type of reaction ,e.g.$ 3A polymerase forms

3A polymers-.

>aving sho%n that en1ymes coul function outsie a living cell$ the next step %as to etermine

their biochemical nature. *any early %orers note that en1ymatic activity %as associate %ith

proteins$ but several scientists ,such as obel laureate 5ichar illstGtter- argue that proteins%ere merely carriers for the true en1ymes an that proteinsper se%ere incapable of catalysis.

>o%ever$ in !'#;$ Hames B. Iumnersho%e that the en1yme urease%as a pure protein an

crystalli1e itF Iumner i lie%ise for the en1yme catalasein !'(. The conclusion that pureproteins can be en1ymes %as efinitively prove byorthropan Itanley$%ho %ore on the

igestive en1ymes pepsin ,!'(0-$ trypsin an chymotrypsin. These three scientists %ere a%are

the !'4; obel Pri1e in :hemistry.67This iscovery that en1ymes coul be crystalli1e

eventually allo%e their structures to be solve byx2ray crystallography. This %as first one forlyso1yme$ an en1yme foun in tears$ saliva an egg %hitesthat igests the coating of some

bacteriaF the structure %as solve by a group le by 3avi :hilton Phillipsan publishe in!';8.6"7This high2resolution structure of lyso1yme mare the beginning of the fiel of structural

biologyan the effort to unerstan ho% en1ymes %or at an atomic level of etail.6'7

Metabolism
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Iantorio Iantorioin his steelyar balance$ fromArs de statica medecina$ first publishe !;!4

The term metabolismis erive from the )ree *etabolismos for &change&$ or &overthro%&.6!07

The history of the scientific stuy of metabolism spans 400 years. The first controlle

experiments in human metabolism %ere publishe byIantorio Iantorioin !;!4 in his booArsde statica medecina.6!!7This boo escribes ho% he %eighe himself before an after eating$

sleeping$ %oring$ sex$ fasting$ rining$ an excreting. >e foun that most of the foo he too

in %as lost through %hat he calle &insensible perspiration&.6!#7

20th century

Iince then$ biochemistry has avance$ especially since the mi2#0th century$ %ith the

evelopment of ne% techniJues such as chromatography$ K2ray iffraction$ *5 spectroscopy$raioisotopic labelling$ electron microscopy an molecular ynamics simulations. These

techniJues allo%e for the iscovery an etaile analysis of many molecules an metabolic

path%ays of the cell$ such as glycolysis an the rebs cycle ,citric aci cycle-. +ne of the mostprolific of these moern biochemists %as>ans rebs%ho mae huge contributions to the stuy

of metabolism.6!(7>e iscovere the urea cycle an later$ %oring %ith >ans ornberg$ the citric

aci cycle an the glyoxylate cycle.6!476!876!;7?n !';0$ the biochemist 5obert . :ranereveale his

iscovery of the soium2glucose cotransportas the mechanism for intestinal glucose absorption.6!7This %as the very first proposal of a coupling bet%een the fluxes of an ion an a substrate that

has been seen as sparing a revolution in biology.Toay$ the finings of biochemistry are use in

many areas$ from genetics to molecular biology an from agriculture to meicine.6!"7

Bioenergetics

Bioenergetics is the part of biochemistry concerne %ith the energy involve in maing an

breaing of chemical bons in the molecules foun in biological organisms. )ro%th$

evelopment an metabolism are some of the central phenomena in the stuy of biologicalorganisms. The role of energy is funamental to such biological processes. The ability to harness

energy from a variety of metabolic path%ays is a property of all living organisms. @ife is

epenent on energy transformationsF living organisms survive because of exchange of energy%ithin an %ithout. ?n a living organism$ chemical bons are broen an mae as part of the
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exchange an transformation of energy. nergy is available for %or ,such as mechanical %or-

or for other processes ,such as chemical synthesis an anabolic processes in gro%th-$ %hen %ea

bons are broen an stronger bons are mae. The prouction of stronger bons allo%s releaseof usable energy.6!'7

@iving organisms obtain energy from organic an inorganic materials. /or example$ lithotrophscan oxii1e minerals such as nitrates or forms of sulfur$ such as elemental sulfur$ sulfites$ an

hyrogen sulfie to prouce ATP. ?n photosynthesis$ autotrophs can prouce ATP using lightenergy. >eterotrophs must consume organic compouns. These are mostly carbohyrates$ fats$

an proteins. The amount of energy actually obtaine by the organism is lo%er than the amount

present in the fooF there are losses in igestion$ metabolism$ an thermogenesis. The materialsare generally combine %ith oxygen to release energy$ although some can also be oxii1e

anaerobically by various organisms. The bons holing the molecules of nutrients together an

the bons holing molecules of free oxygen together are all relatively %ea compare %ith thechemical bons holing carbon ioxie an %ater together. The utili1ation of these materials is a

form of slo% combustion. That is %hy the energy content of foo can be estimate %ith a bomb

calorimeter. The materials are oxii1e slo%ly enough that the organisms o not actually proucefire. The oxiation releases energy because stronger bons have been forme. This net energy

may evolve as heat$ or some of %hich may be use by the organism for other purposes$ such as

breaing other bons to o chemistry.

@iving organisms prouce ATP from energy sources via oxiative phosphorylation. The terminalphosphate bons of ATP are relatively %ea compare %ith the stronger bons forme %hen ATP

is broen o%n to aenosine monophosphate an phosphate$ issolve in %ater. >ere it is the

energy of hyration that results in energy release. This hyrolysis of ATP is use as a battery to

store energy in cells$ for intermeiate metabolism. 9tili1ation of chemical energy from suchmolecular bon rearrangement po%ers biological processes in every biological organism.6#07

Entropy[21]

The concept of entropy is efine by the secon la% of thermoynamics$ %hich states that the

entropy of a close system al%ays increases or remains constant.

Entropy changehen an ieal gas unergoes a change$ its entropy may also change. /or cases

%here the specific heat oesnEt change an either volume$ pressure or temperature is alsoconstant$ the change in entropy can be easily calculate.6##7

hen specific heat an volume are constant$ the change in entropy is given byL

.

hen specific heat an pressure are constant$ the change in entropy is given byL
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.

hen specific heat an temperature are constant$ the change in entropy is given byL

.

?n these eJuations is the specific heat at constant volume$ is the specific heat at constant

pressure$ is the ieal gas constant$an is the number of molesof gas.

/or some other transformations$ not all of these properties ,specific heat$ volume$ pressure ortemperature- are constant. ?n these cases$ for only ! mole of an ieal gas$ the change in entropy

can be given by6#(7eitherL

or

.

Enthalpy[24]

nthalpy is a measure of the total energy of a thermoynamic system. ?t inclues the internal

energy$ %hich is the energy reJuire to create a system$ an the amount of energy reJuire to

mae room for it by isplacing its environment an establishing its volume an pressure.

The enthalpy of a system is efine asL

%here

His the enthalpy of the system ,inMoules-$

Uis the internal energyof the system ,in Moules-$pis thepressureat the bounary of the system an its environment$ ,inpascals-$ an

Vis the volumeof the system$ ,in cubic meters-.

ote that the Uterm is eJuivalent to the energy reJuire to create the system$ an that thepVterm is eJuivalent to the energy %hich %oul be reJuire to &mae room& for the system if the

pressure of the environment remaine constant.

ThepVterm may be unerstoo by the follo%ing example of anisobaric process. :onsier gas

changing its volume ,by$ for example$ a chemical reaction- in a cyliner$ pushing a piston$maintaining constant pressurep. The force is calculate from the areaAof the piston an
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efinition of pressurepNFOAL the force isFNpA. By efinition$ %or Wone is WNF$ %here

is the istance traverse. :ombining gives WNpA$ an the prouctAis the volume traverse

by the pistonLA ! V. Thus$ the %or one by the gas is WNpV$ %herepis a constant pressurean Vthe expansion of volume. ?ncluing this p term means that uring constant pressure

expansion$ any internal energy forfeite as %or on the environment oes not affect the value of

enthalpy. The enthalpy change can be efine QHN QUR WN QUR Q,pV-$ %here QUis thethermal energy lost to expansion$ an Wthe energy gaine ue to %or one on the piston.6#87

Gibbs free energy

?n thermoynamics$ the )ibbs free energy ,?9PA: recommene nameL )ibbs energy or )ibbsfunctionF also no%n as free enthalpy6!7 to istinguish it from >elmholt1 free energy- is a

thermoynamic potential that measures the &useful& or process2initiating %or obtainable from

an isothermal$ isobaric thermoynamic system.

The )ibbs free energy$ originally calle available energy$ %as evelope in the !"0s by the

American mathematician Hosiah illar )ibbs. ?n !"($ )ibbs escribe this available energyas the greatest amount of mechanical %or %hich can be obtaine from a given Juantity of a

certain substance in a given initial state$ %ithout increasing its total volume or allo%ing heat topass to or from external boies$ except such as at the close of the processes are left in their initial

conition.6#;7

ree energy of reactions

To erive the )ibbs free energy eJuation for anisolate system$ let "totbe the total entropy of the

isolate system$ that is$ a system that cannot exchange heat or mass %ith its surrounings.

Accoring to the secon la% of thermoynamicsL

an if Q"totN 0 then the process is reversible. The heat transfer #vanishes for an aiabatic

system. Any aiabatic processthat is also reversible is calle an isentropic

process.

o% consier systems$ having internal entropy "int. Iuch a system is thermally connecte to its

surrounings$ %hich have entropy "ext. The entropy form of the secon la% applies only to theclose system forme by both the system an its surrounings. Therefore a process is possible if

.

?f #is heat transferre to the system from the surrounings$ so S#is heat lost by the

surrounings
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so that correspons to entropy change of the surrounings.e no% haveL

*ultiply both sies by $L

#is heat transferre tothe systemF if the process is no% assume to be isobaric$ then #pN QHL

QHis the enthalpy change of reaction ,for a chemical reaction at constant pressure-. Then

for a possible process. @et the change Q%in )ibbs free energy be efine as

&e'.()

otice that it is not efine in terms of any external state functions$ such as Q"extor Q"tot. Then

the secon la% becomes$ %hich also tells us about the spontaneity of the reactionL

fa!oure" reaction,Ipontaneous-

either the for%ar nor the reverse reaction prevails ,Juilibrium-

"isfa!oure" reaction,onspontaneous-

)ibbs free energy %itself is efine as

&e'.*)

but notice that to obtain eJuation ,#- from eJuation ,!- %e must assume that $is constant. Thus$

)ibbs free energy is most useful for thermochemical processes at constant temperature an

pressureL both isothermal an isobaric. Iuch processes onEt move on a+2Viagram$ such as

phase change of a pure substance$ %hich taes place at the saturation pressure an temperature.:hemical reactions$ ho%ever$ o unergo changes in chemical potential$ %hich is a state

function. Thus$ thermoynamic processes are not confine to the t%o imensional +2Viagram.

There is a thir imension for n$ the Juantity of gas. /or the stuy of explosive chemicals$ the

processes are not necessarily isothermal an isobaric. /or these stuies$ >elmholt1 free energyisuse.6#7

?f an isolate system ,#N 0- is at constant pressure ,#N QH-$ then

Therefore the )ibbs free energy of an isolate system isL
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an if Q% 0 then this implies that Q"U 0$ bac to %here %e starte the erivation of Q%

#seful i"entities

for constant temperature

,see:hemical eJuilibrium-.

an rearranging gives

%hich relates the electrical potential of a reaction to the eJuilibrium coefficient for that reaction

,ernst eJuation-.

%here

Q%N change in )ibbs free energy$ QHN change in enthalpy$ $N absolute temperature$Q"N

change in entropy$,N gas constant$ ln N natural logarithm$Qr%N change of reaction in )ibbsfree energy$ Qr%N stanar change of reaction in )ibbs free energy$N eJuilibrium constant$

#rN reaction Juotient$ nN number ofelectronsper moleprouct$FN /araay constant,coulombsper mole-$ anENelectroe potentialof the reaction. *oreover$ %e also haveL

%hich relates the eJuilibrium constant %ith )ibbs free energy.6#"7

Cell $he basic unit of life

The cell is the functional basic unit of life. :ell %as iscovere by %obert &oo'ean is thefunctional unit of all no%n living organisms. ?t is the smallest unit of life that is classifie as a

living thing$ an is often calle the builing bloc of life. Iome organisms$ such as most

bacteria$ are unicellular ,consist of a single cell-. +ther organisms$ such as humans$cat$ogs anbirs$ are multicellular. >umans have about !00 trillion or !0 !4cellsF a typical cell si1e is !0 Vm

an a typical cell mass is ! nanogram. $he largest cells are about 1() *m in the anterior hornin the spinal cor" +hile granule cells in the cerebellum, the smallest, can be some 4 *man

the longest cell can reach from the toe to the lo%er brain stem ,Pseuounipolar cells-.
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10/81

$he largest 'no+n cells are unfertilise" ostrich egg cells +hich +eigh (-( poun"s- ?n !"(8$

before the final cell theory %as evelope$ Han vangelista PurynW observe small &granules&

%hile looing at the plant tissue through a microscope. The cell theory$ first evelope in !"('by *atthias Haob Ichleien an Theoor Ich%ann$ states that all organisms are compose of

one or more cells$ that all cells come from preexisting cells$ that vital functions of an organism

occur %ithin cells$ an that all cells contain the hereitary information necessary for regulatingcell functions an for transmitting information to the next generation of cells. $he +or" cell

comes from the .atin cellula, meaning, a small room-The escriptive term for the smallest

living biological structure %as coine by 5obert >ooe in a boo he publishe in !;;8 %hen hecompare the cor cells he sa% through his microscope to the small rooms mons live in.There

are t%o types of cellsL eu'aryotic an" pro'aryotic. Proaryotic cells are usually inepenent$

%hile euaryotic cells are often foun in multicellular organisms.6#'7

/rigin of life an" Millers eperiment6(07

The experiment

Earths early atmosphereIome evience suggests that arthEs original atmosphere might have

containe fe%er of the reucing molecules than %as thought at the time of the *illerD9reyexperiment. There is abunant evience of maMor volcanic eruptions 4 billion years ago$ %hich

%oul have release carbon ioxie$ nitrogen$hyrogen sulfie,>#I-$ an sulfur ioxie,I+#-into the atmosphere. xperiments using these gases in aition to the ones in the original *illerD

9rey experiment have prouce more iverse molecules. The experiment create a mixture that%as racemic ,containing both @ an 3enantiomers- an experiments since have sho%n that &in

the lab the t%o versions are eJually liely to appear.&6(!7>o%ever$ in nature$ @ amino acis

ominateF later experiments have confirme isproportionate amounts of @ or 3 orienteenantiomers are possible.6(#76((7
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+riginally it %as thought that the primitive seconary atmosphere containe mostly ammonia

an methane. >o%ever$ it is liely that most of the atmospheric carbon %as :+#%ith perhaps

some :+ an the nitrogen mostly #. ?n practice gas mixtures containing :+$ :+#$ #$ etc. givemuch the same proucts as those containing :>4an >(so long as there is no +#. The

hyrogen atoms come mostly from %ater vapor. ?n fact$ in orer to generate aromatic amino

acis uner primitive earth conitions it is necessary to use less hyrogen2rich gaseous mixtures.*ost of the natural amino acis$ hyroxyacis$ purines$ pyrimiines$ an sugars have been mae

in variants of the *iller experiment.6(47

*ore recent results may Juestion these conclusions. The 9niversity of aterloo an 9niversity

of :olorao conucte simulations in #008 that inicate that the early atmosphere of arthcoul have containe up to 40 percent hyrogenXimplying a possibly much more hospitable

environment for the formation of prebiotic organic molecules. The escape of hyrogen from

arthEs atmosphere into space may have occurre at only one percent of the rate previouslybelieve base on revise estimates of the upper atmosphereEs temperature.6(87+ne of the authors$

+%en Toon notesL &?n this ne% scenario$ organics can be prouce efficiently in the early

atmosphere$ leaing us bac to the organic2rich soup2in2the2ocean concept... ? thin this stuymaes the experiments by *iller an others relevant again.& +utgassing calculations using a

chonritic moel for the early earth complement the aterlooO:olorao results in re2establishing

the importance of the *illerD9rey experiment.6(;7

:onitions similar to those of the *illerD9rey experiments are present in other regions of thesolar system$ often substituting ultravioletlight for lightning as the energy source for chemical

reactions. The *urchison meteoritethat fell near *urchison$ ictoria$ Australia in !';' %as

foun to contain over '0 ifferent amino acis$ nineteen of %hich are foun in arth life. :omets

an other icy outer2solar2system boiesare thought to contain large amounts of complex carboncompouns ,such as tholins- forme by these processes$ arening surfaces of these boies.6(7

The early arth %as bombare heavily by comets$ possibly proviing a large supply of complexorganic molecules along %ith the %ater an other volatiles they contribute. This has been useto infer an origin of life outsie of arthL thepanspermiahypothesis. The Miller an" #rey

eperiment6("7,or #reyMiller eperiment-6('7%as an experimentthat simulate hypothetical

conitions thought at the time to be present on the early arth$an teste for the occurrence ofchemical origins of life. Ipecifically$ the experiment teste Alexaner +parinEs an H. B. I.

>alaneEs hypothesis that conitions on the primitive arth favore chemical reactions that

synthesi1e organic compounsfrom inorganic precursors. :onsiere to be the classicexperiment on the origin of life$it %as conucte in !'8#6407an publishe in !'8( by Itanley

*illeran >arol 9reyat the 9niversity of :hicago.64!764#764(7

After *illerEs eath in #00$ scientists examining seale vials preserve from the original

experiments %ere able to sho% that there %ere actually %ell over #0 ifferent amino acisprouce in *illerEs original experiments. That is consierably more than %hat *iller originally

reporte$ an more than the #0 that naturally occur in life. *oreover$ some evience suggests

that arthEs original atmosphere might have ha a ifferent composition than the gas use in the

*illerD9rey experiment. There is abunant evience of maMor volcanic eruptions 4 billion yearsago$ %hich %oul have release carbon ioxie$ nitrogen$ hyrogen sulfie,>#I-$ an sulfur
http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-34http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-35http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-35http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-36http://en.wikibooks.org/w/index.php?title=Solar_system&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Ultraviolet&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Murchison_meteorite&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Murchison,_Victoria&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Comet&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Trans-Neptunian_object&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Tholin&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-37http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-37http://en.wikibooks.org/w/index.php?title=Panspermia&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Panspermia&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-38http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-39http://en.wikibooks.org/w/index.php?title=Experiment&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Early_Earth&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Early_Earth&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Abiogenesis&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Alexander_Oparin&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=J._B._S._Haldane&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=J._B._S._Haldane&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Organic_compound&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Abiogenesis&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Abiogenesis&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-40http://en.wikibooks.org/w/index.php?title=Stanley_Miller&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Stanley_Miller&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Harold_Urey&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=University_of_Chicago&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-41http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-41http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-42http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-43http://en.wikibooks.org/w/index.php?title=Hydrogen_sulfide&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Hydrogen_sulfide&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Sulfur_dioxide&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-34http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-35http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-36http://en.wikibooks.org/w/index.php?title=Solar_system&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Ultraviolet&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Murchison_meteorite&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Murchison,_Victoria&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Comet&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Trans-Neptunian_object&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Tholin&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-37http://en.wikibooks.org/w/index.php?title=Panspermia&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-38http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-39http://en.wikibooks.org/w/index.php?title=Experiment&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Early_Earth&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Abiogenesis&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Alexander_Oparin&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=J._B._S._Haldane&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=J._B._S._Haldane&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Organic_compound&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Abiogenesis&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-40http://en.wikibooks.org/w/index.php?title=Stanley_Miller&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Stanley_Miller&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Harold_Urey&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=University_of_Chicago&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-41http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-42http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-43http://en.wikibooks.org/w/index.php?title=Hydrogen_sulfide&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Sulfur_dioxide&action=edit&redlink=1


12/81

ioxie,I+#- into the atmosphere. xperiments using these gases in aition to the ones in the

original *illerD9rey experiment have prouce more iverse molecules.6(!7

Eperiment

The experiment use%ater,>#+-$ methane,:>4-$ ammonia,>(-$ an hyrogen,>#-. Thechemicals %ere all seale insie a sterile array of glass tubes an flass connecte in a loop$ %ith

one flas half2full of liJui %ater an another flas containing a pair of electroes. The liJui

%ater %as heate to inuce evaporation$ spars %ere fire bet%een the electroes to simulatelightningthrough the atmospherean %ater vapor$ an then the atmosphere %as coole again so

that the %ater coul conense an tricle bac into the first flas in a continuous cycle.

At the en of one %ee of continuous operation$ *iller an 9rey observe that as much as !0D

!8Y of the carbon%ithin the system %as no% in the form of organic compouns. T%o percent ofthe carbon ha forme amino acisthat are use to maeproteinsin living cells$ %ith glycineas

the most abunant. Iugars$ liJuis$ %ere also forme. ucleic acis %ere not forme %ithin the

reaction. But the common #0 amino acis %ere forme$ but in various concentrations.

?n an intervie%$ Itanley *iller stateL &Hust turning on the spar in a basic pre2biotic experiment%ill yiel !! out of #0 amino acis.&6447

As observe in all subseJuent experiments$ both left2hane ,@- an right2hane ,3-optical

isomers%ere create in a racemic mixture.

The original experiment remains toay uner the care of *iller an 9reyEs former stuentProfessor Heffrey Baaat the 9niversity of :alifornia$ Ian 3iego$ Icripps ?nstitution of

+ceanography.6487

+ne2step reactions among the mixture components can proucehyrogen cyanie,>:-$formalehye,:>#+-$

64;7an other active intermeiate compouns ,acetylene$cyanoacetylene$

etc.-L

:+#Z :+ R 6+7 ,atomic oxygen-

:>4R #6+7 Z :>#+ R >#+:+ R >(Z >: R >#+

:>4R >(Z >: R (>#,B*A process-

The formalehye$ ammonia$ an >: then react byItrecer synthesisto form amino acis another biomoleculesL

:>#+ R >: R >(Z >#2:>#2: R >#+

>#2:>#2: R #>#+ Z >(R >#2:>#2:++> ,glycine-

/urthermore$ %ater an formalehye can react via ButlerovEs reactionto prouce various sugars

lie ribose.
http://en.wikibooks.org/w/index.php?title=Sulfur_dioxide&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-NS-31http://en.wikibooks.org/w/index.php?title=Water&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Water&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Water&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Methane&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Ammonia&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Hydrogen&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Evaporation&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Lightning&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Earth%27s_atmosphere&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Water_vapor&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Carbon&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Carbon&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Amino_acids&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Protein&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Glycine&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-44http://en.wikibooks.org/w/index.php?title=Optical_isomerism&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Optical_isomerism&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Optical_isomerism&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Racemic_mixture&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Racemic_mixture&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Jeffrey_Bada&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=University_of_California,_San_Diego&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Scripps_Institution_of_Oceanography&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Scripps_Institution_of_Oceanography&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-45http://en.wikibooks.org/w/index.php?title=Hydrogen_cyanide&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Hydrogen_cyanide&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Hydrogen_cyanide&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Formaldehyde&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-46http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-46http://en.wikibooks.org/w/index.php?title=Acetylene&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Acetylene&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Cyanoacetylene&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Cyanoacetylene&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=BMA_process&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Strecker_synthesis&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Strecker_synthesis&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Glycine&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Formose_reaction&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Sugar&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Ribose&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Sulfur_dioxide&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-NS-31http://en.wikibooks.org/w/index.php?title=Water&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Methane&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Ammonia&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Hydrogen&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Evaporation&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Lightning&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Earth%27s_atmosphere&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Water_vapor&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Carbon&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Amino_acids&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Protein&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Glycine&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-44http://en.wikibooks.org/w/index.php?title=Optical_isomerism&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Optical_isomerism&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Racemic_mixture&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Jeffrey_Bada&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=University_of_California,_San_Diego&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Scripps_Institution_of_Oceanography&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Scripps_Institution_of_Oceanography&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-45http://en.wikibooks.org/w/index.php?title=Hydrogen_cyanide&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Formaldehyde&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-46http://en.wikibooks.org/w/index.php?title=Acetylene&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Cyanoacetylene&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=BMA_process&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Strecker_synthesis&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Glycine&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Formose_reaction&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Sugar&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Ribose&action=edit&redlink=1


13/81

/ther eperimentsThis experiment inspire many others. ?n !';!$ Hoan +r[foun that the

nucleotiebase aeninecoul be mae from hyrogen cyanie,>:- an ammoniain a %ater

solution. >is experiment prouce a large amount of aenine$ %hich molecules %ere formefrom 8 molecules of >:.647Also$ many amino acis are forme from >: an ammonia uner

these conitions.64"7xperiments conucte later sho%e that the other5A an 3A

nucleobasescoul be obtaine through simulate prebiotic chemistry %ith a reucingatmosphere.64'7

There also ha been similar electric ischarge experiments relate to the origin of life

contemporaneous %ith *illerD9rey. An article in$/e Ne0 1or2 $imes,*arch "$ !'8(L'-$ title

&@ooing Bac T%o Billion =ears& escribes the %or of ollman ,illiam- *. *acevin atThe +hio Itate 9niversity$before the *iller "ciencepaper %as publishe in *ay !'8(.

*acevin %as passing !00$000 volt spars through methane an %ater vapor an prouce

&resinous solis& that %ere &too complex for analysis.& The article escribes other early earthexperiments being one by *acevin. ?t is not clear if he ever publishe any of these results in

the primary scientific literature.6citation needed7

. A. ile submitte a paper to "cienceon 3ecember !8$ !'8#$ before *iller submitte his

paper to the same Mournal on /ebruary !4$ !'8(. ileEs paper %as publishe on Huly !0$ !'8(.6807

ile use voltages up to only ;00 on a binary mixture of carbon ioxie,:+#- an %ater in a

flo% system. >e observe only small amounts of carbon ioxie reuction to carbon monoxie$

an no other significant reuction proucts or ne%ly forme carbon compouns. +therresearchers %ere stuying92photolysisof %ater vapor %ithcarbon monoxie.They have

foun that various alcohols$ alehyes an organic acis %ere synthesi1e in reaction mixture.68!7

*ore recent experiments by chemist Heffrey Baa at Icripps ?nstitution of +ceanography,in @a

Holla$ :A- %ere similar to those performe by *iller. >o%ever$ Baa note that in current

moels of early arth conitions$ carbon ioxie annitrogen,#- create nitrites$ %hich estroyamino acis as fast as they form. >o%ever$ the early arth may have ha significant amounts of

iron an carbonate mineralsable to neutrali1e the effects of the nitrites. hen Baa performethe *iller2type experiment %ith the aition of iron an carbonate minerals$ the proucts %ere

rich in amino acis. This suggests the origin of significant amounts of amino acis may have

occurre on arth even %ith an atmosphere containing carbon ioxie an nitrogen.68#7.

3ro'aryotes
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cite_note-51http://en.wikibooks.org/w/index.php?title=Scripps_Institution_of_Oceanography&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=La_Jolla,_CA&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=La_Jolla,_CA&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Nitrogen&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Nitrite&action=edit&redlink=1http://en.wikibooks.org/w/index.php?title=Carbonate_minerals&action=edit&redlink=1http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Cell_and_its_Biochemistry#cite_note-52


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The si1es of proaryotes relative to other organisms an biomolecules

Proaryotes are single2cell organisms that o not have a nucleus$ mitochonria$ or any other

membrane2boun organelles. ?n other %ors$ neither their 3A nor any of their other sites ofmetabolic activity are collecte together in a iscrete membrane2enclose area. ?nstea$

everything is openly accessible %ithin the cell$ some of %hich is free2floating6(7. A istinctionbet%een proaryotes an euaryotes ,meaning true ernel$ also spelle &eucaryotes&- is that

euaryotes o have &true& nuclei containing their 3A. 9nlie proaryotes$ euaryotic

organisms may be unicellular$ as in amoebae$ or multicellular$ as in plants an animals. Theifference bet%een the structure of proaryotes an euaryotes is so great that it is sometimes

consiere to be the most important istinction among groups of organisms. The cell structure of

proaryotes iffers greatly from that of euaryotes. The efining characteristic is the absence of a

nucleus. Also the si1e of 5ibosomes in proaryotes is smaller than that in euaryotes$ %hich isno% %here respiration taes place. The genomes of proaryotes are hel %ithin an irregular

3AOprotein complex in the cytosol calle the nucleoi$ %hich lacs a nuclear envelope.68(7

?n general$ proaryotes lac the follo%ing membrane2boun cell compartmentsL mitochonria

an chloroplasts. ?nstea$ processes such as oxiative phosphorylation an photosynthesis taeplace across the proaryotic plasma membrane. >o%ever$ proaryotes o possess some internal

structures$ such as cytoseletons$ an the bacterial orer Planctomycetes have a membrane

aroun their nucleoi an contain other membrane2boun cellular structures. Both euaryotesan proaryotes contain large 5AOprotein structures calle ribosomes$ %hich prouce protein.

Proaryotes are usually much smaller than euaryotic cells. Proaryotes also iffer from

euaryotes in that they contain only a single loop of stable chromosomal 3A store in an areaname the nucleoi$ %hereas euaryote 3A is foun on tightly boun an organi1e

chromosomes. Although some euaryotes have satellite 3A structures calle plasmis$ ingeneral these are regare as a proaryote feature$ an many important genes in proaryotes are

store on plasmis. Proaryotes have a larger surface2area2to2volume ratio giving them a highermetabolic rate$ a higher gro%th rate$ an$ as a conseJuence$ a shorter generation time compare

to uaryotes. A criticism of this classification is that the %or &proaryote& is base on %hat

these organisms are not ,they are not euaryotic-$ rather than %hat they are ,either archaea orbacteria-. ?n !'$ :arl oese propose iviing proaryotes into the Bacteria an Archaea

,originally ubacteria an Archaebacteria- because of the maMor ifferences in the structure an
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genetics bet%een the t%o groups of organisms. This arrangement of uaryota ,also calle

&uarya&-$ Bacteria$ an Archaea is calle the three2omain system$ replacing the traitional

t%o2empire system.6847

Eu'aryotic cell

The cells of euaryotes,left- anproaryotes,right-

The origin of the euaryotic cell %as a milestone in the evolution of life$ since they inclue all

complex cells an almost all multi2cellular organisms. The timing of this series of events is harto etermineF noll ,#00;- suggests they evelope approximately !.; D #.! billion years ago.

Iome acritarchs are no%n from at least !$;80 million years ago$ an the possible alga )rypania

has been foun as far bac as #$!00 million years ago. /ossils that are clearly relate to moern

groups start appearing aroun !.# billion years ago$ in the form of a re alga$ though recent %orsuggests the existence of fossili1e filamentous algae in the inhya basin ating bac to !.; to

!. billion years ago. Biomarers suggest that at least stem euaryotes arose even earlier. The

presence of steranes in Australian shales inicates that euaryotes %ere present #. billion yearsago.6887

There are many ifferent types of euaryotic cells$ though animals an plants are the most

familiar euaryotes$ an thus provie an excellent starting point for unerstaning euaryotic

structure. /ungi an many protists have some substantial ifferences$ ho%ever.

Animal cell

An animal cell is a form of euaryotic cell that maes up many tissues in animals. The animal

cell is istinct from other euaryotes$ most notably plant cells$ as they lac cell %alls an

chloroplasts$ an they have smaller vacuoles. 3ue to the lac of a rigi cell %all$ animal cells canaopt a variety of shapes$ an a phagocytic cell can even engulf other structures.

There are many ifferent cell types. /or instance$ there are approximately #!0 istinct cell types

in the ault human boy.68;7

+lant cell

Plant cells are Juite ifferent from the cells of the other euaryotic organisms. Their istinctivefeatures areL A large central vacuole ,enclose by a membrane$ the tonoplast-$ %hich maintains
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the cellEs turgor an controls movement of molecules bet%een the cytosol an sap A primary cell

%all containing cellulose$ hemicellulose an pectin$ eposite by the protoplast on the outsie of

the cell membraneF this contrasts %ith the cell %alls of fungi$ %hich contain chitin$ an the cellenvelopes of proaryotes$ in %hich peptioglycans are the main structural molecules The

plasmoesmata$ lining pores in the cell %all that allo% each plant cell to communicate %ith

other aMacent cellsF this is ifferent from the functionally analogous system of gap Munctionsbet%een animal cells. Plastis$ especially chloroplasts that contain chlorophyll$ the pigment that

gives plants their green color an allo%s them to perform photosynthesis >igher plants$

incluing conifers an flo%ering plants ,Angiospermae- lac the flagellae an centrioles that arepresent in animal cells.

Fungal cell

/ungal cells are most similar to animal cells$ %ith the follo%ing exceptionsL A cell %all that

contains chitin @ess efinition bet%een cellsF the hyphae of higher fungi have porous partitions

calle septa$ %hich allo% the passage of cytoplasm$ organelles$ an$ sometimes$ nuclei. Primitive

fungi have fe% or no septa$ so each organism is essentially a giant multinucleate supercellF thesefungi are escribe as coenocytic. +nly the most primitive fungi$ chytris$ have flagella.687

3t/er eu2aryotic cellsuaryotes are a very iverse group$ an their cell structures are eJually

iverse. *any have cell %allsF many o not. *any have chloroplasts$ erive from primary$seconary$ or even tertiary enosymbiosisF an many o not. Iome groups have uniJue

structures$ such as the cyanelles of the glaucophytes$ the haptonema of the haptophytes$ or the

eMectisomes of the cryptomonas. +ther structures$ such as pseuopos$ are foun in variouseuaryote groups in ifferent forms$ such as the lobose amoebo1oans or the reticulose

foraminiferans.

$able 1 Comparison of features of 3ro'aryotic an" Eu'aryotic cells

3ro'aryotes Eu'aryotes

$ypical organisms Bacteria$archaea Protists$/ungi$Plants$ Animals

$ypical size \ !D!0 Vm \ !0D!00 Vm,sperm cells$ apart from the tail$ aresmaller-

$ype of nucleusnucleoi regionF no

real nucleusreal nucleus surroune by ouble membrane
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567 circular ,usually-linear molecules ,chromosomes- %ith histone

proteins

%6789protein8

synthesiscouple in cytoplasm

5A2synthesis insie the nucleusprotein synthesis in cytoplasm

%ibosomes 80IR(0I ;0IR40I

Cytoplasmatic

structurevery fe% structures

highly structure by enomembranes an a

cytoseleton

Cell mo!ementflagellamae of

flagellin

flagella anciliacontaining microtubulesF

lamellipoiaan filopoiacontaining actin

Mitochon"ria noneone to several thousan ,though some lac

mitochonria-

Chloroplasts none in algaeanplants

/rganization usually single cellssingle cells$ colonies$ higher multicellular organisms

%ith speciali1e cells

Cell "i!isionBinary fission,simple

ivision-

*itosis,fission or buing-

*eiosis

3lant cell is "ifferent from animal cell
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Itructure of a typical animal cell

Itructure of a typicalplant cell

Plant cells are euaryotic cells that iffer in several ey respects from the cells of other

euaryotic organisms. Their istinctive features inclueL A large central !acuole$ a %ater2fillevolume enclose by a membrane no%n as the tonoplastmaintains the cellEs turgor$ controls

movement of molecules bet%een the cytosol an sap$ stores useful material an igests %aste

proteins an organelles.

A cell +allcompose of cellulose an hemicellulose$ pectin an in many cases lignin$ are

secrete by the protoplas

Documents

Cell Biochemistry