T. O. Diener discovered a
(1) free infectious RNA
(2) free infectious DNA
(3) infectious protein
Bacterial leaf blight of rice is caused by a species of
In the light of recent classification of living organisms into three domains of life (bacteria, archaea and eukarya), which one of the following statement is true about archaea?
(1) Archaea resemble eukarya in all respects
(2) Archaea have some novel features that are absent in other prokaryotes and eukaryotes
(3) Archaea completely differ from both prokaryotes and eukaryotes
(4) Archaea completely differ from prokaryotes
Thermococcus, Methanococcus and Methanobacterium exemplify
(1) archaebacteria that contain protein homologous to eukarytic core histones
(2) archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled
(3) bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria
(4) bacteria that contain a cytoskeleton and ribosomes
Which of the following is a flowering plant with nodules containing filamentous nitrogen-fixing microorganism?
(1) Casuarina equisetifolia
(2) Crotolaria juncea
(3) Cycas revoluta
(4) Cicer arietinum
Which of the following is a slime mould?
Ergot of rye is caused by a species of:
True nucleus is absent in
Cell wall is absent in
Which of the following shows coiled RNA strand and capsomeres?
(1) Polio virus
(2) Tobacco mosaic virus
(3) Measles virus