OAP AN BANG PHAN BIET
CAU TRUC VA CHLTC NANG CUA CAC LOAI ARN
\ . Cac loai
\ ^ ARN Noi dung \ ^ Oau true
Ohiic nang
mARN (ARN thong tin)
- Mach don t h i n g - Dau 5' CO trinh tU nucleotit dac hieu gom codon md dau de riboxom nhan biet va gan vao
- Truyen thong tin di truyen tU ADN t6i protein
- mARN dung lam khuon de tdng hop protein
tARN (ARN van chuyen)
- Mach don ty xoan, 3 thuy
- Dau 3' mang axit amin
- Bo ba ddi ma dac hieu de nhan ra va bat doi bd sung v6i codon tuong ling tren mARN - Mang axit amin tdl riboxom
- Tham gia dich ma tren mARN thanh trinh ty cac axit amin tren chuoi polipeptit
rARN (ARN riboxom)
- Nho, duoc san xuat tai cac eo thii cap cua NST
- Ke't hop v6i protein tao nen riboxom noi tong hop protein
Hogt dpng cua GV - GV hdi: Phien ma la gl?
- GV nhan xet, danh gia.
- GV cho HS xem phim ve qua trinh phien ma.
- GV yeu cau HS:
Trinh bay ca chd phien ma.
- GV nhan xet, danh gia.
- GV neu cau hdi:
+ Phan tir ADN d trang thai xodn lam the nao de cd the tdng hgp dugc ARN?
+ Khi nao qua trinh phien ma bat dau va ket thiic?
+ Trong phien ma thi mach nao dugc diing lam khudn?
+ Chieu tdng hgp
Hogt dpng cua HS - HS quan sat hlnh 2.2 SGK trang 12, ket hgp vdi kidn thiic THCS de tra ldi.
- HS theo ddi phim tii 1 - 2 lan.
- Yeu cau nhan bidt dugc mdt sd kidn thiic.
+ Phan tii ADN thao xodn.
+ Cd enzxim khdi ddng qua trinh phien ma.
+ Tdng hgp ARN dua tren nguyen tdc bd sung.
+ ARN tdng hgp xong dugc tach khdi ADN va ADN lai xodn lai.
- Dai dien mdt sd HS tra ldi -> ldp nhan xet.
- HS trao ddi nhanh trong nhdm va tra ldi dugc.
+ Mudn topg hap ARN thi budc -Zau A C N chai thao xodn.
+ Khi enzim ARN- pdlimeraza bam vao gen va hoat ddng thi qua trinh phien ma khdi ddng.
+ Mach dugc lam khudn de tdng hgp ARN la mach 3' - 5'.
Npi dung 2. Ca che phien ma
* Khdi niem phien md Phien Tna la qua trinh tdng hgp ARN tren mach khudn ADN.
* Cc che'phien md
Hogt dpng cua GV mARN la chieu nao?
Hogt dpng cda HS
- GV nhan xet, danh gia va yeu cau HS khai quat kie'n thiic ca chd phien ma.
+ Chieu tdng hgp chieu .5' - 3'.
la - HS trinh bay -^ lap nhan xet, bd sung.
- HS khai quat dugc cac budc trong qua trinh phien ma.
Npi dung
* Thdo xodn ADN Enzim ADN- pdlimeraza bam vao vimg khdi dau
- Gen thao xodn —> Id ro mach gdc 3' - 5'
* Tong hgp ARN
- Sau. khi thao xodn ADN bdt ddu tdng hgp mARN tai vi trf dac hieu
Enzim ARN- pdlimeraza trugt dgc mach ma gdc de tdng hgp mARN theo nguyen tdc bd sung (A-U, G-X).
- Chieu tdng hgp 5' - 3' cho de'n khi gap tfn hieu ke't thiic thi dirng qua trinh tdng hgp.
* Ke't qud
- mARN tdng hgp dugc giai phdng.
- Phan tii ADN xodn trd lai.
Hogt dpng ciia GV - GV hdi:
+ Tai sao qua trinh tdng hgp ARN lai dugc dirng lai?
+ So sanh trinh tu nucledtit d phan tir ARN va trinh tu nucledtit d 2 mach ciia phan tii ADN.
- GV yeu cau HS: So sanh phan tir mARN sau phien ma d td bao nhan thuc va td bao nhan so.
- GV nhan xet, danh gia.
Hogt dpng cua HS - HS van dung kien thiic d bai 1 de tra ldi dugc:
+ Qua trinh tdng hgp ARN dugc bdt dau va kdt thiic la nhd hoat ddng ciia enzim ARN-pdlimeraza, cau triic ciia gen ca'u triic.
+ Trinh tu nucledtit cua mARN gidng mach bd sung vdi mach gdc chi thay T = U.
- HS quan sat hlnh 2.2 SGK trang 12 va tra ldi dugc diem khac nhau:
+ Chidu dai phan tii.
+ ca'u triic gen cua te bao nhan so va nhan thuc khac nhau.
+ Sira chira sau phien ma cd d nhan thuc.
Npi dung
* Luu y: Sau phien ma - 0 te' bao nhan so:
mARN dugc true tidp dung lam khudn de tdng hgp protein.
- 0 td bao nhan thuc mARN phai siia ddi cdt bd cac intron va ndi cac exon vdi nhau.
Hogt dpng cua GV Hogt dpng cda HS Npi dung - Van dung: GV cd the
tie'n hanh theo 2 each:
+ Cach thu- nha't: GV vie't len bang trinh tu cac nucledtit d mach gdc ciia phan tii ADN va yeu cau HS xac dinh trinh tu cac nucledtit tren mARN.
+ Cach thii 2: GV ggi 2 - 3 HS len bang vidt trinh tu cac nucledtit cua ADN —> xac dinh chieu mach gdc va trinh tu nucledtit tren mARN.
* Md rdng: GV giang giai: mdt sd vi riit kf sinh d dgng vat chi cd ARN nhung nhd enzim dac biet nd da phien ma ngugc tdng hgp nen ADN mang thdng tin di truyen cua vi riit tao nen kha nang tang sinh vd han ciia td bao kf chii tao thanh khd'i u.
- HS cd the vie't dugc mdt sd dang.
Hogt dpng 2 TIM Hlfiu DICH MA Muc tieu:
- HS hieu va trinh bay dugc qua trinh dich ma.
- HS hieu dugc sau sdc co che phan tu cua hien tugng di truyen.
Hogt dpng ciia GV - GV yeu cau HS: Trinh bay mdi quan he gen va tfnh trang.
- GV neu van dd: Nhu vay thdng tin cat giau trong gen dugc giai ma thanh tfnh trang bieu hien ra kieu hlnh ciia ca the sinh vat.
Qua trinh dich ma didn ra nhu the nao?
- GV yeu cau HS nghien ciiu SGK trang 12 muc II neu khai niem dich ma.
- GV tien hanh nhu sau:
+ Chia ldp thanh 4 nhdm.
+ Phat cho mdi nhdm 1 bd md hlnh ddng vd ca chd dich ma.
+ GV neu yeu cdu:
nghien cdn SGK rdi thd
Hogt dpng cda HS - HS van dung kie'n thiic tra ldi dugc:
+ Trinh tu nucledtit tren ADN quy dinh trinh tc nucledtit tren ARN.
+ Qua dd ADN quy dinh trinh tu cac axit amin cau tao prdtein, bieu hien thanh tfnh trang.
Npi dung
- HS tdm tdt kidn thtic.
- HS hoat ddng nhdm.
+ Ca nhan nghien ciiu thdng tin SGK va hlnh 2.3 trang 13 de ndm bdt kien thiic.
+ Thao luan nhdm thdng nha't kidn thiic ve hoat hoa axit amin va tdng
1. Khai niem
Dich ma la qua trinh tdng hgp prdtein (sinh tdng hgp prdtein).
2. Cac giai doan ciia qua trinh djch ma
Hogt dpng cua GV hien ca che dich ma bang sa dd.
- GV quan sat cac nhdm va giiip dd nhdm cdn yeu.
- De kiem tra viec ndm bdt kien thiic cua HS GV cdn yeu cau: Khi trinh bay ca che dich ma thi cac thanh vien trong nhdm phai thao cac thao tac, trinh bay chat che.
ro rang.
- GV nhan xet, danh gia hoat dgng nhdm.
- GV giiip HS hoan thien kidn thiic.
Hogt dpng cua HS hop chudi pdlipeptit.
+ The hien ca chd dich ma tren so dd.
- Yeu cau cac thao tac:
+ Tao phiic hgp aa-tARN.
+ Gdn tieu phan ribdxdm vao mARN.
+ Bd sung chfnh xac cac phiic hgp vdi cac codon tren mARN.
+ Lien kdt cac axit amin thanh chudi pdlipeptit.
- Dai dien nhdm trinh bay tren sa dd -> ldp nhan xet, bd sung.
- HS khai quat kien thiic.
Npi dung
a) Giai dogn httgt hod axit amin
- Cac axit amin dugc hoat hoa nhd enzim va ATP.
Hogt dpng cua GV Hogt dpng cua HS Npi dung
- Axit amin gan vdi tARN tuang iing tao phiic hgp aa-tARN.
b) Tong hap chuoi pdlipeptit
* Md ddu:
-Ribdxdm gdn vdi mARN d vi trf nhan biet dac hieu gdn ma md dau.
- Bd ba dd'i ma ciia phiic md dau bd sung vdi codon md dau tren mARN va bdt dau tdng hgp protein.
* Keo dai chudi pdlipeptit
- Codon thii 2 tren mARN gdn bd sung vdi anticodon cua phiic hgp thii 2.
- Ribdxdm cd vai trd gia da tARN va phiic hgp aa-tARN.
- Lien ket peptit hlnh thanh giiia aal va aa2.
- Ribdxdm dich chuyen mdt codon lien kdt peptit hlnh thanh gdn aa2 vdi aa3.
- Ribdxdm tidp tuc chuyen dich den cud'i mARN.
Hogt dpng cua GV
- GV hdi:
+ Khi nao ca the sinh vat cdn lugng ldn protein?
+ Lam thd nao de tdng hgp du sd lugng protein cho nhu cau ciia ca the?
- GV yeu cdu HS tdm tdt ca che di truyen.
- GV nhan xet, danh gia va giup HS hoan thien kien thiic.
Hogt dpng cda HS
- HS van dung kidn thiic ket hgp vdi SGK va hlnh 2.4 trang 14 tra ldi dugc:
+ Co the can lugng prdtein de xay dung td bao md thay the cho vung bi tdn thuang.
+ Tang hieu sua't tdng hgp prdtein phan t\x mARN gdn ddng thdi vdi mdt nhdm ribdxdm.
- Mdt vai HS vidt so dd tren bang -^ ldp nhan xet.
Npi dung
* Ket thiic
- Ribdxdm tiep xiic vdi ma kdt thiic tren mARN thi qua trinh dich ma hoan tat.
- Axit amin md dau tach ra khdi chudi pdlipeptit nhd enzim.
- Chudi pdlipeptit tiep tuc hlnh thanh cac cau triic bac cao han trd thanh prdtein cd hoat tfnh sinh hgc.
* Co chd phan tii ciia hien tugng di truyen.
Hogt dpng cuaGV Hogt dpng cua HS Npi dung - Van dung:
+ GV cd the tidn hanh nhu SGV trang 22.
+ GV cho HS vidt len bang cac treplet tren ADN, codon tren mARN, cac bd ba ddi ma tren tARN, cac axit amin.
- HS trinh bay hoac viet tren bang -> ldp nhan xet, bd sung.
ADN
dich ma
trang
phien
mARN ->• prdtein -> tfnh
4. Kiem tra danh gia
- GV yeu cau HS tdm tdt qua trinh phien ma va dich ma bang so dd.
- GV cd the cho HS lam bai tap trdc nghiem.
Cau 1: Enzim tham gia vao qua trinh phien ma la:
a) ADN-pdlimeraza c) Ligaza b) ARN-pdlimeraza d) Restrictaza
Cau 2: Phan tu mARN dugc tdng hgp tren nguyen tdc bd sung theo chieu a) 3' - 5' c) Di chuyen ciia enzim ADN-pdlimeraza b) 5' - 3' d) Ca a, b, c diing
Cau 3: Co che phan tii ciia hien tugng di truydn dugc the hien theo sadd
a) ADN -^ mARN -^ protein -> tfnh trang b) ADN -^ prdtein -^ mARN -> tfnh trang c) mARN -> ADN -> prdtein -> tfnh trang d) mARN -^ protein -^ ADN -^ tfnh trang 5. Dan do
- Hgc bai, tra ldi cau hdi SGK.
- On lai kidn thiic vd gen, ca'u triic gen.
Bai 3