Cau 14: trinh bay cac t/c chinh cua vr

Virut la nhung VSV:

- co kthuoc nho be: trung binh 20 - 300 nm, co kha nang qua dc mang loc cua vk ( nho nhat la nhom pavovres co kthuoc 20nm, lon nhat la nhom poxvres co kthuoc 300nm)

- Co cau tao don jan: chi gom acid nucleic va vo capsid,1 so virut co the co them: vo bao ngoai, cac spike, 1 so enzyme.

- Co kha nang gay benh cho nguoi, dong vat, vk( co kha nang bieu hien nhung tinh chat co ban cua su song)

- vr chi mang 1 (.) 2 loai acid nucleic la or AND or ARN.

- vr k co he thong enzym chuyen hoa va ho hap do do moi hoat dong tong hop fai nho vao he thong enzyme cua tb cam thu.

=> Viec su dung Ksinh de dieu tri cac benh nhiem khuan gay boi vr la k hieu qua.

Cau 15: Tbay cac tp cau tao cua vr & c.nang cua cac tp do

1. Acid nucleic ( AN)

- vr chi mang 1 (.) 2 loai AN: or ADN or ARN, co the la chuoi don or chuoi kep, dang soi dai or dang vong khep kin, co the gom nhieu doan ngan rieng re or 1 chuoi lien tuc.

- vr mang ADN, fan lon la deu mang ADN chuoi kep( tru phage M13)

- vr mang ARN, chu yeu la mang ARN chuoi don( tru reo vres)

- vr mang ADN or ARN 1 chuoi thi co the la chuoi (+) or chuoi (-), neu mang ADN or ARN 2 chuoi thi 1 chuoi (+) & 1 chuoi (-).

+ vr mang ARN chuoi (+) khi xam nhap vao tb cam thu, ARN chuoi (+) co vai tro nhu mARN & co kha nang dc dich ma ngay boi riboxom cua tb cam thu de tong hop protein.

+ vr mang ARN chuoi (-) k co kha nang dic ma ngay ma fai tien hanh sao ma tao ARN chuoi (+). Vi vay nhung vr nay mang tren vo capsid 1 enzym or la ARN fu thuoc ARN polymerase.

* Vai tro cua AN

- Mang toan bo thong tin di truyen ???????

- Khi vr xam nhap vao tb cam thu, AN dc gphong & thuc hien truyen thong tin cho tb, dieu khien cac bao quan (.) tb tong hop cac tphan fuc vu cho qtr nhan len cua vr.

=> + AN quyet dinh kha nang gay nh.trung cua vr (.) tb cam thu tham tri gay fa vo tb.

+ AN quyet dinh chu ky nhan len cua vr (.) tb cam thu.

- AN mang tinh ban KN dac hieu cua vr.

2. Vo capsid

-B/chat la Pr bao boc ben ngoai acid nucleic. Vo dc ctao tu nhieu don vi hinh thai la cac capsomer, moi don vi capsomer lai dc ctao tu 5-6 ptu Pr, moi ptu Pr dc goi la 1 dvi cau truc

-Vo capsid cua vr co 3 loai ctruc: doi xung khoi, dxung xoan, dxung hon hop

*Vtro cua vo capsid

-Bao ve AN k bi ton thuong khi vr xam nhap tu tb nay sang tb khac (ngan enzyme nuclease va cac yeu to fa huy AN khac)

-Ho tro qtrinh xam nhap cua vr vao (.) tb nho cac Pr bam tren vo capsid

-La noi mang khang nguyen cua vr: KN ngung ket, KN trung hoa, KN ket hop bo the

-Giu cho hinh thai va kthuoc cua vr luon dc on dinh

(*) Cac ctruc rieng

a. vo bao ngoai (vo peplon, envelope)

-Boc ngoai vo capsid

-Thuong co nguon goc la mang nguyen sinh chat cua tb bi nhiem vr

*Cnang vo bao ngoai

-Tham gia su bam cua vr tren cac vi tri thich hop cua tb cam thu

-Tham gia vao gdoan lap rap va gphong vr ra khoi tb sau chu ki nhan len

-Tham gia hinh thanh tinh on dinh kthuoc va hthai cua vr

-Tao nen KN dac hieu tren be mat vr

b. Spike

-La nhung diem loi len tren be mat vo capsid or vo bao ngoai, tan cung cua cac spike la cac Pr bam cua vr voi cac receptor dac hieu tren be mat tb cam thu

c. Enzym

-1 so vr co mang enzyme

-Retrovres mang enzyme RT fuc vu cho qtrinh sao ma nguoc

-Vr ARN chuoi (-) mang enzyme. ARN phu thuoc ARN polymerase phuc vu cho qtrinh sao chep ARN chuoi (+)

-Nhom Arbovres va influenza co enzyme gay doc than kinh neuramindas