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

Which one is the wrong pairing for the disease and its causal organism?

(1) late blight of potato-Alternaria solani

(2) Black rust of wheat-Puccinia graminis

(3) Loose smut of wheat-Ustilago nuda

(4) Root-knot of vegetables-Meloidogyne sp.

T. O. Diener discovered a

(1) free infectious RNA

(2) free infectious DNA

(3) infectious protein

(4) bacteriophage

Modern detergents contain enzyme preparations of

(1) acidophiles

(2) alkaliphiles

(3) thermoacidophiles

(4) thermophiles

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