Microbiology and Plant- Microbe Interactions — DU B.Sc. (Hons.) Botany Previous Year Question Papers

1 (a) Find the one correct option for the following multiple-choice questions 1x5=5 (i) Which of the following is a PGPR genus? (ii) Viral nucleic acid may consist of: (A) Only DNA (B) Only RNA (D) Both DNA and RNA simultaneously (iii)Baltimore classification of viruses is primarily based on: (A) Shape of capsid (8) Host specificity ~. (C) Type ofnucleic acid and replication strategy (D) Presence of envelope (iv) Teichoic acids are characteristic components of: (A) Gram-positive bacteria a) Archaeal membranes (C) Gram-negative outer membrane (D) Mycoplasma membrane (v) Which of the following plant bacteria lack a true cell wall? Q) RItizobium a) State True or False of the following statements: (i) During the log phase, bacteria exhibit maximum metabolic activity. (ii) Transformation in bacteria involves transfer of genetic material through direct contact. (iti)All nitrogen fixing cyanobacteria require heterocyst for nitrogen fixation. (iv) Photoautotrophs use organic carbon as their energy source. (V) Antonie van Leeuwenhoek disproved the theory of spontaneous generation. c) Match the Following Column I Column II (i) Prion A. Creutzfeldt-Jakob disease (iii) Spheroplast Penicillin-treated E. coli (iv) Viroid D. T4 bacteriophage particle (v) Virion E. Potato spindle tuber disease 2. Differentiate between the following (any three) 5x3=15 a) Archaea and bacteria b) Bacterial and viral diseases in plants c) PGPR and mycorrhizae d) Prions and Viroids 3. Write short note on the following topics (any three) 5x3=15 a) Microbial world b) Roles of viruses in medical sciences c) Discovery of viruses d) Fermentation 4. Draw well-labelled diagrams of the following (any three): 5x3=15 a) Arbuscular mycorrhizae b) Binary fission c) Bacteriophage d) Gram-negative cell wall a) b) c) Why do rhizobia fix nitrogen inside the root but not in the soil? Why are all viruses considered as obligate intracellular parasites? Endospore formation in bacteria is not a mode of reproduction. Comment.