EXPERIMENT # 2
ThePl a nta ndAni ma lCe l l PLANTCELL I .
L
ANSWERTO QUESTI ONS
Cuc ur bi t ama maxi maDuch. A.Mat ur eTr i c home meCel l s( —s quas h)
1 .U .Und e rt h eL PO,h o wma n yc e l l sd oy o us e ei ne a c ht r i c h o me ? I twa so bs e r ve dt ha tt hes a mp mpl eus e dc o nt a i ne dt hr e e( 3 )c e l l s . 2.Whe r ei st h enuc l e usi nt he s ec e l l s ? Thenuc l e ia r el oc a t e di ns i det hec e l lme mb mbr a ne ,s u r r o unde db yt hec l e a r s pa c e sk no wn wn a st he v a c uo l e .S pe c i fic a l l y ,t he l a r g eg l o bul a r da r k c o l o r e d por t i on. 3 .W .Wh e r ei st h ec y t o p l a s m? Mos toft hec yt opl a s m’ m’ spa r ti sc o nc e nt r a t e da boutt hes i de soft hec e l l . Ho we we v e r ,por t i onsofi tc r e a t e sas pi nde( ort hr e a dl i ke )obj e c t sc oi ne da st he c y t opl a s mi mi cs t r a ndwhi c hhol dst henuc l e usi npl a c e . 4.St ud yPl a t eI V—Th ePl a ntCe l l si ns q u as hh a i r .La b e la l lp a r t ss e e n.I nd i c a t ei t sc o r r e c t ma g ni fic a t i o n. B.Mat A l i um c e paL. ur eOni onCel l( l )
1.Ca ny o udi s t i ngui s ht h ep r o t o pl a s tc l e a r l y? Ye s ,pr ot opl a s tc a nbedi s t i ngui s he dc l e ar l y . 2.Ar ep l a s t i d sp r e s e nti nt h ec e l l ? Ye s ,pl as t i dsa r epr e s e nti nt hec el l . 3 .A .Ar et h e yc o l o r e d ? No, t he ya ppe a rt obec o l or l e s s . 4 .C . Ca ny o ud i s c e r nt h ec y t o p l a s mi cs t r a nd s ? Ye s , t hec y t opl a s mi mi cs t r a ndsc a nbedi s c e r ne d. 5 .H .Ho wma n ynu c l e o l id oy o uo b s e r v e ? The r ea r et hr e e( 3 )nuc l e ol iobs e r v e d. Ho we we v e r ,t hea c t ua li ma geunde rt he s p e c i fie dma gni fic a t i onwa sf a i l e dt oa c c ompl i s h .
6 .Wh a to c c up yt h es p a c e si nb e t we e nt h ec y t o p l a s mi cs t r a nd s ? I npl a nt s ,t he ya r ege ne r a l l yt e r me dpl a s mo de s ma t aa nda r epo r t i o ns o ft hec y t opl a s mt ha tc o nne c tt woa dj a c e n tc e l l st hr oughpor e si nt hec e l l wa l l s .
H i l l ave r t i c e l l at a( C.Mat ur eGr eenLeafCel l sofEl odea : ( ydr Roxb)Hoyl e)
e se a c hc e l lh a vei t so wnwa l l ? 1.Do
Conc l us i ons 1 .DoaDoa d j a c e ntc e l l ss h a r eac o mmo nwa l l ?
Ye s .I nc o mpa c tt i s s ue st hea dj a c e ntc e l l ss ha r ec o mmo nc e l lwa l l .The c y t o pl a s mo ft he s ec e l l sa l s or e ma i nsc o nne c t e dt hr o ug hpl a s mo de s ma t a .
2 .Ofwh a tma t e r i a li st h ec e l lc o mp o s e d ? Thepl a ntc e l lwa l ls u r r o undst hec e l lme mbr a ne .I ti sma deupofmul t i pl e l aye r s ofce l l ul ose whi c h ar e ar r anged i nt o pr i mar y and s ec ondar y wal l s . Cel l ul os ei st hemos tc ommonor gani cc ompound onEar t h.About33 % ofal l pl a ntma t t e ri sc e l l ul os e-t hec e l l ul os ec o nt e ntofc o t t oni s9 0 %a ndwoodi s5 0 % c el l ul os e . Ce l l ul os ei sapol yme r madeofr epeat i ngg l u c o s e mo l e c u l e sa t t a c he de nd t oe nd( Thusc e l l ul os ei sa ne x ampl eofapol ys a c c ha r i de . ) .A c e l l ul os emol e c ul e ma ybef r om s e v e r a lhundr e dt oo ve r1 0 , 0 0 0gl uc o s euni t sl ong.Ce l l ul o s ef r o m wood pul p hast ypi c alc hai nl engt hsbet wee n 300and 1700uni t s ;cot t on and t o t he rpl a ntfib r e sha v ec h a i nl e ng t hsr a ng i ngf r o m8 0 0t o1 0 , 0 0 0uni t s( Kl e mm e a l .2 0 05 ) .Ce l l ul os ei ss i mi l a ri nf or mt oc o mpl e xc a r bohydr a t e sl i kes t a r c ha nd gl yc ogen.Thes e pol ysa c c har i desar e al s o made f r om mul t i pl es ubuni t s of gl uc ose .The di ffer ence bet wee n ce l l ul ose and ot hercompl ex c ar bohydr at e mol e c ul e si sho wt hegl uc o s emol e c ul e sa r el i nke dt oge t he r .I na ddi t i on,c e l l ul os e i sas t r a i ghtc ha i npol yme r ,a nde a c hc e l l ul os emol e c ul ei sl onga ndr odl i ke .Thi s di ffe r sf r om s t a r c h,whi c hi sac o i l e dmol e c ul e .A r e s ul toft he s edi ffe r e nc e si n
s t r uc t ur ei st ha t ,c ompa r e dt os t a r c ha ndot he rc a r b ohydr a t e s , c e l l ul os ec a nnotbe br oke ndowni nt oi t sgl uc os es ubuni t sbyanye nzyme spr oduc e dbyani mal s . Li gni npr o vi de st heme c h a ni c a ls u ppor tf ors t e msa ndl e a v e sa nds uppl i e s t hes t r e ngt ha ndr i gi di t yofpl a ntwa l l s .Li gni npr ovi de st hes t r uc t ur a ls t r e ngt h ne e de db yl a r g et r e e st or e a c hhe i ght si ne x c e s so f1 0 0m.Wi t ho utl i gni nt he s e t r e e swo ul dc o l l a ps eo nt he ms e l v e s .Al s o ,l i g ni na l o ng wi t ho t he rc e l lwa l l c ons t i t ue nt spr ovi de sr e s i s t a nc et odi s e a s e s ,i ns e c t s , c ol dt e mpe r a t ur e s ,a ndot he r s t r e s s e s .Li gni n pl a y sac r uc i a lp ar ti nc o nduc t i ng wa t e ri n pl a nts t e ms .The s t r uc t ur eo fl i gni n ha sno tb e e n pr ope r l y de t e r mi ne da si tus u al l yf r a gme nt s upo ne x t r a c t i o na nd t he r ea ppe a r st ob e no c o ns i s t e n ts t r uc t ur et oi t .The pol ys a c c ha r i dec ompone nt sofpl a ntc e l lwa l l sa r ehi ghl yh ydr ophi l i ca ndt hus pe r me a b l et owa t e r ,whe r e a sl i g ni ni smo r eh ydr o pho bi c .Thec r o s s l i nki ngo f pol ys a c c ha r i de sbyl i gni ni san obs t a c l ef orwa t e ra bs o r p t i on t ot hec e l lwa l l . Thus , l i gni nma ke si tpos s i bl ef ort hepl a nt ’ sv as c ul a rt oc o nduc twa t e re ffic i e nt l y . Li gni ni spr e s e nti na l lva s c ul a rpl a nt s , butnoti nbr yophyt e s ,s uppor t i ngt hei de a t ha tt heor i gi na lf unc t i onofl i gni nwa sr e s t r i c t e dt owa t e rt r a ns por t . 3 .Ho wdoy o ua c c o untf o rt hea ppa r e ntpr e s e nc eo ft henuc l e uswi t hi nt hec e nt r a lv a c uo l eo f s o meEl o de ac e l l s ? Nuc l e uswi t hi nt hec e nt r a lv ac uol eofEl ode ac e l li svi s i bl et ha ni na ny o t he rpa r t sb ec a us et he r ear el e s snumbe ro fc hl or opl a s t st ha tc o ve r st henuc l e us . Ands o me t i me snuc l e usi sal i t t l ebi tt r a ns pa r e n tt ha ti tc a n' tbes e e nwhe nt he r e a r et ooma nyc h l or opl a s t s . 4.* I nwh a tDi r e c t i o ndo e st h es t r e a mi ngo fc y t o p l a s mi nEl o de ap r o c e e d ?
* I st hed i r e c t i o no fs t r e a mi ngt hes a mei na l lc e l l ss h owi ngi t ?
* Do e st hed i r e c t i o no fs t r e a mi ngc h a ng e ?
* I st hes p e e do fmo ve me ntt hes a mei na l lc e l l s ?
I np l antc el l s ,c hl or opl as t sma ybemo v edar ou ndwi t ht h es t r eam,p os s i bl yt oapo si t i onofop t i mum l i ght abs or p t i onf orp hot os y nt h es i s .Th er at eofmo t i oni su sual l yaff ec t edb yl i ghte xpos ur e,t emp er at ur e,and pHl ev el s .
5.Ch a r a c t e r i z ema t ur ep l a ntc e l l si nc o nt r a s tt oy o ungo ne s . Yo ungpl a ntc e l l sof t e nc o nt a i nma n ys ma l lv a c uo l e s ,b uta st hec e l l sma t ur e , t he s euni t et of or m al a r g ec e nt r a lva c uol e .
ANI MALCELL
L
1.Wha ta r et h es h a pe so ft h ec e l l s ? Ov al ,r ods h ape d,c i r c ul a ra nds o mea r ei r r e gul a r .
2.I sav ac uo l eo rac e l lwa l lvi s i b l e ? No, i twa snotvi s i bl e . 3 .Ho wwo ul dy o ud e s c r i b et h ef unc t i o no ft h enuc l e o l us ? The nuc l eus ofmany eukar yot i c ce l l sc ont ai ns a s t r uc t ur ec al l ed a nuc l e o l us .Thenuc l e o l ust a k e supa r o und2 5 %o ft hev ol umeo ft henuc l e us .Thi s s t r uc t ur ei sma deupofpr o t e i nsa ndr i bonuc l e i ca c i ds( RNA) .I t sma i nf unc t i oni s t or e wr i t er i b os o ma lRNA ( r RNA)a ndc o mb i nei twi t hpr o t e i ns .Thi sr e s ul t si n t hef or ma t i ono fi nc o mpl e t er i bos ome s .The r ei sa nuni nt e r r upt e dc h ai nbe t we e n t henuc l e o pl a s ma ndt hei nt e r i o rpa r t so ft henuc l e o l us ,whi c hoc c ur st hr ougha s y s t e m ofnuc l e ol a rpa s s a ge s .
Be c a us eofi t sc l os er e l a t i ons h i pt ot hec hr omos o ma lma t t e ro ft hec e l la nd i t si mpo r t a ntr ol ei npr o duc i ngr i b os o me s ,t henuc l e o l usi st houghtt obet he c a us eo fava r i e t yofdi ffe r e nthuma ndi s e a s e s .
4.I sa nys t r uc t ur ewi t hi nt heb a c t e r i a lc e l lvi s i b l e ?
5 .Wh a ts h a pe sa r ev i s i b l ei nt h es p e c i me n?
