Biological Classification Chapter-Wise Test 19

Correct answer Carries: 4.

Wrong Answer Carries: -1.

What is the ecological role of chemosynthetic autotrophic bacteria described in the chapter?

They cause red tides in marine water.
They recycle nutrients such as nitrogen, phosphorus, iron and sulphur.
They produce fruiting bodies bearing spores.
They form lichens with fungi.
2

Chemosynthetic autotrophic bacteria oxidise inorganic substances such as nitrates, nitrites and ammonia and use the released energy for ATP production. Through these activities, they play an important role in recycling nutrients such as nitrogen, phosphorus, iron and sulphur.

Which bacterial shape is correctly matched with its name?

Coccus—rod-shaped
Bacillus—comma-shaped
Vibrio—comma-shaped
Spirillum—spherical
3

Vibrio is the comma-shaped bacterial form. Coccus is spherical, Bacillus is rod-shaped and Spirillum is spiral-shaped.

What is meant by alternation of generations in plants?

Alternation between autotrophic and heterotrophic nutrition
Alternation between diploid sporophytic and haploid gametophytic phases
Alternation between unicellular and multicellular kingdoms
Alternation between sexual and asexual spores in fungi
2

The plant life cycle has a diploid sporophytic phase and a haploid gametophytic phase that alternate with each other. The duration and independence of these phases vary among different plant groups.

Which statement correctly describes the general body organisation of fungi?

All fungi are unicellular.
All fungi possess tissues and organs.
Fungal bodies are made only of flagellated cells.
Except for yeasts, fungi are generally filamentous.
4

With the exception of unicellular yeasts, fungi are generally filamentous. Their bodies consist of thread-like hyphae, and the network formed by these hyphae is called the mycelium.

What may some bacteria produce under unfavourable conditions?

Asci
Basidia
Spores
Heterocysts in every species
3

Bacteria reproduce mainly by fission, but under unfavourable conditions some of them produce spores. These spores help them persist when environmental conditions are unsuitable.

Which of the following correctly describes viral replication?

Viruses take over the machinery of a host cell to replicate.
Viruses replicate independently outside living cells.
Viruses reproduce mainly by binary fission.
Viruses manufacture their own ribosomes outside the host.
1

Viruses are inert outside their specific host cells. After infecting a living cell, they take over the host-cell machinery to produce new viral particles; therefore, they are obligate parasites.

What do cyanobacteria often form in polluted water bodies?

Basidiocarps
Ascocarps
Blooms
Diatomaceous earth
3

Cyanobacterial colonies are generally surrounded by a gelatinous sheath and often form blooms in polluted water bodies. Cyanobacteria may be unicellular, colonial or filamentous.

In which fungal groups does an intervening dikaryotic stage commonly occur?

Phycomycetes and Deuteromycetes
Ascomycetes and Basidiomycetes
Only Phycomycetes
Only Deuteromycetes
2

In Ascomycetes and Basidiomycetes, plasmogamy may not be followed immediately by karyogamy. An intervening dikaryotic stage with two nuclei per cell, written as n + n, occurs and is called the dikaryophase.

Which asexual spores are formed by Phycomycetes?

Conidia only
Basidiospores
Zoospores or aplanospores
Ascospores
3

Phycomycetes reproduce asexually by motile zoospores or non-motile aplanospores. These spores are produced endogenously within a sporangium.

Who demonstrated that viruses could be crystallised?

Dmitri Ivanowsky
M. W. Beijerinck
T. O. Diener
W. M. Stanley
4

W. M. Stanley demonstrated in 1935 that viruses could be crystallised. The crystals consisted largely of proteins, and viruses were found to remain inert outside their specific host cells.

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