Q.1. All eukaryotic unicellular organisms belong to
Ans. (b) Protista
Monera: Kingdom of prokaryotes.
All eukaryotic unicellular organisms belong to Protista.Protista
Q.2. The five-kingdom classification was proposed by
(a) R.H. Whittaker
(b) C. Linnaeus
(c) A. Roxberg
Ans. (a) R.H. Whittaker
This phylogenetic classification was proposed by R.H. Whittaker (1969). He created a new kingdom ‘Fungi’.
The five-kingdom classification is as follows:
Whittaker has used 5 criteria for the 5 kingdom classification and are as follows:
(ii) Cell structure
(iii) Phylogenetic relationships
(iv) Mode of nutrition
(v) Thallus organisation
Q.3. Organisms living in salty areas are called:
Ans. (b) Halophiles
Q.4. Naked cytoplasm, multi-nucleated and saprophytic are the characteristics of
(d) Slime moulds
Ans. (d) Slime moulds
Slime moulds are saprophytic protists, without cell walls. The spores of slime moulds possess true walls. Thalloid multinucleate body of a slime mould is called Plasmodium. Spores are dispersed by air currents.
(i) Acellular slime mould: Physarum
(ii) Cellular slime mould: Dictyostelium
Q.5. An association between roots of higher plants and fungi is called
Ans. (c) Mycorrhiza
Q.6. A Dikaryon is formed when
(a) Meiosis is arrested
(b) The two haploid cells do not fuse immediately
(c) Cytoplasm does not fuse
(d) None of the above
Ans. (b) The two haploid cells do not fuse immediately
In some fungi, the fusion of two haploid cells immediately results in diploid cells (2n). However, in other fungi (ascomycetes and basidiomycetes), an intervening dikaryotic stage (n + n, i.e. two nuclei per cell) occurs. Such a condition is called a dikaryon and the phase is called dikaryo phase of fungus. A dikaryotic cell has two dissimilar haploid nuclei.
Q.7. Contagium vivum fluidum was proposed by
(a) D. J. Ivanowsky
(b) M. W. Beijerinek
(d) Robert Hooke
Ans. (b) M. W. Beijerinek
Q.8. Association between mycobiont and phycobiont are found in
Ans. (c) Lichens
Association between mycobiont and phycobiont are found in lichens.
Q.9. Difference between Virus and Viroid is
(a) Absence of protein coat in viroid but present in the virus.
(b) Presence of low molecular weight RNA in the virus but absent in viroid.
(c) Both (a) and (b)
(d) None of the above.
Ans. (a) Absence of protein coat in viroid but present in the virus.
Viroids are smaller than viruses and the cause of potato spindle tuber disease, chrysanthemum stunt disease. It was found to be a free RNA and lacked the protein coat that is found in viruses, hence the name viroid.
Q.10. With respect to the fungal sexual cycle, choose the correct sequence of events.
(a) Karyogamy, Plasmogamy and meiosis
(b) Meiosis, Plasmogamy and Karyogamy
(c) Plasmogamy, Karyogamy and Meiosis
(d) Meiosis, Karyogamy and Plasmogamy
Ans. (c) Plasmogamy, Karyogamy and Meiosis
The sexual cycle involves the following three steps:
(i) The fusion of protoplasms between two motile or non-motile gametes called plasmogamy. Plasmogamy is the fusion of two haploid cells without nuclear fusion.
(ii) Fusion of two nuclei is called Karyogamy.
(iii) Meiosis in zygote resulting in haploid spores.
Q.11. Viruses are non-cellular organisms but replicate themselves once they infect the host cell. To which of the following kingdom do viruses belong to?
(d) None of these
Ans. (d) None of these
Q.12. Members of Phycomycetes are found in
(i) Aquatic habitats
(ii) On decaying wood
(iii) Moist and damp places
(iv) As obligate parasites on plants
Choose from the following options:
(a) None of the above
(b) (i) and (iv)
(c) (ii) and (iii)
(d) All of the above
Ans. (d) All of the above
Members of Phycomycetes are found in aquatic habitats, on decaying wood, moist and damp places and as obligate parasites on plants.
Q.1. What is the principle underlying the use of cyanobacteria in agricultural fields for crop improvement?
Q.2. Suppose you accidentally find an old preserved permanent slide without a label. In your effort to identify it, you place the slide under the microscope and observe the following features:
(b) Well defined nucleus
(c) Biflagellate—one flagellum lying longitudinally and the other transversely.
What would you identify it as? Can you name the kingdom it belongs to?
Q.3. How is the five-kingdom classification advantageous over the two kingdom classification?
Two Kingdom system of classification with Plantae and Animalia kingdoms.
Five Kingdom Classification:
(i) Fungi were placed in a separate kingdom—kingdom fungi.
(ii) It has put together, organisms which were placed in different kingdoms in earlier classifications.
(iii) Kingdom Protista brought together Chlamydomonas, Chlorella (earlier placed in algae within plants and both having cell walls) with Amoeba and Paramoecium (earlier placed in the animal kingdom and both lacking cell walls).
(iv) Animal and plant kingdoms become more homogenous than they are in the two kingdom classification. So, it is advantageous over the two kingdom classification.
Q.4. Polluted water bodies have usually a very high abundance of plants like Nostoc and Oscillatoria. Give reasons.
Q.5. Are chemosynthetic bacteria—autotrophic or heterotrophic?
Ans. Chemosynthetic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production. So chemosynthetic bacteria are autotrophic in nature.
Q.6. The common name of pea is simpler than its botanical (scientific) name Pisum sativum. Why then is the simpler common name not used instead of the complex scientific/botanical name in biology?
Ans. As we know that pea (vernacular name or local name) is simpler than its botanical (scientific) name Pisum sativum. These local names would vary from place to place, even within a country.
One would probably recognize the confusion that would be created if we did not find ways and means to talk to each other and refer to organisms we are talking about.
Hence, there is a need to standardize the naming of living organisms such that a particular organism is known by the same name all over the world.
Q.7. A virus is considered as a living organism and an obligate parasite when inside a host cell. But the virus is not classified along with bacteria or fungi. What are the characters of the virus that are similar to non-living objects?
Ans. Viruses are living organisms inside a host cell. But the virus is not classified along with bacteria or fungi because they have an inert crystalline structure outside the living cell. They are inert outside their specific host cell and cannot multiply of their own because they lack cellular machinery to use its genetic material.
Q.8. In the five-kingdom system of Whittaker, how many kingdoms are eukaryotes?
In Whittaker's five-kingdom system, four kingdoms (Protista, Fungi, Plantae and Animalia) belong to eukaryotes.