1.Briefly describe the important methods by which plant viruses get transmitted.
2. Comment briefly on the integrated method of controlling plant viruses. 3. Scrapie and mad-cow diseases are caused by
(a) Retrovirus (c) Viroids
(b) Prions (d) Satellite virus
4. The word “prion” was coined by
(a) Diener (c) Alper
(b) Raymer (d) Prusiner
5. Bacteriophage 174 contains
(a) ssRNA (c) ssDNA
(b) dsRNA (d) dsDNA
6. Tailed phages are the largest virus group and they comprise more than
(a) 65% Phages (c) 85% Phages
(b) 75% Phages (d) 95% Phages
7. Escherichia coli is infected by
(a) Phage MS2 (c) Phage T4
(b) Phage M13 (d) All of these
8. Prion infected material can be inactivated by
(a) Irradiation (c) Boiling
(b) Incineration (d) Autoclaving
9. Which type of virus contains the enzyme lysozyme that helps in penetration?
(a) Animal viruses (c) Bacteriophages
(b) Plant viruses (d) Mycophages