5

Biological Classification

This Chapter '’Biological Classification’' is taken from

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ISBN : 9789386323064
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Chapter
BIOLOGICAL
CLASSIFICATION

• Biological classification was first proposed by Aristotle • Copeland classified organisms into four kingdoms; Monera
who used simple morphological characters to classify plants
(all prokaryotes), Protista (unicellular eukaryotes),
and animals.
Metaphyta (multicellular plants) and Metazoa (multicellular
• Linnaeus initially separated plants and animals in two
kingdoms i.e., Kingdom Plantae and Kingdom Animalia. eukaryotes).

• In three kingdom system, kingdom Protista was included • Most accepted system of classification is Five system
along with kingdom Plantae and kingdom Animalia created classification which was given by Whittaker.
by Haeckel.

Kingdom Cellular Organisation Movement Nutrition Reproduction

1. Monera Unicellular, without By flagella (tubulin- Absorptive or Asexual
(All Prokaryotes) nucleus or membranous dynein system) photosynthetic
organelle.
2. Protista Unicellular, eukaryote By flagella, cilia, Absorptive, Both sexual and
(Protozoans, with nucleus and pseudopodia and photosynthetic & asexual
unicellular algae) membranous mucilage holozoic
organelles. propulsion
3. Fungi Multicellular eukaryote Non-motile Heterotrophic Asexual and
(Multicellular coenocytic, no plastids, (saprophytic/ sexual both
decomposers) cells wall of cellulose, Parasitic)
chitin.
4. Plantae Multicellular, higher Non-motile Autotrophic or Asexual and
(All plants) organisation photosynthetic sexual both
eukaryotes, cellulosic
cell wall, plastids
present.
5. Animalia Multicellular, higher Highly motile with Heterotrophic Both sexual and
(All animals) organization, all type of motile (holozoic or asexual but in
eukaryotes without cell machinery saprozoic) higher forms
wall and chlorophyll. only sexual

• The proteobacteria is the largest group in terms of the

• This kingdom comprises bacteria (mycoplasma, number of species. They are sometimes referred to as the
purple bacteria. Mitochondria were derived from
archaebacteria, eubacteria, actinomycetes, etc.) and
proteobacteria by endosymbiosis. E. coli, Yersinia pestis,
cyanobacteria.
Vibrio cholerae, and Salmonella typhimurium are all
• The earliest living organisms may have been thermophiles. proteobacteria.
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• Most archaea live in environments that are extreme in one • Mycoplasmas have the least amount of DNA and are the
way or another: temperature, salinity, oxygen concentration, smallest bacteria. They lack cell walls. Some are 0.2 mm in
or pH. The archaea lack peptidoglycan in their cell walls. size. They may have the minimum amount of DNA necessary
• All methanogens are obligate anaerobes. Methanogens to code for the essential properties of a living cell.
release approximately 2 billion tons of methane gas into
Earth’s atmosphere. Approximately a third of this methane
comes from methanogens in the guts of grazing herbivores. • Protista include all unicellular eukaryotic microorganisms.
Methanopyrus lives on the ocean bottom near volcanic
vents. These can live at 110oC.
• They are a group of diatoms (Triceratium, Pieurosigma,
Navicuia, Cymbella, Amphipleura) and golden brown
• Bacteria are the simplest, most primitive unicellular photosynthetic microscopic protists.
organisms.
• Diatoms are very good pollution indicators.
• Each bacterial cell contains a single chromosomes (nuclear
• The siliceous frustules of diatoms do not decay easily. They
material) that is not enclosed in a nuclear membrane.
pile up at the bottom of water reservoirs and form big heaps
• According to shape, bacteria are grouped into four types –
called diatomite or diatomaceous earth.
Coccus or spherical shaped, bacillus or rod-shaped bacteria,
spirillum or spiral/curved shaped bacteria, vibrio or comma-
shaped bacteria. • Dinoflagellates are mostly marine and photosynthetic.
• Autotrophic nutrition consists of manufacture of organic • Very often, red dinoflagellates (e.g., Gonyaulax) undergo
materials from inorganic raw materials with the help of energy such rapid multiplication that they make the sea appear red
obtained from outside sources. It is of two types, (red tides).
chemosynthesis and photosynthesis. The bacteria
performing these modes of nutrition are respectively called
chemoautotrophs and photo-autotrophs. • It includes Euglena-like flagellates which have plant like
• Photoautotrophic Bacteria: The bacteria possess characteristics (chlorophyll) in addition to some animal
photosynthetic pigments of two types, bacteriochlorophyll characteristics. They ingest food particles and carry on
and bacteriophaeophytin. photosynthesis.
• Chemoautotrophic Bacteria : They are able to manufacture • An osmoregulatory contractile vacuole is found.
their organic food from inorganic raw materials with the help • Instead of a cell wall, they have a protein rich layer called
of energy derived from exergonic chemical reactions pellicle which makes their body flexible.
involving oxidation of an inorganic substance present in
the external medium.
• Bacteria reproduce both asexually as well as sexually. • They are unicellular, saprophytic organism that lack cell walls
Asexual reproduction in bacteria is by binary fission which and have the plasma membrane as their outer covering.
takes place in favourable conditions or by endospore • They move through pseudopodia.
formation.
Sexual reproduction is not associated with gamete formation • The body moves along decaying twigs and leaves engulfing
but takes place through the transfer of naked DNA. Hence organic material.
referred to as sexual recombination or genetic recombination
which may be- Conjugation, Transformation, Transduction.
• Classification of protozoa is mainly based on locomotory
organelles. Protistan protozoa are divisible into four phyla—
• Cyanobacterial cells are larger and more elaborate than
zooflagellata, sarcodina, sporozoa and ciliata.
bacteria. Cell structure is typically prokaryotic – one
envelope organisation with peptidoglycan wall, naked DNA,
70S ribosomes and absence of membrane bound structures • They are protozoan protists which possess one to several
like endoplasmic reticulum, mitochondria, golgi bodies, flagella for locomotion.
plastids, lysosomes and sap vacuoles.
• The body is covered by a firm pellicle. Cyst formation is
• Heterocyst is a large-sized pale coloured thick-walled cell
also present.
which occurs in terminal, intercalary or lateral position in Examples : Trichonympha, Lophomonas, Giardia,
filamentous cyanobacteria, e.g., Nostoc.
Trypanosoma, Leishmania and Trichomonas.
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• Fungi are non-vascular, non-seeded, non-flowering,
• They develop pseudopodia for locomotion and ingestion multicellular decomposers and mineralisers of organic
of food. wastes and help in recycling of matter in the biosphere.
• The body is without periplast (with a covering of only • In true fungi the plant body is thallus. It may be non-mycelial
plasmalemma) or have a shell. or mycelial.
• Entamoeba histolytica causes the disease known as • Hyphae are usually branched tube like structure bounded
amoebic dysentery or amoebiasis. Entamoeba coli is by a cell-wall of chitin.
commensal parasite and does not produce any disease. Fungi have three types of reproduction.
Entamoeba gingivalis or mouth amoeba is found in tartar 1. Vegetative reproduction : Budding, Fission, Oidia,
of teeth and in pus pockets of bleeding gums. The condition Chlamydospores, Fragmentation.
is called as pyorrhoea. 2. Asexual reproduction
Asexual reproduction in fungi may be of the following types.
(a) Zoospore formation : They may be uniflagellate (e.g.,
• They are develop from paristic mode of life (usually Synchytrium) or biflagellate (e.g., Saprolgenia)
endoparasites). (b) Aplanospore formation : They are non-flagellate spores
• The body is covered by elastic pellicle or cuticle and have a that develop inside sporangia e.g., Rhizopus, Mucor.
single nucleus contractile vacuoles are absent.
(c) Conidia : Conidia are non-motile, thin walled exogenous
• Plasmodium vivax causes benign tertian fever. Plasmodium spores produced on a conidiophore e.g., Aspergillus
falciparum causes malignant tertian fever or cerebral malaria and Penicillium.
or pernicious malaria or black-water fever. Plasmodium ovale 3. Sexual reproduction
causes benign tertian fever. Sexual reproduction is reduced in fungi and take place by
two fusing gametes. It includes 3 stages:
(a) Plasmogamy or fusion of two protoplasts
• Fungi are achlorophyllus organisms and hence they live as (b) Karyogamy or fusion of two nuclei
heterotrophs i.e., as parasites and saprophytes. (c) Meiosis or reduction division

Group Examples Morphology Asexual Reproduction Sexual Miscellaneous

Reproduction Information
Zygomycota Zygote fungi, Coenocytic Spores formed in Hyphal extensions In soil and decaying
black bread hyphae, chitosan sporangia on aerial fuse, karyogamy, matter
mould cell walls hyphae resistant
zygosporangia
Ascomycota Sac fungi, yeast, Septate hyphae, Abundant spores in Dikaryotic hyphae in Plant parasites,
Penicillium chitin cell walls, chains or clusters, ascocarp, lichens, genetic
some unicellular called conidia karyogamy in asci, studies, decomposers
ascospores
Basidiomycota Club fungi, Dikaryotic hyphae Form conidia less Basidiocarps, Edible mushrooms,
mushrooms, with complex commonly than karyogamy in plant parasites,
puffballs, shelf pores, mycelium ascomycetes basidia, forms mycorrhizae
fungi, rusts extensive, chitin basidiospores
Deuteromycota Fungi imperfecti Moulds, rapidly Form conidia No sexual stage, Non-phylogenetic
Alternaria growing hyphae may have form division, some
Trichoderma parasexuality produce antibiotics

– Presence of chloroplasts.
– Photosynthetic mode of nutrition (oxygenic
• In this kingdom are included multicellular, eukaryotic,
photosynthesis), e.g., different types of algae (green,
photosynthetic organisms (kingdom of multicellular
brown, red algae), bryophytes, pteridophytes,
producers or Metaphyta).
gymnosperms and angiosperms.
• Main characters of this kingdom are : – Reproduction is both asexual and sexual.
– Cellulosic cell wall.
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• The organisms are made up of eukaryotic cells. • T.O.Diener (1971) discovered some new infections agents,
• The cells do not contain cell wall, but contain only cell which are still smaller than viruses.
membrane.
• Viroids contain only very low molecular weight RNA and
• They do not perform photosynthesis but have heterotrophic
not protein coat.
nutrition.
• They have the power of locomotion. • Viroids cause potato spindle tuber disease (PSTV),
Chrysanthemum stunt, Citrus exocortis, cucumber pale fruit
etc.
• The term ‘virus’ has been derived from latin, which means
poison or venom or viscous fluid.
• They are obligate parasites, i.e., can live inside living host • Lichens shows symbiotic relationships.
only. • In lichens, there are 2 components; i.e., algal partner called
• They have either RNA or DNA. phycobiont and fungal partner called mycobiont.
• They have character of both living and non-living. • Lichens are economically important as food and fodders,
• Bacteriophage : Bacterial viruses or bacteriophages (viruses dyes, as a source of medicines etc.
that infect the bacteria) are usually double stranded DNA • They are very good pollution indicators – they do not grow
viruses. in polluted areas.

1. In Five kingdom system, the main basis of classification is 10. Malignant tertian malarial parasite is
(a) structure of nucleus (b) mode of nutrition (a) Plasmodium falciparum (b) P. vivax
(c) structure of cell wall (d) asexual reproduction (c) P. ovale (d) P. malariae
2. Trypanosoma belongs to class 11. The organisms which do not derive energy directly or
(a) Sarcodina (b) Zooflagellata indirectly from sun are
(c) Ciliata (d) Sporozoa (a) Chemosynthetic bacteria
3. The infective stage of malarial parasite Plasmodium that (b) Pathogenic bacteria
enters human body is (c) Symbiotic bacteria
(a) Merozoite (b) Sporozoite (d) Mould
(c) Trophozoite (d) Minuta form 12. African sleeping sickness is due to
4. Which one belongs to monera? (a) Plasmodium vivax transmitted by Tse tse fly
(a) Amoeba (b) Escherichia (b) Trypanosoma lewsii transmitted by Bed Bug
(c) Gelidium (d) Spirogyra (c) Trypanosoma gambiense transmitted by Glossina
5. The main difference in Gram (+)ve and Gram (–)ve bacteria palpalis
resides in their (d) Entamoeba gingivalis spread by Housefly.
(a) Cell wall (b) Cell membrane 13. In Amoeba and Paramoecium osmoregulation occurs
(c) Cytoplasm (d) Flagella through
6. Which is true about Trypanosoma ? (a) Pseudopodia (b) Nucleus
(a) Polymorphic (b) Monogenetic (c) Contractile vacuole (d) General surface
(c) Facultative Parasite (d) Non-pathogenic 14. Bacteria lack alternation of generation because there is
7. Amoebiasis is prevented by (a) Neither syngamy nor reduction division
(a) Eating balanced food (b) Eating plenty of fruits (b) Distinct chromosomes are absent
(c) Drinking boiled water (d) Using mosquito nets (c) No conjugation
8. Plasmodium, the malarial parasite, belongs to class (d) No exchange of genetic material
(a) Sarcodina (b) Ciliata 15. The part of life cycle of malarial parasite Plasmodium vivax,
(c) Sporozoa (d) Dinophyceae that is passed in female Anopheles is
9. A non-photosynthetic aerobic nitrogen fixing soil bacterium (a) Sexual cycle
is (b) Pre-erythrocytic schizogony
(a) Rhizobium (b) Clostridium (c) Exo-erythrocytic schizogony
(c) Azotobacter (d) Klebsiella (d) Post-erythrocytic schizogony
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16. Escherichia coli is used extensively in biological research 28. The plasmids pesent in the bacterial cells are
as it is (a) circular double helical DNA molecules.
(a) Easily cultured (b) Easily available (b) circular double helical RNA molecules.
(c) Easy to handle (d) Easily multiplied in host (c) linear double helical DNA molecules.
17. Genophore/bacterial genome or nucleoid is made of (d) linear double helical RNA molecules.
(a) Histones and non-histones 29. Which one of the following statements about viruses is
(b) RNA and histones correct?
(c) A single double stranded DNA
(a) Viruses possess their own metabolic system.
(d) A single stranded DNA
(b) Viruses contain either DNA or RNA.
18. Schizogont stage of Plasmodium occurs in human cells is
(c) Viruses are facultative parasites.
(a) Erthrocytes
(b) Liver cells (d) Viruses are readily killed by antibiotics.
(c) Erythrocytes and liver cells 30. A few organisms are known to grow and multiply at
(d) Erythrocytes, liver cells and spleen cells temperatures of 100–105ºC. They belong to
19. Tobacco Mosaic Virus (TMV) genes are (a) Marine archaebacteria
(a) Double stranded RNA (b) Single stranded RNA (b) Thermophilic sulphur bacteria
(c) Polyribonucleotides (d) Proteinaceous (c) Hot-spring blue-green algae (cyanobacteria)
20. Temperature tolerance of thermal blue-green algae is due to (d) Thermophilic, subaerial fungi
(a) Cell wall structure 31. Transfer of genetic information from one bacterium to another
(b) Cell organisation in the transduction process is through
(c) Mitochondrial structure (a) Conjugation
(d) Homopolar bonds in their proteins (b) Bacteriophages released from the donor bacterial strain
21. Non-symbiotic nitrogen fixers are (c) Another bacterium
(a) Azotobacter (b) Pseudomonas (d) Physical contact between donor and recipient strain
(c) Soil Fungi (d) Blue-green algae 32. Photosynthetic bacteria have pigments in
22. Nitrogen fixer soil organisms belong to
(a) leucoplasts (b) chloroplasts
(a) Mosses (b) bacteria
(c) chromoplasts (d) chromatophores
(c) Green algae (d) Soil fungi
33. Yeast and Pencillium producing fungus are included under
23. Protistan genome has
(a) Basidiomycetes (b) Zygomycetes
(a) Membrane bound nucleoproteins embedded in
(c) Ascomycetes (d) Phycomycetes
cytoplasm.
(b) Free nucleic acid aggregates. 34. What is true for cyanobacteria?
(c) Gene containing nucleoproteins condensed together (a) Oxygenic with nitrogenase
in loose mass. (b) Oxygenic without nitrogenase
(d) Nucleoprotein in direct contact with cell substance. (c) Non-oxygenic with nitrogen
24. Protists obtain food as (d) Non-oxygenic without nitrogenase
(a) Photosynthesisers, symbionts and holotrophs 35. What is true for plasmid ?
(b) Photosynthesisers (a) Plasmids are widely used in gene transfer.
(c) Chemosynthesisers (b) These are found in virus.
(d) Holotrophs
(c) Plasmid contains gene for vital activities.
25. Which of the following organism possesses characteristics
(d) These are main part of chromosome.
of both a plant and an animal?
36. Which statement is correct for bacterial transduction ?
(a) Bacteria (b) Euglena
(a) Transfer of some genes from one bacteria to another
(c) Mycoplasma (d) Paramoecium
bacteria through virus.
26. Azotobacter and Bacillus polymyxa are the examples of
(b) Transfer of genes from one bacteria to another bacteria
(a) symbiotic nitrogen-fixers
by conjugation.
(b) non-symbiotic nitrogen-fixers (c) Bacteria obtained its DNA directly.
(c) ammonifying bacteria (d) Bacteria obtained DNA from other external source.
(d) disease-causing bacteria 37. The chief advantage of encystment to an Amoeba is
27. In bacterial chromosomes, the nucleic acid polymers are (a) the chance to get rid of accumulated waste products.
(a) linear DNA molecule (b) the ability to survive during adverse physical
(b) circular DNA molecule conditions.
(c) of two types-DNA and RNA (c) the ability to live for sometime without ingesting food.
(d) linear RNA molecule (d) protection from parasites and predators.
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38. Which of the following statements is not true for 46. Plant decomposers are
retroviruses? (a) Monera and fungi (b) Fungi and plants
(a) DNA is not present at any stage in the life cycle of (c) Protista and Animalia (d) Animalia and Monera
retroviruses. 47. There exists a close association between the alga and the
(b) Retroviruses carry gene for RNA-dependent DNA fungus within a lichen. The fungus
polymerase. (a) provides protection, anchorage and absorption for
(c) The genetic material in mature retroviruses is RNA. the alga.
(d) Retroviruses are causative agents for certain kinds of (b) provides food for the alga.
cancer in man. (c) fixes the atmospheric nitrogen for the alga.
39. The most thoroughly studied of the known bacteria-plant (d) releases oxygen for the alga.
interactions is the 48. Which of the following environmental conditions are
(a) Cyanobacterial symbiosis with some aquatic ferns. essential for optimum growth of Mucor on a piece of bread?
(b) Gall formation on certain angiosperms by A. Temperature of about 25°C
Agrobacterium. B. Temperature of about 5° C
(c) Nodulation of Sesbania stems by nitrogen fixing C. Relative humidity of about 5%
bacteria.
D. Relative humidity of about 95%
(d) Plant growth stimulation by phosphate-solubilising
E. A shady place
bacteria.
F. A brightly illuminated place
40. All of the foll owing stat ements co nce rning the
actinomycetes filamentous soil bacterium Frankia are Choose the answer from the following options :
correct EXCEPT that Frankia (a) A, D and E only (b) B, D and E only
(a) Can induce root nodules on many plant species. (c) B, C and F only (d) A, C and E only
(b) Cannot fix nitrogen in the free-living state. 49. Which pair of the following belongs to Basidiomycetes?
(c) Forms specialized vesicles in which the nitrogenase (a) Puffballs and Claviceps
is protected from oxygen by a chemical barrier (b) Peziza and stink borns
involving triterpene hopanoids. (c) Morchella and mushrooms
(d) Like Rhizobium, it usually infects its host plant (d) Birds nest fungi and puffballs
through root hair deformation and stimulates cell 50. ‘Comma’ shaped bacteria are known as
proliferation in the host’s cortex. (a) coccus (b) spiral
41. Lichens indicate SO2 pollution because they (c) lophotrichus (d) vibrio
(a) Show association between algae and fungi. 51. In Rhizopus the fusion of two different thalli to form
(b) Grow faster than others. zygospore is called
(c) Are sensitive to SO2. (a) spermaciation (b) gametangial contact
(d) Flourish in SO2 rich environment. (c) gametangial copulation (d) Both ‘a’ and ‘b’
42. Ustilago caused plant diseases called smuts because 52. Maximum number of antibiotics are obtained from:
(a) fungi (b) bacteria
(a) They parasitise cereals. (c) virus (d) plants
(b) Mycelium is back. 53. Substances secreted by bacteria are
(c) They develop sooty masses of spores. (a) proteins (b) toxins
(d) Affected parts becomes completely black. (c) interferons (d) antibiotics
43. Claviceps purpurea is causal organism of 54. Virus envelope is known as:
(a) Smut of Barley (b) Rust of Wheat (a) Capsid (b) Virion
(c) Ergot of Rye (d) Powdery Mildew of Pea (c) Nucleoprotein (d) Core
44. White rust disease is caused by 55. In bacteria site of respiration is :
(a) Claviceps (b) Alternaria (a) Mesosome (b) Episome
(c) Phytophthora (d) Albugo candida (c) Plasmid (d) Cytoplasm
45. Which one of the following is not true about lichens? 56. Which one of the following pairs is correctly matched ?
(a) Their body is composed of both algal and fungal cells. (a) Rhizobium - Parasite in the roots of leguminous plants
(b) Some form food for reindeers in arctic regions. (b) Mycorrhizae - Mineral uptake from soil
(c) Some species can be used as pollution indicators. (c) Yeast - Production of biogas
(d) These grow very fast at the rate of about 2 cm per year. (d) Myxomycetes - The diseases ringworm
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57. Myxomycetes are 58. Which is a unicellular fungus ?
(a) saprobes or parasites, having mycelia. asexual (a) Yeast (b) E.coli
reproduction by fragmentation.
(c) Nostoc (d) Albugo
(b) slimy mass of multinucleate protoplasm, having
pseudopodia like structures for engulfing food, 59. Rhizopus belongs to
reproduction through fragmentation or zoospores.
(a) zygomycetes (b) basidiomycetes
(c) prokaryotic organisms, cellular or acellular, saprobes or
autotrophic, reproduce by binary fission. (c) ascomycetes (d) deuteromycetes
(d) eukaryotic, single-celled or filamentous, saprobes or 60. Which one is not a mode of reproduction ?
autotrophic, asexual reproduction by division of haploid
(a) Budding (b) Plasmogamy
individuals, sexual reproduction by fusion of two cells
or their nuclei. (c) Oogamy (d) Ascospore formation

Hints & Solutions

1. (b) The five kingdom classification is a mode of 11. (a) Chemosynthetic bacteria does require sunlight as a
classification based on the following criteria source of energy directly or indirectly. The energy for
• Complexity of cell structure the synthesis of food is obtained by the oxidation of
• Complexity of body structure certain inorganic substances present in the medium.
• Modes of nutrition 12. (c) African sleeping sickness disease also called as
• Ecological life styles trypansomiasis is caused by parasite Trypanosoma
• Phylogenetic relationship gambiense of class zooflagellata. The parasite is
2. (b) 3. (b) transmitted (vector) through bite of Tse-Tse fly
4. (b) Kingdom Monera includes all prokaryotes– (Glossina palpalis).
Mycoplasma, bacteria, actinomycetes, blue-green 13. (c) Contractile vacuole in Amoeba and Paramecium
algae, archaebacteria, methanogens. Escherichia is maintain the water balance of the cell. This is known as
bacteria, Amoeba, Gelidium come under Protista, osmoregulation.
Spirogyra is algae.
14. (a) In bacteria asexual reproduction through binary fission
5. (a) Gram +(ve) and Gram –(ve) bacteria separates on the
is the most common method of multiplication. Sexual
basis of their cell wall composition. The bacteria which
reproduction which comprises syngamy and meiosis
retain blue or purple colour after staining are Gram +ve
is entirely absent. Hence no gamete formation takes
e.g. Bacillus subtilis and which loses blue colour is
place. In sexually reproducing organism alternation of
Gram –ve e.g. E. coli. In Gram –ve stain is washed due
to high lipid content in the cell wall having thick wall, generation occurs.
Gram +ve has single layered cell wall. 15. (a) Plasmodium vivax completes sexual cycle or
6. (a) Trypanosoma is polymorphic i.e. it exists in different gamogony in female Anopheles mosquito. Asexual
forms in the successive stages of its life cycle. cycle is passed in man (schizogony).
7. (c) Amoebiasis or amoebic dysentry is caused by a parasite 16. (a) Escherichia coli, lives as a symbiont in human intestine.
Entamoeba histolytica present in the upper part of It shares our food but checks the growth of putrefying
large intestine of human. It is caused due to ingesting bacteria. It produces vitamin B as well as vitamin K. It
contaminated food of water with cyst (trophozoite) of can be easily cultured in simple nutrient medium.
Entamoeba. It feeds on RBCs of intestinal blood 17. (c) The bacterial genome/nucleoid is made of double
capillaries and damages intestinal mucosa secreting stranded DNA without histone protein. The bacterial
an enzyme - histolysin. genome thus represented by a single circular double
8. (c) helical DNA. The genome contains some 100 chemical
9. (c) Azotobacter is free living soil bacteria that are able to sites or loci. Each locus contains many genes. E coli
pick up dinitrogen from the soil and fixes it into organic contains about 4000 genes.
nitrogenous material like amino acid. 18. (c)
10. (a) In human beings different types of malaria are caused 19. (b) Viruses are :
by 4 different species of Plasmodium. They are : (i) Double stranded DNA or ds DNA - Hepatitis B
1. Benign Tertian Malaria – Plasmodium vivax. (ii) Single stranded DNA or ss DNA - coliphage
2. Malignant (Pernicious or cerebral) Tertian Malaria (iii) Double stranded RNA or ds RNA - Reo virus,
– Plasmodium falciparum. wound tumor virus
3. Quartan Malaria – Plasmodium malariae. (iv) Single stranded RNA or ss RNA - Tobacco mosaic
4. Mild Tertian Malaria – Plasmodium ovale. virus (TMV)
 13
20. (d) Some of the blue green algae can tolerate extremes of 41. (c) Lichens typically grow in harsh environments in nature,
temperature due to presence of gelatinous sheath, and most lichens, especially epiphytic fruticose species and
compactness of protein molecules in protoplasm. those containing cyanobacteria, are sensitive to
21. (a) Azotobacter is non-symbiotic, free living nitrogen fixing manufactured pollutants. Hence, they have been
bacteria. widely used as pollution indicator organisms.
42. (d) Smut disease caused by Ustilago species of
22. (b) Only some bacteria and blue green algae
basidiomycetes fungi. It is characterised by formation
(Cyanobacteria) has capacity to fix atmospheric
of black coloured chlamydospores or teleutospores
nitrogen.
called smut spores due to which the affected part
• Bacteria : Azotobacter, Rhizobium, Frankia etc. becomes black.
• Blue green algae : Nostoc, Oscillatoria, Anabaena, 43. (c) The fungus that causes the disease ‘Ergot of Rye’ is
etc. Claviceps purpurea. It contains many poisonous
23. (a) Protistans are eukaryotes and their genetic material is alkaloids. The hallucinogenic drug LSD is extracted
organised in form of nucleus. DNA is associated with from this fungi.
histone protein. 44. (d) Albugo candida is an obligate parasite causing white
24. (a) Members of kingdom protista have diverse mode of rust on members of family Cruciferae and other hosts.
nutrition. They are photosynthetic, saprophytic 45. (d) 46. (a)
parasitic and ingestive. They are major heterotroph. 47. (a) Lichens (coined by Theophrastus) are composite or
25. (b) The Euglena is an organism, which possesses both dual organisms which are formed by a fungus partner
the characteristics of plants and animals, as it can move or mycobiont (mostly ascomycetes) and an algal partner
with a flagella and also contains chlorophyll. (mostly blue green algae). Fungus forms the body of
lichen as well as its attaching and absorbing structures.
26. (a) 27. (b) 28. (a) Algae performs photosynthesis and provides food to
29. (b) Viruses have either DNA or RNA as the genetic material. the fungus.
Viruses having RNA as the genetic material are known 48. (a) Mucor is a fungus and most of the fungi require the
a retroviruses. optimum temperature of about 15-30ºC, good moisture
30. (a) These are archaebacteria which can tolerate high content in atmosphere and not very dark and not very
temperature. lightened place. So the Mucor requires a temperature
31. (b) Transfer of genetic information from one bacterium to of about 25ºC, humidity about 95% and a shady place
another by physical contact is called conjugation while to grow fully.
if it takes place by some other medium like virus there it 49. (d) The class Basidiomycetes includes those members that
is called transduction. produce their basidia and basidiospores on or in a
basidiocarp.
32. (d) Chloroplasts, chromoplasts and leucoplasts are the
50. (d)
types of plastids found in higher plants. Chloroplasts
contain the green pigment chlorophyll. Chromoplasts 51. (c) Gametangia copulation is the intermixing of protoplasts
contain coloured pigments. Leucoplasts are colourless of the mature male and female gametangia by the
and store starch granules. dissolution of septum. e.g., Rhizopus.
52. (b)
33. (c)
53. (b) Some bacteria secretes poisonous chemical called
34. (a) Cyanobacteria are oxygenic photoautotroph. Many toxins which cause food poisoning. The principal kind
members perform nitrogen fixation. of food poisoning is Staphylococcus and Clostridium
35. (a) Plasmids are small intranuclear circular DNAs which botulinum type of food poisoning.
carry extrachromosomal genes in bacteria. 54. (a) Virus envelope is known as capsid. The capsid is
36. (a) 37. (b) composed of protein subunits called capsomere.
38. (a) Retroviruses have RNA as the genetic material and 55. (a)
hence they exhibit reverse transcription whereby DNA 56. (b) Mycorrhizae present in the soil help in the uptake of
is synthesized on RNA template. They have reverse minerals from soil. These organisms also help in the
transcriptase as the enzyme. binding of roots to the soil.
57. (b) Myxomycetes are acellular plasmodial slime molds i.e.
39. (b) This phenomenon has been successfully used in
a group of 4 fungus which reproduces through
genetic engineering to produce disease resistant
fragmentation or zoospore.
varieties of plants.
58. (a) Yeast is the only member in kingdom fungi which is
40. (b) Frankia, is a nitrogen fixing mycelial bacterium which unicellular. Nostoc is blue green algae. E. coli is
is associated symbiotically (and not free living) with bacterium Albugo is a Parasitic fungi.
the root nodules of several non legume plants. 59. (a) 60. (c)