,radioisotopes & ,life ,processes ,! ,und]/&+ ! ,atom ,s]ies ,nucle> en]gy is play+ a vital role 9 ! life ( e man1 woman1 & *ild 9 ! ,unit$ ,/ates today4 ,9 ! ye>s ahead x w affect increas+ly all ! peoples ( ! e>?4 ,x is ess5tial t all ,am]icans ga9 an und]/&+ ( ?is vital =ce if !y are to dis*>ge ?\ghtfully _! responsibilities z citiz5s & if !y are to realize fully ! myriad b5efits t nucle> en]gy (f]s !m4 ,! ,unit$ ,/ates ,atomic ,en]gy ,commission provides ?is booklet to help y a*ieve su* und]/&+4 ,illu/ration3 ,edw>d ,j4 ,brun5kant ,edw>d ,j4 ,brun5kant1 ,director ,division ( ,te*nical ,in=mation ,,unit$ ,,/ates ,,atomic ,,en]gy ,,commission ,dr4 ,gl5n ,t4 ,seaborg1 ,*airman ,james ,t4 ,ramey ,wilfrid ,e4 ,johnson ,dr4 ,!os ,j4 ,?ompson ,dr4 ,cl>5ce ,e4 ,l>son ,radioisotopes ,,& ,,life ,,processes by ,walt] ,e4 ,kisieleski & ,r5ato ,bas]ga ,,cont5ts ,,introduction #a ,,cell ,,!ory3 ,,dna ,,is ,,! ,,secret ,,( ,,life #b ,,radioactive ,,isotopes3 ,,! ,,biological ,,detectives #aj ,,dna ,,syn!sis3 ,,! ,,autobiography ,,( ,,cells #ae ,,rna ,,syn!sis3 ,,h[ ,,to ,,translate ,,"o ,,language ,,into ,,ano!r #be ,,prote9 ,,syn!sis3 ,,! ,,molecules ,,t ,,make ,,! ,,diff]5ce #ce ,,cell ,,cycle ,,& ,,g5e ,,action3 ,,life ,,is ,,! ,,secret ,,( ,,dna #cg ,,isotopes ,,9 ,,rese>*3 ,,prob+ ,,! ,,canc] ,,problem #dc ,,conclusions #de ,,sugge/$ ,,ref]5ces #dg ,unit$ ,/ates ,atomic ,en]gy ,commission ,division ( ,te*nical ,in=mation ,libr>y ( ,congress ,catalog ,c>d ,numb]3 #ff-faijh #aiff2 #aifg7,rev47 ,,! ,,cov] ,! cov] design portrays ! int]-relation%ips sugge/$ by ! title ( ?is booklet3 ,on a trefoil symboliz+ radiation are sup]impos$ a divid+ cell1 a plant1 an animal1 & a d\ble helix ( a molecule ( deoxyribonucleic acid1 a mat]ial unique 9 & fundam5tal to all liv+ ?+s4 ,,! ,,au?ors ,illu/ration3 ,,walt] ,e4 ,,kisieleski is an ,associate ,sci5ti/ 9 ! ,division ( ,biology & ,m$ic9e ( ! ,argonne ,national ,laboratory4 ,he 0 =m]ly associate pr(essor ( *emi/ry at ,loyola ,univ]sity 9 ,*icago4 ,8 und]graduate /udies 7 at ,james ,millik9 ,univ]sity 9 ,decatur1 ,ill9ois1 & 8 graduate /udies 7 at ! ,univ]sity ( ,*icago4 ,he receiv$ an ,honor>y ,doctor ( ,sci5ce degree f ,james ,millik9 ,univ]sity 9 #aifb4 ,9 #aieh he 0 a delegate to ! ,second ,atoms = ,peace ,conf]5ce 9 ,g5eva1 ,switz]l&4 ,he 0 visit+ lectur] 9 ! dep>tm5t ( bio*emi/ry at ! ,univ]sity ( ,oslo 9 ,norway 9 #aifc4 ,dr4 ,kisieleski is %[n op]at+ an automatic w9d[less /rip c\nt] t scans pap] *romatograms & ?us locates label$ sub/ances4 ,illu/ration3 ,,r5ato ,,bas]ga 0 born 9 ,milan1 ,italy1 & receiv$ a m$ical degree f ! ,univ]sity ( ,milan 9 #aidi4 ,he is pres5tly rese>* pr(essor ( pa?ology at ! ,fels ,rese>* ,in/itute at ,temple ,univ]sity ,m$ical ,s*ool 9 ,philadelphia1 & associate editor ( ! j\rnal1 ,canc] ,rese>*4 ,=m]ly he 0 associate pr(essor ( pa?ology at ,nor?we/]n ,m$ical ,s*ool 9 ,*icago1 :]e he 0 ! recipi5t ( a ,rese>* ,c>e] ,developm5t ,aw>d f ! ,national ,in/itutes ( ,heal?4 ,radioisotopes ,,& ,,life ,,processes ,by ,,walt] ,e4 ,,kisieleski & ,,r5ato ,,bas]ga ,,introduction ,"h & else:]e we %all n obta9 ! be/ insight into ?+s until we actually see !m gr[+ f ! beg9n+4 ,ari/otle ,! nature ( life has excit$ ! int]e/ ( human be+s f ! e>lie/ times4 ,al?\gh x is /ill n kn[n :at life is1 ! *>act]i/ics t set liv+ ?+s ap>t f lifeless matt] are well kn[n4 ,"o feature common to all liv+ ?+s1 f "o-cell$ creatures to complex animals l man1 is t !y are all compos$ ( microscopic units kn[n z cells4 ,! cell is ! smalle/ portion ( any organism t exhibits ! prop]ties we associate ) liv+ mat]ial4 ,9 spite ( ! imm5se v>iety ( sizes1 %apes1 & /ructures ( liv+ ?+s1 !y all h ?is 9 common3 ,!y are compos$ ( cells1 & liv+ cells conta9 simil> compon5ts t op]ate 9 simil> ways4 ,"o might say t life is a s+le process & t all liv+ ?+s op]ate on a s+le plan4 ,! pa/ few ye>s h be5 a "t ( rapid progress 9 our und]/&+ ( ! me*anisms t control ! function ( liv+ sy/ems4 ,?is progress has be5 made possible by ! developm5t ( new exp]im5tal te*niques & by ! p]fection ( in/rum5ts t detect :at happ5s 9 ! t9y _w ( molecules4 ,prom95t among ! me?ods t h contribut$ to ! explosive gr[? 9 our und]/&+ ( biology is ! use ( radioactive isotopes z laboratory tools4 ,9 ?is booklet we %all attempt to give an acc\nt1 9 *emical t]ms1 ( ! mat]ials f :i* liv+ matt] is made & ( "s ( ! *emical reactions t und]lie ! manife/ations & ! ma9t5ance ( life4 ,to accompli% ?is1 we h *os5 to describe ?ree types ( molecules t h become ! basis ( mod]n biology3 deoxyribonucleic acid 7,,dna71 ribonucleic acid 7,,rna71 & prote9s4 ,we w %[ h[ radioactive isotopes c be us$ to pry into ! inn]mo/ secrets ( ^! sub/ances4 ,be=e we c und]/& ! function ( ^! preci\s molecules1 h[ev]1 x w be necess>y to review ! /ructure ( a cell & ! physical nature ( radioactive isotopes4 ,,cell ,,!ory3 ,,dna ,,is ,,! ,,secret ,,( ,,life ,we h se5 t all organisms are compos$ ( ess5tially l p>ts1 namely cells2 t ^! cells are =m$ & gr[ 9 accordance ) ess5tially ! same laws2 h5ce t ^! processes mu/ ev]y:]e result f ! op]ation ( ! same =ces4 ,!odor ,s*wann ,unit ( ,life ,! cell !ory1 bas$ on ! concept t high] organisms consi/ ( small] units call$ cells1 0 =mulat$ 9 #ahch by two ,g]man biologi/s1 ,ma?ias-,jacob ,s*leid51 a botani/1 & ,!odor ,s*wann1 an anatomi/4 ,! !ory _h f>-rea*+ effect ^u ! /udy ( biological ph5om5a4 ,x sugge/$ t liv+ ?+s _h a common basis ( organization4 ,appreciation ( its full significance1 h[ev]1 _h to await m precise k ( ! /ructure & activities ( cells4 ,"s organisms1#a = in/ance1 amoebae1 consi/ ( a s+le cell ea* & are !re=e call$ unicellul> organisms4 ,high] animals are multicellul>1 conta9+ aggregations ( cells gr\p$ into tissues & organs4 ,a man1 = in/ance1 consi/s ( millions ( _m diff]5t cells p]=m+ a v>iety ( diff]5t functions4 ,cells ( high] animals diff] va/ly f "o ano!r 9 size1 %ape1 & function2 !y are specializ$ cells4 ,illu/ration3 ,figure #a ,"o ( ! e>lie/ photographs ( cells tak5 ) a microscope4 ,?is photomicrograph %[s cells 9 ! blood ( a pigeon4 ,x 0 made by ,j4 ,j4 ,woodw>d1 ,u4 ,s4 ,army surgeon1 9 #ahga4 ,woodw>d _h made ! fir/ cell micrograph 7a graphic reproduction ( ! image ( an object =m$ by a microscope7 9 #ahff4 ,!re is a rem>kable simil>ity1 moreov]1 9 ! molecul> composition & metabolism#b ( all liv+ ?+s4 ,?is simil>ity has be5 tak5 to mean t life c\ld h orig9at$ only once 9 ! pa/ & _h a specific *emical composition on :i* its metabolic processes dep5d$4 ,?is /ructure & metabolism 7 h&$ d[n to subsequ5t liv+ ?+s by reproduction1 & all v>iations !reaft] result$ f occasional mutation1 or *anges 9 ! nature ( ! h]$ity-transmitt+ units4 ,"o ( ! mo/ extraord9>y ( all ! attributes ( life is its ord]$ complexity1 bo? 9 function & /ructure4 ,x is agre$ among biologi/s t ! functional manife/ations ( life include movem5t1 respiration1 gr[?1 irritability 7reaction to environm5tal *anges71 & reproduction & t ^! ph5om5a are !re=e possess$ by all cells4 ,! fir/ f\r ( ^! c be gr\p$ "u a s+le ^w3 metabolism4 ,we c !re=e say t liv+ ?+s h two common prop]ties3 metabolism & reproduction4 ,!re=e1 :5 we say we are /udy+ life processes1 we actually are /udy+ ! metabolism & reproduction ( cells4 ,s9ce metabolism is ! sum ( ! bio*emical reactions tak+ place 9 a liv+ organism1 x prop]ly belongs to ! field ( inve/igation ( bio*emi/s4 ,cell reproduction is ! conc]n ( bo? bio*emi/s & morphologi/s#c s9ce x c be /udi$ by ei!r bio*emical or morphological te*niques4 ,cell ,/ructure ,illu/ration3 ,figure #b ,g5]aliz$ diagram ( a cell1 %[+ ! organelles1 or 8little organs01 ( its int]nal /ructure4 ,! organelles t are label$ are important = ?is booklet4 ,cell membrane ,cytoplasm ,*romat9 ,mito*ondrion ,nucleolus ,endoplasmic reticulum ,nucleus ,nucle> membrane ,! basic /ructure ( a cell is %[n 9 ,figure #b4 ,ea* cell consi/s ( a d5se inn] /ructure call$ ! nucleus1 :i* is surr\nd$ by a less d5se mass ( cytoplasm4 ,! nucleus is sep>at$ f ! cytoplasm by a d\ble envelope1 call$ ! nucle> membrane1 :i* is pepp]$ ) p]=ations4 ,! cytoplasm conta9s a network ( membranes1 :i* =m ! b\nd>ies ( c\ntless canals & vesicles 7or p\*es71 & is lad5 ) small bodies call$ ribosomes4 ,?is membran\s network is call$ ! endoplasmic reticulum & is di/9ct f ! mito*ondria1 :i* are membran\s organelles 7little organs7 /ructurally indep5d5t ( o!r compon5ts ( ! cytoplasm4 ,! out] coat ( ! cell is call$ ! cell membrane1 or plasma membrane1 & =ms ! cell b\nd>y4 ,illu/ration3 ,figure #c ,electron micrograph ( a prim>y sp]matocyte cell ( a gras%opp]1 %[+ ! nucleus 7,n71 endoplasmic reticulum 7,,er71 mito*ondrion 7,m71 *romat9 7,c71 nucle> membrane or nucle> envelope 7,,ne71 cell membrane 7,,cm71 & int]cellul> space 7,i74 ,! magnification is ab\t #be1jjj times ! actual size4 ,! nucleus1 :i* 9 _m cells is ! l>ge/ & mo/ c5tral body1 is ( special importance4 ,x conta9s a numb] ( ?readlike bodies1 or *romosomes1 t are ! c>ri]s ( ! cell's h]$ity-controll+ sy/em4 ,^! conta9 granules ( a mat]ial call$ *romat91 :i* is ri* 9 a nucleic acid1 ,,dna 7deoxyribonucleic acid74 ,! *romosomes usually are n readily se5 9 ! nucleus except :5 ! cell1 along ) its nucleus1 is divid+4 ,:5 ! nucleus is n divid+1 a sph]ical body1 ! nucleolus1 c be se54 7,9 "s nuclei !re may be m ?an "o47 ,:5 ! nucleus is divid+1 ! nucleolus disappe>s4 ,n all cells possess all ^! /ructures4 ,= in/ance1 ! r$ cells ( ! blood d n h a nucleus1 & 9 o!r cells ! endoplasmic reticulum is at a m9imum4 ,! diagram 7,figure #b7 is valid = a great majority ( ! cells ( high] organisms4 ,! cell /ructures %[n 9 ,figure #c are visible ) an electron microscope4 ,!y conta9 ! *emical compon5ts ( ! cell4 ,! *ief classes ( ^! con/itu5ts are ! c>bohydrates 7sug>s71 ! lipids 7fats71 ! prote9s1 & ! nucleic acids4 ,h[ev]1 a cell also conta9s wat] 7ab\t #gj ( ! cell weight is due to wat]7 & sev]al o!r organic & inorganic comp\nds1 su* z vitam9s & m9]als4 ,c>bohydrates s]ve mo/ly z food/uff )9 ! cell4 ,!y c be /or$ 9 sev]al relat$ =ms4 ,fur!r1 !y may s]ve a numb] ( functions outside ! cell1 especially z /ructural units4 ,9 ?is way /ructure & function are correlat$4 ,lipids 9 ! cell occur 9 a great v>iety ( types3 alcohols1 fats1 /]oids1 phospholipids1 & aldehydes4 ,!y are f\nd 9 all fractions ( ! cell4 ,_! mo/ important functions seem to be to =m membranes & to give ^! membranes specific p]meability4 ,!y are also important z /ores ( *emical en]gy1 mo/ly 9 ! =m ( neutral fats4 ,illu/ration3 ,figure #d ,sci5ti/s us+ an electron microscope 7left7 & an optical microscope 7"r7 9 fundam5tal bio*emical rese>*4 ,bo? in/rum5ts are important tools 9 /udies ( life processes4 ,! prote9s occur 9 _m cell /ructures & are ( _m k9ds3 ,enzymes1 ! cataly/s = ! cell's metabolic processes1 are prote9s1 = in/ance4 ,! nucleic acids are ,,dna & ,,rna 7ribonucleic acid71 :i* function toge!r to manufacture ! cell's prote9s4 ,s9ce a l>ge %>e ( ! rema9+ pages w be devot$ to a discussion ( prote9s & nucleic acids1 at ?is po9t we ne$ only emphasize t ^! two types ( mat]ials are int]relat$ 9 _! function & t bo? are ess5tial4 ,! ,two ,nucleic ,acids ,x is n v fruitful to discuss :e!r prote9s or nucleic acids are m important4 ,t "q is some?+ l ! "o ab\t ! *ick5 & ! egg4 ,we _c ?9k ( "o )\t ?9k+ ( ! o!r4 ,al?\gh our insight into ! mutual dep5d5ce ( ^! two mat]ials has greatly increas$ 9 rec5t ye>s & al?\gh we "k ! relation betwe5 !m is a fundam5tal factor 9 su* ev5ts z reproduction1 mutation1 & diff]5tiation 7or specialization7 ( cells1 our und]/&+ ( _! int]play is f> f complete4 ,real und]/&+ ( ! relation betwe5 !m w\ld give u insight into ! ess5ce ( gr[?--bo? normal & abnormal--or1 inde$1 "o c\ld almo/ say1 into ! complexity ( life itself4 ,illu/ration3 ,figure #e ,photomicrograph ( ,p>amecia1 "o-cell$ animals1 magnifi$ #aajj times4 ,_m ( ! same /ructures t appe> 9 ,figure #c c be se5 "h4 ,?is photo 0 tak5 ) an 8int]f]5ce0 microscope design$ to p]mit cont9u\s v>iation ( contra/ 9 ! subject "u /udy4 ,practically all ! ,,dna ( mo/ cells is conc5trat$ 9 ! nucleus4 ,,rna1 on ! o!r h&1 is di/ribut$ ?r\gh\t ! cell4 ,"s ,,rna is pres5t 9 ! nucleus1 b mo/ ( x is associat$ ) m9ute p>ticles 9 ! cytoplasm kn[n z microsomes1 "s ( :i* are especially ri* 9 ,,rna & are accord+ly nam$ ribosomes4 ,^! are mu* small] p>ticles ?an ! mito*ondria4 ,illu/ration3 ,figure #f ,/ages ( ! mitotic cycle 9 a hypo!tical cell ) f\r *romosomes4 7a7 ,int]phase 7b7 ,e>ly prophase 7c7 ,prophase 7d7 ,metaphase 7e7 ,anaphase 7f7 ,telophase 7g7 ,int]phase1 daught] cells ,mitosis ,"o ( ! mo/ rem>kable *>act]i/ics ( cells is _! ability to gr[ & divide4 ,new cells come f preexi/+ cells4 ,:5 a cell rea*es a c]ta9 /age 9 its life1 x divides into two p>ts4 ,^! p>ts1 aft] ano!r p]iod ( gr[?1 c 9 turn divide4 ,9 ?is way plants & animals gr[ to _! normal size & injur$ tissues are repair$4 ,cell division occurs :5 "s ( ! cont5ts ( ! cell h be5 d\bl$ by replication1 or copy+ 7to be discuss$ lat]74 ,! division ( a cell results 9 two r\ghly equal new p>ts1 ! daught] cells4 ,! process ( cell division is kn[n z mitosis & is diagramm$ 9 ,figure #f4 ,mitosis is a cont9u\s process2 ! foll[+ /ages ( ! process are designat$ only = conv5i5ce4 ,dur+ int]phase ! cell is busy metaboliz+1 syn!siz+ new cellul> mat]ials1 & prep>+ = self-duplication by syn!siz+ new *romosomes4 ,9 prophase ! *romosomes1 ea* n[ compos$ ( two id5tical /r&s call$ *romatids1 %ort5 by coil+1 & ! nucleolus & nucle> membrane disappe>4 ,dur+ metaphase ! *romosomes l9e up 9 "o plane ne> ! cell equator4 ,at anaphase ! si/] *romatids ( ea* *romosome sep>ate1 & ea* "p moves t[>d ! ends1 or poles1 ( ! cell4 ,dur+ telophase ! *romosomes uncoil & return to invisibility2 a new nucleus1 nucleolus1 & nucle> membrane are recon/itut$ at ea* end1 & division ( ! cell body occurs betwe5 ! new nuclei1 =m+ ! two new cells4 ,ea* daught] cell !reby receives a full set ( *romosomes1 &1 s9ce ! g5es are 9 ! *romosomes1 ea* daught] cell has ! same g5etic complem5t4 ,illu/ration3 ,figure #g ,photomicrograph ( cells ( ! ,trillium plant1 :i* has five *romosomes1 9 anaphase4 ,note ! duplicate sets ( *romosomes mov+ to opposite poles ( ! cell4 ,all life processes use up en]gy & !re=e require fuel4 ,! mito*ondria h a c5tral role 9 ! reactions by :i* ! en]gy ( sug>s is suppli$ = cellul> activity4 ,! importance ( ?is vital activity is obvi\s4 ,9 ?is booklet1 h[ev]1 we are conc]n$ ) ! processes1 involv+ nucleic acids & prote9s1 t c be describ$ z mak+ up 8! g5e-action sy/em04 ,! g5e-action sy/em is ! s]ies ( bio*emical ev5ts t regulate & direct all life processes by 8transcription0 ( ! g5etic 8in=mation0 conta9$ 9 molecules ( ,,dna4 ,,radioactive ,,isotopes3 ,,! ,,biological ,,detectives ,man 444 has f\nd ways to amplify 8 s5ses 444 &1 ) a v>iety ( in/rum5ts & te*niques1 has add$ k9ds ( p]ception t 7 miss+ f 8 orig9al end[m5t4 ,gl5n ,t4 ,seaborg ,atomic ,/ructure ,practically ev]yone n[adays is to "s ext5t famili> ) ! atomic /ructure ( matt]4 ,atomic en]gy1 nucle> reactors1 & radioisotopes are t]ms 9 ev]yday usage4 ,h[ev]1 to appreciate h[ radioisotopes c be appli$ to ! /udy ( life processes1 we mu/ h at lea/ a work+ k ( _! prop]ties1 _! prep>ation1 & _! limitations4 ,x is !re=e appropriate to exam9e !m 9 detail s t ! succe$+ *apt]s w be m easily und]/ood4 ,accord+ to pres5t-day !ory1 an atom consi/s ( a nucleus#d t is made up ( protons & neutrons#e & is surr\nd$ by electrons4 ,9 ea* atom !re is an equal numb] ( protons 7positively *>g$7 9 ! nucleus & electrons 7negatively *>g$7 mov+ conc5trically ar\nd ! nucleus2 s9ce neutrons h no electrical *>ge & s9ce protons & electrons cancel ea* o!r's *>ges1 ! :ole atom is electrically neutral1 or un*>g$4 ,ea* atom is id5tifi$ by an atomic numb] & an atomic weight4 ,! atomic numb] ( an elem5t 7= example1 c>bon1 nitrog51 oxyg57 is det]m9$ by ! numb] ( protons1 or positive *>ges1 c>ri$ by ! nucleus 7or by ! numb] ( electrons surr\nd+ ! nucleus1 :i* is ! same74 ,! atomic weight is ! weight ( an atom z comp>$ ) t ( ! atom ( c>bon1 :i* is tak5 z a /&>d4 ,! weight1 or mass1 ( an atom is due *iefly to its protons & neutrons because ! mass ( its electrons is negligible4 ,isotopes ,atoms ( ! same elem5t1 t is1 atoms ) ! same numb] ( protons & electrons1 may v>y slightly 9 mass because ( hav+ diff]5t numb]s ( neutrons4 ,s9ce ! *emical behavior ( an elem5t dep5ds ^u its electrons' electrical *>ges1 extra neutrons 7:i* d n h an electrical *>ge7 may affect ! mass ( an atom )\t di/urb+ its *emical prop]ties4 ,atoms hav+ ! same atomic numb] b diff]5t atomic weights are call$ isotopes4 ,= example1 z %[n 9 ,figure #h1 ! isotope ,h1 or ord9>y hydrog51 consi/s ( a nucleus conta9+ a proton 7*>ge3 #a2 mass3 #a7 ar\nd :i* revolves an electron 7*>ge3 -#a2 mass3 negligible72 ,h1 kn[n z deut]ium1 conta9s an additional nucle> p>ticle1 a neutron 7*>ge3 #j2 mass3 #a72 ,h1 or tritium1 conta9s two neutrons4 ,s9ce ! *emical behavior ( an elem5t dep5ds ^u ! numb] ( its electrons1 ^! ?ree atoms1 al?\gh diff]+ 9 weight1 behave id5tically 9 *emical reactions4 ,= conv5i5ce1 ! atomic weight is writt5 z a sup]script to ! left ( ! elem5t's symbol4 ,= in/ance ,c is ! isotope ( c>bon ) an atomic weight ( #ad 7ord9>y c>bon is ! isotope ) an atomic weight ( #ab1 & x is writt5 ,c74 ,illu/ration3 ,figure #h ,isotopes ( hydrog54 ,hydrog5 7,h7 ,deut]ium 7,h7 ,tritium 7,h7 ,practically all elem5ts h m ?an "o isotope4 ,!re are two g5]al classes ( isotopes1 /able & radioactive4 ,/able isotopes h no di/+ui%+ *>act]i/ic o!r ?an _! mass2 radioactive isotopes n only diff] f _! bro!rs 9 mass b also are *>act]iz$ by un/able nuclei4 ,:5 ! nucleus ( an atom is un/able1 because ( an unbalanc$ numb] ( protons & neutrons1 a r$i/ribution occurs soon] or lat]1 & ! atom decomposes spontane\sly & emits "o ( sev]al k9ds ( radiations4 ,because ( _! common mode ( action & effects on liv+ organisms1 ^! diff]5t k9ds ( radiations are kn[n collectively z ioniz+ radiations4 ,all radioactive elem5ts emit "o or m ( ?ree types ( p5etrat+ 7ioniz+7 rays4 ,alpha rays or p>ticles are d\ble-*>g$ helium nuclei1 ,he 7atomic numb]3 #b2 mass3 #d74 ,!y are emitt$ by _m heavy radioactive elem5ts1 su* z radium1 uranium1 & plutonium4 ,beta rays or p>ticles c be ei!r positive or negative4 ,negative beta p>ticles are high-spe$ electrons & are emitt$ by _m radioactive elem5ts4 ,positive beta p>ticles are positively *>g$ electrons 7positrons71 h only a transitory exi/5ce1 & are less common4 ,gamma rays are electromagnetic radiations1 a t]m t also describes radi[aves1 infr>$ rays1 visible light1 ultraviolet light1 & ,x rays4 ,gamma rays are usually emitt$ aft] ! emission ( alpha or beta p>ticles4 ,9 our /udies ( life processes1 we are int]e/$ only 9 ! radioactive isotopes t emit gamma rays or beta p>ticles4 ,radioactive ,isotopes ,radioactive isotopes occur z m9or con/itu5ts 9 _m natural mat]ials1 f :i* !y c be conc5trat$ by fractionation proc$ures4 ,9 a v limit$ numb] ( cases1 m significant am\nts ( a radioactive isotope1 = example1 radium or radioactive lead1 c be f\nd 9 nature4 ,mo/ radioactive isotopes 9 use today1 h[ev]1 are prep>$ artificially by nucle> reactions4 ,:5 a high-en]gy p>ticle1 su* z a proton1 a deut]on1 an alpha p>ticle1 or a neutron1 collides ) an atom1 a reaction takes place1 lead+ to ! =mation ( a new1 un/able comp\nd--a man-made radioactive isotope4 ,! great usefulness ( radioactive isotopes1 z we %all see lat]1 is t !y c be detect$ & id5tifi$ by prop] in/rum5ts4 ,bio*emi/s h long recogniz$ ! desirability ( 8tagg+0 or 8label+0 a molecule to p]mit trac+ or keep+ track ( ! 8label0 & consequ5tly ( ! molecule z x moves ?r\gh a reaction or process4 ,s9ce ! radiations emitt$ by radioactive isotopes c be detect$ & measur$1 we c readily foll[ a molecule tagg$ ) a radioactive atom4 ,illu/ration3 ,figure #i ,a laboratory te*nologi/ prep>+ dissolv$ biological mat]ials z "p ( a /udy ( ! uptake ( radioactive sub/ances 9 liv+ organisms4 ,note ! radiation-detection in/rum5t at "r4 ,! e>lie/ bio*emical /udies employ+ radioactive isotopes g back to #aibd1 :5 ,george de ,hevesy us$ natural radioactive lead to inve/igate a biological process4 ,x 0 only aft] ,_w ,w> ,,ii1 h[ev]1 :5 artificially made radioactive isotopes 7 readily available1 t ! te*nique ( us+ isotopic trac]s became popul>4 ,9 our inve/igations ( life processes1 we are especially int]e/$ 9 ?ree radioactive isotopes3 ,h1 ! hydrog5 atom ( mass #c2 ,c1 ! atom ( c>bon ) atomic weight #ad2 & ,p1 ! atom ( phosphorus ) atomic weight #cb4 ,^! radioactive isotopes are important because ! correspond+ /able isotopes ( hydrog51 c>bon1 & phosphorus are pres5t 9 practically all cellul> compon5ts t are important 9 ma9ta9+ life4 ,) ! ?ree radioactive isotopes1 !re=e1 we c tag or label ! molecules t p>ticipate 9 life processes4 ,illu/ration3 ,figure #aj ,a visit+ sci5ti/ at an ,,aec laboratory uses radioactive tritium 7,h7 to /udy ! effect ( radiation on bean *romosomes4 ,! fam\s sci5ti/1 ,george de ,hevesy1 also us$ beans 9 conduct+ ! fir/ biological /udies ev] made ) radioisotopes4 ,hydrog5-#c is a weak beta emitt]2 t is1 x emits beta p>ticles ) a v l[ en]gy 7#j4jah ,mev#f7 & !re=e ) a v %ort range4 ,c>bon-#ad is also a weak beta emitt] 7#j4aed ,mev71 al?\gh ! beta p>ticles emitt$ by ,c h a high] en]gy & !re=e a long] range ?an ^? emitt$ by ,h4 ,! beta p>ticles emitt$ by phosphorus-#cb are q en]getic 7#a4fi ,mev7 & h a long] range4 ,radioactive ,isotopes' ,value 9 ,biological ,/udies ,to biologi/s1 !n1 ! ess5tial feature 9 ! use ( radioactive isotopes is ! possibility ( prep>+ 8label$0 samples ( any organic molecule involv$ 9 biological processes4 ,) label$ samples x is possible to di/+ui% ! behavior & keep track ( ! c\rse ( molecules involv$ 9 a p>ticul> biological function4 ,9 ?is capacity ! isotope may be lik5$ to a dynamic & revolution>y type ( 8atomic microscope01 :i* c actually be incorporat$ into a liv+ process or a specific cell4 ,j z a real microscope p]mits exam9ation ( ! /ructural details ( cells1 isotopes p]mit exam9ation ( ! *emical activities ( molecules1 atoms1 & ions z !y react )9 cells4 7,nei!r optical nor electron microscopes are p[]ful en\gh = u to see any?+ z small z a molecule cle>ly47 ,,dna ,,syn!sis3 ,,! ,,autobiography ,,( ,,cells ,"h1 surely1 is ! prime sub/ance ( life itself4 ,isaac ,asimov ,! _m *>act]i/ic features ( ea* liv+ species1 its complex ar*itecture1 its p>ticul> behavior patt]ns1 ! +5i\s modifications ( /ructure & function t enable x to compete & survive--all ^! mu/ pass1 figuratively speak+1 ?r\gh ! eye ( an ultramicroscopic ne$le be=e !y are br\ght toge!r z a new1 individual organism4 ,! ?read t passes ?r\gh ! eye ( ?is ne$le is a /r& ( ! filam5t\s molecule1 deoxyribonucleic acid 7,,dna74 ,let u n[ outl9e ! rese>* t l$ to ^! conclusions4 ,,dna 9 ,somatic & ,g]m9al ,cells ,"o ( ! fundam5tal laws ( mod]n biology--:i* /ates t ! ,,dna cont5t ( somatic cells is con/ant = any giv5 species--0 fir/ set =? 9 a rese>* report ( #aidh4 ,?is f9d+ means t 9 any giv5 species1 su* z a m\se or a man1 all cells except ! g]m9al cells conta9 ! same am\nt ( ,,dna4 ,g]m9al cells1 t is1 ! sp]m cells ( ! male sem5 & ! female egg1 conta9 exactly half ! am\nt ( ,,dna ( ! somatic cells4 ,?is mu/ be ! case1 s9ce ,,dna is ! h]$it>y mat]ial1 & ea* individual's h]$ity is %ap$ half by 8 fa!r & half by 8 "m4 ,"o t5-trillion? ( an ounce ( ,,dna f a fa!r & "o t5-trillion? ( an ounce ( ,,dna f ! "m toge!r conta9 all ! specifications to produce a new human be+4 ,a l>ge am\nt ( ,,dna mu/ be manufactur$ by an individual organism z x develops f a f]tiliz$ egg 7"o s+le cell7 to an adult conta9+ sev]al million cells4 ,= in/ance1 a m\se cell conta9s ab\t #g picograms ( ,,dna 7"o picogram is "o million? ( a microgram1 or "o million? ( "o million? ( a gram74 ,a :ole m\se conta9s 9 its body approximately #be milligrams 7#be ?\s&?s ( a gram7 ( ,,dna1 & all ?is ,,dna 0 syn!siz$ by ! cells z ! m\se grew to adul?ood4 ,s9ce ! am\nt ( ,,dna p] cell rema9s con/ant & s9ce ea* cell divides into two cells1 x is app>5t t ea* new cell receives ! am\nt ( ,,dna *>act]i/ic ( t species4 ,once we realize t a cell t is mak+ new ,,dna 7z mo/ cells d7 mu/ divide to keep ! am\nt ( ,,dna p] cell con/ant1 x foll[s t a cell t is mak+ ,,dna is "o t is soon de/9$ to divide4 ,if we c n[ m>k newly made ,,dna ) a radioactive isotope1 we c actually m>k & ?us id5tify cells t are prep>+ to divide4 ,! task c be divid$ into two p>ts3 7#a7 to label ! newly made ,,dna & 7#b7 to detect ! newly made1 label$ ,,dna4 ,replication ( ,,dna ,figure #aa is a diagram %[+ ! ess5tial /ructure ( ! l>ge ,,dna molecule4 ,accord+ to ! ,watson-,crick model1#g ! molecule consi/s ( two /r&s ( small] molecules twi/$ ar\nd ea* o!r to =m a d\ble helix4 ,ea* /r& consi/s ( a sequ5ce ( ! small] molecules l9k$ l9e>ly to ea* o!r4 ,^! small] molecules are call$ nucleotides1 & ea* consi/s ( ?ree /ill small] molecules1 a sug> 7deoxyribose71 phosphoric acid1 & a nitrog5 base4 ,ea* nucleotide & its ne>e/ neighbor are l9k$ toge!r 7betwe5 ! sug> ( "o & ! phosphoric acid ( ! neighbor74 ,?is leaves ! nitrog5 base free to atta* itself1 ?r\gh hydrog5 bond+1 to ano!r nitrog5 base 9 ! opposite /r& ( ! helix4 ,9 ! ,,dna ( high] organisms1 !re are only f\r types ( nitrog5 bases3 ad59e1 guan9e1 ?ym9e1 & cytos9e4 ,ad59e 9 ei!r /r& ( ! helix pairs only ) ?ym9e 9 ! opposite /r&1 & vice v]sa1 & guan9e pairs only ) cytos9e1 & vice v]sa1 s t ea* /r& is complem5t>y 9 /ructure to ! o!r /r& 7see ,figure #ab74 ,! full /ructure resembles a long twi/$ ladd]1 ) ! sug> & phosphate molecules ( ! nucleotides =m+ ! uprights & ! l9k$ nitrog5 bases =m+ ! rungs4 ,ea* upright /r& is ess5tially a mirror image ( ! o!r1 al?\gh ! two ends ( any "o rung are dissimil>4 ,illu/ration3 ,figure #aa ,diagrammatic /ructure ( ! ,,dna molecule z propos$ by ! ,watson-,crick model4 ,,dna3 ,diagrammatic s+le-/r& *emical =mula ,,dna3 ,/ructural arrangem5t ,:5 ,,dna is replicat$1 or copi$1 z ! organism gr[s1 ! two nucleotide /r&s sep>ate f ea* o!r by disjo9+ ! rungs at ! po9t :]e ! bases meet1 & ea* /r& !n makes a new & simil>ly complem5t>y /r&4 ,! result is two d\ble-/r&$ ,,dna molecules1 ea* ( :i* is id5tical to ! p>5t molecule & conta9s ! same g5etic mat]ial4 ,:5 ! cell divides1 ea* ( ! two daught] cells gets "o ( ! new d\ble /r&s2 ea* new cell ?us always has ! same am\nt ( ,,dna & ! same g5etic mat]ial z ! p>5t cell4 7,all t has be5 said s f> ab\t ,,dna replication dep5ds ^u an assumption t ! ,,dna molecule is 9 "s way untwi/$ to all[ sep>ation ( two helical /r&s1 b !re is no compell+ reason to believe t su* an untwi/+ does inde$ take place1 nor d we "k1 if ! untwi/+ does take place1 h[ x is accompli%$4 ,mu* t has be5 said 9 ! la/ few p>agraphs is !re=e purely speculative4 ,x is1 h[ev]1 bas$ on s\nd obs]vation & is a m logical explanation ?an o!rs t h be5 advanc$47 ,illu/ration3 ,figure #ab ,! pair+ ( ! nucleotide bases t make up ,,dna4 ,illu/ration3 ,figure #ac ,! ,,dna molecule & h[ x replicates4 7a7 ,! con/itu5t submolecules4 7b7 ,assembly ( subunits 9 complete ,,dna molecule4 7c7 8,unzipp+0 ( ! d\ble nucleotide /r&4 7d7 & 7e7 ,! =m+ ( a new /r& by ea* individual /r&4 7f7 ,,dna molecule 9 twi/$ d\ble-/r& configuration4 ,adapt$ f ,viruses & ! ,nature ( ,life1 ,w5dell ,m4 ,/anley & ,evans ,c4 ,val5s1 ,e4 ,p4 ,dutton ,co41 ,inc41 #aifa1 ) p]mission4 ,label+ ,,dna ) a ,radioactive ,isotope ,( ! f\r bases 9 ,,dna1 ?ree are also f\nd 9 ! o!r nucleic acid1 ,,rna2 b ! f\r?1 ?ym9e1 is f\nd only 9 ,,dna4 ,!re=e1 if ?ym9e c\ld be label$ & introduc$ into a numb] ( cells1 includ+ a cell 9 :i* ,,dna is be+ =m$1 we w\ld specifically label ! newly syn!siz$ ,,dna1 s9ce nei!r ! old ,,dna nor ! ,,rna w\ld make use ( ! ?ym9e4 ,we c\ld 9 ?is way m>k cells prep>+ to divide4 7,actually1 ?ym9e itself is n tak5 up 9 mammalian cells1 b its nucleoside is4 ,a nucleoside is ! base plus ! sug>1 or1 9 o!r words1 ! nucleotide m9us ! phosphoric acid47 ,! nucleoside ( ?ym9e is call$ ?ymid9e1 & we say t ?ymid9e is a specific compon5t ( ,,dna & c be us$1 bo? 9 laboratory /udies & 9 liv+ organisms1 = label+ ,,dna4 ,?ymid9e label$ ) radioactive comp\nds is available z ,c-?ymid9e 7?ymid9e ) a /able c>bon atom replac$ by a radioactive c>bon atom7 & z ,h-?ymid9e 7?ymid9e 9 :i* a /able hydrog5 atom has be5 replac$ by tritium74 ,?us1 :5 cells actively mak+ ,,dna are expos$ to radioactive ?ymid9e1 !y incorporate x1 & ! ,,dna becomes radioactive4 ,we h ?us f\nd a way to complete ! fir/ "p ( ! task1 ! label+ ( new ,,dna4 ,we /ill mu/ f9d out h[ to di/+ui% label$ ,,dna among ! _m compon5ts ( ! cell4 ,we might d x ) a sy/em bas$ on measur+ ! am\nt ( radioactivity incorporat$ into ! ,,dna ( cells expos$ to radioactive ?ymid9e1 z an approximation ( ! frequ5cy ( cell division 9 ! gr\p ( cells4 ,h[ev]1 a bett] me?od = /udy+ cells syn!siz+ ,,dna1 & ?us prep>+ to divide1 is ! use ( high-resolution autoradiography4 ,detect+ ,,dna ) ,autoradiography ,autoradiography is bas$ on ! same pr9ciple z photography4 ,j z photons ( light imp++ on a photographic emulsion produce an image1 s d beta p>ticles 7or alpha p>ticles7 emitt$ by decompos+ radioactive atoms4 ,a photographic emulsion is a susp5sion ( cry/als ( a silv] halide 7usually silv] bromide7 emb$d$ 9 gelat94 ,:5 cry/als ( silv] bromide are /ruck by beta p>ticles1 ! silv] atoms are ioniz$ & =m a lat5t image1 s call$ because x is invisible to our eyes4 ,aft] ! emulsion is develop$ & fix$1 ea* little aggregate ( r$uc$ silv] atoms becomes a visible black speck on ! emulsion4 ,! di/ribution & comb9ation ( ! specks make up ! photographic image 7see ,figure #ad74 ,9 ord9>y photography su* an image is a negative1 :i* has to be conv]t$ into ! positive photograph by pr9t+4 ,9 autoradiography we are satisfi$ to look at ! negative image s9ce ! clu/]s ( develop$ silv] atoms1 appe>+ "u a light microscope z black dots1 supply all ! in=mation we ne$4 ,illu/ration3 ,figure #ad ,s*ematic diagram ( a radioautograph4 ,! di/9ction ( hav+ made ! fir/ autoradiograph belongs to ! ,fr5* physici/1 ,anto9e ,h5ri ,becqu]el2 & to ano!r ,fr5*man1 ,a4 ,lacassagne1 goes ! cr$it = hav+ introduc$ ?is te*nique into biological /udies4 ,lacassagne us$ autoradiography to /udy di/ribution ( radioactive polonium 9 animal organs4 ,aft] ,_w ,w> ,,ii1 :5 radioactive isotopes 7 fir/ available 9 appreciable quantities1 autoradiography 0 fur!r p]fect$ ?r\gh ! ef=ts ( su* sci5ti/s z ,c4 ,p4 ,leblond 9 ,canada1 ,s4 ,r4 ,pelc 9 ,engl&1 & ,p4 ,r4 ,fitzg]ald 9 ! ,unit$ ,/ates4 ,today autoradiography is suffici5tly precise to locate radioactively label$ sub/ances 9 individual cells & ev5 9 *romosomes & o!r /ructures )9 ! cell4 ,two conditions mu/ be met to a*ieve ?is high resolution3 7#a7 ,! radiation f ! radioactive elem5t 9 ! cells mu/ be ( v %ort range4 7#b7 ,! cells mu/ rema9 9 close contact ) ! photographic emulsion ?r\gh\t ! v>i\s exp]im5tal manipulations4 ,:5 ^! conditions are met1 ! black dots w appe> 9 ! emulsion directly above ! cell or cell "p f :i* ! radiation came 7see ,figure #ad74 ,%ortness ( range is satisfi$ by use ( tritium1 s9ce its beta p>ticles travel only ab\t #a micron 7"o ?\s&? ( a millimet]7 & ! diamet]s ( mammalian cells range f #ae to #dj or m microns4 ,a mammalian-cell nucleus is at lea/ #g to #h microns 9 diamet]4 ,illu/ration3 ,figure #ae ,cells be+ prep>$ = autoradiography4 7a7 ,cells be+ coat$ ) a photographic emulsion4 7b7 ,coat$ cells be+ expos$ to produce a lat5t image4 ,! condition ( close contact betwe5 cells & emulsion is a*iev$ by ! te*nique ( dip-coat+ autoradiography4 ,9 ?is process ! glass slide on :i* ! cells are c>ri$ is dipp$ into a melt$ photographic emulsion 7see ,figure #ae;a71 a ?9 film ( :i* cl+s to ! slide4 ,aft] x has be5 dri$1 ! slide is plac$ 9 a lighttight box & kept 9 a refrig]ator = ! desir$ p]iod ( exposure1 usually sev]al days or weeks4 ,dur+ ?is p]iod dis9tegrat+ radioactive atoms )9 ! cells cont9ue to emit beta p>ticles1 :i*1 9 turn1 produce a lat5t image 9 ! ov]ly+ emulsion4 ,aft] ! exposure is complete1 ! slide is develop$ & fix$ l a photographic plate1 & a /a9 is appli$ :i* p5etrates ! emulsion s t ! outl9es ( ! cells & _! int]nal /ructures c be se54 ,! fix+ process removes all silv] bromide t has n be5 ioniz$ s t ! emulsion is r$uc$ to a ?91 transp>5t film ( gelat9 cov]+ ! /a9$ cells & conta9+ only ! clu/]s ( silv] gra9s t 7 /ruck by ! beta p>ticles4 ,illu/ration3 ,figure #af ,radioautographs ( tumor cells4 ,above1 tumor cells & blood cells4 ,bel[1 magnification ( tumor cells4 ,:5 ! f9i%$ autoradiograph is exam9$ "u ! microscope1 x w look l ! radioautographs ( tumor cells 9 ,figure #af4 ,9 ! upp] micrograph ! tumor cells are ! l>g] ones & ! small] ones are blood cells4 ,! d5se /ructures 9 ! c5t] ( ! tumor cells are nuclei4 ,! cells 7 expos$ to tritium-label$ ?ymid9e1 & ^? syn!siz+ ,,dna at ! "t ( exposure took up ! ?ymid9e & became radioactive4 ,!y c be id5tifi$ by ! black dots ov]ly+ ! nuclei2 ! dots are ! aggregates ( silv] gra9s /ruck by ! beta p>ticles4 ,notice t only ! nuclei conta9 radioactivity2 ! reason = ?is is t radioactive ?ymid9e is incorporat$ only into ,,dna localiz$ 9 ! nuclei ( cells4 ,?is picture id5tifies n only ! cells t 7 mak+ ,,dna at ! "t ! label 0 adm9i/]$ b also ! cells t 7 de/9$ to divide 9 ! imm$iate future1 s9ce cells syn!size ,,dna 9 prep>ation = cell division4 ,if we want to comp>e two populations ( cells to f9d out :i* is prolif]at+ 7divid+7 m actively1 c\nt+ ! fraction ( cells label$ w give ! numb] ( cells syn!siz+ ,,dna 9 prep>ation = cell division4 ,( c\rse1 a r\gh approximation ( ! prolif]at+ activity c be obta9$ by simply c\nt+ ! numb] ( cells actually divid+4 ,b ) tritiat$ ?ymid9e we c obta9 n only mu* m accurate measurem5ts b also consid]able in=mation t _c be obta9$ by simply c\nt+ ! numb] ( cells 9 mitosis4 ,we %all discuss ! cell cycle lat] on1 b = ! mom5t we %\ld emphasize t mu* ( our k ( ! cell cycle /ems f ! use ( high-resolution autoradiography4 ,x is cle> t autoradiography enables u to f9d out :i* cells are divid+ 9 a cell population & h[ _m ( !m d s4 ,= in/ance1 9 a giv5 tissue or organ1 n all cells are capable ( divid+ into two daught] cells4 ,9 ! epid]mis1 :i* is ! ?9 out] lay] ( ! sk91 only cells 9 ! deepe/ portion c divide4 ,! o!r cells1 al?\gh orig9at+ f cells 9 ! deep lay]1 h lo/ ! capacity to divide1 & ev5tually die )\t fur!r division4 ,if we take a bit ( sk91 expose x to tritiat$ ?ymid9e1 & det]m9e ! am\nt ( radioactivity incorporat$ into ! sk9 cells' ,,dna1 we obta9 a fair measurem5t ( ! am\nt ( ,,dna be+ syn!siz$4 ,h[ev]1 ?is purely bio*emical inve/igation _c possibly give any in=mation on :i* specific cells are syn!siz+ ,,dna4 ,= ?is1 autoradiography provides ! in=mation we ne$4 ,,rna ,,syn!sis3 ,,h[ ,,to ,,translate ,,"o ,,language ,,into ,,ano!r ,ma!maticians are l ,fr5*m53 :atev] y say to !m !y translate into _! own language1 & =?) x is some?+ entirely diff]5t4 ,wolfgang von ,goe! ,we h m5tion$ previ\sly t !re are two ma9 types ( nucleic acids3 ,,dna1 ! g5etic mat]ial itself1 & ,,rna1 ! molecule t translates ! g5etic message f ,,dna into t]ms ! cell c use z 8in/ructions0 = mak+ prote94 ,cells diff] f ea* o!r on ! basis ( k9ds ( prote9s !y conta91 &1 s9ce diff]5ces among cells det]m9e diff]5ces among organisms1 x foll[s t diff]5ces 9 ! composition ( ,,dna s]ve to expla9 ! v>iety 9 liv+ organisms populat+ ! _w4 ,h[ev]1 if diff]5ces betwe5 two organisms c be expla9$ by diff]5ces 9 ! *emical composition ( _! respective ,,dna's1 h[ c we expla9 diff]5ces betwe5 cells ( ! same organism8 ,h[ c we expla9 t cells ( ! human pancreas secrete insul91 :]eas o!r cells 9 man produce no insul98 ,or h[ c we expla9 t c]ta9 cells make bone & o!rs make fat8 ,if inde$ all cells 9 ! same organism conta9 ! same am\nt & k9d ( ,,dna 7s9ce all ,,dna 9 an organism d]ives f ! duplication ( ! ,,dna ( ! f]tiliz$ egg cell & its desc5dants71 x w\ld seem1 at fir/ glance1 t ,,dna is n ! molecule responsible = diff]5ces among ! cells4 ,! cl>ification ( ?is app>5t contradiction is f\nd 9 ! rem>kable prop]ties ( ! o!r nucleic acid1 ! translator molecule1 ,,rna4 ,?ree ,k9ds ( ,,rna ,9 ! fir/ place1 !re are at lea/ ?ree diff]5t k9ds ( ,,rna4 ,! l>ge/ quantity is a special k9d call$ ribosomal ,,rna1 or r-,,rna4 ,x is f\nd 9 close conjunction ) prote9s & makes up ! /ructural frame ^u :i* ! prote9-syn!siz+ ma*9]y is built4 ,! r-,,rna & ! prote9s to :i* x is firmly b\nd =m ! ribosomes1 ! ,,rna-ri* microsomes t are atta*$ to ! endoplasmic reticulum4 ,prote9s are syn!siz$ on ribosomes4 ,we %all see lat] :at det]m9es ! diff]5ces among prote9s & h[ ^! diff]5ces are dictat$ directly by ,,rna & indirectly by ,,dna4 ,besides r-,,rna1 !re is a k9d ( ,,rna call$ soluble ,,rna1 or transf] ,,rna1 or s-,,rna4 ,x comb9es ) r-,,rna to complete ! sequ5ce ( ev5ts t syn!sizes ! prote9s4 ,a bond betwe5 r-,,rna & s-,,rna is e/abli%$ by a ?ird ,,rna molecule call$ mess5g] ,,rna1 or template ,,rna1 or m-,,rna4 ,?is m-,,rna molecule is truly ! mess5g] t c>ries ! g5etic message f ,,dna to ! prote9-syn!siz+ app>atus4 ,dr4 ,mi*ael ,%imk91 a ,temple ,univ]sity sci5ti/1 9 8 analogy has comp>$ ! ,,dna ,,rna prote9 sequ5ce to ! activities ( a newspap] /aff4 ,,dna is ! editor2 m-,,rna molecules are copyboys :o c>ry ! editorials to ! typesett]s1 ! r-,,rna & s-,,rna1 :o !n take ! 8lett]s0 ( nucleic acid & set !m into slots 9 accordance ) ! editor's directions4 ,!re are also work]s :o melt d[n outworn lett]s & /ill o!r work]s :o make new lett]s = fur!r use2 ^! are ! enzymes1 special k9ds ( prote9s4 ,if we wi% to cont9ue ! analogy1 we may say t ea* k9d ( cell 9 ! organism has a diff]5t sub$itor1 :o writes t cell's own editorial4 ,actually we might say t all cells h ! same bo>d ( editors 9 common1 b only "o editor functions 9 any giv5 type ( cell4 ,9 biological t]ms ?is means t only a portion ( all ! cellul> ,,dna is active 9 ea* cell4 ,! active ,,dna is ! ,,dna t makes m-,,rna t w c>ry in/ructions to ! prote9-syn!siz+ ma*9]y ( t type ( cell4 ,cells ( ! same organism !re=e diff] f ea* o!r on ! basis ( ! segm5t ( ,,dna t is active 9 mak+ m-,,rna4 ,let u n[ see h[ we c use radioactive isotopes to inve/igate ! syn!sis ( ,,rna4 ,label+ ,,rna ) a ,radioactive ,isotope ,,rna syn!sis is inve/igat$ ) radioactive trac]s 9 ! same way z ,,dna syn!sis4 ,if we c m>k1 ) a radioactive atom1 a small molecule t is incorporat$ into newly =m$ ,,rna1 we c !n trace ! c\rse ( ! label$ ,,rna molecule ) a radiation-detection device4 ,,dna _h "o advantage 9 ?is reg>d--! fact t "o comp\nd1 ?ymid9e1 0 a precursor ( ,,dna1 a specific mat]ial t c\ld be incorporat$ only into ,,dna4 ,we d n "k simil> specific precursors ( ,,rna4 ,b we "k sev]al precursors t are pr$om9antly incorporat$ into ,,rna2 ! mo/ common ( ^! are ! nucleosides ad59e1 cytid9e1 & urid9e1 & ! small] molecule1 orotic acid4 ,all ^! precursors c be label$ ) ei!r ,h or ,c1 & _! incorporation into ,,rna c be measur$4 ,detect+ ,,rna ) ,autoradiography ,z 9 ,,dna syn!sis1 we c use autoradiography to foll[ ! incorporation ( precursors into ,,rna4 ,by prop] treatm5t ( ! tissues1 we c make sure t all ! radioactivity visible by autoradiography is due to label$ ,,rna1 ev5 ?\gh "s ( ! precursor also ent]s ,,dna molecules4 ,ev5 s1 ! k9d ( in=mation obta9$ f autoradiographs ( tissues expos$ to ,,rna precursors is diff]5t f t obta9$ ) ,,dna precursors4 ,! advantage ( high-resolution autoradiography 9 ,,dna /udies is ! possibility ( id5tify+ p>ticul> cells t are syn!siz+ nucleic acid4 ,?is advantage is app>5tly lo/ 9 ! case ( ,,rna4 ,! reason is t1 at any giv5 "t1 only a few cells are mak+ ,,dna1 :]eas practically all cells are syn!siz+ ,,rna con/antly4 ,! only exceptions are cells 9 ! midpo9t ( mitosis4 ,at ! beg9n+ 7prophase7 & at ! end ( cell division 7telophase71 ,,rna is syn!siz$4 ,if we want a quantitative measurem5t ( ,,rna syn!sis1 o!r me?ods1 to be exam9$ pres5tly1 are consid]ably m precise4 ,b autoradiography c /ill give u valuable in=mation4 ,o!r ,me?ods ( ,detect+ ,,rna ,if we look at cells soon aft] !y h be5 expos$ to an ,,rna precursor1 we f9d t ! radioactivity detectable by autoradiography is only 9 ! nuclei ( ! cells4 ,no radioactivity c be detect$ 9 ! cytoplasm1 al?\gh we "k t ! cytoplasm ( liv+ cells conta9s l>ge am\nts ( r-,,rna & s-,,rna4 ,"o or two h\rs lat]1 h[ev]1 radioactive ,,rna appe>s 9 ! cytoplasm z well z 9 ! nucleus4 ,:at autoradiography is tell+ u is t ,,rna is made 9 ! nucleus & !n is sl[ly transf]r$ to ! cytoplasm4 ,autoradiography _c tell u :e!r ! ,,rna t has be5 newly syn!siz$ 9 ! nuclei ( cells is m-,,rna1 s-,,rna1 or r-,,rna4 ,! me?ods necess>y to make ?is di/9ction are bas$ on ! *emical fractionation ( ! tissue1 isolation ( ,,rna1 det]m9ation ( its am\nt by quantitative analysis1 & det]m9ation ( ! am\nt ( radioactivity by physical me?ods4 ,let u exam9e ^! /eps sep>ately4 ,illu/ration3 ,figure #ag ,inject+ a m\se ) a radioactive solution4 ,*emical ,fractionation ( ,tissue ,aft] an animal has be5 inject$ ) a radioactive precursor ( ,,rna1 "s ( x w be incorporat$ into ,,dna z well z into ,,rna 7rememb] t ! precursors ( ,,rna lack specificity71 & "p ( ! precursor w be brok5 d[n into small] molecules4 ,! inject$ animal c be sacrific$1 & an organ or ano!r tissue1 = in/ance1 ! liv]1 c be remov$4 ,!n ! liv] is homog5iz$1 t is1 gr\nd to a pulp ) a mod]n v]sion ( ! mort> & pe/le4 ,! homog5ate 7pulp7 is treat$ ) cold 7weak7 acid4 ,prote9s & nucleic acids are insoluble 9 cold acids & !re=e precipitate to ! bottom ( ! te/ tube4 ,all molecules t are soluble 9 a cold acid are left 9 ! sup]natant 7! rema9+ liquid72 among ^! are small molecules1 l ^? ( ! ,,rna precursor4 ,! precipitate 7! solid mat]ial t settles to ! bottom71 n[ conta9+ prote9s & nucleic acids1 is !n treat$ ) a /rong alkali1 = in/ance1 sodium hydroxide4 ,alkali w dige/ ,,rna into small] molecules b does n affect ,,dna4 ,if we n[ add acid to ! solution1 ,,dna1 be+ insoluble 9 acid1 w precipitate aga92 ,,rna1 hav+ be5 brok5 d[n into small molecules1 w rema9 9 ! sup]natant4 ,,dna c !n be extract$ f ! precipitate by boil+ 9 /rong acid4 ,prote9s f ! tissue rema9 9 ! f9al residue4 ,we h n[ fractionat$ ! tissue into f\r portions3 ! acid-soluble fraction 7conta9+ small molecules71 ,,rna1 ,,dna1 & prote9s4 7,! cell's lipids & sug>s come out dur+ alcohol r9ses betwe5 ! weak acid & ! alkali /eps47 ,*emical analysis all[s u to measure precisely ! am\nt ( ,,rna or ,,dna 9 its respective fraction & !re=e 9 ! tissue or organ4 ,! am\nt ( radioactivity 9 ! ,,rna fraction c !n be det]m9$ by a te*nique kn[n z liquid sc9tillation c\nt+4 ,liquid ,sc9tillation ,c\nt+ ,liquid sc9tillation c\nt+ is ! pref]r$ me?od = ! measurem5t ( l[-en]gy beta-emitt+ radioisotopes commonly us$ 9 cell-fractionation /udies 7see ,figure #ah74 ,x is conv5i5t1 s5sitive1 & rapid = r\t9e measurem5t ( radiation 9 hydroc>bons1 o!r organic comp\nds1 & aque\s solutions conta9+ su* isotopes z ,h1 ,c1 & ,p4 ,liquid sc9tillation solutions %>e ) o!r sc9tillat+ mat]ials ! prop]ty ( conv]t+ into visible light ! en]gy deposit$ 9 !m by ioniz+ radiation4 ,9 !ory1 if a sample ( a beta emitt] is dissolv$ 9 a liquid sc9tillator solution1 e beta p>ticle emitt$ w be absorb$ completely because ! range ( p5etration ( beta p>ticles 9 liquids is q %ort 7rang+ f #j4jjh millimicron = ,h to #g4i millimicrons = ,p 9 a m$ium ( unit d5sity74 ,! k9etic en]gy ( ! beta p>ticles is l>gely us$ up 9 ! ionization & excitation ( ! mo/ abundant molecul> species pres5t1 ! solv5t 9 :i* ! sc9tillat+ mat]ial 0 dissolv$4 ,a fraction ( ! en]gy ?us exp5d$ by ea* beta p>ticle is transf]r$ f excit$ solv5t molecules to sc9tillator molecules2 ?us ! electrons 9 ! atoms ( ! sc9tillator molecules are rais$ to an excit$ 7high] en]gy7 /ate4 ,:5 ^! electrons return to ! gr\nd1 or unexcit$1 /ate1 a fraction ( !m emit a photon ( light4 ,?us ea* beta p>ticle produces a bur/ ( photons4 ,illu/ration3 ,figure #ah ,te*nician plac+ a tray ( samples 9 a liquid sc9tillation c\nt]4 ,! radioactivity ( ea* sample is record$ z ! trays revolve4 ,if a vessel conta9+ ! liquid sc9tillator & ! radioactive sample is plac$ ne> a suitably s5sitive in/rum5t kn[n z a photomultipli] tube1 ea* bur/ ( sc9tillator photons activates ?is device & causes x to release a bur/ ( photoelectrons4 ,ea* bur/ ( photoelectrons is multipli$ successively 9 a s]ies ( electronic /eps2 z a result1 !re is a suitably l>ge electrical-output pulse to be record$4 ,"o ( ! pr9cipal advantages ( ! liquid sc9tillation me?od is ! ease ( sample prep>ation4 ,we ne$ only transf] a kn[n volume ( a liquid sample or weigh a giv5 mass ( a solid sample into a sample bottle1 add a kn[n am\nt ( ! liquid sc9tillator solution1 & /ir until !re is a homog5e\s solution4 ,samples ?us prep>$ are plac$ 9 a refrig]at$ c\nt+ app>atus4 ,aft] a %ort wait+ p]iod to all[ "t = ! samples to cool & = a natural1 %ort-liv$ phosphoresc5ce 7due to exposure to room light7 to subside1 ! samples are ready to be measur$4 ,illu/ration3 ,figure #ai ,plac+ radioactive samples 9 a refrig]at$ unit = liquid sc9tillation c\nt+4 ,"o disadvantage ( liquid sc9tillation c\nt+ is t diff]5t comp\nds %[ diff]5t degrees ( qu5*+ 7loss ( emitt$ photons71 & ! effect mu/ be *eck$ = ea* class ( comp\nds 9 ea* conc5tration range4 ,?is *eck+ is usually done ) an int]nal /&>d te*nique1 ! sample be+ c\nt$ be=e & aft] a /&>d1 or kn[n1 emitt] is add$4 ,ano!r difficulty is t ! be/ sc9tillat+ solv5ts are n ! be/ *emical solv5ts = mo/ biological mat]ials4 ,! solubility problem is also aggravat$ by ! l[ temp]atures at :i* liquid sc9tillation c\nt]s are usually op]at$ = m effective in/rum5t p]=mance4 ,) ! me?od we h describ$1 we c obta9 a fairly accurate idea ( ! rate ( ,,rna syn!sis 9 a giv5 tissue4 ,!re are o!r ?+s we w\ld l to "k ab\t ,,rna4 ,! fir/ ( ^! is ! k9d ( ,,rna be+ syn!siz$4 ,dur+ alkal9e dige/ion all k9ds ( ,,rna are brok5 d[n into _! compon5t nucleotides2 we mu/ !re=e use o!r me?ods if we wi% to "k ! k9d ( ,,rna 9 :i* ! radioactivity ( ! precursor has be5 incorporat$4 ,isolation ( ,,rna ,native ,,rna1 t is1 ,,rna n brok5 d[n into its small] con/itu5ts1 c be obta9$ 9 a v>iety ( ways1 b ! mo/ popul> "o makes use ( ph5ol extraction1 :i* removes ,,dna & prote9s & leaves ,,rna 9 solution4 ,if ?is ph5ol-purifi$ ,,rna is dissolv$ 9 a conc5trat$ sug> solution & spun 9 a c5trifuge at a v high velocity1 x w sep>ate into ?ree major compon5ts4 ,^! compon5ts sep>ate because !y h diff]5t molecul> weights1 & ! l>g] ! molecule1 ! fa/] x =ms a s$im5t 9 ! c5trifugal field4 ,two ( ^! compon5ts are s-,,rna1 ! lighte/ ( all1 & r-,,rna1 :i* is divid$ into two subfractions4 ,we c also id5tify a ?ird compon5t1 m-,,rna1 ) ! c5trifuge sy/em b only ) "s difficulty & only aft] label+ x ) a radioactive precursor1 because ! am\nt ( m-,,rna 9 a cell is v small4 ,illu/ration3 ,figure #bj ,diagram ( asc5d+ pap] *romatography4 ,quantitative ,analysis ,ano!r important feature ( ,,rna 7or ,,dna1 = t matt]7 is its base composition1 t is1 ! p]c5tage ( ea* ( ! nucleotides t make x up4 ,! f\r bases t1 ) ribose & phosphoric acid1 comprise ! ,,rna molecule are guan9e1 ad59e1 cytos9e1 & uracil4 ,x w be not$ t ?ree ( ! f\r--guan9e1 ad59e1 & cytos9e--are ! same z ^? 9 ,,dna1 b ?ymid9e 9 ,,dna has be5 replac$ by ano!r base1 uracil4 ,to det]m9e ! p]c5tage ( ea* base 9 a giv5 ,,rna molecule1 we mu/ dige/ ,,rna ) alkali to produce mononucleotides1 :i* are small] molecules1 ea* consi/+ ( a base1 ribose1 & phosphoric acid4 ,we c n[ sep>ate ! f\r nucleotides by us+ pap] *romatography 7see ,figure #bj74 ,illu/ration3 ,figure #ba ,a pap] *romatography %[+ sep>ation ( am9o acids 9 two directions4 ,radioactivity 9 samples !n produc$ ?is record by radioautography4 ,9 ?is te*nique a mixture ( comp\nds is deposit$ on ! edge ( a special type ( pap]4 ,?is edge is !n imm]s$ 9 a solv5t t sl[ly p]meates ! pap] 7at a con/ant spe$7 by capill>y action4 ,z ! solv5t moves f ! imm]s$ edge t[>d ! o!r edge1 :i* is hang+ freely1 x c>ries ! mixture ( nucleotides ) x4 ,ea* ( ! comp\nds 9 ! mixture travels at a diff]5t spe$1 h[ev]2 ?us1 z ! solv5t front moves along ! pap]1 ! dissolv$ comp\nds are sep>at$ f ea* o!r & appe> z di/9ct spots on ! pap]4 ,to locate ! nucleotides on ! pap] & to det]m9e ! p]c5tage composition1 we c use a *romatogram scann]1 a device t scans ! pap] *romatograms1 measures ! radiation f !m1 & ?us locates ! label$ sub/ances 7see ,figure #bb74 ,illu/ration3 ,figure #bb ,record+ ( radioactivity 9 a sample by radioautography & pap] *romatography4 ,! peaks ( ! trace prep>$ by a *romatogram scann] co9cide ) ! areas ( sep>at$ compon5ts on ! same *romatogram1 z reveal$ by radioautography4 ,! radioautograph is sup]impos$ on ! *romatogram record+4 ,ano!r te*nique us$ to sep>ate ! nucleotides ( ,,rna is column *romatography4 ,9 ?is me?od mixtures ( nucleotides are sep>at$ z !y pass d[n a column ( *emicals 7see ,figure #bc74 ,illu/ration3 ,figure #bc ,/ud5ts visit+ ,argonne ,national ,laboratory li/5 to a sci5ti/ expla9 ! column *romatography process1 9 :i* mixtures ( nucleotides are sep>at$ z !y pass d[n a column ( *emicals4 ,we h n[ le>n$ h[ to use radioisotopes to inve/igate ! syn!sis ( ,,rna1 ! molecule t translates ! ,,dna message into ! language ( prote9s4 ,let u n[ see :at we c le>n ab\t ! syn!sis & function ( prote9s4 ,,prote9 ,,syn!sis3 ,,! ,,molecules ,,t ,,make ,,! ,,diff]5ce ,if a man w beg9 ) c]ta9ties he %all end 9 d\bts2 b if he w be cont5t to beg9 ) d\bts he %all end 9 c]ta9ties4 ,francis ,bacon ,prote9s occupy a c5tral position 9 ! /ructure & function+ ( liv+ matt] & are intimately connect$ ) all ! metabolic reactions t ma9ta9 life4 ,"s prote9s s]ve z /ructural elem5ts ( ! body1 = in/ance1 hair1 wool1 & ! scl]oprote9s ( bone & collag51 ! latt] an important con/itu5t ( connective tissue4 ,o!r prote9s are enzymes1 :i* are extremely important s9ce !y regulate all metabolic reactions4 ,mo/ ( ! prote9s 9 ! tissues ( actively function+ organs1 su* z ! liv] & ! kidney1 are enzymes4 ,o!r prote9s p>ticipate 9 muscul> contraction1 & /ill o!rs are hormones or oxyg5 c>ri]s4 ,special prote9s call$ hi/ones are associat$ ) g5e function1 & ! antibodies t an organism produces to def5d itself f bact]ia are also prote9s4 ,! diff]5ces 9 prote9s1 especially 9 enzymes1 acc\nt = diff]5ces among cells4 ,x is n[ appropriate to ask :at makes "o prote9 diff]5t f ano!r4 ,we "k t ! /ructure ( a prote9 dep5ds ^u sev]al factors1 su* z ! molecul> weight4 ,b ! ma9 diff]5ces among prote9s dep5d ^u ! sequ5ce1 or ord]1 ( ! am9o acids t are l9k$ toge!r 9 ! prote9 molecules4 ,am9o ,acids & ,prote9 ,/ructure ,am9o acids are ! fundam5tal /ructural units ( prote9s4 ,!re are #bj am9o acids f\nd frequ5tly 9 mammalian prote9s1 & ^! molecules may be l9k$ to "o ano!r to =m a *a9 call$ a polypeptide *a94 ,! /ructure ( a prote9 !n dep5ds on3 7#a7 ! quantity ( ea* am9o acid pres5t2 7#b7 ! sequ5ce ( am9o acids 9 ! polypeptide *a92 7#c7 ! l5g? ( ! polypeptide *a91 t is1 ! molecul> weight2 & 7#d7 ! fold+ & ! side 7nonl9e>7 arrangem5t ( ! polypeptide *a9 molecules1 t is1 ! second>y & t]ti>y /ructures4 ,h[ c we inve/igate prote9 syn!sis by us+ radioactive isotopes8 ,s9ce prote9s are made up ( am9o acids1 ! logical conclusion1 aft] :at we h le>n$ ab\t ,,dna syn!sis & ,,rna syn!sis1 is t ! be/ way w\ld be to m>k an am9o acid & foll[ its incorporation into a molecule ( prote94 ,we c\ld label a mixture ( sev]al am9o acids1 b1 = ! sake ( cl>ity1 we w describe ! incorporation ( a s+le label$ am9o acid4 ,label+ an ,am9o ,acid ) a ,radioactive ,isotope ,suppose we h ! am9o acid leuc9e label$ ) ,c & we inject a solution conta9+ x into an exp]im5tal animal4 ,s9ce leuc9e is incorporat$ into prote9s1 if we isolate ! prote9s & det]m9e bo? ! am\nt ( prote9s & ! am\nt ( radioactivity1 we c measure fairly accurately ! rate ( prote9 syn!sis4 ,autoradiography1 by ! way1 is ( little help 9 /udy+ mo/ prote9 syn!sis because all cells are always syn!siz+ prote9s & s are all label$ aft] a s+le exposure to a radioactive am9o acid4 ,) ,,rna precursors autoradiography at lea/ told u :]e ,,rna 0 be+ made1 b ) am9o acids we d n ev5 get ?is in=mation because prote9s are syn!siz$ bo? 9 ! nucleus & 9 ! cytoplasm4 ,"u ^! circum/ances radio*emical me?ods are bett] = /udy+ prote9 syn!sis4 ,prote9s are isolat$ f ! residue left aft] a nucleic-acid extraction process simil> to t describ$ previ\sly1 & ! am\nt ( prote9 is det]m9$ by a simple colorimetric analysis bas$ on comp>ison ( ! color ( ! solution ) a /&>d color4 ,! am\nt ( radioactivity 7rememb] t we are n[ us+ a precursor label$ ) ,c7 c be det]m9$ ) a gas-fl[ c\nt]1 :i* is probably m widely us$ at pres5t ?an any o!r in/rum5t = c\nt+ beta emitt]s1 *iefly because ( its reliability & l[ co/4 ,illu/ration3 ,figure #bd ,a college *emi/ry major analyz+ a sample ( radioactive mat]ials ) an in/rum5t kn[n z a proportional beta c\nt]4 ,,cell ,,cycle ,,& ,,g5e ,,action3 ,,life ,,is ,,! ,,secret ,,( ,,dna ,"s circum/antial evid5ce is v /rong1 z :5 y f9d a tr\t 9 ! milk4 ,h5ry ,david ,?oreau ,= a biologi/ int]e/$ 9 ! me*anism ( cell prolif]ation1 ! mo/ important ev5t 9 ! life ( a cell 01 until v rec5tly1 cell division4 ,z we m5tion$1 :5 a cell divides into two daught] cells1 x und]goes a process call$ mitosis2 mitosis itself is subdivid$ into f\r /ages call$ prophase1 metaphase1 anaphase1 & telophase4 ,mitosis 9 mo/ cells takes less ?an "o h\r4 ,betwe5 "o mitosis & ! next1 !re c be an int]val1 f a few h\rs to sev]al days 9 l5g?1 dur+ :i* a cell is said to be 9 int]phase4 ,! entire p]iod betwe5 ! midpo9ts ( two successive mitoses is call$ ! cell cycle4 ,int]phase ,until a few ye>s ago1 we knew v little ab\t int]phase4 ,9 fact1 9 "o classic book on hi/ology1#h :ile a description ( mitosis requir$ almo/ #ab pages1 int]phase 0 dismiss$ 9 less ?an six l9es6 ,! reason = ?is lack ( int]e/ 01 ( c\rse1 ! fact t no adequate me?ods 7 available = /udy+ metabolic activities ( cells 9 int]phase4 ,! me?ods ( high-resolution autoradiography & radio*emical analysis ( syn*roniz$ cell populations h become available only 9 ! pa/ few ye>s4 ,we n[ "k t metabolic activities dur+ int]phase are ( prim>y importance 9 und]/&+ ! me*anism ( cell division4 ,x is1 9 fact1 ! ord]ly sequ5ce ( metabolic ev5ts occurr+ 9 int]phase t leads f "o mitosis to ! next4 ,! ,cell ,cycle ,figure #be is a diagram ( ! cell cycle4 ,try to imag9e ! cell cycle z a race track & individual cells z c>s t race ar\nd x4 ,y are sitt+ at ! f9i% wire1 :i* is mitosis 7we *ose mitosis because x is easy to recognize :5 ! cell is obs]v$ ) ! aid ( a microscope74 ,at a c]ta9 "t dur+ ! race1 all ! c>s 9 a portion ( ! track1 say a #bjj-y>d sector ( ! back/ret*1 are spray$ ) a blue dye z !y race by4 ,^! c>s are n[ m>k$1 j z cells syn!siz+ ,,dna are m>k$ if briefly expos$ to tritiat$ ?ymid9e1 ! common radioactive precursor ( ,,dna4 ,z soon z ^! c>s h be5 spray$1 y obs]ve all ! c>s z !y pass ! f9i% l9e 9 front ( y4 ,at fir/1 y w see c>s t 7 ne>e/ ! wire & 7 n spray$2 !n ! dye-m>k$ c>s w pass2 & f9ally m unm>k$ c>s1 ^? t _h pass$ ! f9i% l9e b _h n rea*$ ! spray area :5 ! m>k+ 0 done1 w come by4 ,if y replace ! words spray1 c>s1 & wire ) ! words radioactivity1 cells1 & mitosis1 y h describ$ ! cell cycle & ! fl[ ( cells 9 ! cycle4 ,n[1 if all c>s 7 go+ at ! same spe$1 y c\ld calculate ) great accuracy ! "t tak5 = any "o c> to g ar\nd ! track1 or f ! f9i% l9e to ! back/ret*1 or ?r\gh ! spray sector1 & s on4 ,h[ev]1 s9ce c>s move at diff]5t spe$s1 y c only obta9 an av]age "t = all spray$ c>s4 ,simil>ly1 s9ce individual cells behave diff]5tly1 y c only obta9 av]ages ( ! times ^! cells sp5d 9 ! v>i\s portions ( ! cell cycle4 ,illu/ration3 ,figure #be ,,! ,,cell ,,cycle ,^! cell-cycle portions are f\r 9 numb]1 accord+ to nom5clature orig9at$ by ,a4 ,h[>d & ,s4 ,r4 ,pelc1 two ,engli% inve/igators :o fir/ describ$ ! cycle3 7#a7 mitosis2 7#b7 ,g1 :i* is ! p]iod betwe5 mitosis & ,,dna syn!sis2 7#c7 ,s phase1 :i* is ! p]iod dur+ :i* ,,dna is replicat$2 & 7#d7 ,g1 :i* is ! p]iod betwe5 ,,dna syn!sis & ! next mitosis4 ,only cells 9 ! ,s phase 7,,dna syn!sis7 are m>k$ :5 expos$ to a radioactive precursor ( ,,dna4 ,,dna ,syn!sis & ! ,cell ,cycle ,because x has sev]al important implications 9 biology & m$ic9e1 x is important to rememb] t ,,dna syn!sis occurs only dur+ ! %ort1 well-def9$ ,s p]iod ( ! cell cycle4 ,o!r syn!tic processes g on ?r\gh\t ! cycle4 ,we m5tion$1 = in/ance1 t all cells c be label$ by a brief exposure to a radioactive am9o acid1 a precursor ( prote9s2 ?is means t prote9 syn!sis occurs ?r\gh\t ! entire cell cycle1 includ+ mitosis4 ,:5 we use a radioactive ,,rna precursor1 all cells except ^? 9 anaphase & metaphase are label$2 ?is means t ,,rna syn!sis occurs ?r\gh\t ! entire cycle except dur+ anaphase & metaphase4 ,b a radioactive tag on a ,,dna precursor reveals t only dur+ ! ,s phase is !re ,,dna syn!sis4#i ,x is also important to rememb] t a cell t has syn!siz$ ,,dna is a cell t1 ) a few exceptions1 w divide 9 ! v ne> future4 ,?us1 = an und]/&+ ( ! me*anisms t control cellul> prolif]ation1 x is important to inve/igate ! factors t control ,,dna syn!sis4 ,our rec5t k ( ! cell cycle has !re=e l$ to a %ift 9 ! focus ( inve/igation f mitosis to ,,dna syn!sis4 ,ano!r po9t to rememb] is t n all cells keep go+ ?r\gh ! cell cycle indef9itely4 ,z %[n 9 ,figure #be1 :5 a cell divides1 ! daught] cells h two alt]natives1 ei!r to g ?r\gh ano!r cycle or to leave x altoge!r4 ,cells t leave ! cycle are call$ diff]5tiat$ cells & w ev5tually die )\t any fur!r division4 ,_m cells 9 an adult organism also h lo/ ! capacity to make ,,dna & !re=e ! capacity to divide4 ,^! cells (t5 h o!r specializ$ functions 9 ! body2 examples are n]ve cells & muscle cells4 ,! syn!sis ( o!r macromolecules 7giant molecules1 l ,,dna7 connect$ ) ! g5e-action sy/em is ano!r field ( active inve/igation4 ,we h describ$ h[ we c inve/igate ! syn!sis ( prote9s & ,,rna ) radioactive isotopes1 & we h giv5 "s in=mation on ! g5e-action sy/em1 :i* is also %[n 9 ,figure #bf4 ,! g5etic mat]ial ( a cell is ,,dna4 ,! ,,dna molecule is 9 ! =m ( a d\ble-/r&$ helix t is support$ by a prote9 backbone4 ,g5es are (t5 describ$ z simply segm5ts ( ,,dna4 ,!y diff] f ea* o!r only 9 ! ord] 9 :i* ! f\r nucleotide bases t make up ,,dna are arrang$4 7,look at ,figure #ac aga947 ,s9ce a s+le g5e is usually made up ( sev]al hundr$ bases1 x is easy to imag9e ! inf9ite v>iety ( g5es t c\ld exi/ by simply *ang+ ! ord] ( ! f\r bases sev]al hundr$ times4 ,illu/ration3 ,figure #bf ,,! ,,g5e-,,action ,,sy/em ,n all g5es 9 ! cells ( a liv+ organism are active4 ,9 fact1 mo/ ( !m are inactive1 or1 z g5etici/s say1 repress$4 ,:at represses g5es to make !m inactive is n kn[n1 b _m inve/igators believe ! activity1 or lack ( x1 is regulat$ by prote9s call$ hi/ones4 ,if a g5e is repress$1 no?+ happ5s2 x rema9s inactive1 presumably until some?+ removes ! repress+ factor4 ,b an active g5e sets 9 motion a tra9 ( ev5ts t results 9 activation ( "o ( ! processes ( life3 ,! g5e's ,,dna directs ! manufacture ( ,,rna1 :i* 9 turn br+s ab\t ! syn!sis ( a specific prote9 to c>ry out a specific metabolic process4 ,9 o!r words1 all ! activities ( ! cell are dictat$ by active g5es 7! ,,dna molecules7 ?r\gh ! m$iation ( ,,rna & are execut$ by prote9s4 ,"h is :at happ5s z ne>ly z sci5ti/s c recon/ruct x3 ,translation ( ! ,g5etic ,message ,! ,,dna ( a p>ticul> active g5e manufactures a molecule ( m-,,rna by ! same k9d ( replication t x uses = mak+ m ,,dna4 ,9 m-,,rna ! sequ5ce ( bases is ! same z 9 ! p>5t ,,dna segm5t2 = ?is reason1 m-,,rna is also call$ ,,dna-l ,,rna4 ,z %[n 9 ,figure #ab1 a cytos9e molecule 9 m-,,rna corresponds to a cytos9e molecule 9 ,,dna1 a guan9e to a guan9e1 & s on1 except t ! m-,,rna has uracil 9 all ! places :]e ?ym9e occurs 9 ,,dna4 ,! ord] ( ! nucleotides 9 ! m-,,rna is ! same z t 9 ! ,,dna1 s ! m-,,rna c>ries ! g5etic code ( ! g5e t made x4 ,?is process1 all ( :i* occurs 9 ! cell nucleus1 is "o ( copy+1 or transcription1 r ?an translation1 s9ce ! same 8codewords0 7! nucleic-acid bases7 are reproduc$4 ,! new m-,,rna molecule !n travels f ! nucleus to ! cytoplasm & atta*es itself to an unoccupi$ ribosome 7see ,figure #bg74 ,"h x fits to a molecule ( r-,,rna & bl5ds its %ape geometrically1 or spatially1 ) ! %ape ( ! r-,,rna 9 lock-&-key1 or jigsaw-puzzle1 fa%ion4 ,! comb9$ new ,,rna molecule is n[ capable ( manufactur+ a specific prote94 ,illu/ration3 ,figure #bg ,prote9 syn!sis 9 a ribosome 7microsome71 & its control by ,,dna 9 ! nucleus1 us+ ,,rna z an int]m$i>y4 ,adapt$ f ,pr9ciples ( ,biology1 ,neal ,d4 ,buffaloe1 ,pr5tice-,hall1 ,inc41 #aifb1 ) p]mission4 ,at ?is po9t an s-,,rna molecule arrives1 br++ ) x "o am9o-acid molecule1 :i* !n comb9es ) o!r am9o acids 9 ! specific ord] dictat$ by ! ,,rna to =m a specific prote94 ,aft] ! am9o acids h be5 =m$ into ! prote9 molecule1 !y deta* !mselves f ! s-,,rna molecule4 ,! s-,,rna molecule has two recognition sites by :i* x mat*es up to its neighbors3 ,"o recognizes1 or 8fits01 ! am9o acid1 & ! o!r recognizes a correspond+ triplet ( bases on m-,,rna4 ,!re is ?us a p>ticul> s-,,rna molecule = ea* am9o acid & a p>ticul> triplet ( bases on ! m-,,rna molecule = ea* triplet ( bases t is specific to ! s-,,rna molecule4 ,9 ?is process ! ma*9]y has translat$ ! nucleic-acid code into ! prote9 code2 t is1 x has translat$ a sequ5ce ( ! bases into a sequ5ce ( am9o acids4 ,?is process is !re=e call$ translation ( ! g5etic message4 ,once ! prote9 has be5 syn!siz$1 x w become active 9 p]=m+ "s ( ! cell's metabolic activities4 ,! g5e-action sy/em actually is some:at m elaborate ?an ?is4 ,!re are fe$back me*anisms1 g5es t control ! activity ( o!r g5es1 ei!r directly or ?r\gh ! production ( specific prote9s1 & s on4 ,h[ev]1 ! s*eme j outl9$ gives a fair1 if simplifi$1 idea ( h[ ! g5etic message is c>ri$ to ! entire cell & h[ x is translat$ into actual life processes4 ,,isotopes ,,9 ,,rese>*3 ,,prob+ ,,! ,,canc] ,,problem 444 a riddle wrapp$ 9 a my/]y inside an enigma4 ,w9/on ,*ur*ill ,! v>i\s proc$ures 9 :i* radioactive isotopes play a major role h be5 appli$ to _m /udies & inve/igations 9 ! fields ( biology & m$ic9e4 ,9 fact1 mo/ ( ! concepts ( mod]n biology t we h be5 discuss+ 9 ?is booklet owe _! discov]y to ! judici\s use ( radioisotopes4 ,to illu/rate h[ radioisotopes c be us$ to solve a practical problem1 we h *os5 a typical example1 ! inve/igation1 at a molecul> level1 ( ! effectiv5ess ( an anti-canc] drug4 ,sev]al drugs t ex]t a b5eficial effect1 at lea/ tempor>ily1 on ! c\rse ( c]ta9 canc]s h be5 us$ by doctors = sev]al ye>s4 ,mo/ ( !m 7 discov]$ empirically1 t is1 by accid5t1 dur+ r\t9e trials aga9/ canc]s4 ,doctors "k !y "w b d n always "k h[4 ,!y w\ld also l to "k ! me*anism ( ! drugs' action at ! molecul> level s t ! k might op5 ! way to ! discov]y ( o!r drugs m effective aga9/ canc] & less toxic aga9/ normal cells4 ,! foll[+ exp]im5t %[s h[ ! molecul> effect ( an anti-canc] drug is /udi$4 ,illu/ration3 ,figure #bh ,te*nician prep>+ tissues = comp>ative /udies4 ,cells gr[+ 9 tissue cultures are (t5 us$ to te/ anti-canc] drugs 7see ,figure #bh74 ,^! cells1 d]iv$ f human cell l9es1 are gr[n 9 glass or pla/ic bottles z a susp5sion 9 a nutri5t m$ium4 ,to beg91 a culture is divid$ into halves4 ,to "o half is add$ ! anti-canc] drug ,act9omyc9 ,d4 ,! o!r half w cont9ue to gr[ )\t addition ( o!r sub/ances & w s]ve z a control1 or comp>ison4 ,aft] a suitable "t has elaps$ = ! drug to act on ! cultur$ cells1 simil> portions ( ! drug-treat$ cells & ! control cells w be te/$ 9 sev]al ways4 ,"o portion ( ea* k9d ( cells is incubat$ ) ,h-?ymid9e to det]m9e ! effect ( ! drug on ,,dna syn!sis4 ,two o!r portions are incubat$ ) ,h-cytid9e to /udy ! effect on ,,rna syn!sis4 ,ano!r pair w be te/$ ) ,c-leuc9e to inve/igate prote9 syn!sis4 ,! effect ( ! drug1 ( c\rse1 is det]m9$ by comp>+ ! untreat$ control ) ! drug-treat$ culture4 ,! bio*emical1 autoradiographic1 & c\nt+ te*niques t we describ$ previ\sly are all us$ to det]m9e ! uptake ( ! radioisotopes into ! cell's compon5ts4 ,*romatography is us$ to asc]ta9 if ! drug has *ang$ ! conc5tration ( precursors 7?ymid9e1 cytid9e1 or leuc9e7 9 ! nutri5t m$ium1 s9ce a *ange 9 ^! c\ld produce mislead+ results4 ,f9ally1 if ! drug is f\nd to h an effect on ,,rna1 we c inve/igate ! type ( ,,rna t is affect$ by c5trifug+ ph5ol-purifi$ ,,rna4 ,! results w disclose ! prim>y site 7,,dna1 ,,rna1 or prote9s7 ( ! drug action on cell metabolism4 ,m elaborate exp]im5ts c p9po9t m intimately ! me*anism ( action4 ,by /udy+ ! life processes ( cells1 we c advance t[>d a common d5om9ator 9 anti-canc] drugs t w lead to an effective anti-canc] treatm5t4 ,,conclusions ,?us1 ! task is1 n s mu* to see :at no "o has se5 yet2 b to ?9k :at nobody has ?\ght yet1 ab\t :at ev]ybody sees4 ,ar?ur ,s*op5hau] ,! use ( radioactive isotopes 9 ! /udy ( life processes is ( importance 9 und]/&+ !m4 ,) ! use ( autoradiographic & radio*emical te*niques1 x is possible to obta9 valuable in=mation reg>d+ ! life ( cells & ! intimate me*anisms by :i* life processes det]m9e ! fate ( ! entire organism4 ,our k ( ! cell cycle & ( ! g5e-action sy/em has be5 useful 9 det]m9+ h[ organisms gr[ & h[ canc] cells behave4 ,x has be5 det]m9$ t c]ta9 normal adult cells divide m frequ5tly ?an "s canc] cells & t ! gr[? ( canc]s dep5ds n s mu* on ! spe$ ( cellul> prolif]ation z on ! numb] ( cells actually divid+4 ,illu/ration3 ,figure #bi ,radioautograph %[+ ,,dna syn!sis dur+ *romosome replication4 ,*romosomes f cells 9 ! root tip ( ! ,tradescantia plant 7 label$ ) ,h-?ymid9e4 ,9 ,a & ,b1 ! midportion ( ,,dna syn!sis1 ! radioisotope is di/ribut$ ?r\gh\t ! *romosome arms2 9 ,c1 ne> ! end ( ,,dna syn!sis1 x is conf9$ ma9ly to ! end ( ! arms4 ,k ( ! cell cycle has also br\ght new insight to ! control ( cell division1 z 9 /udies relat$ to ! !rapy ( canc]4 ,! mo/ important problem n[ is1 n ! control ( cell division1 b ! control ( ! syn!sis ( ,,dna4 ,our in=mation on ! g5e-action sy/em provides broad new opportunity = ! inve/igation ( _m life processes4 ,hormone action1 processes by :i* ! body develops immunity to disease1 & ev5 cell division itself are app>5tly regulat$ ?r\gh ! g5e-action sy/em4 ,?is1 9 turn1 (f]s possibilities = inve/igations meant to control ^! processes4 ,x is difficult to *>t ! future c\rse ( mod]n molecul> biology1 b x is n difficult to pr$ict t ! next few ye>s w br+ to biology ! same k9d ( sweep+ advances t revolutioniz$ physics a few decades ago4 ,! ,,dna molecule has be5 call$ ! atom ( life4 ,:5 we h h>ness$ x1 ! h>ness+ ( ! uranium atom w seem1 9 comp>ison1 a result ( sci5tific adolesc5ce4 ,:5 man has ma/]$ ! g5etic code1 he'll hold a va/ p[] 9 8 h&s--p[] ov] ! nature ( com+ g5]ations4 ,,sugge/$ ,,ref]5ces ,books ,! ,cell1 ,c>l ,p4 ,swanson1 ,pr5tice-,hall1 ,inc41 ,englewood ,cliffs1 ,new ,j]sey1 #aifd1 #aad pp41 #a4ge4 ,inside ! ,liv+ ,cell1 ,j4 ,a4 ,v4 ,butl]1 ,basic ,books1 ,inc41 ,new ,york1 #aiei1 #agd pp41 #c4ie4 ,life & ,en]gy1 ,isaac ,asimov1 ,d\bl$ay ,company1 ,inc41 ,g>d5 ,city1 ,new ,york1 #aifb1 #chj pp41 #d4ie4 ,appli$ ,nucle> ,physics1 ,erne/ ,c4 ,poll>d & ,william ,l4 ,davidson1 ,john ,wiley ,sons1 ,inc41 ,new ,york1 #aief1 #ceb pp41 #f4jj4 ,adv5tures 9 ,radioisotope ,rese>*1 ! collect$ works1 ) rec5t annotations1 ( ,george de ,hevesy1 ,p]gamon ,press1 ,inc41 ,new ,york1 #aifa1 #ajdg pp4 7#b volumes71 #cj4jj4 ,! ,bio*emi/ry ( ,nucleic ,acids1 ,j4 ,n4 ,davidson1 ,john ,wiley ,sons1 ,inc41 ,new ,york1 #d? edition1 #aifj1 #bhg pp41 #d4be4 ,! ,ma*9]y ( ! ,body1 ,a4 ,j4 ,c>lson & ,c4 ,johnson1 ,! ,univ]sity ( ,*icago ,press1 ,*icago1 ,ill9ois1 #aifa1 #geb pp41 #f4ej4 ,life3 ,an ,introduction to ,biology1 ,george ,g4 ,simpson & ,william ,s4 ,beck1 ,h>c\rt1 ,brace ,_w1 ,inc41 ,new ,york1 #bnd edition1 #aife1 #hfi pp41 #h4ie4 ,f ,cell to ,te/ ,tube1 ,rob]t ,w4 ,*amb]s & ,alma ,payne1 ,*>les ,scribn]'s ,sons1 ,new ,york1 #aifb1 #baf pp41 #a4de4 ,isotopic ,trac]s 9 ,biology1 ,m4 ,d4 ,kam51 ,academic ,press ,inc41 ,new ,york1 #crd edition1 #aieg1 #dgd pp41 #i4ej4 ,autoradiography 9 ,biology & ,m$ic9e1 ,g4 ,a4 ,boyd1 ,academic ,press ,inc41 ,new ,york1 #aiee1 #cii pp41 #aj4jj4 ,a ,trac] ,exp]im5t3 ,trac+ ,bio*emical ,reactions ) ,radioisotopes1 ,m>t9 ,d4 ,kam51 ,holt1 ,r9eh>t ,w9/on1 ,inc41 ,new ,york1 #aifd1 #abg pp41 #a4bh4 ,molecul> ,biology3 ,g5es & ! ,*emical ,control ( ,liv+ ,cells1 ,j4 ,m4 ,b>ry1 ,pr5tice-,hall1 ,inc41 ,englewood ,cliffs1 ,new ,j]sey1 #aifd1 #aci pp41 #c4ce4 ,elem5t>y ,biophysics3 ,select$ ,topics1 ,h]man ,t4 ,ep/e91 ,addison-,wesley ,publi%+ ,company1 ,inc41 ,read+1 ,massa*usetts1 #aifc1 #abb pp41 #b4ie 7h>dback71 #a4ge 7pap]back74 ,articles ,autobiographies ( ,cells1 ,r4 ,bas]ga & ,w4 ,kisieleski1 ,sci5tific ,am]ican1 #bji3 #ajc 7,augu/ #aifc74 ,electrons1 ,enzymes1 & ,en]gy1 ,mi*ael ,g4 ,del ,duca & ,john ,m4 ,fuscoe1 ,int]national ,sci5ce & ,te*nology1 #ci3 #ef 7,m>* #aife74 ,sci5tific ,am]ican1 #bje 7,septemb] #aifa74 ,?is is a special issue on ! liv+ cell4 ,! two articles cit$ bel[ are ( p>ticul> int]e/3 ,h[ ,cells ,divide1 ,daniel ,mazia1 #bje3 #aja4 ,! ,liv+ ,cell1 ,jean ,bra*et1 #bje3 #ej4 ,reports ,liquid ,sc9tillation ,c\nt+3 ,proce$+s ( a ,conf]5ce ,held at ,nor?we/]n ,univ]sity1 ,augu/ #bj-bb1 #aieg1 ,c4 ,g4 ,bell1 ,jr4 & ,f4 ,n4 ,hayes 7,eds471 ,p]gamon ,press1 ,inc41 ,new ,york1 #aieg1 #bib pp41 #aj4jj4 ,atomic ,en]gy ,rese>*3 ,life & ,physical ,sci5ces2 ,reactor ,developm5t2 & ,wa/e ,managem5t1 ,a ,special ,report ( ! ,u4 ,s4 ,atomic ,en]gy ,commission 7,decemb] #aifa71 ,sup]9t5d5t ( ,docum5ts1 ,u4 ,s4 ,gov]nm5t ,pr9t+ ,(fice1 ,wa%+ton1 ,d4 ,c4 #bjdjb1 #ccc pp41 #b4be4 ,booklets ,radioisotopes 9 ! ,s]vice ( ,man1 ,f]n& ,lot1 ,national ,ag5cy = ,int]national ,publications1 #cag ,ea/ #cd? ,/reet1 ,new ,york #ajjaf1 #aieh1 #hb pp41 #a4jj4 ,sci5ce & ,canc]1 ,m4 ,b4 ,%imk91 ,public ,heal? ,s]vice ,publication ,no4 #aafb1 ,sup]9t5d5t ( ,docum5ts1 ,u4 ,s4 ,gov]nm5t ,pr9t+ ,(fice1 ,wa%+ton1 ,d4 ,c4 #bjdjb1 #aifd1 #acg pp41 #j4fj4 ,motion ,pictures ,! ,cell3 ,/ructural ,unit ( ,life1 #aj m9utes1 s\nd1 color or black & :ite1 #aidi1 ,coronet ,films1 ,inc41 #fe ,e4 ,s\? ,wat] ,/reet1 ,*icago1 ,ill9ois #fjfja4 ,cont9uity ( ,life3 ,*>act]i/ics ( ,plants & ,animals1 #aa m9utes1 s\nd1 color or black & :ite1 #aied1 ,audio-,visual ,c5t]1 ,indiana ,univ]sity1 ,bloom+ton1 ,indiana #dgdje4 ,,dna3 ,molecule ( ,h]$ity1 #af m9utes1 s\nd1 color 7,no4 #ahbe71 black & :ite 7,no4 #ahbf74 #aifj1 ,encyclopa$ia ,britannica ,films1 ,inc41 ,wilmette1 ,ill9ois #fjjia4 ,! ,sci5ce ( ,g5etics1 ,,aibs ,second>y ,s*ool ,film ,s]ies1 ,no4 #acbhj1 #be m9utes1 s\nd1 color1 #aifb1 ,mc,graw-,hill ,book ,company1 ,inc41 #ccj ,we/ #dbnd ,/reet1 ,new ,york #ajjcf4 ,available = loan )\t *>ge f ! ,,aec ,headqu>t]s ,film ,libr>y1 ,division ( ,public ,in=mation1 ,u4 ,s4 ,atomic ,en]gy ,commission1 ,wa%+ton1 ,d4 ,c4 #bjede1 & o!r ,,aec film libr>ies3 ,trac+ ,liv+ ,cells1 ,*all5ge ,film ,no4 #aa1 #bi m9utes1 s\nd1 black & :ite1 #aifb4 ,produc$ by ,ross-,mc,elroy ,productions = ! ,national ,educational ,television & ,radio ,c5t] "u a grant f ,argonne ,national ,laboratory4 ,?is nonte*nical film demon/rates "s ( ! uses ( radioisotopes 9 ! /udy ( cell division & 9 m$ical !rapy4 ,! ,et]nal ,cycle1 #ab m9utes1 s\nd1 black & :ite1 #aied4 ,produc$ by ! ,h&el ,film ,corporation4 ,?is nonte*nical film illu/rates ! use ( radioisotope trac]s 9 biological rese>* & is suitable = int]m$iate- ?r\gh college-level audi5ces4 ,*romosome ,label+ by ,tritium1 #ae m9utes1 s\nd1 color1 #aieh4 ,produc$ by ! ,jam ,h&y ,organization = ! ,u4 ,s4 ,atomic ,en]gy ,commission4 ,?is te*nical film discusses ! advantages ( tritium ov] o!r radioisotopes z label+ mat]ial 9 autoradiography4 ,a is = ,atom1 #ae m9utes1 s\nd1 color1 #aiec4 ,produc$ by ! ,g5]al ,electric ,company4 ,?is nonte*nical film expla9s ! /ructure ( ! atom1 natural & artificially produc$ elem5ts1 /able & un/able atoms1 pr9ciples & applications ( nucle> reactors1 & ! b5efits ( atomic radiation to biology1 m$ic9e1 indu/ry1 & agriculture4 ,x is suitable = elem5t>y- ?r\gh high-s*ool audi5ces4 ,,footnotes #a;,an organism is a complete liv+ plant or animal4 #b,metabolism is ! sum ( ! life-su/a9+ activities 9 a liv+ organism1 includ+ nutrition1 production ( en]gy1 & syn!sis 7build+7 ( new liv+ mat]ial4 #c,morphologi/s are biologi/s specializ+ 9 ! /ructure ( organisms or 9 ! /udy ( :ole organisms4 ,bio*emi/s1 by contra/1 /udy *emical reactions ( biological mat]ials4 #d,?is is n to be confus$ ) a cell nucleus4 ,?is ^w 0 borr[$ f biology = atomic !ory1 h[ev]4 #e;,an exception is ! hydrog5 atom1 :i* has no neutron 9 its nucleus4 #f,mev is ! abbreviation = million electron volts4 #g;,a concept = :i* ,james ,d4 ,watson ( ! ,unit$ ,/ates & ,francis ,h4 ,c4 ,crick ( ,engl& %>$ a ,nobel ,prize 9 #aifb4 #h,! /udy ( tissues4 #i,!re are additional1 m subtle metabolic ev5ts t lead to ! syn!sis ( ,,dna1 b !y are n important 9 ?is discussion4 ,,photo ,,cr$its ,figure #a ,arm$ ,=ces ,in/itute ( ,pa?ology ,negative ,no4 #daef ,figure #c ,dr4 ,t4 ,tahmisian1 ,argonne ,national ,laboratory ,figure #d ,oak ,ridge ,national ,laboratory 7photo on "r7 ,figure #e ,osc> ,w4 ,ri*>ds1 ,am]ican ,optical ,company ,figure #g ,brookhav5 ,national ,laboratory ,figure #i ,battelle-,nor?we/ ,laboratory ,figure #aj ,oak ,ridge ,national ,laboratory ,figure #ai ,argonne ,national ,laboratory ,figure #bc ,argonne ,national ,laboratory ,figure #bd ,argonne ,national ,laboratory ,figure #bh ,argonne ,national ,laboratory ,figure #bi ,brookhav5 ,national ,laboratory ,?is booklet is "o ( ! 8,und]/&+ ! ,atom0 ,s]ies4 ,comm5ts are invit$ on ?is booklet & o!rs 9 ! s]ies2 please s5d !m to ! ,division ( ,te*nical ,in=mation1 ,u4 ,s4 ,atomic ,en]gy ,commission1 ,wa%+ton1 ,d4 ,c4 #bjede4 ,publi%$ z "p ( ! ,,aec's educational assi/ance program1 ! s]ies includes ^! titles3 ,accel]ators ,animals 9 ,atomic ,rese>* ,atomic ,fuel ,atomic ,p[] ,safety ,atoms at ! ,sci5ce ,fair ,atoms 9 ,agriculture ,atoms1 ,nature1 & ,man ,books on ,atomic ,en]gy = ,adults & ,*ildr5 ,c>e]s 9 ,atomic ,en]gy ,comput]s ,controll$ ,nucle> ,fusion ,cryog5ics1 ,! ,uncommon ,cold ,direct ,conv]sion ( ,en]gy ,fall\t ,f ,nucle> ,te/s ,food ,pres]vation by ,irradiation ,g5etic ,effects ( ,radiation ,index to ! ,,uas ,s]ies ,las]s ,micro/ructure ( ,matt] ,neutron ,activation ,analysis ,nonde/ructive ,te/+ ,nucle> ,clocks ,nucle> ,en]gy = ,desalt+ ,nucle> ,p[] & ,m]*ant ,%ipp+ ,nucle> ,p[] ,plants ,nucle> ,propulsion = ,space ,nucle> ,reactors ,nucle> ,t]ms1 ,a ,brief ,gloss>y ,our ,atomic ,_w ,pl[%>e ,plutonium ,p[] f ,radioisotopes ,p[] ,reactors 9 ,small ,packages ,radioactive ,wa/es ,radioisotopes & ,life ,processes ,radioisotopes 9 ,indu/ry ,radioisotopes 9 ,m$ic9e ,r>e ,e>?s ,rese>* ,reactors ,,snap1 ,nucle> ,space ,reactors ,s\rces ( ,nucle> ,fuel ,space ,radiation ,spectroscopy ,syn!tic ,transuranium ,elem5ts ,! ,atom & ! ,ocean ,! ,*emi/ry ( ! ,noble ,gases ,! ,elusive ,neutr9o ,! ,fir/ ,reactor ,! ,natural ,radiation ,environm5t ,:ole ,body ,c\nt]s ,y\r ,body & ,radiation ,a s+le copy ( any "o booklet1 or ( no m ?an ?ree diff]5t booklets1 may be obta9$ free by writ+ to3 ,,usaec1 ,p4 ,o4 ,,box #fb1 ,,oak ,,ridge1 ,,t5nessee #cghcj ,complete sets ( ! s]ies are available to s*ool & public libr>ians1 & to tea*]s :o c make !m available = ref]5ce or = use by gr\ps4 ,reque/s %\ld be made on s*ool or libr>y lett]heads & indicate ! propos$ use4 ,/ud5ts & tea*]s :o ne$ o!r mat]ial on specific aspects ( nucle> sci5ce1 or ref]5ces to o!r read+ mat]ial1 may also write to ! ,oak ,ridge address4 ,reque/s %\ld /ate ! topic ( int]e/ exactly1 & ! use int5d$4 ,9 all reque/s1 include 8,zip ,code0 9 return address4 ,pr9t$ 9 ! ,unit$ ,slates ( ,am]ica ,,usaec ,division ( ,te*nical ,in=mation ,ext5sion1 ,oak ,ridge1 ,t5nessee ,transcrib]'s ,notes --,reta9$ publication in=mation f ! pr9t$ edition3 ?is e,book is public-doma9 9 ! c\ntry ( publication4 --,:]e possible1 ,,utf sup]script & subscript numb]s are us$2 "s e-read] fonts may n support ^! *>act]s4 --,9 ! text v]sion only1 und]l9$ or italiciz$ text is delimit$ by und]scores4 --,9 ! text v]sion only1 sup]script text is prec$$ by c>et & delimit$ by brackets4 --,9 ! text v]sion only1 subscript$ text is prec$$ by und]score & delimit$ by brackets4