Biological Classification

Infectious proteins are present in –

1. Viroids
2. Geminiviruses
3. Satellite viruses
4. Prions

T.O. Diener discovered a

1. free infectious DNA
2. infectious protein
3. bacteriophage
4. free infectious RNA

Oxygenic photosynthesis occurs in

1. Oscillatoria
2. Rhodospirillum
3. Chlorobium
4. Chromatium

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

1. Black rust of wheat – Puccinia graminis
2. Loose smut of wheat – Ustilago nuda
3. Root knot of vegetables – Meloidogyne sp.
4. Late blight of potato – Alternaria solani

Bacterial leaf blight of rice is caused by a species of

1. Alternaria
2. Erwinia
3. Xanthomonas
4. Pseudomonas

Thermococcus, Methanococcus and Methanobacterium exemplify

1. bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria
2. bacteria that contain a cytoskeleton and ribosomes
3. archaebacteria that contain protein homologous to eukaryotic core histones
4. archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled

In the light of recent classification of living organisms into three domains of life (bacteria, archaea and eukarya), which one of the following statements is true about archaea?

1. Archaea completely differ from both prokaryotes and eukaryotes.
2. Archaea completely differ from prokaryotes.
3. Archaea resemble eukarya in all respects.
4. Archaea have some novel features that are absent in other prokaryotes and eukaryotes.

Cellulose is the major component of cell walls of

1. Pseudomonas
2. Saccharomyces
3. Pythium
4. Xanthomonas

Which one of the following is a slime mould?

1. Physarum
2. Thiobacillus
3. Anabaena
4. Rhizopus

Which one of the following statements about Mycoplasma is wrong?

1. They are pleomorphic.
2. They are sensitive to penicillin.
3. They cause diseases in plants.
4. They are also called PPLO.