Chapter 2

Virus contains (a) Protein (b) DNA (d) RNA (d) (a) and either (b) or (c)

Virus infected plants generally have (a) Single stranded DNA (b) Double stranded DNA (c) Double stranded RNA (d) Single stranded RNA

Viruses which infect animals have (a) Single stranded RNA (b) Double stranded RNA (c) Double stranded DNA (d) Any of the above

Bacteriophage generally have (a) Single stranded RNA (b) Double stranded RNA (c) Double stranded DNA (d) Any of the above

Capsomeres may be arranged in (a) Helical (b) Polyhedral (c) Ellipsoid (d) Either (a) or (b)

In virus infected plants the following symptoms can be observed (a) Mosaic formation and stunted growth (b) Leaf rolling and curling (c) Yellowing and vein clearing (d) All of these

Select the total number of diseases from the following which can be caused by virus in plant or animals. Mumps, Small pox, Rust, Smut, Herpes, Influenza, Potato spindle tuber, Red rot of sugar cane, Turnip mosaic, Black rot crucifier (a) 4 (b) 5 (c) 7 (d) 8

Potato spindle tuber disease is caused by (a) Virus (b) Viroids (c) Lichens (d) Fungi

'Viroids' is discovered by (a) Ivanowsky (b) T. O. Diener (c) Beijerinck (d) Stanley

Viroids are (a) Free protein (b) Free RNA (c) Free DNA (d) Free saccharides

The molecular weight of RNA of viroid is (a) High (b) Low (c) Very high (d) Any of the above

Lichens are symbiotic association between (a) Algae and bacteria (b) Bacteria and fungus (c) Algae and fungus (d) Fungus and root of higher plant

In lichen, the algal component is called and fungal component is called (a) mycobiont, phycobiont (b) phycobiont, mycobiont (c) phycobiont, mycorrhazia (d) mycorrhaiza, mycobiont

Which one of the following is heterotrophic in lichen? (a) Fungus (b) Algae (c) Both (a) and (b) (d) None

Lichens are (a) Pollution indicators (b) Symbiotic association between algae and fungus (c) Pioneer species in primary succession on rocks (d) All of the above

Which of the following is incorrect about lichens? (a) Algae part is autotrophic (b) Fungus part absorb nutrient and minerals (c) Fungus provide shelter to algae (d) Algae provide shelter to fungus