Some hyperthermophilic organisms that grow in highly acidic (pH2) habitats belong to the two groups called

(1) eubacteria and archaea

(2) cyanobacteria and diatoms

(3) protists and mosses

(4) liverworts and yeasts

Infectious proteins are present in

(1) gemini viruses

(2) prions

(3) viroids

(4) satellite viruses

Oxygenic photosynthesis occurs in

(1) Chromatium

(2) Oscillatoria

(3) Rhodospirillum

(4) Chlorobium

T. O. Diener discovered a

(1) free infectious RNA

(2) free infectious DNA

(3) infectious protein

(4) bacteriophage

Bacterial leaf blight of rice is caused by a species of

(1) Xanthomonas

(2) Pseudomonas

(3) Alternaria

(4) Erwinia

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?

(1) Rhizopus

(2) Physarum

(3) Thiobacillus

(4) Anabaena

Ergot of rye is caused by a species of:

(1) Phytophthora

(2) Uncinula

(3) Ustilago

(4) Claviceps