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7/22/2019 Cng ngh nui cy m t bo thc vt

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Chng 2. NHNG KHI NIM C BN

2.1. Hc thuyt t bo

Nm 1662, Robert Hooke thit k knh hin vi n gin u tin v quan st

c cu trc ca ming bc bn bao gm nhiu ht nh, ng gi cc ht nh l t bo

(cells). Nm 1675, Anton Van Leeuwenhoek xc nhn c th ng vt cng bao gm cc

t bo. ng quan st di knh hin vi thy mu ng vt c cha cc hng cu v ng

gi l cc t bo mu. Nhng mi n nm 1838, Matthias Jacob Schleiden (nh thc

vt hc) v 1839, Theodor Schwann (nh ng vt hc) mi chnh thc xy dng hc

thuyt t bo. Schleiden v Schwann khng nh rng: Mi c th ng thc vt u bao

gm nhng th tn ti hon ton c l p, ring r v tch bit, chnh l t bo. C th

ni Schleiden v Schwann l hai ng t ca hc thuyt t bo. Tuy nhin, c hai ngkhng phi l cc tc gi u tin pht biu mt nguyn tc no , m ch l din t

nguyn tc y r rng v hin nhin ti mc n c ph bin rng ri v cui cng

c a s cc nh sinh hc thi y tha nhn.

2.1.1. Tnh ton th ca t bo (cell totipotency).

Haberlandt (1902) l ngi u tin xng ra phng php nui cy t bo

thc vt chng minh cho tnh ton th ca t bo. Theo ng mi mt t bo bt k ca

mt c th sinh vt a bo u c kh nng tim tng pht trin thnh mt c th hon

chnh.Nh vy mi t bo ring r ca mt c th a bo u cha y ton b lng

thng tin di truyn cn thit ca c sinh vt v nu g p iu kin thch hp th mi t

bo c th pht trin thnh mt c th sinh vt hon chnh. Hn 50 nm sau, cc nh

thc nghim v nui cy m v t bo thc vt mi t c thnh tu chng minh cho

kh nng tn ti v pht trin c l p ca t bo. Tnh ton th ca t bo thc vt

c tng bc chng minh. Ni bt l cc cng trnh: Miller v Skoog (1953) to c

r t mnh m ct t thn cy thuc l, Reinert v Steward (1958) to c phi v

cy c rt hon chnh t t bo n nui cy trong dung dch, Cocking (1960) tch c

t bo trn v Takebe (1971) ti sinh c cy hon chnh t nui cy t bo trn ca lcy thuc l. K thut to dng (cloning) cc t bo n c phn l p trong iu kin in

vitro chng minh mt thc t rng cc t bo soma, di cc iu kin thch hp, c

th phn ha pht trin thnh mt c th thc vt hon chnh. S pht trin ca mt c

th trng thnh t t bo n (hp t) l kt qu ca s hp nht s phn chia v phn

ha t bo. biu hin tnh ton th, cc t bo phn ha u tin tri qua giai on

Cng ngh nui cy m t bo thc vt ThS. Vu Ngc Dung


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phn phn ha (dedifferentiation) v sau l giai on ti phn ha (redifferentiation).

Hin tng t bo trng thnh tr li trng thi phn sinh v to ra m callus khng

phn ha (undifferentiation) c gi l phn phn ha, trong khi kh nng cc t bo

phn phn ha to thnh cy hon chnh (whole plant) hoc cc c quan thc vt c

gi l ti phn ha. ng vt, s phn ha l khng th o ngc tr li. Nh vy, sphn ha t bo l kt qu c bn ca s pht trin nhng c th bc cao, n thng

c gi l cytodifferentiation.

2.1.2. Th bi v gen

Gen quyt nh cc tnh trng thc vt. C tnh trng tng ng vi mt gen

nhng cng c nhiu tnh trng lin quan n nhiu gen, cc tnh trng gi l tnh

trng n gen v tnh trng a gen.

Hai gen nm trn mt v tr nht nh trn nhim sc th tng ng gi l allen.

Tuy cng tham gia quyt nh mt tnh trng nhng mi allen qui nh mt c im

ring. V d mu hoa, mt allen c th mang thng tin di truyn cho hoa mu , allen

kia cho hoa mu trng.Trng hp ny ta c c th d hp t v tnh trng mu hoa, nu

c 2 allen u mang thng tin di truyn cho mu th ta c c th ng hp t. i vi

c th d hp t, mt allen c th l allen tri, allen cn li l allen ln. Allen tri quyt

nh tnh trng. C trng hp tri hon ton v tri khng hon ton. Tri khng hon

ton khi t hp 2 allen s cho tnh trng trung gian.

Th bi l danh t ch s b nhim sc th c trong t bo, m, c th thc vt vi

qui nh chung l cc t bo sinh sn c 1 b nhim sc th c gi l th n bi.Hp t, sn phm dung hp ca 2 giao t n bi, c th l nh bi vi s nhim sc th

2n. Tt c cc t bo soma hnh thnh do s phn chia hp t u l nh bi. Trn thc t

c th tm thy cng lc nhiu mc bi th khc nhau cc m khc nhau ca c th

thc vt.(4n, 8n) l hin tng a bi ha do ni gim phn. Khong mt na thc vt

bt cao mc a bi th. S nhim sc th c bn ca loi l X ( l s n bi nh nht

trong dy a bi), cc c th c X nhim sc th c gi l th nht bi phn bit vi

th n bi.

V d : cy la m c 2n=42 . Trn thc t n l th lc bi 6X, trong s nhim

sc th c bn ca loi l X=7. Th n bi ca cy la c n=3X=21 nhim sc th.

2.1.3.Th bo t v th giao t

Th bo t gm c hp t v tt c cc t bo sn sinh t hp t k c ht phn

trong ti phn v non.



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Th giao t gm c ht phn ny mm v tt c cc t bo do n sn sinh ra, bao gm

cc giao t. Khi 2 giao t khc ging dung hp, th bo t 2n c ti lp. thc vt bc

cao, th giao t thng khng qu 3 t bo trong 2 t bo l cc giao t.

cc loi thc vt mc th bi dao ng theo chu trnh sau:

S 2.1. Chu trnh dao ng mc bi th

thc vt bc cao, th giao t ( trong cc trng hp c bit, c th pht trin

thnh bo t n bi) cha n nhim sc th. Th bo t n bi c th ra hoa nhng cc

bo t hnh thnh khng c sc sng. To th bo t n bi v nhng cy n bi kp l

mc ch ca nui cy ti phn v ht phn.

2.1.4. Sinh sn hu tnh v sinh sn v tnh

Sinh sn v tnh l hin tng 1 c th to ra cc c th mi t mt phn c quan

sinh dng ca mnh, khng h c s tham ca cc yu t quy nh gii tnh, c th con

sinh ra hon ton ging ht c th m. Sinh sn v tnh c rt nhiu hnh thc. sinh vt

n bo c phn i t bo. Mt s c th a bo bc thp th mt t bo sinh dng

phn chia to ra mt nhnh mi v sau tch ra khi c th chnh nh thy tc chng

hn, cng c th mt mu ca c th m t ra ri n mc ra mt c th khc kiu nh

to lam. Mt s khc th c hn mt loi t bo sinh sn ring nhng m vn hon ton

khng c tnh cht gii tnh g c m ch l t c th m to ra m thi. chnh l hin

tng sinh sn v tnh bng bo t. Bo t cc c th n bo c th l khi mi trngbt li th chng t rt nc ra khi t bo, tr thnh dng tim sinh i thi c sng

li. sinh vt a bo th ti ng cc t bo gi l bo t v tnh. n ma sinh sn

chng s pht tn cc t bo ra mi trng xung quanh. Khi gp iu kin thun li th

mi bo t to ra mt c th mi. thc vt th khc, n tn ti c hai kiu sinh sn v


Th bo t (2n)

Th tinh

Bo t (n)

giao t (n) Th giao t (n)

Gim phn

Th bo t n bi (n)


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tnh v hu tnh. Sinh sn v tnh y cng l t mt phn ca c th m tch ra v to

ra mt c th mi.

Sinh sn hu tnh phi c s tham gia ca cc yu t quy nh gii tnh, bao gm

c v ci. Cc yu t ny c th trn cng mt c th hay khc c th, bn cht ca

cc yu t l do cc nhim sc th gii tnh quy nh. Sinh sn hu tnh cng c nhiukiu. Kiu s khai nht l tip hp, l hin tng hai t bo c, ci trao i nhn cho

nhau. Sau l sinh sn hu tnh bng bo t nh ru, dng x,... Ln ti nhng lp

trn th l th tinh vi s tham gia ca cc giao t c v ci, mi loi giao t nm cc

t bo khc nhau.

2.2. T bo thc vt.

C th sng cu to t mt t bo n c hoc mt phc hp cc t bo. T bo rt

a dng, khc nhau v hnh thi, kch thc, cu trc v chc nng. T bo ng vt v tbo thc vt l nhng bin i ca cng mt kiu c s ca n v cu trc. Trn c s

hc thuyt t bo c hnh thnh do Mathias Schleiden v Theodor Schawn vo

na u th k XIX. Thut ng t bo ln u tin c Robert Hooke t ra vo nm

1665 da trn nhng quan st cc khoang nh c vch bao quanh ca nt bn v v sau

ng cn quan st thy trn m ca nhiu cy khc. Ni cht ca t bo v sau mi c

pht hin v c gi l cht nguyn sinh, cn thut ng th nguyn sinh l do

Hanstein xng nm 1880 ch cht nguyn sinh c trong 1 t bo n c. Nhn

c Robert Brown pht hin nm 1831.

Mi t bo l mt h thng m, t duy tr v t sn xut: t bo c th thu nhn

cht dinh dng, chuyn ha cc cht ny thnh nng lng, tin hnh cc chc nng

chuyn bit v sn sinh th h t bo mi nu cn thit. Mi t bo cha mt bn mt m

ring hng dn cc hot ng trn.

Mi t bo u c mt s kh nng sau:

- Sinh sn thng qua phn bo

- Trao i cht t bo bao gm thu nhn cc vt liu th, ch bin thnh cc thnh

phn cn thit cho t bo, sn xut cc phn t sinh nng lng v cc sn phm

ph. thc hin c cc chc nng ca mnh, t bo cn phi hp thu v sdng c ngun nng lng ha hc d tr trong cc phn t hu c. Nng

lng ny c gii phng trong cc con ng trao i cht

- Tng hp cc protein, y l nhng phn t m nhim nhng chc nng c

bn ca t bo, v d nh enzyme. Mt t bo ng vt thng thng cha

khong 10,000 loi protein khc nhau.

http://vi.wikipedia.org/wiki/Sinh_t%E1%BB%95ng_h%E1%BB%A3p_proteinhttp://vi.wikipedia.org/wiki/Proteinhttp://vi.wikipedia.org/w/index.php?title=Enzyme&action=edithttp://vi.wikipedia.org/wiki/%C4%90%E1%BB%99ng_v%E1%BA%ADthttp://vi.wikipedia.org/wiki/Proteinhttp://vi.wikipedia.org/w/index.php?title=Enzyme&action=edithttp://vi.wikipedia.org/wiki/%C4%90%E1%BB%99ng_v%E1%BA%ADthttp://vi.wikipedia.org/wiki/Sinh_t%E1%BB%95ng_h%E1%BB%A3p_protein


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- p ng vi cc kch thch, hoc thay i ca mi trng bn trong v bn

ngoi nh nhng thay i v nhit ,pH hoc ngun dinh dng.

- Di chuyn cc ti tit.

2.2.1. Cu trc ca t bo thc vtCc t bo thc vt cc c th khc nhau, hoc cc m, cc c quan khc nhau

ca cng mt c th s khng ging nhau v hnh dng, kch thc v cu trc nhng v

bn cht c bn cc t bo u c mt s c im chung.

T bo thc vt chia lm 2 phn chnh: Thnh t bo v phn nguyn sinh cht, y

l phn quyt nh nhng c tnh sng ch yu ca t bo thc vt.

Hnh 2.1. M hnh cu trc t bo thc vt in hnh

Mi t bo u c mng t bo, dng bao bc t bo, cch bit thnh phn ni

bo vi mi trng xung quanh, iu khin nghim ngt s vn chuyn vo v ra ca cccht, duy tr in th mng v nng cc cht bn trong v bn ngoi mng. Bn trong

mng l mt khi t bo cht c (dng vt cht chim ton b th tch t bo). Mi t

bo u c cc phn t DNA, vt liu di truyn quan trng v cc phn t RNA tham gia

trc tip qu trnh tng hp nn cc loi protein khc nhau, trong c cc enzyme. Bn

http://vi.wikipedia.org/wiki/M%C3%B4i_tr%C6%B0%E1%BB%9Dnghttp://vi.wikipedia.org/wiki/Nhi%E1%BB%87t_%C4%91%E1%BB%99http://vi.wikipedia.org/wiki/PHhttp://vi.wikipedia.org/w/index.php?title=Dinh_d%C6%B0%E1%BB%A1ng&action=edithttp://vi.wikipedia.org/w/index.php?title=V%E1%BA%ADn_%C4%91%E1%BB%99ng_(t%E1%BA%BF_b%C3%A0o)&action=edithttp://vi.wikipedia.org/wiki/T%C3%BAi_ti%E1%BA%BFthttp://vi.wikipedia.org/wiki/M%C3%A0ng_t%E1%BA%BF_b%C3%A0ohttp://vi.wikipedia.org/w/index.php?title=%C4%90i%E1%BB%87n_th%E1%BA%BF_m%C3%A0ng&action=edithttp://vi.wikipedia.org/wiki/V%E1%BA%ADt_li%E1%BB%87u_di_truy%E1%BB%81nhttp://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Proteinhttp://vi.wikipedia.org/w/index.php?title=Enzyme&action=edithttp://vi.wikipedia.org/w/index.php?title=Enzyme&action=edithttp://vi.wikipedia.org/wiki/H%C3%ACnh:Plant_cell_structure.pnghttp://vi.wikipedia.org/wiki/M%C3%B4i_tr%C6%B0%E1%BB%9Dnghttp://vi.wikipedia.org/wiki/Nhi%E1%BB%87t_%C4%91%E1%BB%99http://vi.wikipedia.org/wiki/PHhttp://vi.wikipedia.org/w/index.php?title=Dinh_d%C6%B0%E1%BB%A1ng&action=edithttp://vi.wikipedia.org/w/index.php?title=V%E1%BA%ADn_%C4%91%E1%BB%99ng_(t%E1%BA%BF_b%C3%A0o)&action=edithttp://vi.wikipedia.org/wiki/T%C3%BAi_ti%E1%BA%BFthttp://vi.wikipedia.org/wiki/M%C3%A0ng_t%E1%BA%BF_b%C3%A0ohttp://vi.wikipedia.org/w/index.php?title=%C4%90i%E1%BB%87n_th%E1%BA%BF_m%C3%A0ng&action=edithttp://vi.wikipedia.org/wiki/V%E1%BA%ADt_li%E1%BB%87u_di_truy%E1%BB%81nhttp://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Proteinhttp://vi.wikipedia.org/w/index.php?title=Enzyme&action=edit


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trong t bo, vo mi thi im nht nh t bo tng hp nhiu loi phn t sinh hc

khc nhau.

2.2.1.1. Thnh t bo

Thnh t bo l cu trc thit yu i vi nhiu qu trnh sinh l v pht trin cathc vt. L lp v bao bc, thnh t bo c vai tr nh b khung xng qui nh hnh

dng t bo. Thnh t bo c mi quan h mt thit n th tch v p sut ca t bo do

rt cn thit cho qu trnh trao i nc bnh thng thc vt. Thnh t bo thc vt

tham gia xc nh di c hc ca cu trc thc vt, cho php chng sinh trng n

mt cao kh ln.

S a dng v chc nng ca thnh t bo bt ngun t s a dng v phc tp

trong cu trc ca chng. Nhn chung cc thnh t bo c chia thnh hai nhm chnh:

thnh s cp v thnh th cp. Thnh s cp hnh thnh bi cc t bo ang tng trng

v thng c coi l tng i cha bit ha. Thnh th cp c hnh thnh sau khi tbo ngng tng trng, c mc chuyn ha cao c v thnh phn v cu trc.

Trong thnh t bo s cp cc vi si xeluloza c gn cht trong mt mng li hydrat

ha cao. Mng li ny bao gm s cc nhm polisaccarit thng l hemixenluloza v

pectin cng 1 lng nh protein cu trc.

B khung t bo l mt thnh phn quan trng, phc tp v linh ng ca t bo.

N cu thnh v duy tr hnh dng t bo; l cc im bm cho cc bo quan; h tr qu

trnh thc bo (t bo thu nhn cc cht bn ngoi); v c ngcc phn t bo trong qu

trnh sinh trng v vn ng. cc protein tham gia cu thnh b khung t bo gm nhiuloi v c chc nng a dng nh nh hng, neo bm, pht sinh cc tm mng.

2.2.1.2. Cc bo quan

Khng bo

Khng bo l mt khoang ln nm trong trung tm cht nguyn sinh ca t bo.

Nhng t bo thc vt trng thnh thng c mt khng bo ln cha y nc v

chim t 80-90% th tch t bo. Khng bo c bc trong mt lp mng gi l mng

khng bo (tonoplast). Trong khng bo cha nc, cc mui v c, ng, cc enzim

v nhiu cht trao i th cp.

Mng sinh cht

Ranh gii gia thnh t bo vi cht nguyn sinh cng nh gia cht nguyn sinh

vi khng bo c hnh thnh bi cc mng. Mng sinh cht ngn cch cht nguyn

sinh vi mi trng xung quanh nhng cng cho php cht nguyn sinh c th hp th

hay o thi cc cht khc ra khi t bo.

http://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_t%E1%BB%AD_sinh_h%E1%BB%8Dc&action=edithttp://vi.wikipedia.org/w/index.php?title=B%C3%A0o_quan&action=edithttp://vi.wikipedia.org/w/index.php?title=Th%E1%BB%B1c_b%C3%A0o&action=edithttp://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_t%E1%BB%AD_sinh_h%E1%BB%8Dc&action=edithttp://vi.wikipedia.org/w/index.php?title=B%C3%A0o_quan&action=edithttp://vi.wikipedia.org/w/index.php?title=Th%E1%BB%B1c_b%C3%A0o&action=edit


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Mng t bo - Tm o ngoi

V bc bn ngoi ca mt t bo eukaryote gi l mng sinh cht (plasma

membrane). Mng ny cng c cc t bo prokaryote nhng c gi l mng t bo

(cell membrane). Mng c chc nng bao bc v phn tch t bo vi mi trng xungquanh. Mng c cu thnh bi mt lp lipid kp v cc protein. Cc phn t protein

hot ng nh cc knh vn chuynvbm c nm khm vo lp lipidmt cch linh

ng (c th di chuyn tng i). V bc bn ngoi ca mt t bo eukaryote gi l

mng sinh cht (plasma membrane).

Mng li ni cht

Mng ni cht l mt h thng mng phc to,th hin trn bn ct ngang l h thng

cc ti dp hoc cc ng nh gm hai lp mng v gia l mt khong hp

T bo cht

Bn trong cc t bo l mt khng gian cha y dch th gi l t bo cht

(cytoplasm). N bao hm c hn hp cc ion, cht dch bn trong t bo v c cc bo

quan. Cc bo quan bn trong t bo cht u c h thng mng sinh hc phn tch

vi khi dung dch ny. Cht nguyn sinh (cytosol) l ch ring phn dch th, ch

khng c cc bo quan.i vi cc sinh vt prokaryote, t bo cht l mt thnh phn

tng i t do. Tuy nhin, t bo cht trong t bo eukaryote thng cha rt nhiu bo

quan v b khung t bo. Cht nguyn sinh thng cha cc cht dinh dng ha tan,

phn ct cc sn phm ph liu, v dch chuyn vt cht trong t bo to nn hin tngdng cht nguyn sinh. Nhn t bo thng nm bn trong t bo cht v c hnh dng

thay i khi t bo di chuyn. T bo cht cng cha nhiu loi mui khc nhau, y l

dng cht dn in tuyt vi to mi trng thch hp cho cc hot ng ca t bo.

Mi trng t bo cht v cc bo quan trong n l yu t sng cn ca mt t bo.

Nhn t bo - trung tm t bo: Nhn t bo l bo quan ti quan trng trong t

bo eukaryote. N cha ccnhim sc th ca t bo, l ni din ra qu trnh nhn i

DNA v tng hp RNA. Nhn t bo c dng hnh cu v c bao bc bi mt lp

mng kp gi l mng nhn. Mng nhn dng bao ngoi v bo v DNA ca t bo

trc nhng phn t c th gy tn thng n cu trc hoc nh hng n hot ng

ca DNA. Trong qu trnh hot ng, phn t DNA c phin m tng hp cc phn

t RNA chuyn bit, gi l RNA thng tin (mRNA). Cc mRNA c vn chuyn ra

ngoi nhn, trc tip tham gia qu trnh tng hp cc protein c th. cc loi

prokaryote, cc hot ng ca DNA tin hnh ngay ti t bo cht (chnh xc hn l ti

vng nhn).

http://vi.wikipedia.org/w/index.php?title=M%C3%A0ng_sinh_ch%E1%BA%A5t&action=edithttp://vi.wikipedia.org/w/index.php?title=L%E1%BB%9Bp_lipid_k%C3%A9p&action=edithttp://vi.wikipedia.org/w/index.php?title=K%C3%AAnh_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/w/index.php?title=K%C3%AAnh_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/w/index.php?title=B%C6%A1m_(t%E1%BA%BF_b%C3%A0o)&action=edithttp://vi.wikipedia.org/wiki/Lipidhttp://vi.wikipedia.org/wiki/Lipidhttp://vi.wikipedia.org/w/index.php?title=Nhi%E1%BB%85m_s%E1%BA%AFc_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=Nhi%E1%BB%85m_s%E1%BA%AFc_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=Nh%C3%A2n_%C4%91%C3%B4i_DNA&action=edithttp://vi.wikipedia.org/w/index.php?title=Nh%C3%A2n_%C4%91%C3%B4i_DNA&action=edithttp://vi.wikipedia.org/w/index.php?title=T%E1%BB%95ng_h%E1%BB%A3p_RNA&action=edithttp://vi.wikipedia.org/w/index.php?title=T%E1%BB%95ng_h%E1%BB%A3p_RNA&action=edithttp://vi.wikipedia.org/w/index.php?title=M%C3%A0ng_nh%C3%A2n&action=edithttp://vi.wikipedia.org/wiki/Phi%C3%AAn_m%C3%A3http://vi.wikipedia.org/wiki/MRNAhttp://vi.wikipedia.org/wiki/Sinh_t%E1%BB%95ng_h%E1%BB%A3p_proteinhttp://vi.wikipedia.org/wiki/Prokaryotehttp://vi.wikipedia.org/w/index.php?title=V%C3%B9ng_nh%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=M%C3%A0ng_sinh_ch%E1%BA%A5t&action=edithttp://vi.wikipedia.org/w/index.php?title=L%E1%BB%9Bp_lipid_k%C3%A9p&action=edithttp://vi.wikipedia.org/w/index.php?title=K%C3%AAnh_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/w/index.php?title=B%C6%A1m_(t%E1%BA%BF_b%C3%A0o)&action=edithttp://vi.wikipedia.org/wiki/Lipidhttp://vi.wikipedia.org/w/index.php?title=Nhi%E1%BB%85m_s%E1%BA%AFc_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=Nh%C3%A2n_%C4%91%C3%B4i_DNA&action=edithttp://vi.wikipedia.org/w/index.php?title=Nh%C3%A2n_%C4%91%C3%B4i_DNA&action=edithttp://vi.wikipedia.org/w/index.php?title=T%E1%BB%95ng_h%E1%BB%A3p_RNA&action=edithttp://vi.wikipedia.org/w/index.php?title=M%C3%A0ng_nh%C3%A2n&action=edithttp://vi.wikipedia.org/wiki/Phi%C3%AAn_m%C3%A3http://vi.wikipedia.org/wiki/MRNAhttp://vi.wikipedia.org/wiki/Sinh_t%E1%BB%95ng_h%E1%BB%A3p_proteinhttp://vi.wikipedia.org/wiki/Prokaryotehttp://vi.wikipedia.org/w/index.php?title=V%C3%B9ng_nh%C3%A2n&action=edit


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Ribosome - b my sn xut protein: Ribosome c c trong t bo eukaryote v

prokaryote. Ribosome c cu to t cc phn t protein v RNA ribosome (rRNA).

y l ni thc hin qu trnh sinh tng hp protein t cc phn t mRNA. Qu trnh ny

cn c gi ldch m v thng tin di truyn m ha trong trnh t phn t DNA truyn

qua trnh t RNA quyt nh trnh t amino acid ca phn t protein. Qu trnh nycc k quan trng i vi tt c mi t bo, do mt t bo thng cha rt nhiu phn

t ribosomethng hng trm thm ch hng nghn phn t.

Ty th v lc lp - cc trung tm nng lng : Ty thl bo quan trong t bo

eukaryotec hnh dng, kch thc v s lng a dng v c kh nng t nhn i. Ty

th c genome ring, c lp vi genome trong nhn t bo. Ty th c vai tr cung cp

nng lng cho mi qu trnh trao i cht ca t bo. Lc lp cng tng t nh ty th

nhng kch thc ln hn, chng tham gia chuyn ha nng lng mt tri thnh cc

cht hu c (trong qu trnhquang hp). Lc lp ch c cc t bo thc vt.

Mng li ni cht v b my Golgi - nh phn phi v x l cc i phn t:

Mng li ni cht (ER) l h thng mng vn chuyn cc phn t nht nh n cc a

ch cn thit ci bin hoc thc hin chc nng, trong khi cc phn t khc th tri ni

t do trong t bo cht. ER c chia lm 2 loi: ER ht (rm) v ER trn (nhn). ER ht

l do cc ribosome bm ln b mt ngoi ca n, trong khi ER trn th khng c

ribosome. Qu trnh dch m trn cc ribosome ca ER ht thng tng hp cc

protein tit (protein xut khu). Cc protein tit thng c vn chuyn n phc h

Golgi thc hin mt s ci bin, ng gi v vn chuyn n cc v tr khc nhau trongt bo. ER trn l ni tng hp lipid, gii c v b cha calcium.

Lysosome v peroxisome - h tiu ha ca t bo: Lysosome v peroxisome

thng c v nh h thng x l rc thi ca t bo. Hai bo quan ny u dng cu,

mng n v cha nhiu enzyme tiu ha. V d, lysosome c th cha vi chc enzyme

phn hu protein, nucleic acid vpolysacharidem khng gy hi cho cc qu trnh khc

ca t bo khi c bao bc bi lp mng t bo.

Vt liu di truyn - Yu t duy tr thng tin gia cc th h : Vt liu di truyn

l cc phn t nucleic acid (DNA v RNA). Hu ht cc sinh vt s dng DNA lu trdi hn thng tin di truyn trong khi ch mt vi virus dng RNA cho mc ch ny.

Thng tin di truyn ca sinh vt chnh l m di truyn quy nh tt c protein cn thit

cho mi t bo ca c th. Tuy nhin, mt nghin cu mi y cho thy c th mt s

RNA cng c s dng nh l mtbn lu i vi mt s gene phng sai hng.

http://vi.wikipedia.org/wiki/Ribosomehttp://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/wiki/Prokaryotehttp://vi.wikipedia.org/w/index.php?title=RRNA&action=edithttp://vi.wikipedia.org/wiki/MRNAhttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/wiki/Th%C3%B4ng_tin_di_truy%E1%BB%81nhttp://vi.wikipedia.org/wiki/DNAhttp://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Amino_acidhttp://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/wiki/Trao_%C4%91%E1%BB%95i_ch%E1%BA%A5thttp://vi.wikipedia.org/w/index.php?title=L%E1%BB%A5c_l%E1%BA%A1p&action=edithttp://vi.wikipedia.org/wiki/N%C4%83ng_l%C6%B0%E1%BB%A3ng_m%E1%BA%B7t_tr%E1%BB%9Dihttp://vi.wikipedia.org/wiki/Quang_h%E1%BB%A3phttp://vi.wikipedia.org/wiki/Quang_h%E1%BB%A3phttp://vi.wikipedia.org/wiki/Th%E1%BB%B1c_v%E1%BA%ADthttp://vi.wikipedia.org/wiki/M%E1%BA%A1ng_l%C6%B0%E1%BB%9Bi_n%E1%BB%99i_ch%E1%BA%A5thttp://vi.wikipedia.org/w/index.php?title=Protein_ti%E1%BA%BFt&action=edithttp://vi.wikipedia.org/wiki/Ph%E1%BB%A9c_h%E1%BB%87_Golgihttp://vi.wikipedia.org/wiki/Ph%E1%BB%A9c_h%E1%BB%87_Golgihttp://vi.wikipedia.org/wiki/Lipidhttp://vi.wikipedia.org/wiki/Calciumhttp://vi.wikipedia.org/wiki/Lysosomehttp://vi.wikipedia.org/wiki/Peroxisomehttp://vi.wikipedia.org/w/index.php?title=Enzyme&action=edithttp://vi.wikipedia.org/wiki/Nucleic_acidhttp://vi.wikipedia.org/w/index.php?title=Polysacharide&action=edithttp://vi.wikipedia.org/w/index.php?title=Polysacharide&action=edithttp://vi.wikipedia.org/w/index.php?title=Polysacharide&action=edithttp://vi.wikipedia.org/wiki/Nucleic_acidhttp://vi.wikipedia.org/wiki/DNAhttp://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Sinh_v%E1%BA%ADthttp://vi.wikipedia.org/wiki/Th%C3%B4ng_tin_di_truy%E1%BB%81nhttp://vi.wikipedia.org/wiki/Th%C3%B4ng_tin_di_truy%E1%BB%81nhttp://vi.wikipedia.org/wiki/Virushttp://vi.wikipedia.org/wiki/M%C3%A3_di_truy%E1%BB%81nhttp://vi.wikipedia.org/w/index.php?title=B%E1%BA%A3n_l%C6%B0u&action=edithttp://vi.wikipedia.org/wiki/Genehttp://vi.wikipedia.org/wiki/Ribosomehttp://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/wiki/Prokaryotehttp://vi.wikipedia.org/w/index.php?title=RRNA&action=edithttp://vi.wikipedia.org/wiki/MRNAhttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/wiki/Th%C3%B4ng_tin_di_truy%E1%BB%81nhttp://vi.wikipedia.org/wiki/DNAhttp://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Amino_acidhttp://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/wiki/Trao_%C4%91%E1%BB%95i_ch%E1%BA%A5thttp://vi.wikipedia.org/w/index.php?title=L%E1%BB%A5c_l%E1%BA%A1p&action=edithttp://vi.wikipedia.org/wiki/N%C4%83ng_l%C6%B0%E1%BB%A3ng_m%E1%BA%B7t_tr%E1%BB%9Dihttp://vi.wikipedia.org/wiki/Quang_h%E1%BB%A3phttp://vi.wikipedia.org/wiki/Th%E1%BB%B1c_v%E1%BA%ADthttp://vi.wikipedia.org/wiki/M%E1%BA%A1ng_l%C6%B0%E1%BB%9Bi_n%E1%BB%99i_ch%E1%BA%A5thttp://vi.wikipedia.org/w/index.php?title=Protein_ti%E1%BA%BFt&action=edithttp://vi.wikipedia.org/wiki/Ph%E1%BB%A9c_h%E1%BB%87_Golgihttp://vi.wikipedia.org/wiki/Ph%E1%BB%A9c_h%E1%BB%87_Golgihttp://vi.wikipedia.org/wiki/Lipidhttp://vi.wikipedia.org/wiki/Calciumhttp://vi.wikipedia.org/wiki/Lysosomehttp://vi.wikipedia.org/wiki/Peroxisomehttp://vi.wikipedia.org/w/index.php?title=Enzyme&action=edithttp://vi.wikipedia.org/wiki/Nucleic_acidhttp://vi.wikipedia.org/w/index.php?title=Polysacharide&action=edithttp://vi.wikipedia.org/wiki/Nucleic_acidhttp://vi.wikipedia.org/wiki/DNAhttp://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Sinh_v%E1%BA%ADthttp://vi.wikipedia.org/wiki/Th%C3%B4ng_tin_di_truy%E1%BB%81nhttp://vi.wikipedia.org/wiki/Virushttp://vi.wikipedia.org/wiki/M%C3%A3_di_truy%E1%BB%81nhttp://vi.wikipedia.org/w/index.php?title=B%E1%BA%A3n_l%C6%B0u&action=edithttp://vi.wikipedia.org/wiki/Gene


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9

cc sinh vt prokaryote, vt liu di truyn l mt phn t DNA dng vng n

gin. Phn t ny nm mt vng t bo cht chuyn bit gi l vng nhn. Tuy nhin,

i vi cc sinh vt eukaryote, phn t DNA c bao bc bi cc phn t protein to

thnh cu trc nhim sc th, c lu gi trong nhn t bo (vi mng nhn bao bn

ngoi). Mi t bo thng cha nhiu nhim sc th (s lng nhim sc th trong mi tbo l c trung cho loi). Ngoi ra, cc bo quan nh ty thv lc lp u c vt liu di

truyn ring ca mnh (xem thm thuyt ni cng sinh).

V d, mt t bo ngi gm hai genome ring bit l genome nhn v genome ty th.

Genome nhn (l th lng bi) bao gm 46 phn t DNA mch thng to thnh cc

nhim sc th ring bit. Genome ty th l phn t DNA mch vng, kh nh v ch m

ha cho mt vi protein quan trng.

2.2.2. Cc qu trnh chc nng ca t bo2.2.2.1. Sinh trng v trao i cht ca t bo

Gia nhng ln phn bo, cc t bo thc hin hng lot qu trnh trao i cht ni

bo nhm duy tr s tn ti cng nh sinh trng ca mnh. Trao i cht l cc qu trnh

m t bo x l hay ch bin cc phn t dinh dng theo cch ring ca n. Cc qu

trnh trao i cht c chia lm 2 nhm ln:

Qu trnh d ha (catabolism) nhm phn hu cc phn t hu c phc tp thu

nhn nng lng (di dng ATP) v lc kh;

Qu trnh ng ha (anabolism) s dng nng lng v lc kh xy dng cc

phn t hu c phc tp, c th v cn thit.

Mt trong cc con ng trao i cht quan trng l ng phn (glycolysis), con

ng ny khng cn oxy. Mi mt phn t glucose tri qua con ng ny s to thnh

4 phn t ATP v y l phng thc thu nhn nng lng chnh ca cc vi khun k kh.

i vi cc sinh vt hiu kh, cc phn tpyruvat, sn phm ca ng phn, s tham

gia vo chu trnh Kreb (hay cn gi l chu trnh TCA) phn hu hon ton thnh CO2,

ng thi thu nhn thm nhiu ATP. sinh vt eukaryote, chu trnh TCA tin hnh trong

ty th trong khi sinh vtprokaryote li tin hnh ngay t bo cht.

2.2.2.2. Sinh tng hp protein

S qu trnh sinh tng hp protein:

http://vi.wikipedia.org/w/index.php?title=V%C3%B9ng_nh%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=Nhi%E1%BB%85m_s%E1%BA%AFc_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=M%C3%A0ng_nh%C3%A2n&action=edithttp://vi.wikipedia.org/wiki/Lo%C3%A0ihttp://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/w/index.php?title=L%E1%BB%A5c_l%E1%BA%A1p&action=edithttp://vi.wikipedia.org/wiki/Thuy%E1%BA%BFt_n%E1%BB%99i_c%E1%BB%99ng_sinhhttp://vi.wikipedia.org/w/index.php?title=Genome_ty_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=L%C6%B0%E1%BB%A1ng_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/wiki/ATPhttp://vi.wikipedia.org/w/index.php?title=L%E1%BB%B1c_kh%E1%BB%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=%C4%90%C6%B0%E1%BB%9Dng_ph%C3%A2n&action=edithttp://vi.wikipedia.org/wiki/Oxyhttp://vi.wikipedia.org/w/index.php?title=Glucose&action=edithttp://vi.wikipedia.org/wiki/ATPhttp://vi.wikipedia.org/w/index.php?title=K%E1%BB%8B_kh%C3%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=Pyruvat&action=edithttp://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/wiki/Prokaryotehttp://vi.wikipedia.org/w/index.php?title=V%C3%B9ng_nh%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=Nhi%E1%BB%85m_s%E1%BA%AFc_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=M%C3%A0ng_nh%C3%A2n&action=edithttp://vi.wikipedia.org/wiki/Lo%C3%A0ihttp://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/w/index.php?title=L%E1%BB%A5c_l%E1%BA%A1p&action=edithttp://vi.wikipedia.org/wiki/Thuy%E1%BA%BFt_n%E1%BB%99i_c%E1%BB%99ng_sinhhttp://vi.wikipedia.org/w/index.php?title=Genome_ty_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=L%C6%B0%E1%BB%A1ng_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/wiki/ATPhttp://vi.wikipedia.org/w/index.php?title=L%E1%BB%B1c_kh%E1%BB%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=%C4%90%C6%B0%E1%BB%9Dng_ph%C3%A2n&action=edithttp://vi.wikipedia.org/wiki/Oxyhttp://vi.wikipedia.org/w/index.php?title=Glucose&action=edithttp://vi.wikipedia.org/wiki/ATPhttp://vi.wikipedia.org/w/index.php?title=K%E1%BB%8B_kh%C3%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=Pyruvat&action=edithttp://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/wiki/Ty_th%E1%BB%83http://vi.wikipedia.org/wiki/Prokaryote


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Hnh 2.2. Qu trnh sinh

tng hp protein

10

Trong vng cht nhn, cc gene cphin m thnh nhng phn t RNA. Sau

khi thc hin cc sa i sau phin m, phn t mRNA trng thnh c vn chuyn ra

t bo cht tin hnh tng hp protein ti y. Cc ribosome tin hnh dch m ca

mRNA nh mi lin kt hydro theo nguyn tc b sung giab ba m sao trn mRNA

vib ba i m trn tRNA tng ng. Nhng phn t protein sau khi c tng hpthng c tin hnh mt s sa i cho ph hp vi chc nng, v d gn thm cc

gc ng

Sinh tng hp protein l qu trnh t bo tng hp

nhng phn t protein c trng v cn thit cho hot

ng sng ca mnh. Qu trnh phin m l qu trnh

tng hp nhng phn tRNA thng tin da trn trnh t

khun ca DNA. Trn khun mRNA mi c to ra,mt phn t protein s c to thnh nh qu trnh dch

m.

B my t bo chu trch nhim thc hin qu

trnh tng hp protein l nhng ribosome. Ribosome

c cu to t nhng phn t RNA ribosome v khong

80 loi protein khc nhau. Khi cc tiu n v ribosome

lin kt vi phn t mRNA th qu trnh dch m c

tin hnh. Khi , ribosome s cho php mt phn t RNA

vn chuyn (tRNA) mang mt loi amino acid c trng i

vo. tRNA ny bt buc phi cb ba i m c trnh t b

sung vib ba m sao trn mRNA. Cc amino acid ln lt tng ng vi trnh t cc b

ba nucleotide trn mRNA s lin kt vi nhau to thnh mt chuipolypeptide.

2.2.2.3. Hnh thnh cc t bo mi

Phn bo l qu trnh sinh sn t mt t bo (gi l t bo m) phn chia thnh hai

t bo non. y l c ch chnh ca qu trnh sinh trng ca sinh vt a bo v l hnh

thc sinh sn ca sinh vt n bo. Nhng t bo prokaryote phn chia bng hnh thc

phn ct(binary fission) hoc ny chi (budding). T bo eukaryote th s dng hnh thc

phn bo lnguyn phn (mitosis) (mt hnh thcphn bo c t). Nhng t bo lng

bi th c th tin hnh gim phn to ra t bo n bi. Nhng t bo n bi ng

vai trgiao ttrong qu trnh th tinh hnh thnh hp t (lng bi). Trong phn bo,

http://vi.wikipedia.org/w/index.php?title=RNA_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/wiki/Nh%C3%A2n_t%E1%BA%BF_b%C3%A0ohttp://vi.wikipedia.org/wiki/Genehttp://vi.wikipedia.org/wiki/Phi%C3%AAn_m%C3%A3http://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Ribosomehttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=Li%C3%AAn_k%E1%BA%BFt_hydro&action=edithttp://vi.wikipedia.org/wiki/Nguy%C3%AAn_t%E1%BA%AFc_b%E1%BB%95_sunghttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_m%C3%A3_sao&action=edithttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_%C4%91%E1%BB%91i_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_%C4%91%E1%BB%91i_m%C3%A3&action=edithttp://vi.wikipedia.org/wiki/%C4%90%C6%B0%E1%BB%9Dnghttp://vi.wikipedia.org/wiki/%C4%90%C6%B0%E1%BB%9Dnghttp://vi.wikipedia.org/wiki/Proteinhttp://vi.wikipedia.org/wiki/Phi%C3%AAn_m%C3%A3http://vi.wikipedia.org/wiki/RNA_th%C3%B4ng_tinhttp://vi.wikipedia.org/wiki/RNA_th%C3%B4ng_tinhttp://vi.wikipedia.org/wiki/DNAhttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/wiki/Ribosomehttp://vi.wikipedia.org/w/index.php?title=RNA_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/w/index.php?title=RNA_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/wiki/Amino_acidhttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_%C4%91%E1%BB%91i_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_m%C3%A3_sao&action=edithttp://vi.wikipedia.org/w/index.php?title=Polypeptide&action=edithttp://vi.wikipedia.org/w/index.php?title=Sinh_v%E1%BA%ADt_%C4%91a_b%C3%A0o&action=edithttp://vi.wikipedia.org/w/index.php?title=Sinh_v%E1%BA%ADt_%C4%91%C6%A1n_b%C3%A0o&action=edithttp://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_c%E1%BA%AFt&action=edithttp://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_c%E1%BA%AFt&action=edithttp://vi.wikipedia.org/w/index.php?title=N%E1%BA%A3y_ch%E1%BB%93i&action=edithttp://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/w/index.php?title=Nguy%C3%AAn_ph%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=Nguy%C3%AAn_ph%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_b%C3%A0o_c%C3%B3_t%C6%A1&action=edithttp://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_b%C3%A0o_c%C3%B3_t%C6%A1&action=edithttp://vi.wikipedia.org/w/index.php?title=L%C6%B0%E1%BB%A1ng_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/w/index.php?title=L%C6%B0%E1%BB%A1ng_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/w/index.php?title=Gi%E1%BA%A3m_ph%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=%C4%90%C6%A1n_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/w/index.php?title=Giao_t%E1%BB%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=Giao_t%E1%BB%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=Giao_t%E1%BB%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=Th%E1%BB%A5_tinh&action=edithttp://vi.wikipedia.org/w/index.php?title=H%E1%BB%A3p_t%E1%BB%AD&action=edithttp://vi.wikipedia.org/wiki/Nh%C3%A2n_t%E1%BA%BF_b%C3%A0ohttp://vi.wikipedia.org/wiki/Genehttp://vi.wikipedia.org/wiki/Phi%C3%AAn_m%C3%A3http://vi.wikipedia.org/wiki/RNAhttp://vi.wikipedia.org/wiki/Ribosomehttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=Li%C3%AAn_k%E1%BA%BFt_hydro&action=edithttp://vi.wikipedia.org/wiki/Nguy%C3%AAn_t%E1%BA%AFc_b%E1%BB%95_sunghttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_m%C3%A3_sao&action=edithttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_%C4%91%E1%BB%91i_m%C3%A3&action=edithttp://vi.wikipedia.org/wiki/%C4%90%C6%B0%E1%BB%9Dnghttp://vi.wikipedia.org/wiki/Proteinhttp://vi.wikipedia.org/wiki/Phi%C3%AAn_m%C3%A3http://vi.wikipedia.org/wiki/RNA_th%C3%B4ng_tinhttp://vi.wikipedia.org/wiki/DNAhttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=D%E1%BB%8Bch_m%C3%A3&action=edithttp://vi.wikipedia.org/wiki/Ribosomehttp://vi.wikipedia.org/w/index.php?title=RNA_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/w/index.php?title=RNA_v%E1%BA%ADn_chuy%E1%BB%83n&action=edithttp://vi.wikipedia.org/wiki/Amino_acidhttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_%C4%91%E1%BB%91i_m%C3%A3&action=edithttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_ba_m%C3%A3_sao&action=edithttp://vi.wikipedia.org/w/index.php?title=Polypeptide&action=edithttp://vi.wikipedia.org/w/index.php?title=Sinh_v%E1%BA%ADt_%C4%91a_b%C3%A0o&action=edithttp://vi.wikipedia.org/w/index.php?title=Sinh_v%E1%BA%ADt_%C4%91%C6%A1n_b%C3%A0o&action=edithttp://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_c%E1%BA%AFt&action=edithttp://vi.wikipedia.org/w/index.php?title=N%E1%BA%A3y_ch%E1%BB%93i&action=edithttp://vi.wikipedia.org/wiki/Eukaryotehttp://vi.wikipedia.org/w/index.php?title=Nguy%C3%AAn_ph%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=Ph%C3%A2n_b%C3%A0o_c%C3%B3_t%C6%A1&action=edithttp://vi.wikipedia.org/w/index.php?title=L%C6%B0%E1%BB%A1ng_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/w/index.php?title=L%C6%B0%E1%BB%A1ng_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/w/index.php?title=Gi%E1%BA%A3m_ph%C3%A2n&action=edithttp://vi.wikipedia.org/w/index.php?title=%C4%90%C6%A1n_b%E1%BB%99i&action=edithttp://vi.wikipedia.org/w/index.php?title=Giao_t%E1%BB%AD&action=edithttp://vi.wikipedia.org/w/index.php?title=Th%E1%BB%A5_tinh&action=edithttp://vi.wikipedia.org/w/index.php?title=H%E1%BB%A3p_t%E1%BB%AD&action=edit


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qu trnh nhn i DNA(dn n nhn i nhim sc th) ng vai tr cc k quan trng

v thng din ra tik trung gian gia cc ln phn chia.

Cc pha trong chu k t bo:

Pha G0 l mt giai on ca chu k t bo cell cycle m t bo trng thi lng yn.

Pha G1 l pha pht trin u tin ca chu k.

Pha S, trong pha ny DNA c sao chp, ch S xut pht t synthesis of DNA c

ngha l tng hp DNA (cn gi l axt nhn ADN: Axt Dezoxy riboNucleic).

Pha G2 l pha pht trin th hai, cng l pha chun b cho t bo phn chia.

Pha M, hay pha phn bo mitosis, v trng thi hot ng ca t bo (cytokinesis), sphn chia t bo thc s din ra to thnh hai t bo mi ging nhau.

H thng kim sot, cn gi l cc im kim sot, kim tra cc tn thng ca DNA

v cc sai st trong cc qu trnh quan trng ca chu k t bo. Trong trng hp c s

khng tng thch no , cc im kim sot c th chn qu trnh lun chuyn qua cc

pha ca chu k t bo. Chng hn nh, im kim sot iu khin sao chp DNA v gi

cho t bo sao chp hon ton DNA trc khi bc vo qu trnh phn bo (mitosis).

Cng vy, im kim sot con thoi (spindle checkpoint) s ngn cn qu trnh chuyn

dch t pha bin k (metaphase) sang pha hu k trong (anaphase) trong qu trnh phnbo nu nh khng c tt c cc nhim sc th (chromosomes) tp trung nh vo thoi

phn bo.

Nu h thng ny pht hin c iu g bt thng, th mt mng li cc phn t

dn truyn thng tin (signal transduction) s hng dn t bo ngng phn chia ngay.

Chng cn cn th gip cho t bo bit c c th sa cha tn thng hay khng hay

l khi ng qu trnh t bo cht c lp trnh, mt dng ca n c gi l apoptosis.

Qu trnh t bo cht c lp trnh gip hn ch cc t bo tn thng pht trin. V d

nh, mt protein, c gi l p53, nhn cm cc tnh hiu xut pht t cc DNA tn

thng. N p ng bng cch kch thch sn xut ra cc protein c ch dng qu trnh

sao chp DNA li. Nu chc nng ca p53 khng hot ng ng th dn n vic ng

cc DNA tn thng khng c kim tra. Hu qu trc tip ca iu l cc gene tn

thng s pht trin sang cc dng ung th. Ngy nay, nhng thm d cho thy p53 c

http://vi.wikipedia.org/w/index.php?title=Nh%C3%A2n_%C4%91%C3%B4i_DNA&action=edithttp://vi.wikipedia.org/w/index.php?title=Nh%C3%A2n_%C4%91%C3%B4i_DNA&action=edithttp://vi.wikipedia.org/w/index.php?title=Nhi%E1%BB%85m_s%E1%BA%AFc_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=K%E1%BB%B3_trung_gian&action=edithttp://vi.wikipedia.org/w/index.php?title=K%E1%BB%B3_trung_gian&action=edithttp://vi.wikipedia.org/w/index.php?title=Nh%C3%A2n_%C4%91%C3%B4i_DNA&action=edithttp://vi.wikipedia.org/w/index.php?title=Nhi%E1%BB%85m_s%E1%BA%AFc_th%E1%BB%83&action=edithttp://vi.wikipedia.org/w/index.php?title=K%E1%BB%B3_trung_gian&action=edit


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phi hp vi nhiu loi ung th khc nhau nh l mt vi dng ung th v v ung th i

trng.

Mt vi t bo nh l t bo thn kinh, khng bao gi phn chia khi n lun

dng li pha G0. Tuy nhin, cc nghin cu gn y cho thy nhng trng hp tnthng cht t bo th t bo thn kinh vn c th i vo li chu k t bo. Ngoi ra cc

cht c ch chu k t bo ngn cn t bo khi ci cht c lp trnh c bit nh l

apoptosis.

2.3. Thc vt

C th thc vt c cu to t nhng n v hnh thi c gi l t bo, mi t

bo c lin kt vi nhng t bo khc bi cht kt dnh gian bo bao quanh. Trong

khi lin kt c nhng nhm t bo khc bit v hnh thi hoc v chc nng hoc chai vi nhng nhm khc. Nhng nhm nh th c gi l m. Mt s m cu to n

gin, ch gm mt loi t bo, nhng m khc phc tp hn gm nhiu hn mt kiu t

bo

Cc m t bo trong c th thc vt u c ngun gc t hp t tc l t t bo

trng th tinh qua cc giai on pht trin ca phi v sau pht trin thnh c th

trng thnh. C th thc vt sinh trng nh c m phn sinh. M phn sinh ngn phn

chia v phn ha thnh cc phn mi ca chi v r. l s sinh trng s cp. S sinh

trng th cp thc vt hai l mm v ht trn l do hot ng ca m phn sinh thcp c gi l tng pht sinh. Trong s sinh trng th cp cn c tng phn sinh bn l

m phn sinh th cp hnh thnh nn chu b. Tng pht sinh v tng sinh bn c gi l

m phn sinh bn v n v tr bn ca than v r phn bit vi m phn sinh s cp l

m phn sinh ngn.

C th thc vt c phi pht trin k t khi ht ny mm gm r pht trin xung

t v chi gm thn mang l pht trin trong kh quyn. S pht trin ca chi v r l t

cc t bo ca m phn sinh ngn. Thn l v r c gi l c quan dinh dng. Khi

trng thnh th hoa c hnh thnh. Sau s th phn l s th tinh v s hnh thnh

phi, ht v qu. Nhng c quan c gi l c quan sinh sn. Chu trnh pht trin ca

c th thc vt c th k t khi hp t hnh thnh v kt thc trc khi xy ra s th tinh

ca cc giao t to nn th h sau.



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2.3.1. S ny mm ca ht v s pht trin ca cy con

a. S ny mm ca ht

S ny mm ca ht bt u khi ht hp thu rt nhiu nc v tng th tch ln

mt cch ng k, c khi n 200%. Kt qu ca s hp thu nc ny lm cho phi gii

phng gibberellin, v y l yu t cm ng tng hp mt s cc enzim thy gii trong

c c amylaza. Nhng enzim ny thy phn nhng cht d tr trong phi nh, cung

cp nng lng cho s tng trng ca phi. T bo bt u phn ct, tng hp thm t

bo cht mi, gia tng kch thc nh s hp thu nc. Phi tng trng lm bung v

ht ra v nhanh chng hnh thnh mt cy con, c r v thn phn bit.

Hnh 2.3. S ny mm ca ht

Khi ht ny mm, trc h dip c mc ra trc tin. Trc h dip mc xung

theo chiu trng lc, d ht nm theo hng no. Cng lc trc thng dip bt u

pht trin nhanh chng, r mm phn cui ca trc h dip, to ra mt h thng r con

gn vo trong t v hp thu nc v mui khong. mt s cy song t dip, phn

trn ca trc h dip mc di ra thnh dng hnh vm, mc ngc ln v chui ra khi mt

t. Khi trc h dip l ra ngoi khng kh, n mc thng ln, t dip v trc thngdip c a ra khi mt t. Sau trc thng dip bt u mc di ra. y l kiu

ny mm thng a.

Nhng cy Song t dip khc, th d nh u H lan, Nhn c mt kiu ny mm

hi khc, nhng cy ny, trc h dip khng mc thnh hnh vm v t dip khng



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c a ln khi mt t. Thay vo l trc thng dip bt u mc di ra ngay sau

khi h thng r con bt u c hnh thnh; n lun lun mc thng ng v chng bao

lu nh ra khi mt t. Kiu ny mm ny tng t nh ht La, Bp... thuc cc cy

n t dip, ch c mt t dip, nhng giu phi nh . y l kiu ny mm h a.

Bp trc thng dip bt u di ra ngay sau khi h thng r c thnh lp. Thn nonc dip tiu (l u tin hnh ng) bao bc.

b. S pht trin ca cy con

u tin cy con tng trng hi chm, nhng sau tng trng vi mt tc

nhanh hn trong mt thi gian di hn v cui cng chm li v c th dng tng trng

khi cy sp trng thnh. nhng cy a nin, s tng trng tip tc xy ra trong sut

i sng ca cy, trong khi nhng cy nht nin nh cc cy u, cy C ci... tng

trng ngng li khi cy trng thnh v cy cht i sau mt ma sinh trng. S tngtrng ca r v thn ca cy con c c l nh s phn ct v s tng di ca t bo.

Hai hot ng ny chu nh hng ca nhiu hormon sinh trng khc nhau, c bit l

auxin, gibberellin v cytokinin. nhng cy ch c m s cp th s phn ct t bo v

s tng di ca t bo ty thuc vo s hot ng ca hai m phn sinh ngn r v ngn

thn.

2.3.2. S tng trng ca r v thn

a. S tng trng ca r

S hot ng ca m phn sinh ngn r lm cho r tng trng. M phn sinh r

c bo v bi mt chp r hnh nn, gm mt khi t bo khng phn ct c. Khi r

mc di ra v u r mc su vo trong t th mt s t bo mt ngoi ca chp r c

th b tn thng v sau c thay th bng nhng t bo mi do s phn ct t bo

ca m phn sinh ngn. Ngay sau ca chp r l vng m phn sinhngn r, vng ny

ngn v gm nhng t bo nh c kh nng phn chia tch cc. Phn ln cc t bo mi

c to ra nm xa chp r. M phn sinh tip tc phn ct cho t bo mi v u r tip

tc mc su vo trong t. Chnh cc t bo c to ra t m phn sinh ny s thnh lp

m s cp cho r.



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Khi cc t bo c mi c y ra khi vng m phn sinh ngn, do s lng

t bo tng ln s phn ct chm li th s gia tng kch thc t bo l qu trnh chnh.

Phn ln s tng kch thc lm r tng trng

chiu di nhiu hn l chiu rng. S tng di ca

t bo chu tc ng ca cc hormon m c bit lauxin v gibberellin. Vng t bo tng di nhiu

nht l vng ngay sau vng m phn sinh v thng

di ch vi milimet. K tip l vng t bo trng

thnh, ni y t bo bt u trng thnh v c

hnh thnh dng c trng. Vng ny d nhn bit

nh cc lng ht c mc di ra t nhng t bo

biu b.

b. S tng trng ca thn

S phn ct t bo m phn sinh


Hnh 2.4 Cu to ca r


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ngn thn to ra m s cp ca thn v khi s khi ca l Cc t bo mi c to ra

t m phn sinh ngn thn gn nh ngn, mc di y ngn thn thng ng ln. S

tng trng ca thn khc vi s tng trng ca r l c s to ra l pha bn ca nh

ngn thn. Cch khong u n m phn sinh ngn thn to ra nhng khi s khi ca

l (leaf primordia), sau ny s to ra nhng l mi. Ni l mc ra t thn gi l mt

(node) v khong gia hai mt l lng (internode). Phn ln thn di ra l do s tng di

ca t bo nhng lng cn non.

nh ca thn l mt chui nhng lng cha c mc di ra. Nhng khi s

khi ca l rt nh ngn cch cc lng un cong; cc khi s khi gi hn, to hn ca l

bao ly cc khi s khi tr hn, nh hn bn trong. Cu trc gm m phn sinh ngn

v cc lng cha c tng di c bao bc trong cc khi s khi ca l c gi l

chi (bud). nhng cy tng trng theo ma th chi c bo v bi nhng vy, l

nhng l bin i mc t di y ca chi. Vo ma xun, khi cc chi ng ny n ra,

th cc vy che ch rng i v nhng lng cha bn trong cc chi bt u tng di mt

cch nhanh chng. Do cc lng s dn dn c tch xa nhau ra, s phn ct t boxy ra khi s khi ca l v to ra l non. Trc khi l c hnh thnh mt cch

hon chnh, mt u nh ca m phn sinh thng mc ra gia y l v lng. Mi mt

vng m phn sinh mi ny s to ra mt chi bn (lateral, axillary bud) c c im

tng t nh chi ngn . S tng di ca cc lng ca chi bn trong ma sinh trng k

tip s to ra nhnh.


Hnh 2.5. nh ct dc ca chi ngn


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2.3.3. S chuyn ha ca t bo

Tt c nhng t bo mi c sinh ra t m phn sinh th c bn ging nhau,

chng s tr thnh cc loi m khc nhau. Qu trnh t bo thay i t nhng hnh dng

cha trng thnh n trng thnh gi l s chuyn ha (differentiation).

Trong s tng trng ca r v thn, t bo bt u chuyn ha thnh cc loi m

khc nhau khi chng vn cn trong vng m phn sinh. Sau khi s phn ct t bo v

s tng di ca t bo hon tt, t bo bt u trng thnh c hnh dng nht nh.

lt ct ngang c th phn bit c ba vng ng tm ngay sau m phn sinh ca r l

lp tin b (protoderm), k tip l mt vng m cn bn dy nm ngay di tin b v

trong cng l m tin dn truyn (provascular tissue) gm nhng t bo. Ngay trong phi,

tin b ngoi tr thnh biu b, m cn bn tr thnh v v ni b, phn trong cng to ra

m dn truyn s cp, chu lun v tng tng libe g. S chuyn ha trong thn angtng trng cng theo cch tng t ngoi tr c hai vng m cn bn, mt vng nm

gia tin b v tr tin dn truyn s to ra v v ni b, v mt vng th hai nm trong

tr tin dn truyn s tr thnh li. S tng trng theo ng knh ca r v thn ty

thuc vo s thnh lp m th cp do s hot ng ca nhng m phn sinh bn, c bit

l tng tng libe g. Di nh hng ca auxin, nhng t bo mi c to ra pha

ngoi ca tng tng s chuyn ha thnh m libe th cp, trong khi nhng t bo mi

c to ra pha trong ca tng tng s to nn m g th cp.

Hnh 2.6. S chuyn ho ca r non



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Thc vt c xu hng mc v hng c nh sng. t mt chu cy trong phng,

cy s mc cong hng v pha ca s, nu xoay cy hng vo trong, sau mt thi gian

ngn cy li mc hng v pha ca s. Hin tng cy p ng li vi nh sng bi s

xoay ny c gi l quang hng ng (phototropism) ca thc vt. Thc vt cn c

cc tnh hng ng khc nh a hng ng (gravitropism) l p ng ca cy hngtheo chiu ca trng lc, thy hng ng (hydrotropism) p ng vi nc.

p ng ny l do s sinh trng chuyn ha; mt pha ca thn cy hay r mc

nhanh hn pha bn kia, lm cho cy cong i. Thn c quang hng ng dng, xoay

v hng c nh sng; r th ngc li, c quang hng ng m, xoay trnh nh sng.

ngha thch nghi ca quang hng ng thn l xoay thn l nhn c nh sng

ti a cn thit cho s quang hp.

2.4. Phng th nghim

2.4.1. Cc thit b , dng c cn thit ca phng th nghim nui cy m

Mt phng th nghim nui cy m t bo thng bao gm:

-Phng ra dng c

-Phng chun b mi trng, hp tit trng v cha dng c

- Phng cy v trng

- Phng nui mu

- Phng quan st v thu nhn s liu

S tng quan nh sau:

1.Phng ra v sn xut nc ct

2. Phng sy hp, kho thy tinh sch


1 2 3 4 5

6

78910


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3. Phng chun b mi trng

4. Phng chun b mu

5. Phng cy v trng

6. Phng nh

7. Phng knh hin vi8. Phng nui

9.Phng nui

10. Phng sinh ha

Bn cnh phng th nghim cn c h thng nh li v vn m trng cy

ly nguyn liu nui cy v trng cy ti sinh trong qu trnh chn lc nvitro.

a. Phng ra v ct nc:

Phng ra dng c phi c bn ra ln , c ng thot nc ring cho axit, c

k cc thit b:

- My ct nc mt ln

- My ct nc hai ln

- My sn xut nc kh ion

b.Phng sy hp:

- T sy 60-6000C (loi c dung tch ln)

- Ni p sut loi nh (20-30 lt)

- Ni p sut loi ln (70-100 lt)

c.Phng chun b mi trng:- pH meter

- My khuy t

- Cn phn tch 10-4 g

- Cn k thut 100-2g

- My rt mi trng

- Bp in

- Microwave

- T lnh 100-200 l

- T lnh su (-20 n -800C)d. Phng cy v trng

Phng cy v trng nn l mt phng nh, kn, sn v tng cn c lt gch

men hoc sn lau chi v kh trng thng xuyn. Ca phng cy nn l ca knh v

trong khi thao tc cy rt d b pht n cn do cn phi d lin lc vi bn ngoi

trong lc cn thit. Trn tng gn n UV kh trng phng.



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C hai loi t cy thng c s dng: t cy tnh v t cy thi kh v trng.

Trong t cy phi c n trng d lm vic v c n UV kh trng trc khi lm

vic

- Laminar

-Qut thng gi- n t ngoi treo trn hoc treo tng

- Thit b lc khng kh

- Gi v bn mi trng

- B dng c cy, n cn

e. Phng nui mu cy:

Tt c cc mu cy u c nui trong iu kin nhit nh sng, m,

di chiu sng, thng kh thch hp.

Phng nui c nhit 15-300C ty theo mu cy v mc ch ca th nghim.

Nhit phi c phn b u trong ton phng nui, phi c y nh sng hunh

quang v c th iu khin c cng v thi gian chiu sng. Phng nui phi

c thi kh ng nht v bin m c iu chnh t 20-98%.

- Phng nui sng: tng nn sn mu trng. Cc gi n c lp n ng

chiu sng. Trong phng cn gn cc my mc kim tra chnh xc nhit , m.

- Phng nui ti nui m so v cc x l c bit. Phng cn tt c cc iu

kin nh phng sng ch khc l khng cn lp n chiu sng cho cy, ca s cn c

che kn bng vi en.

- Cc gin n hunh quang nhiu ngn, c chiu sng ch bnh nui cyt 2000-3000 lux.

- My iu ha nhit

- My lc nm ngang 100-200 vng/pht

- Cc thit b v dng c nui cy t bo n

-T m.

f. Phng sinh ha :

Phng ny dng tin hnh cc phn tch sinh ha, phn t v di truyn.

- T ht, t m

- Cn cc loi- My ct tiu bn

- My o pH

- Ly tm lnh

- My in di, my soi AND

- My PCR,my sc k,quang ph



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- T lnh thng, t lnh su

- L vi sng

- Pipet t ng cc loi

- My soi v chp nh gel

-Cc t ng ha cht, t ht kh c.* Cc nhn t m bo thnh cng trong nui cy m t bo thc vt: c 3 nhn t

chnh:

- m bo iu kin v trng.

-Chn ng mi trng v chun b mi trng ng cch

- Chn m cy v x l m cy thch hp trc v sau khi cy.

2.4.2. Cc th tc c bn trong phng th nghim:

2.4.2.1. Cn

Vic chun b mi trng i hi thao tc cn phi chnh xc. Trc ht cn phi

c t v tr n nh, khng b rung, khng kh khng b dao ng nhiu. Cn v da

cn phi c gi gn sch s. Quan trng nht l khng c cn qa trng lng cho

php v nn s dng cc vt ng ha cht c trng lng nh hoc bng giy khi cn.

Khng c ha cht tip xc trc tip vi mt cn.

2.4.2.2. ong cht lng

Cc dng c thy tinh c chia vch (ng ht c chia , cc thy tinh c chia

vch, ng ong) cn thit pha mi trng. ng ong c th tch 10,20,100 v 1000ml

c s dng ong nhng cht lng c th tch ln cn ng ht c chia , bnh nhmc dung ong nhng th tch cn chnh xc. ong cc dung dch ch chnh xc khi

y ca khng kh ngang vi vch nh du.

2.4.2.3. Xc nh pH

pH ca mi trng cy hu ht c chnh 5,5 +-0,1 trc khi hp kh

trng. pH nh hng n kh nng ha tan ca cc ion trong mi trng khong, kh

nng ng t agar v s tng trng ca t bo. V vy xc nh chnh xc pH l cn

thit. Murashige v Shoog nhn thy rng pH 5,7-5,8 thch hp duy tr s ha tan cc

cht khong trong mi trng MS. Nu mi trng MS c s dng dng lng th cth chnh pH 5, mi trng cy huyn ph c pH thp phn no gim bt tnh trng

nhim.

pH ca mi trng thng c iu chnh bng NaOH hoc HCl sau khi

pha xong mi trng v chun b a v hp kh trng. C th chnh pH bng pH k

bn, pH k cm tay hoc giy o pH. Thng th nhit cao s lm tng tnh axit ca



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mi trng. Mann v cng s nhn thy rng nu trc khi hp pH=5,7 th sau khi hp

pH =5, Nu mun pH =5,7-5,9 th trc khi hp kh trng cn iu chnh pH n 7.

2.4.2.4. Ra dng c thy tinh v bnh nui cy bng plastic

Thng thng bnh nui cy sau khi s dng cn phi c ra k bng x bng

bt cho ht cc cht bm trn thnh chai ri trng li nhiu ln bng nc sch cui cngtrng li bng nc ct. Cc dng c thy tinh b qu bn cn phi c ngm trong axit

HCl hoc sulfuric sau ra sch bng nc my v trng bng nc ct. Cc bnh mi

trng b nhim trng trong qu trnh nui cy cn phi c hp tit trng trc khi ra.

Cc dng c thy tinh sau khi ra phi c sy kh trong t sy v c ct cn thn.

2.5. m bo iu kin v trng

2.5.1. ngha ca v trng trong nui cy m v t bo thc vt

Mi trng nui cy m v t bo thc vt c cha ng, mui khong,

vitamin..rt thch hp cho cc loi nm v vi khun pht trin. Do tc phn bo ca

nm v vi khun ln hn nhiu so vi cc t bo thc vt, nu trong mi trng nui cy

b nhim bo t nm hoc vi khun th sau vi ngy s ph y vi khun hoc nm,khi

m nui cy s cht dn th nghim phi b i.

Thng thng mt chu k nui cy m v t bo thc vt di t 1-5 thng, trong khi th

nghim vi sinh vt c th kt thc trong mt vi ngy. Nh vy mc v trng trong th

nghim nui cy m v t bo thc vt i hi rt nghim ngt, iu kin ny c bit

quan trng trong nui cy t bo n trong cc bioreactor.C 3 ngun nhim tp chnh:

- Dng c thy tinh, mi trng v nt y khng c v trng tuyt i.

- Trn b mt hoc bn trong m nui cy tn ti cc si nm, bo t vi khun.

- Trong qu trnh thao tc lm ri nm hoc vi khun theo bi ln mi trng.

2.5.2.Kh trng

2.5.2.1. Kh trng phng cy v t cy

Phng cy thng l phng c din tch hp, rng t 10-15m2

, c hai lp ca trnh khng kh chuyn ng t bn ngoi trc tip a bi vo. Sn v tng c lt

gch men d lau chi. Trc khi a vo s dng bung cy cn c x l bng hi

Formol bng cch rt formaldehyde (formalin)4% ra mt s da petri ri rc vi ni

trong phng cho bc hi t nhin. ng kn ca phng cy trong 24 gi, sau b

formaldehyde i v kh hi formaldehyde d bng dung dch NH3 25% trong 24 gi. Cc



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dng c mang vo bung cy u v trng trc: t qun o chong, m vi, khu trang,

dao ko..Trn bn cy thng xuyn c mt n cn s dng khi cy v mt cc ng

cn 95% nhng dng c lm vic

Trc khi cy, th nghim vin cn ra tay bng x phng v lau k n khuu

tay bng cn 900

. m bo mc v trng cao cn c mt n t ngoi treo trntrn.

Phng cy ln c kh trng tin nht l bng n cc tm.Thi gian kh trng

ty theo kch thc ca phng v n cc tm ch c s dng khi khng c ngi.

Phng cng c th c kh trng bng cch lau ra hai ln/thng vi cc dung dch

chng nm. Phng nh hn v t cy cng c kh trng bng tia cc tm hay cc dung

dch kh trng. T cy thi gi c kh trng bng cch m qut gi v lau tt c cc

b mt bng cn 95% trong 15 pht trc khi bt u lm vic.

Phng nui cng c kh trng trc ht l bng x bng bt. Sau lau bng

dung dch hypoclorit sodium 2% hoc bng cn 95%. Tt c sn, trn u c lau nh

vy mi tun. Cn thn khng nn khuy ng nhng ni b nhim trnh pht tn bo

t.Cn gim s chuyn ng ca khng kh trong bung cy n mc ti thiu v vy tt

c cc dng c phc v vic cy u phi chun b y trong khi cy trnh i li ra

vo bung cy nhiu ln.

2.5.2.2. Kh trng bnh cy v cc dng c khc

a. Dng c:

Dng c thy tinh dung cho nui cy m v t bo thc vt phi l bnh thy tinh

trong sut nh sng qua c mc ti a v trung tnh trnh kim t bnh thytinh gy nh hng n s pht trin ca m nui cy.

Cn ra sch dng c thy tinh trc khi a vo s dng. Thng thng ch cn x l

bng sulfochromate mt ln u khi a vo s dng v sau ch cn ra sch bng x

phng, trng nhiu ln bng nc my cui cng trng bng nc ct. Sauk hi ro

nc dng c thy tinh cn c v trng bng cch sy 160 0C/gi. Sau khi ngui

c ly ra ct vo ch t bi.

Dng c kim loi, giy nhm cn c kh trng bng khng kh nng (130-

1700C) trong 2-4 gi trong t sy. Tt c cc vt dng ny phi c gi kn trc khi

kh trng nhng khng c gi bng giy v giy b phn r 1700C. Khng nn hp

kh trng dng c kim loi v iu kin nng m s lm cho kim loi b r st v b n

mn.

Trc khi s dng cc dng c c kh trng bng khng kh nng, cc dng

c c ly ra khi giy gi, nhng vo cn 950 v t trn ngn la n cn. Sauk hi



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dng xong, dng c ny phi c t li bng cn trc khi s dng tip. Khi s dng

cn cn lu y n s an ton ti a v rt d b pht.

Autoclave l phng php kh trng bng hi nc di p sut nht nh.Nt

gn, vi, cc dng c thy tinh, bnh nui cy bng plastic, nt cao su, pipet, nc, mi

trng khong u c th kh trng bng ni hp. Gn nh tt c vi sinh u b chtbi hi nc trong ni hp trong 10-15 pht 1210C.

b. Nt y:

Thng dng nht l nt y lm bng bng khng thm nc. Nt phi tng

i cht m bo bi khng i qua c, ng thi nc t mi trng khng b bc

hi qu d dng trong qu trnh nui cy. Bng khng thm nc l loi nt n gin

nht nhng c nhc im sau:

+ Nu khi hp nt bng b t hoc dnh mi trng th v sau s b nhim nm

nht l cc th nghim nui cy trong thi gian di.

+Thao tc lm nt bng chm, khng thun tin khi nui cy trn qui m ln.

+ Ch dng c mt vi ln sau phi b.

Hin nay ngi ta s dng nhiu loi np y khc nhau thay th nt bong.

Cc hng sn xut dng c nui cy m cung cp loi np ng nghim v bnh tam gic

bng nha chu nhit c th hp 1200C m khng b bin dng. Mt s phng th

nghim s dng np inox hoc cao su rt thun tin cho vic vt trng.

Cc dung dch m dng pha ch mi trng (dung dch mui khong,

vitamin..) cn c bo qun trong t lnh. Dung dch vitamin nn chia thnh nhiu loi

nh v bo qun trong ngn ca t lnh. Khng nn pha mt lng qu ln dung dchm cc cht sinh trng, thng ch nn dng cc l c dung tch 100-200 ml.

c. Kh trng mi trng khong:

kh trng mi trng khong thng s dng hai phng php hp tit trng

v lc bng mng lc v trng. Mi trng nui cy, nc ct v cc ha cht n nh

khc c th cha trong bnh thy tinh v y bng nt gn, giy nhm hoc np nha.

Tuy nhin mi trng c cc cht khng bn nhit th cn s dng phin lc milipore. Ni

chung mi trng khong c hp tit trng 1210C, 1 atm. Vi nhng th tch nh

(100 ml hoc t hn) thi gian kh trng l15-20 pht. Vi lng mi trng ln th phi

kh trng trong 30-40 pht. p sut khng nn cao qu 1 atm vi p sut cao s lm phnhy carbohydrate v cc phc hp nhy cm vi nhit

Bng 2.1 . Thi gian ti thiu hp kh trng mi trng nui cy m 1210C (Burgerr, 1988)

Thi gian kh trng ti thiu (pht)Th tch mi trng (ml)



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2420-25265028,510031,525035500

401000 482000553000634000

Nhiu loi protein, vitamin, amino axit, hormone..khng bn nhit v vy nn

dng phin lc micropore kh trng. Phin lc milipore hoc phin lc seitz u c th s

dng vi kch thc l khng ln hn 0,2 m. Cc bnh ng thy tinh cn phi c

hp tit trng trc khi lc.

Mi trng khong c cht khng bn nhit c th c tin hnh chun b theo

cc bc sau: u tin cc cht khong bn vi nhit c hp tit trng, sau lmlnh xung cn 50-600C trong iu kin v trng khi nhng cht khng bn vi nhit

s c lc v trng. Dung dch kh trng ny s phi hp vi nhau trong iu

kin v trng to ra mt mi trng hon chnh

2.5.2.3.Kh trng mu cy thc vt

Cc loi mu cy thng c s dng trong nui cy m

V mt nguyn tc, cc t bo cn sng phn ha u c kh nng phn phn ha

tr li trng thi tr ha v ti lp kh nng phn chia. Tuy nhin c th nhn xt chung l

cc m ang pht trin mnh (m phn sinh ngn, tng tng) khi t vo mi trng

c cha mt lng cht sinh trng thch hp u c kh nng to m so cao. bt

u nghin cu nhn ging v tnh mt cy nht nh, trc tin ngi ta ch y n chi

nch v m phn sinh ngn.Cc m thc vt thng c s dng nui cy l:

- nh sinh trng thn, r

- Chi bn

- Tng tng

- Vy c

- Chi ngn

- Nhu m l, nhu m v thn- Chi ny t c

Cn bit l tuy mang mt lng thng tin di truyn nh nhau, cc m khc nhau trn

cng mt cy c th cho cc m so pht trin khc nhau vi kh nng ti sinh chi, r

hay cy hon chnh rt khc nhau. V vy khi khi u chn ging, nhn ging mt cy



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c th trc ht cn tm hiu phn ng ca cc b phn khc nhau ca cy trong nui cy

cc nng cht sinh trng khc nhau.

Kh trng mu cy l vic lm kh v mu sng khng th kh bng nhit cao

m phi gi c bn cht sinh hc ca n. Do mu cy thc vt phi c kh trng

bng cc dung dch kh trng. Cc dung dch kh trng thng dng l hypocloritcalcium, hypoclorit sodium, chlorua thy ngn, oxi gi T l v trng thnh cng ph

thuc thi gian kh trng v nng cc cht kh trng v kh nng xm nhp ca

chng vo cc k lch li lm trn b mt m nui cy, kh nng y ht cc bt kh bm

trn b mt m nui cy. Cc dung dch dng kh trng mu phi bo v c m

thc vt nhng thi gian kh trng phi tiu dit ngun gy nhim l nm v vi

khun.

Cc mu cy khi chn la phi c ra trc bng x phng di dng nc

chy ri mi cho vo ngm trong dung dch kh trng

tng tnh linh ng v kh nng xm nhp ca cht dit khun, thng thng ngi ta

x l m nui cy trong cn 70% trong 30 giy, sau mi x l trong dung dch dit

khun. Trong thi gian x l, m cy phi c ngp hon ton trong dung dch dit

khun. Khi x l xong m cy c ra nhiu ln trong nc ct v trng (3-5 ln).

Nhng phn trn m cy b tc nhn v trng lm cho trng phi ct b trc khi

t m cy ln mi trng. trnh nh hng trc tip ca tc nhn v trng ln m

cy, nn ch y li mt lp bc ngoi khi ngn m vo dung dch dit khun. Lp cui

cng ny s c ct b hoc bc i trc khi t m cy ln mi trng.

i vi nhng mu kh kh trng th vic x l mu phi c lp li sau 24-48 htrc khi cy. iu ny cho php nhng vi sinh vt cha cht c thi gian pht trin n

giai on nhy cm vi thuc kh trng.

Bng 2.2. Nng v thi gian s dng 1 s cht dit khun x l m cy thc vt

Stt Cht kh trng Nng Thi gian kh

trng (pht)

Hiu qu

1 Hypochloritecalcium

9-10% 5-30 Rt tt

2 Hypochlorite

sodium

0,5-5% 5-50 Rt tt

3 Nc bromine 1-2% 2-10 Rt tt4 Oxy gi 3-12% 5-15 Tt5 Chlorua thy 0,1-1% 2-10 Tt



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ngn6 Nitrate bc 1% 5-30 Tt7 Khng sinh 4-50mg/l 30-60 kh

Cc cht khng sinh trn thc t t c s dng v tc dng khng trit v c

nh hng xu ngay ln s sinh trng ca m cy.

Vic x l thnh cng ngun gy nhim phn ln ph thuc vo k thut x l

trong nui cy v trng. Cc ngun gy nhim l bi tc, tay, qun o v vy trong khi

cy phi ra tay,lau bng cn 700 ti khy tay, tay o phi xon cao ln, kp tc gn..

Khng ni chuyn hoc nhy mi trong khi ang cy. Khi cy khng nn chm tay vo

mt trong ca bnh cy cng nh cc dng c cy. Khng a vo t cy cc bnh cy

b nhim v bo t c th pht tn trong t cy.

2.6. Mi trng

Mt trong nhng yu t quan trng nht trong s tng trng v pht trin hnh

thi ca t bo v m thc vt trong nui cy m l thnh phn mi trng nui cy.

Thnh phn mi trng nui cy t bo v m thc vt thay i ty theo loi v b phn

nui cy. i vi cng mt mu cy nhng ty theo mc ch th nghim th thnh phn

mi trng cng s thay i ty theo giai on phn ha ca mu cy.

2.6.1. Thnh phn ho hc ca cc mi trng nui cy m, t bo thc vtMi trng nui cy m v t bo thc vt tuy rt a dng nhng u gm mt s

thnh phn c bn sau:

1- Cc mui khong a lng v vi lng

2- Cc vitamin

3- Cc amino axt

4- Ngun cc- bon: mt s cc loi ng

5- Cc cht iu ho sinh trng

6- Cc cht hu c b sung: nc da, dch chit nm men, dch chit khoai ty,

bt chui kh...

7- Cht lm thay i trng thi mi trung: cc loi thch (agar)

Tt c cc hp cht ny u tham gia vo mt hoc nhiu chc nng trong s sinh

trng v phn ho ca thc vt nui cy in vitro.



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Cc nh khoa hc s dng cc mi trng nui cy rt khc nhau. Vic la chn

mi trng nui cy vi thnh phn ho hc c trng ph thuc vo mt s yu t:

1- i tng cy trng hoc m nui cy khc nhau c nhu cu khc nhau v thnh

phn mi trng.

2- Mc ch nghin cu hoc phng thc nui cy khc nhau (nui cy to m sophi ho hoc phi v tnh, nui cy t bo trn hoc dch lng t bo, vi nhn

ging)

3- Trng thi mi trng khc nhau (c, lng, bn lng).

2.6.1.1. Cc cht khong

i vi cy trng, cc cht v c ng vai tr rt quan trng. V d, Mg l mt

phn ca phn t dip lc, Ca l thnh phn ca mng t bo, N l thnh phn quan trng

ca amino axt, vitamin, protein v cc axt nucleic. Tng t, Fe, Zn v Mo cng l

thnh phn ca mt s enzym.Cc mi trng khc nhau c hm lng v thnh phn cht khong khc nhau, v

d thnh phn v nng khong ca mi trng White hoc Knop kh ngho nn,

nhng li rt giu mi trng MS v B5.

Mui khong l thnh phn khng th thiu trong cc mi trng nui cy m v

t bo thc vt:

- Mui khong l cc vt liu (ngun N, S, P....) cho s tng hp cc cht hu c.

Nit, lu hunh, pht-pho l cc thnh phn khng th thiu ca cc phn t protein, cc

axt nucleic v nhiu cht hu c khc. Canxi v axt boric c tm thy ch yu thnht bo, c bit l canxi c nhim v quan trng gip n nh mng sinh hc.

- ng vai tr nh mt thnh phn khng th thiu ca nhiu enzym (l cc co-

factor): Magie, km, st... v nhiu nguyn t vi lng l nhng phn quan trng ca cc

enzym.

- Cc ion ca cc mui ho tan ng vai tr quan trng n nh p sut thm thu

ca mi trng v t bo, duy tr th in ho ca thc vt. V d, K v C rt quan trng

trong iu ho tnh thm lc ca t bo, duy tr in th v tham gia hot ho nhiu

enzym.

Trong mi trng, cc mui khong c chia thnh cc nguyn t vi lng v a

lng:

- Cc cht dinh dng a lng bao gm su nguyn t: nitrogen (N), phosphorus

(P), potassium (K), calcium (Ca), magnesium (Mg) v sulphur (S) tn ti di dng mui

khong, l thnh phn ca cc mi trng dinh dng khc nhau. Tt c cc nguyn t

ny l rt cn thit cho sinh trng ca m v t bo thc vt. Mi trng nui cy phi



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Amonium ch yu c d tr r nh ngun nit hu c. Nitrat c th c

vn chuyn theo mch xylem n cc b phn ca cy, ti n s tham gia vo qu

trnh ng ho nit. Nitrat c th c d tr khng bo v thc hin chc nng quan

trng trong vic iu chnh s thm thu v cn bng ion ca cy trng.

S bin i nitrat: Nitrat khng th s dng ngay lp tc sinh tng hp cccht hu c phc tp m trc tin cn phi c kh thnh amoniac. Phn ng din ra

nh sau:

NO3- + 8H+ + 8e- NH3 + 2 H2O + OH-

Phn ng ny c thc hin qua 2 bc nh hai enzym: nitrat- v nitrit

reductaza. Trc tin, nitrat c bin i thnh nitrit nh nitrat reductaza. Tip theo,

nitrit b kh thnh amoniac nh enzym nitrit reductaza. S bin i ca nitrat thnh nitrit

din ra trong t bo cht. Trong hu ht cc cy trng, s kh nitrat c th din ra c l

v nh chi. S kh nitrat din ra mc no ph thuc rt ln vo cc nhn t nh:loi, tui cy, nng nitrat. C th, cc loi cy thn g c kh nng kh nitrat rt cao.

Khi nng nitrat thp, s kh hu nh din ra r. Ngc li, nu nng nitrat cao

th qu trnh ny din ra c l. Cc cation kt hp vi nitrat c vai tr quan trng trong

vic hp thu nitrat. Nu cation l K+ th hot ng ca enzym nitrat reductaza r thp v

nitrat s c vn chuyn ln cc nh chi ca cy. Trong trng hp cation l Ca 2+ th

s kh r li din ra mnh hn.

S kh nitrit thnh NH3 nh enzym nitrit reductaza din ra trong l cy, trong

in t cn thit cho phn ng ny c cung cp t s kh cc hp cht st trong h

thng quang hp.

S kh nit cha trong cc hp cht: Amonium v amoniac l nhng cht c

i vi thc vt ngay nng thp. Do chng cn c chuyn ho tht nhanh

thnh cc hp cht phn t lng nh c cha N nh: asparagin, arginin, allantoin v

betain. Sinh tng hp glutamin v glutamat din ra c r v nh chi l cc qu trnh

c bn trong s chuyn ho amonium.

Bn cnh s kh c tnh ca amonium v amoniac, cc hp cht cha nit phn

t lng thp cn c mt s chc nng khc. Chc nng quan trng nht l cung cp N

trong cc lin kt hu c v -NH2 c thc vt hp th nh ngun N hu c cho qu

trnh sinh tng hp cc amino axt v protein. Cc hp cht phn t lng nh ny cn

c s dng lm cht mang cation nh Mn, Cu vn chuyn cc cation qua h thng

mch dn trong cy. Ngoi ra, chng cn nh mt kho d tr nit d tha. Ngc li vi

con ngi v ng vt, thc vt khng th bi tit cc hp cht nit hu c nh ur

nhng nh c ch ny cho php thc vt d tr c nit hu c.



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c. Phospho (P):

Photpho l nguyn t quan trng trong i sng thc vt . N tham gia vo vic vn

chuyn nng lng, sinh tng hp protein, acid nuclic v tham gia cu trc ca mng.

Trong mi trng nui cy, Photpho c cung cp di dng mono hay

dihydrogenphosphate potasium hay sodium. Ion photphate ha tr 1 v 2 c th chuyni ln nhau ty theo pH. Ion H2PO4- chim u th pH nh hn 7, y l c tnh ca

hu ht mi trng nui cy m t bo thc vt cng l ion d c thc vt hp th

nht. Photpho thng c cung cp di dng photphate ha tan hn ch.

Nng photphate ha tan cao trong mi trng s lm gim s tng trng ca

m, c th do calcium v mt s nguyn t vi lng b kt ta trong mi trng hoc b

gim hp thu vo trong m. Nng ion photphate cho vo mi trng cao nht l 18,9

mM, trung bnh l 1,7 mM, hu ht cc mi trng cha photphate khong 1.3 mM.

Phospho dng HPO42-

c hp th nh h thng r ca thc vt v ngc li vinitrat, sunfat, n khng b kh. N c th c mt trong thc vt di dng P v c hoc

dng hp cht este (R-O-P). Nng lng thu c khi gii phng mt nguyn t P khi

cc lin kt (cao nng lng) l rt quan trng i vi qu trnh trao i cht ca t bo.

Axit nucleic : P l mt nguyn t thit yu trong cu to ca DNA v RNA ni

cc n phn t axt ribonucleic to thnh i phn t.

Phospholipid: Phospholipid ca mng sinh hc cng c cha mt lng ln P.

Trong nhng phospholipid ny, P (qua lin kt este) to nn cu ni gia diglyxerit vi

mt amin, axit amin hoc mt ru. Phospholipid c mt u ho nc, phn tdiglyxerit v mt u k nc c cha PO43-. C hai u c chc nng quan trng trong

vic gi n nh mng t bo. Mng t bo bao gm hai lp phospholipid n ghp li

to thnh lp mng kp lipid. u a nc ca lp phospholipid quay ra ngoi hng v

pha cc phn t nc trong khi ui k nc li quay vo pha trong gia hai lp ca

mng t bo v tng tc ln nhau.

Qu trnh chuyn ho nng lng: Phospho dng lin kt este cao nng (C-P)

rt quan trng i vi qu trnh chuyn ho nng lng v tng hp sinh hc thc vt.

ng vai tr quan trng hn na l cc lin kt cao nng gia hai nguyn t P nh trong

phn t ATP (P-P = 30 kJ). Nng lng gii phng trong sut qu trnh thu phn

glucoza, qu trnh oxi ho, phosphoryl ho hoc quang hp c s dng tng hp

ATP. Ngc li nng lng ny khi cn li c gii phng ra qua phn ng thu phn

ATP thnh ADP v P v c. V vy ATP c chuyn ho v tng hp mi lin tc. Mt

gram nh r ang trong giai on trao i cht mnh c th tng hp 5g ATP/ ngy vi

tc tng hp trung bnh l 30 giy.



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Vng d tr P (phosphat): Trong t bo bao gm hai vng d tr phosphat khc

nhau. Vng trao i, ch yu phosphat dng este, nm trong t bo cht v ty th. Vng

khng trao i, ch yu l dng P v c, nm trong khng bo. Nu ngng cung cp P

cho cy, nng P v c trong khng bo ngay lp tc s gim trong khi vng trao i

tc gim chm hn nhiu. Khi tng cng cung cp P, nng P cha trong cc cquan ca t bo cng tng theo, tuy nhin khi tng qu mc bnh thng th ch c P v

c trong khng bo tng ln. V vy c th ni, P d tha c d tr khng bo di

dng P v c.

Cc enzym: P v c cng c kh nng iu chnh tt trong nhiu qu trnh trao

i cht ca thc vt. Vy nn s phn b P l cn thit iu chnh qu trnh trao i

cht ca t bo. c chua, s gim P v c khng bo trong t bo cht kch thch hot

tnh ca enzym phosphofructokinaza. Enzym ny l enzym quan trng trong s phn gii

c cht ca phn ng thu phn glyco v lm tng s h hp ca t bo trong qu trnhchn. Cng trong thi gian ny, s thiu ht P c th lm chm qu trnh chn ca qu.

Trong qu trnh tng hp tinh bt ca lc lp, P cng ng mt vai tr quan trng.

Ch vi nng thp, P v c c th gy c ch qu trnh tng hp tinh bt. S d nh

vy l do ADP-gluco-pyrophosphorylaza, enzym quan trng nht trong qu trnh tng

hp tinh bt, b km hm bi P v c v c kch thch nh cc triossephosphat. V th,

s cn bng gia cc hp cht c cha P l rt quan trng trong iu ho tng hp tinh

bt lc lp. Ngoi ra, P v c cng tham gia qu trnh ny theo mt con ng khc.

Cc phn t vn chuyn phosphat mng t bo s mang P v c vo t bo v cc

triosephosphat ra ngoi t bo, lm nng P v c trong lc lp tng, triosephosphat

gim. iu ny li tc ng n qu trnh tng hp tinh bt theo c ch trnh by

trn. Ribuloza biphosphat (RuBP), vi vai tr nh mt cht nhn CO2, l hp cht quan

trng trong s c nh CO2. S ti tng hp ny i hi phi c cc triosephosphat. Khi

nng P v c cao s kch thch gii phng cc triosephossphat ra khi lc lp, gy

thiu ht cc cht ny, do lm km hm qu trnh c nh CO 2. Ngoi ra, phospho cn

quan trng trong vic iu khin hot ng ca nhiu enzym khc. Nng phospho ti

u cho s sinh trng ca thc vt l 0,3 0,5 g/ kg trng lng kh. S thiu P lm cy

chm ln, l cy c mu xanh thm do trong thi gian b thiu P, s pht trin ca lchm hn s tng hp dip lc t nn lm tng nng dip lc t trong l cy.

d. Lu hunh (S):

Lu hunh nh SO42- c hp th r cy vi tc chm. Ging nh nitrat, lu

hunh phi c kh trc khi s dng sinh tng hp cc hp cht c cha lu hunh



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nh amino axt, protein v enzym. Lu hunh dng cha kh c kt hp trong cc

sulpholipid v cc polysaccharid.

S ng ho lu hunh: Bc u tin trong qu trnh ng ho lu hunh l s

hot ho gc SO42- nh enzym ATP sulfurylaza. Phn ng ny to ra adenosine

phosphosulfate (APS) v P v c. Tip theo l hai qu trnh ho hc hon ton khc nhau.Mt qu trnh khng din ra s kh lu hunh m to lin kt vi cc polysaccharide

trong sulpholipid. Trong qu trnh th hai, lu hunh c kh thnh nhm SH (nhm

thiol) v nhm sulfuryl ca APS c vn chuyn ti gluthantione (Glut-SH). Sau

nhm SH c vn chuyn ti cho acetylserine v phn tch thnh acetat v cystein.

Cystein l sn phm bn u tin trong qu trnh ng ho v l tin cht ca tt c cc

hp cht hu c c cha lu hunh trong thc vt, v d nh: protein, co-enzym, cc hp

cht trao i cht th cp... Qu trnh ng ho lu hunh ch yu din ra lc lp. Khi

thiu lu hunh, sinh tng hp protein b km hm, lng dip lc t trong l cy b gimst.

Cc protein: Lu hunh c mt trong cc protein c cha cystein v methionin.

C hai axt amin ny u l tin cht ca tt c cc hp cht c cha lu hunh trong thc

vt. Lu hunh, cu t hp thnh ca nhiu coenzym v cc nhm prosthetic, c chc

nng quan trng trong rt nhiu phn ng oxy ho kh, c biu din nh sau:

R-SH + HS-R R-S-S-R.

Gc R c th l phn cn li ca phn t cystein nhng cng c th l tripeptit

gluthatione. Gluthatione tan c trong nc v do , n ng vai tr nh mt h oxiho kh lc lp v dch bo. Cu lu hunh gia hai phn t cystein rt quan trng

trong cu trc bc ba ca phn t protein v hot ng ca enzym. Nhm SH, nh

cp trn c trong thnh phn ca cc coenzym v APS, to thnh mt phn ca nhm

chc nng trong phn t enzym.

Cc metallothionein: Cc hp cht phn t lng thp c cha lu hunh-

metallothionein, thng hay c tm thy trong thc vt. Hu ht cc cht ny u c

cha cystein. c bit, cc kim loi nh: ng, cadimi v km thng lin kt trong

metallothionein. Gn nh chc chn nhng phn t protein nh ny tham gia vo s bi

tit cc ion kim loi trn khi chng d tha, trc khi lin kt vi nhm chc nng SH

ca cc enzym.

Lu hunh cha b kh: Lu hunh dng cha b kh l thnh phn cu to

sulpholipid, l phn t to thnh cu trc ca mng sinh hc. Lu hunh thng c mt

dng hp cht este ca lu hunh v ng 6 cacbon, v d nh glucoza. Sulpholipid c



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S gin ca t bo: S tng kch thc ca khng bo trung tm trong t bo l

mt qu trnh quan trng trong s gin t bo. hnh thnh khng bo, u tin l s

tng kch thc ln ca thnh t bo, tip theo kh nng thm thu ca khng bo tng

ln. iu ny c th t c nh s tch t K+ gy ra s tng mnh v th tch ca khng

bo do tnh thm. GA3 v K+

dng nh c tc dng h tr nhau trong vai tr lm tngchiu cao cy.

S cn bng ion: K+ c vai tr quan trng cho vic duy tr cn bng ion. N trung

ho cc anion km linh ng trong t bo cht v rt nhiu cc anion linh ng trong

mch xylem, libe v khng bo. Trong qu trnh trao i nitrat, K+ c chc nng ch yu

l vn chuyn ion NO3- qua nhng khong cch di trong mch xylem hoc d tr trong

khng bo. Sau qu trnh kh nitrat trong l cy, lng K+ cn li c s dng tng

hp cc axit hu c trung ho ion K+. Cc mui kali ca cc axit hu c nh kali malat

c vn chuyn ti r, sau K

+

c th nhn ion nitrat t bo r v vn chuyn chngqua mch xylem.

f. Canxi (Ca):

Calcium cng l mt cation ch yu gip cn bng cc anion trong cy nhng cch

thc khng ging nh K+ v Mg+ v Ca2+ khng phi l ion linh ng. Calciun c th lin

kt cc phn t sinh hc li vi nhau do n gp phn vo trong cu trc v hot ng

sinh l ca mng t bo v phin gia ca thnh t bo . S hot ng ca nhiu enzim

khc ca thc vt cng ph thuc vo Ca2+ v calcium l ng yu t vi nhng enzim

phn gii ATP.Trong nui cy t bo, Ca2+ c vai tr trong s pht sinh hnh thi ng thi vi s

cm ng ca cc cht iu ha sinh trng c bit l auxin v cytokinin.

Ca2+ l thnh phn quan trng ca thnh t bo v mng t bo. S lng ln Ca2+

gn trn thnh t bo ng vai tr ch yu trong cng c vng chc cho thnh t bo

v iu ho cu trc mng t bo.

Ion Ca2+ t do c mt trong t bo nng rt thp, khong 1M c tc dng

ngn chn s kt ta P v c. Do hm lng ion Ca 2+ trong t bo thp nn khng c s

cnh tranh vi ion Mg2+

v v tr gn cation v trnh lm bt hot enzym. Ion Ca2+

ch cth di chuyn qua mng t bo theo mt chiu (Ca 2+ ch ra ngoi t bo c nhng

khng vo c), do m bo c nng ion Ca2+ ni bo thp. c bit trong cc

t bo l, c mt lng ln canxi lin kt vi cc khng bo. Canxi cn thit cho s thit

lp cn bng ion nh trung ho cc anion hu c v v c. Hu nh canxi dng lin kt

to mui ocxalat. Mc d hp cht ny kh tan nhng n c vai tr duy tr nng ion



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Ca2+ thp trong lc lp v t bo cht. Mui canxiocxalat cn c chc nng iu chnh s

thm thu ca t bo. Canxi c vai tr quan trng trong qu trnh nhn ln ca t bo v

r. Ngoi ra s pht trin ca ng phn cng ph thuc vo canxi, y l qu trnh c

nh hng nh canxi ngoi bo. IAA tham gia vo qu trnh vn chuyn canxi. Cht c

ch auxin nh TIBA cng c ch s phn phi Ca2+

trong thc vt lm xut hin s thiuht canxi.

Vai tr ca Ca i vi thnh t bo: Pectin l thnh phn quan trng ca mng

lin kt gia cc b bo vi nhau v c phn hu nh enzym polygalacturonase. Tuy

nhin, Ca c ch mnh hot ng ca polygalacturonaza. Hot ng mnh ca enzym

ny c ghi nhn khi thiu Ca. Nu nng Ca c th hu ht cc pectin s tn ti

di dng mui canxipectat. Nh vy, thnh t bo c kh nng chng chu tt i vi

hot ng ph hu ca enzym polygalacturonaza. S c mt ca ion Ca 2+ cng c vai tr

quan trng trong vic ngn chn s xm nhim nm.Ion Ca2+ c tc ng ln n s n nh ca mng t bo. S thiu ion Ca 2+ s lm

tng kh nng thot ra ngoi mng t bo ca cc hp cht phn t lng nh. Mng t

bo c th s b phn hu hon ton khi thiu ht nghim trng ion Ca2+. Ion Ca2+ c kh

nng lm n nh mng t bo thng qua s tng tc vi cc nhm phosphat, cacboxyl

ca hp cht phospholipid v protein c mt trong mng t bo.

Cc enzym: Khc vi magie l nguyn t tham gia vo qu trnh hot ho ca rt

nhiu enzym, canxi ch c tc ng ln mt vi enzym nh: amilaza v ATPaza. Ca ch

yu kch thch cc enzym mng t bo, m hot ng ca nhng enzyme ny c quinh nh cu trc mng. Tuy nhin, ion Ca2+ cng c tc dng km hm mt s enzym

ca t bo cht. Calmodulin trong t bo c kh nng hot ho cc enzym nh

phospholipaza bng cch to thnh phc ca Ca2+ - calmodulin vi enzym. Ngoi ra,

ngi ta cn cho rng calmodulin c vai tr trong vic vn chuyn ion Ca 2+ ti khng

bo.

g. Magi (Mg):

Magnesium l nguyn t cn thit cho s sinh tng hp dip lc t v ng thi n

cng tham gia vo cu trc ca mt s enzim vn chuyn photphate. Ion Mg+

l mt ionlinh ng, c th khuych tn vo trong t bo nh K+ v vy c vai tr nh mt cation

c th trung ha cc cation v cc acid hu c. Mi trng nui cy m thc vt thng

cha Mg vi nng khng thay i nhiu trung bnh l 6,8mM. MgSO 4 l ngun b

sung ion Mg+ duy nht cho m cy.



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Mg2+ l mt ion rt linh ng c kh nng hnh thnh phc vi cc nhm chc nng

khc nhau.

Vai tr Mg2+ ca i vi quang hp: Mg2+ l nguyn t trung tm trong phn t

chlorophyl ca h quang hp I v II. Trong phn t chlorophyl, cc photon c hp th

to ra dng in t, t to ra ATP v NADPH ng vai tr quan trng i vi c nhCO2. Nu Mg2+ c mt vi nng ti u th khong 10 - 20% ion Mg2+ trong l c c

nh lc lp. Nng cao cc ion Mg2+ v K+ l cn thit duy tr pH khong 6,5 7,5

trong lc lp v t bo cht, tri vi khng bo pH ch vo khong 5- 6. Trong mt

chng mc no , pH xc nh cu trc ca protein v enzym nn n nh hng n qu

trnh sinh tng hp protein v chc nng ca lc lp.

Vai tr Mg2+ i vi hot tnh ca cc enzym: Mg2+ l ion cn thit cho cu trc

bc ba ca nhiu phc enzym-c cht v n to ra dng cu trc khng gian ph hp gia

enzym v c cht. Mg2+ tham gia vo qu trnh tng hp protein vi nhiu cp khcnhau. Mg2+ to thnh cu ni gia cc di n v ca ribosome. Khi thiu Mg2+, cc di

n v s b tch ra v qu trnh tng hp protein b ngng li. S hot ng ca cc

enzym nh: RNA polymeraza tham gia vo qu trnh sinh tng hp RNA i hi phi c

mt Mg2+, do thiu Mg2+ s km hm sinh tng hp RNA. l cy, 25% protein tng

s nm trong lc lp, nu thiu Mg2+ th ngay lp tc cu trc v chc nng ca lc lp b

nh hng.

Mg2+ cn quan trng trong hot ng ca enzym ribulose biphosphat cacboxylaza.

y l mt enzym ph thuc nhiu vo pH v Mg2+

. Lin kt ca Mg2+

vi enzym lmtng i lc vi c cht CO2 v Vmax.

Vai tr Mg2+ i vi chuyn ho nng lng: Mg l mt cht khng th thiu

trong qu trnh chuyn ho nng lng ca thc vt do vai tr quan trng ca n i vi

sinh tng hp ATP (ADP + P v c = ATP), c bit l lc lp. Trong qu trnh ny,

Mg2+ to thnh cu ni gia enzym v ADP. Ngoi ra, Mg2+ cn c kh nng to phc vi

ATP. Enzym ATPaza vn chuyn cc nhm phosphoryl cao nng, cung cp cho protein

hoc ng. Mc d Mg2+ c nhiu chc nng nh vy nhng hu nh n li tn ti

dng d tr trong khng bo. Ti y, n ng vai tr nh mt ion trung ho vi cc

anion hu c v v c trong vic cn bng ion.

2.6.1.3. Cc nguyn t vi lng (Fe, B, Cl, Co, Cu, Mn, Mo, Zn...)

Cc nguyn t v c cn mt lng nh nhng khng th thiu cho sinh trng

ca m v t bo thc vt c gi l cc nguyn t vi lng. l cc ion: iron (Fe),

manganese (Mn), zinc (Zn), boron (B), copper (Cu), v molybdenum (Mo). Fe d ng

nh thch hp hn khi c cung cp di dng chelate Fe, v Zn c dng bnh



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thng trong cc mi trng nui cy. Cc dng mui tatrate v citrate Fe kh ha tan v

thng hay kt ta trong mi trng. Vn ny c th khc phc bng cch dng

diaminetetraacetic acid (EDTA)-chelate Fe thay cho citrate Fe, c bit i vi qu trnh

to phi. Tuy nhin, cc dng chelate EDTA khng hon ton n nh trong mi trng

nui cy dng lng.Mt s mi trng nui cy c lm giu bng cobalt (Co), iodine (I) v sodium

(Na), nhng cc yu cu nghim ngt v cc nguyn t ny cho sinh trng ca t bo

khng c thit l p. Ni chung, nng thng c s dng i vi Cu v Co l 0,1

mol/L, Fe v Mo l 1 mol/L, I l 5 mol/L, Zn l 5-30 mol/L, Mn l 20-90 mol/L v

B l 2-5100 mol/L c b sung vo mi trng nui cy ty thuc vo yu cu ca

tng th nghim.

Vic chia thnh cc nguyn t vi lng v a lng ch yu da trn nhu cu ca

thc vt i vi cc cht ny. Nhu cu ca thc vt i vi cc nguyn t a lng l ln

hn, vi nng > 0.5 mM. Cc nguyn t vi lng c s dng trong mi trng

nng < 0.5 mM.

Nhu cu ca cy i vi nguyn t vi lng l rt thp. Do vy nhng nguyn t

ny cng c mt trong mi trng cc nng tng ng. Hu ht cc nguyn t vi

lng s dng lng nmol. Mt s nguyn t vi lng c nhu cu nh hn c th thay

th d dng bng s ln tp ngu nhin ca chng trong cc thnh phn ca mi trng

nh agar, cc cht b sung nh nc da, dch chit nm men (yeast extract), cc mui

v nc. Tm quan trng ca mt s nguyn t vi lng trong thnh phn mi trng cncha c hiu mt cch r rng. Co, Al, Ni... c th c li i vi thc vt nhng cng

c th l khng cn thit. Trong thc t, hu ht cc nguyn t vi lng ch c phn

khong ca mui (cation) l quan trng, cn vai tr cc anion c th l khng cn thit.

Ion SO42- d tha trong mi trng v ch yu pht sinh t cc mui MgSO4, K2SO4

Nhu cu ca thc vt i vi cc nguyn t a lng ln hn. Nguyn t a lng

c nng cao nht trong cc mi trng nui cy m v t bo thc vt. Nhn c

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