Biological Classification

Which one of the following is incorrectly matched?

1. Root pressure – guttation
2. Puccinia – smut
3. Root – exarch protoxylem
4. Cassia – imbricate aestivation

Select the correct combination of the statements (i – iv) regarding the characteristics of certain organisms. (i) Methanogens are archaebacteria which produce methane in marshy areas. (ii) Nostoc is a filamentous blue-green alga which fixes atmospheric nitrogen. (iii) Chemosynthetic autotrophic bacteria synthesise cellulose from glucose. (iv) Mycoplasma lack a cell wall and can survive without oxygen. The correct statements are

1. (ii) and (iii)
2. (i), (ii) and (iii)
3. (ii), (iii) and (iv)
4. (i), (ii) and (iv)

Black (stem) rust of wheat is caused by

1. Alternaria solani
2. Ustilago nuda
3. Puccinia graminis
4. Xanthomonas oryzae

Given below is the diagram of a bacteriophage. In which one of the options all the four parts A, B, C and D are correct? [Figure]

1. A Collar, B Tail fibres, C Head, D Sheath
2. A Tail fibres, B Head, C Sheath, D Collar
3. A Head, B Sheath, C Collar, D Tail fibres
4. A Sheath, B Collar, C Head, D Tail fibres

Virus envelope is known as

1. capsid
2. virion
3. nucleoprotein
4. core

Single-celled eukaryotes are included in

1. protista
2. fungi
3. archaea
4. monera

Some hyperthermophilic organisms that grow in highly acidic (pH 2) habitats belong to the two groups

1. eubacteria and archaea
2. cyanobacteria and diatoms
3. protists and mosses
4. liverworts and yeasts

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.

Which pair of the following belongs to basidiomycetes?

1. Puffballs and Claviceps
2. Peziza and stinkhorns
3. Morchella and mushrooms
4. Bird's nest fungi and puffballs

Which of the following environmental conditions are essential for optimum growth of Mucor on a piece of bread? Choose the answer from the following options.

1. B, C and F only
2. A, C and E only
3. A, D and E only
4. B, D and E only

What is common about Trypanosoma, Noctiluca, Monocystis and Giardia?

1. These are all parasites
2. These are all unicellular protists
3. They have flagella
4. They produce spores

The causative agent of mad-cow disease is a-

1. Virus
2. Bacterium
3. Prion
4. Worm

The bacterium ( Clostridium botulinum) that causes botulism is-

1. A facultative aerobe
2. An obligate aerobe
3. A facultative anaerobe
4. An obligate anaerobe

Barophilic prokaryotes

1. grow and multiply in very deep marine sediments
2. occur in water containing high concentrations of barium hydroxide
3. readily grow and divide in sea water enriched in any soluble salt of barium
4. grow slowly in highly alkaline frozen lakes at high altitudes.

There exists a close association between the alga and the fungus within a lichen. The fungus

1. provides protection, anchorage and absorption for the alga
2. provides food for the alga
3. fixes the atmospheric nitrogen for the alga
4. releases oxygen for the alga

Auxospores and hormogonia are formed, respectively, by

1. some diatoms and several cyanobacteria
2. some cyanobacteria and many diatoms
3. several cyanobacteria and several diatoms
4. several diatoms and a few cyanobacteria.

Which of the following unicellular organisms has a macronucleus for trophic function and one or more micronuclei for reproduction?

1. Euglena
2. Amoeba
3. Paramecium
4. Trypanosoma

Which of the following statements is not true for retroviruses?

1. DNA is not present at any stage in the life cycle of retroviruses.
2. Retroviruses carry gene for RNA-dependent DNA polymerase.
3. The genetic material in mature retroviruses is RNA.
4. Retroviruses are causative agents for certain kinds of cancer in man.

Viruses that infect bacteria multiply and cause their lysis, are called

1. lysozymes
2. lipolytic
3. lytic
4. lysogenic

Lichens are well known combination of an alga and a fungus where fungus has

1. a saprophytic relationship with the alga
2. an epiphytic relationship with the alga
3. a parasitic relationship with alga
4. a symbiotic relationship with alga

When a fresh-water protozoan possessing a contractile vacuole, is placed in a glass containing marine water, the vacuole will

1. increase in number
2. disappear
3. increase in size
4. decrease in size