Chuyn

Chuyn : Di truyn hc phn t - Bi dng HSG mn Sinh hc 9

Di y l mt vi bi trong chuyn : Di truyn hc phn t ti bin son ging dy, bi dng cho HSG mn Sinh hc 9. Mong qu thy c c v cho nhn xt, gp . Mi kin qu bu ca qu thy c xin c gi vo a ch email - mrcongdst@gmail.com. Trn trng cm n.

CHUYN : DI TRUYN HC PHN TCHNG I: C S L THUYT

BI 1: NUCLTIT

I. Phn loi nucltit

- Nhm cc xiribnucltit: Gm 4 loi nucltit l Anin (vit tt l A), Timin (vit tt l T), Xitzin (vit tt l X - ting anh vit tt l C - Cytosine) v Guanin (vit tt l G).

- Nhm cc Ribnucltit: Gm 4 loi nucltit l Adenin (vit tt l A), Uraxin (vit tt l U), Xitzin (vit tt l X - ting anh vit tt l C - Cytosine) v Guanin (vit tt l G).

II. c im chung ca cc nucltit

- Cc nucltit u l nhng hp cht hu c c to nn bi 5 nguyn t l cacbon (C), hidro (H), xi (O), nit (N) v phtpho (P).

- Mi nucltit u c cu trc gm 3 thnh phn l 1 phn t axit phtphoric (H3PO4 - cn gi l nhm phtphat), 1 phn t ng pentz (ng 5 cacbon - c 5 nguyn t cacbon trong phn t) v 1 phn t baznitric, trong phn t axit phtphoric lin kt vi phn t ng pentz bng lin kt ha tr (cn gi l lin kt phtphoieste) v phn t ng pentz lin kt vi phn t baznitric bng lin kt N - gliczit.

Hnh 1.1: S cu trc ca 1 nucltit

- Mi nucltit u c khi lng trung bnh l 300 n v cacbon (vC) v chiu di trung bnh l 3,4 Angstron (A0) (1vC = 1/12 khi lng nguyn t C12 = 1,6602.10-24 gam; 1A0 = 10-1nm = 10-4 = 10-7 mm).

III. c im ring v cu trc ca tng loi nucltit

- Cu trc ca tng loi nucltit:Nhm nucltitLoi nucltitThnh phn cu trc

xiribnucltitAnin (A)H3PO4 - ng 5 cacbon (loi C5H10O4) - Baznitric loi Anin

Timin (T)H3PO4 - ng 5 cacbon (loi C5H10O4) - Baznitric loi Timin

Xitzin (X)H3PO4 - ng 5 cacbon (loi C5H10O4) - Baznitric loi Xitzin

Guanin (G)H3PO4 - ng 5 cacbon (loi C5H10O4) - Baznitric loi Guanin

RibnucltitAnin (A)H3PO4 - ng 5 cacbon (loi C5H10O5) - Baznitric loi Anin

Uraxin (U)H3PO4 - ng 5 cacbon (loi C5H10O5) - Baznitric loi Uraxin

Xitzin (X)H3PO4 - ng 5 cacbon (loi C5H10O5) - Baznitric loi Xitzin

Guanin (G)H3PO4 - ng 5 cacbon (loi C5H10O5) - Baznitric loi Guanin

- Lu : + V cc nucltit thuc nhm xiribnucltit hay nhm Ribnucltit ch khc nhau v thnh phn baznitric nn tn gi ca mi loi nucltit chnh l tn gi ca baznitric cu to nn n. + Phn t ng 5 cacbon cu to nn cc xirbnucltit thuc loi C5H10O4 c tn gi l xiribz, cn phn t ng cu to nn cc ribnucltit thuc loi C5H10O5 c tn gi l ribz. Nm nguyn t cacbon trong ng pentz (xiribz, ribz) u c nh s th t t 1 n 5 v km theo du , bn trn.IV. Chc nng ca cc nucltit- Cc xiribnucltit (A, T, G, X) l cc n phn cu to nn mt loi axit nuclic c tn gi l axit xiribnuclic, vit tt l ADN, tn ti ch yu trong cc nhim sc th (NST) trong nhn ca t bo.- Cc ribnucltit (A, U, G, X) l cc n phn cu to nn mt loi axit nuclic c tn gi l axit ribnuclic, vit tt l ARN, gm ba loi ch yu l ARN thng tin (mARN), ARN vn chuyn (tARN) v ARN ribxm (rARN), c tng hp ch yu trong nhn ca t bo sau chng s ri nhn ra t bo cht thc hin chc nng.GHI NH

- Mi nucltit c khi lng phn t trung bnh l 300 vC v c chiu di trung bnh l 3,4 A0.

- Trong mi nuctit c 1 lin kt ha tr c hnh thnh gia phn t axit phtphoric v phn t ng pentz.- Cc nucltit A, T, G, X l cc n phn cu to ca ADN, cn cc nucltit A, U, G, X l cc n phn cu to ca ARN.

- ADN v ARN u l cc axit nuclic.

BI 2: CU TO HA HC V CU TRC KHNG GIAN CA ADN

I. Cu to ha hc ca phn t ADN- ADN l mt loi axit nuclic c cu to t cc nguyn t Cacbon (C), Hir (H), xi (O), Nit (N) v Phtpho (P).- ADN thuc loi i phn t, c kch thc ln, c th di ti hng trm v khi lng ln t n hng triu, hng chc triu vC.

- ADN c cu to theo nguyn tc a phn, gm hng vn, hng triu n phn l cc nucltit thuc 4 loi l Anin (A), Timin (T), Xitzin (X) v Guanin (G).II. Cu trc khng gian ca phn t ADN1. M hnh cu trc khng gian ca phn t ADN do J.Oatxn v F.Crick cng b nm 1953 (cn gi l m hnh cu trc khng gian dng B ca ADN)

- ADN l mt chui xon kp gm hai mch plynucltit chy song song, ngc chiu vi nhau v xon u quanh mt trc theo chiu t tri sang phi, ngc chiu kim ng h, to thnh cc chu k xon, mi chu k xon cao 34A0 gm 10 cp nucltit v c ng knh l 20A0.

- Trn mi mch ca ADN, cc nucltit lin kt vi nhau theo chiu dc bng cc lin kt ha tr c hnh thnh gia phn t ng ca nucltit ny vi phn t axit phtphoric ca nucltit k tip.

- Cc nucltit gia hai mch ca ADN lin kt vi nhau theo tng cp bng cc lin kt hir theo nguyn tc b sung, ngha l A ca mch ny lin kt vi T ca mch kia bng 2 lin kt hir v ngc li, G ca mch ny lin kt vi X ca mch kia bng 3 lin kt hir v ngc li.

Hnh 2.1 (a, b, c): M hnh cu trc mt on phn t ADN

- Do cc nucltit gia hai mch ca ADN lin kt vi nhau thnh tng cp theo nguyn tc b sung cho nn:+ Trnh t sp xp cc nucltit trong hai mch n ca ADN c tnh cht b sung cho nhau, ngha l t trnh t sp xp cc nucltit ca mch ny c th suy ra trnh t sp xp cc nucltit ca mch kia.

+ Trong mi phn t ADN, s anin bng s timin v s guanin bng s xitzin, do (A + G) = (T + X) hay (A + X) = (T + G) v t s (A +T)/(G + X) l c trng cho tng phn t ADN ca tng loi sinh vt.

2. Nguyn tc b sung (NTBS) trong cu trc khng gian ca phn t ADN

- Biu hin: Cc nucltit gia hai mch ca ADN lin kt vi nhau theo tng cp bng cc lin kt hir theo nguyn tc b sung, ngha l A ca mch ny lin kt vi T ca mch kia bng 2 lin kt hir v ngc li, G ca mch ny lin kt vi X ca mch kia bng 3 lin kt hir v ngc li.- H qu:

+ a n tnh cht b sung ca hai mch n trong phn t ADN, v vy khi bit trnh t sp xp cc nucltit ca mch n ny th c th suy ra trnh t sp xp cc nucltit ca mch n kia.+ Trong mi phn t ADN, s anin bng s timin v s guanin bng s xitzin, do (A + G) = (T + X) hay (A + X) = (T + G) v t s (A +T)/(G + X) l c trng cho tng phn t ADN ca tng loi sinh vt.

- ngha:

+ NTBS m bo cho cu trc khng gian ca phn t ADN c n nh thc hin chc nng mang v bo qun thng tin di truyn.

+ NTBS to ra cho ADN c c nhng c tnh quan trng l t nhn i theo ng mu ban u v phin m to ra cc ARN trong qu trnh truyn t thng tin di truyn qua cc th h t bo v c th.

+ S vi phm NTBS c th lm thay i cu trc ca ADN v s lng, thnh phn v trnh t sp xp cc nucltit t to ra cc ADN mi gp phn lm tng tnh a dng v phong ph cho cc loi sinh vt. III. Tnh a dng v c th ca phn t ADN- ADN ca mi loi sinh vt c c trng bi cc yu t:

+ S lng, thnh phn v trnh t sp xp ca cc nucltit trong mi phn t ADN.

+ T l (A + T)/(G + X) trong mi phn t ADN.

+ Hm lng ADN trong nhn t bo.

- Yu t quy nh tnh c th ca mi loi ADN l s lng, thnh phn v trnh t sp xp cc nucltit trong phn t.

- ADN c tnh a dng l do s lng, thnh phn v trnh t sp xp khc nhau ca cc loi nucltit to nn.- Tnh a dng v tnh c th ca ADN l c s phn t cho tnh a dng v tnh c th ca cc loi sinh vt.GHI NH

BI 3: QU TRNH T NHN I V CHC NNG CA PHN T ADNI. Qu trnh t nhn i ca phn t ADN (cn gi l t sao, ti bn hay tng hp).1. a im v thi im din ra

Qu trnh t nhn i ca phn t ADN din ra trong nhn t bo, ti cc nhim sc th k trung gian khi NST dng si mnh dn xon.

2. Cc yu t tham gia

- Phn t ADN m: L khun mu to ra ADN con.

- Cc nucltit A, T, G, X (loi xiribnucltit) t do trong mi trng ni bo: L nguyn liu hnh thnh mch mi ca ADN con.- Mt s enzim v yu t c nhng tc dng tho xon, tch mch, gi cho mch trng thi dui, lin kt cc nucltit vi nhau.- Ngun nng lng ATP (anzin triphtphat).3. Din bin c bn

- Khi bt u qu trnh t nhn i, nh tc dng ca cc enzim v yu t c nhng tc dng tho xon, tch mch, gi cho mch trng thi dui nn hai mch n ca phn t ADN m tch nhau dn dn v tr thnh mch khun tng hp ra mch mi trong mi ADN con. - Cc nucltit trn mi mch n ca phn t ADN m sau khi c tch ra ln lt lin kt vi cc nucltit t do trong mi trng ni bo theo nguyn tc A lin kt vi T bng 2 lin kt hir hay ngc li, G lin kt vi X bng 3 lin kt hir hay ngc li dn hnh thnh mch mi trong mi ADN con.- Khi qu trnh t nhn i kt thc, hai phn t ADN con c to thnh, chng ging nhau v ging vi ADN m, trong mi ADN con c 1 mch l mch khun ca ADN m (mch c), mch cn li c tng hp mi t cc nucltit t do trong mi trng ni bo.

Hnh 3.1: S minh ha qu trnh t nhn i ca ADN

4. Kt qu

- T 1 phn t ADN m ban u khi kt thc qu trnh t nhn i (nhn i 1 ln) to ra 2 phn t ADN con ging nhau v ging vi ADN m.

- Lu :

+ T 1 phn t ADN m ban u sau k ln t nhn i2k phn t ADN con.

+ T a phn t ADN m ban u, mi phn t t nhn i k ln a.2k phn t ADN con.

5. Cc nguyn tc

- Nguyn tc khun mu: Mch mi ca ADN con c tng hp da trn mch khun ca ADN m.- Nguyn tc b sung: Mch mi ca ADN con c tng hp t cc nucltit t do trong mi trng ni bo bng cch lin kt vi cc nucltit trn mch khun ca ADN m theo nguyn tc: A lin kt vi T bng 2 lin kt hir hay ngc li, G lin kt vi X bng 3 lin kt hir hay ngc li.

- Nguyn tc gi li mt na (bn bo ton): Trong mi ADN con c 1 mch l mch ca ADN m (mch c), mch cn li c tng hp mi.

6. ngha Qu trnh t nhn i ca ADN l c s cho s nhn i ca NST, l c s phn t ca hin tng di truyn v sinh sn, duy tr cc c tnh ca tng loi n nh qua cc th h, m bo s lin tc sinh si ny n ca sinh vt.II. Bn cht ca gen v chc nng ca ADN

1. Bn cht ca gen

- Gen l mt on ca phn t ADN c chc nng di truyn xc nh, trung bnh mi gen gm khong 600 n 1500 cp nucltit c trnh t xc nh.

- Mi phn t ADN trong t bo ca mi loi sinh vt cha nhiu gen c phn b theo chiu di ca phn t ADN.

- Ty theo chc nng m gen c phn thnh nhiu loi, trong mi gen cu trc u lu gi thng tin quy nh cu trc ca mt loi prtin gi l thng tin di truyn. Thng tin di truyn lu gi trn mi gen cu trc c xc nh bi s lng, thnh phn v trnh t sp xp cc b gm 3 nucltit k tip nhau nm trn mch m gc ca gen v c gi chung l cc triplet hay m di truyn.Hnh 3.2: Bng m di truyn ca cc gen cu trcCc axt amin:

Phe - Phninalanin, Leu - Lxin, Ile - Izlxin, Met - Mtinin, Val - Valin, Ser - Xrin, Pro - Prlin, Thr - Threnin, Ala - Alanin, Tyr - Tirzin, His - Histiin, Gln - Gluatmin, Asn - Asparagin, Lys - Lizin, Asp - Axit Aspactic, Glu - Axit Glutamic, Cys - Xistin, Trp - Triptphan, Arg - Acginin, Gly - Glixin)

2. Chc nng ca ADN- ADN mang cc gen v vy ADN l ni lu gi, bo qun thng tin di truyn ngha l thng tin v cu trc ca prtin.

- Nh c tnh t nhn i nn ADN thc hin c s truyn t thng tin di truyn qua cc th h t bo v c th.GHI NH

BI 4: ARN V QU TRNH TNG HP ARNI. Cu trc v chc nng ca cc loi ARN

1. Cc loi ARN v chc nng ca chng

- ARN thng tin (mARN): C vai tr truyn t thng tin quy nh cu trc ca prtin cn tng hp.

- ARN vn chuyn (tARN): C chc nng vn chuyn axit amin tng ng ti ni tng hp prtin, mi loi tARN ch vn chuyn 1 loi axit amin.

- ARN ribxm: L thnh phn cu to nn ribxm - ni tng hp prtin.

2. Cu trc chung ca cc loi ARN

- ARN c cu to t cc nguyn t C, H, O, N v P, thuc loi i phn t nhng c kch thc v khi lng nh hn nhiu so vi ADN.

- ARN c cu to theo nguyn tc a phn, gm hng trm, hng nghn n phn l cc nucltit thuc 4 loi l A, U, G v X.

- Phn t ARN ch c 1 mch plinucltit do cc nucltit lin kt vi nhau theo chiu dc bng cc lin kt ha tr c hnh thnh gia phn t ng ca nucltit ny vi phn t axit phtphoric ca nucltit k tip to thnh.3. c im c trng v cu trc ca mARN, tARN v rARN

a. c im c trng v cu trc ca mARN

- Mch plinucltit ca mARN tn ti dng mch thng, trong , c 3 nucltit k tip nhau to thnh 1 b ba m sao gi chung l cc codon hay m di truyn.- Trong mi phn t mARN lun c 1 b ba m u l b ba AUG (b ba ny c chc nng khi u s dch m v m ha cho axit amin mtinin sinh vt nhn chun hoc axit foocmin mtinin sinh vt nhn s), cc b ba m ha axit amin v 1 b ba kt thc c th l UAG hoc UAA hoc UGA.

Hnh 4.1: M hnh cu trc ca phn t mARN

Hnh 4.2: Bng m di truyn ca mARNb. c im c trng v cu trc ca tARN- Mch plinucltit ca tARN c cun tr li to thnh kiu ba thy nh kiu l ch ba, trong ba thy ny c:+ Mt thy mang b ba nucltit c hiu gi l b ba i m (anticodon) s b sung vi m sao (codon) trn mARN, mi tARN c 1 b ba i m c trng.

+ Mt thy gn vi ribxm.

+ Mt thy c chc nng nhn din enzim gn axit amin tng ng vi tARN.- Trong phn t tARN, nhng vng m mch plinucltit vn li to xon kp th cc nucltit nhng vng cng ghp cp v lin kt vi nhau bng lin kt hir theo nguyn tc b sung: A lin kt vi U, G lin kt vi X. c. c im c trng v cu trc ca rARN: Mch plinucltit ca rARN c nhng on cun li to xon kp, ti cc nucltit cng ghp cp v lin kt vi nhau bng lin kt hir theo nguyn tc b sung: A lin kt vi U, G lin kt vi X.

Hnh 4.4: M hnh cu trc ca phn t rARN

II. Qu trnh tng hp ARN (cn gi l qu trnh phin m)1. a im v thi im xy ra: Qu trnh tng ARN din ra trong nhn t bo, ti cc NST k trung gian khi NST ang dng si mnh dn xon.

2. Cc yu t tham gia

- Mt on ca phn t ADN tng ng vi 1 gen.

- Cc nucltit A, U, G, X t do trong mi trng ni bo.- Cc loi enzim v ngun nng lng ATP

3. Din bin c bn

- Khi bt u tng hp ARN, di tc dng ca enzim, gen c tho xon v tch dn 2 mch n, trong ch c 1 mch c dng lm khun tng hp ARN do mch ny c gi l mch khun hoc mch gc, mch cn li c gi l mch b sung.

- Cc nucltit A, U, G, X t do trong mi trng ni bo bt cp v lin kt vi cc nucltit trn mch khun ca gen hnh thnh dn dn mch ARN theo nguyn tc b sung, trong :+ U ca mi trng ni bo bt cp v lin kt vi A trn mch khun bng 2 lin kt hir.

+ A ca mi trng ni bo bt cp v lin kt vi T trn mch khun bng 2 lin kt hir.

+ G ca mi trng ni bo bt cp v lin kt vi X trn mch khun bng 3 lin kt hir.

+ X ca mi trng ni bo bt cp v lin kt vi G trn mch khun bng 3 lin kt hir.- Khi kt thc, phn t ARN c hnh thnh lin tch khi gen ri tip tc hon thin v cu trc to thnh ARN hon chnh v sau n ri nhn i ra t bo cht thc hin qu trnh tng hp prtin.4. Kt qu

- 1 gen: Phin m 1 ln1 phn t ARN; phin m k lnk phn t ARN.- a gen: Cng phin m 1 lna phn t ARN; cng phin m k lna.k phn t ARN.

5. Cc nguyn tc

- Nguyn tc khun mu: Phn t ARN c tng hp da trn khun mu ca 1 mch n ca gen, mch ny c gi l khun hoc mch gc.

- Nguyn tc b sung: Mch ARN c hnh thnh t cc nucltit A, U, G, X t do trong mi trng ni bo bng cch bt cp v lin kt vi cc nucltit trn mch khun ca gen theo nguyn tc:

+ U ca mi trng ni bo bt cp v lin kt vi A trn mch khun bng 2 lin kt hir.

+ A ca mi trng ni bo bt cp v lin kt vi T trn mch khun bng 2 lin kt hir.

+ G ca mi trng ni bo bt cp v lin kt vi X trn mch khun bng 3 lin kt hir.

+ X ca mi trng ni bo bt cp v lin kt vi G trn mch khun bng 3 lin kt hir.

6. ngha: To ra cc ARN tham gia vo qu trnh tng hp prtin, m bo cho qu trnh truyn t thng tin di truyn t ADN - gen n prtin v s hnh thnh cc tnh trng ca c th.

III. Mi quan h gia gen v ARN

- S : Gen (1 on ADN) ARN.- Bn cht: Trnh t cc nucltit trn mch khun ca gen quy nh trnh t cc nucltit trong mch ARN.

GHI NH

BI 5: CU TRC V CHC NNG CA PRTINI. Cu trc ca prtin1. Cu trc ha hc ca prtin

- Prtin l hp cht hu c c cu to bi 4 nguyn t chnh l C, H, O, N v c th cn c mt s nguyn t khc nh Fe, Zn, S

- Prtin thuc loi i phn t, c khi lng v kch thc ln, v kch thc c th di ti 0,1 , v khi lng c th t ti hng triu vC.

- Prtin c cu trc theo nguyn tc a phn, gm hng trm n phn l cc axit amin thuc hn 20 loi khc nhau nhng cc loi axit amin ny u c cu trc chung gm nguyn t C trung tm, nhm amin, nhm cacboxin v gc R.

Hnh 5.1: Cc axit amin v cu trc chung ca cc axit amin2. Cc bc cu trc khng gian ca prtin- Cu trc bc 1: L trnh t sp xp cc axit amin trong chui axit amin, cu trc ny c gi vng nh cc lin kt peptit c hnh thnh gia cc axit amin, chui axit amin c nhiu lin kt peptit cho nn cn c gi l chui plipeptit. - Cu trc bc 2: L chui axit amin cun li to cc vng xon l xo u n (dng xon) hoc to thnh nhng phin gp np (dng gp ), cu trc ny c gi vng nh cc lin kt hir gia cc axit amin gn nhau.- Cu trc bc 3: L hnh dng khng gian ba chiu ca prtin do cu trc bc 2 cun xp to thnh kiu c trng cho tng loi prtin, cu trc ny c gi vng nh cc lin kt isunphua hoc lin kt hir.

- Cu trc bc 4: L cu trc ca mt s loi prtin gm hai hoc nhiu chui axit amin cng loi hay khc loi kt hp vi nhau. - Lu :+ Cu trc bc 1 c xc nh v mt di truyn, c vai tr ch yu trong vic xc nh tnh c th v quy nh cc bc cu trc khng gian cao hn ca prtin. Cu trc bc 3 v bc 4 l cc bc cu trc ch yu gip prtin thc hin c chc nng sinh hc.+ Cc yu t ca mi trng nh nhit cao, pH,c th ph hy cc cu trc khng gian 3 chiu ca prtin lm cho chng mt chc nng, hin tng ny gi l hin tng bin tnh ca prtin.3. Tnh a dng v c th trong cu trc ca prtin- Tnh a dng v c th ca prtin c xc nh bi s lng, thnh phn v trnh t sp xp cc axit amin trong chui axit amin to nn mi phn t prtin.

- Tnh a dng v c th ca prtin cn c th hin cc dng cu trc khng gian ca prtin, c bit l cu trc bc 3 v bc 4, s chui axit amin.

II. Chc nng ca prtin

- i vi t bo v c th, prtin c nhiu chc nng quan trng nh:

+ Prtin l thnh phn quan trng cu to nn cc b phn ca t bo, t hnh thnh nn cc c im gii phu, hnh thi ca cc m, cc c quan, h c quan v c th. V d:

Histn l loi prtin tham gia vo cu trc ca NST. Clagen v elastin l cc loi prtin cu to nn da v m lin kt. Kratin l loi prtin cu to nn mng, sng, tc v lng.+ Prtin to nn cc enzim c chc nng xc tc cho cc phn ng sinh ha xy ra trong qu trnh trao i cht ca t bo v c th. V d:

Pepsin l loi enzim c trong dch v ca d dy c vai tr xc tc cho phn ng phn ct prtin chui di thnh cc prtin chui ngn gm t 3 - 10 axit amin.

ARN - plimenaza l loi prtin xc tc trong qu trnh tng hp ARN.

+ Prtin to nn phn ln cc hoocmn c vai tr iu ha cc qu trnh trao i cht trong t bo v c th. V d:

Insulin l loi hoocmn c vai tr iu ha lng ng trong mu. Tiroxin l loi hoocmn c vai tr iu ha sc ln ca c th.

+ Prtin to nn cc khng th c vai tr bo v c th chng li cc vi khun, virut gy bnh.

+ Prtin tham gia vn chuyn cc cht, to ra s vn ng ca t bo v c th. V d:

Hmglbin l loi prtin trong hng cu ca ngi c vai tr vn chuyn O2 v CO2. Actin v miozin l cc loi prtin to nn s vn ng ca t bo v c th.

Nhm phtphat (H3PO4)

ng Pentz (ng 5 cacbon)

Baznitric

Lin kt ha tr

Lin kt N - glicozit

Hnh 1.2: Cng thc cu to ca ng 5 cacbon,

axit phtphoric v cc baznitric

Tnh a dng v c th

ADN

Cu to ha hc

5 nguyn t: C, H, O, N, P

Kch thc v khi lng ln

Nguyn tc a phn, n phn l cc Nu A, T, G, X

Cu trc khng gian

Hai mch

Xon u theo chu k

Chy song song, ngc chiu nhau

Trn mi mch cc Nu lk vi nhau bng lk ha tr

Gia 2 mch cc Nu lk vi nhau bng lk hir theo NTBS

S lng, thnh phn v trnh t sp xp cc Nu quy nh

A = T v G = X

Tnh cht b sung ca hai mch

C s cho tnh a dng v c th ca cc loi sinh vt quy nh

Khun mu

ADN

Mang cc gen

Lu gi, bo qun thng tin di truyn (thng tin v cu trc ca prtin)

T nhn i

C s tham gia ca nhiu yu t

Trong nhn, ti cc NST k trung gian

Truyn t thng tin di truyn

Hnh thnh mch mi trong ADN con

3 giai on

Tho xn, tch mch

Gi li mt na (1 mch c, 1 mch mi)

Kt thc: To ra 2 ADN con

Nguyn tc

NTBS: A lin kt vi T, G lin kt vi X

Hnh 4.3: M hnh cu trc ca phn t tARN

Hnh 4.5: S tng hp phn t ARN

Chc nng: Tng hp prtin

ARN

Qu trnh tng hp (phin m)

Trong nhn, ti cc NST k trung gian, NST dng mnh, dn xon

Cc yu t tham gia: gen, nucltit t do (A, U, G, X), enzim

3 giai on

Gen tho xon, tch mch

Hnh thnh mch ARN t cc nucltit t do (A, U, G, X)

ARN hon thin v cu trc, i ra t bo cht

ngha: Gen EMBED Equation.DSMT4 ARN

c im ring

mARN: Mch thng, mang cc b ba m sao (codon),

truyn t thng tin di truyn

tARN: Xon, 3 thy, 1 thy mang b ba i m v 1 thy mang axit amin, vn chuyn axit amin

rARN: C nhiu vng xon, tham gia cu to ribxm

3 loi (mARN

tARN, rARN)

Nguyn t: C, H, O, N, P

c im chung

i phn t nhng nh hn ADN

Cu trc

a phn, n phn: A, U, G, X

1 mch n

Nguyn tc: Khun

mu v b sung

Hnh 5.2: Cc bc cu trc khng gian ca prtin

Gio vin bin son: Nguyn Vn Cng - Trng THCS o S Tch - Trc Ninh - Nam nh10

_1489604200.unknown

_1492288813.unknown

_1493071966.unknown

_1493072007.unknown

_1492891181.unknown

_1492293202.unknown

_1492286814.unknown

_1492286856.unknown

_1492286789.unknown

_1489437016.unknown

_1489604162.unknown

_1488954844.unknown