1. Which is true about Trypanosoma?
(a) Polymorphic (b) Monogenetic
(c) Facultative Parasite
(d) Non-pathogenic
2. Amoebiasis is prevented by
(a) eating balanced food
(b) eating plenty of fruits
(c) drinking boiled water
(d) using mosquito nets
3. Plasmodium, the malarial parasite,belongs to class
(a) Sarcodina
(b) Ciliata
(c) Sporozoa
(d) Dinophyceae
4. A nonphotosynthetic aerobic nitrogen fixing soil bacterium is
(a) Rhizobium
(b) Clostridium
(c) Azotobacter
(d) Klebsiella
5. Absorptive heterotrophic nutrition is exhibited by
(a) Algae
(b) Fungi
(c) Bryophytes
(d) Pteridophytes
6. Who discovered Plasmodium in R.B.C of human beings?
(a) Ronald Ross
(b) Mendel
(c) Laveran
(d) Stephens
7. Malignant tertian malarial parasite is
(a) Plasmodium falciparum
(b) P. vivax
(c) P. ovale
(d) P. malariae
8. Name the organisms which do not derive energy directly or indirectly from sun
(a) Chemosynthetic bacteria
(b) Pathogenic bacteria
(c) Symbiotic bacteria
(d) Mould
9. African sleeping sickness is due to
(a) Plasmodium vivax transmitted by Tse tse fly
(b) Trypanosoma lewsii transmitted by Bed Bug
(c) Trypanosoma gambiense transmitted by Glossina palpalis
(d) mitochondria
10. In Amoeba and Paramecium osmoregulation occurs through
(a) pseudopodia
(b) nucleus
(c) contractile vacuole
(d) general surface
11. Bacteria lack alternation of generation because there is
(a) neither syngamy nor reduction division
(b) distinct chromosomes are absent
(c) no conjugation
(d) no exchange of genetic material
12. The part of life cycle of malarial passed in female Anopheles is
(a) sexual cycle
(b) pre-erythrocytic schizogony
(c) exoerythrocytic schizogony
(d) post-erythrocytic schizogony
13. Organisms which are indicator of SO2 pollution of air
(a) Mosses
(b) Lichens
(c) Mushrooms
(d) Puffballs
14. Escherichia coli is used extensively in biological research as it is
(a) easily cultured
(b) easily available
(c) easy to handle
(d) easily multiplied in host
15. Genophore/bacterial genome or nucleoid is made of
(a) histones and nonhistones
(b) RNA and histones
(c) a single double stranded DNA
16. If all ponds and puddles are destroyed, the organism likely to be destroyed is
(a) Leishmania
(b) Trypanosoma
(c) Ascaris
(d) Plasmodium
17. Schizogont stage of Plasmodium occurs in human cells
(a) Erthrocytes
(b) Liver cells
(c) Erythrocytes and liver cells
(d) Erythrocytes, liver cells and spleen cells
18. Reverse transcriptase is
(a) RNA dependent RNA polymerase
(b) DNA dependent RNA polymerase
(c) DNA dependent DNA polymerase
19. Tobacco Mosaic Virus (TMV) genes are
(a) double stranded RNA
(b) single stranded RNA
(c) polyribonucleotides
(d) proteinaceous
20. Organelle/organoid involved in genetic engineering is
(a) plasmid
(b) mitochondrion
(c) golgi apparatus
(d) lomasome
Solution: (a)
21. The term antibiotic was first used by
(a) Flemming
(b) Pasteur
(c) Waksman
(d) Lister
22. Temperature tolerance of thermal
blue-green algae is due to
(a) cell wall structure
(b) cell organisation
(c) mitochondrial structure
(d) homopolar bonds in their proteins
23. Nonsymbiotic nitrogen fixers are
(a) Azotobacter
(b) Pseudomonas
(c) soil fungi
(d) blue-green algae
24. Rickettsiae constitute a group under
(a) bacteria
(b) viruses
(c) independent group between bacteria and
viruses
(d) fungi
25. Nitrogen fixer soil organisms belong
to
(a) mosses
(b) bacteria
(c) green Algae
(d) soil Fungi
26. Protistan genome has
(a) membrane bound nucleoproteins embedded in cytoplasm
(b) free nucleic acid aggregates
(c) gene containing nucleoproteins condensed together in loose mass
(d) ucleoprotein in direct contact with cell substance
27. Entamoeba coli causes
(a) Pyrrhoea
(b) Diarrhoea
(c) Dysentery
(d) None
28. Protists obtain food as
(a) photosynthesisers, symbionts and
holotrophs
(b) photosynthesisers
(c) chemosynthesisers
(d) holotrophs
29. Protista includes
(a) heterotrophs
(b) chemoheterotrophs
(c) chemoautotrophs
(d) all the above
30. Ustilago caused plant diseases called smut because
(a) they parasitise cereals
(b) mycelium is back
(c) they develop sooty masses of spores
(d) affected parts becomes completely black.
31. Claviceps purpurea is causal organism of
(a) Smut of Barley
(b) Rust of Wheat
(c) Ergot of Rye
(d) Powdery Mildew of Pea.
32. Decomposers are organisms that
(a) illaborate chemical substances, causing death of tissues
(b) operate in living body and simplifying organic substances of cells step by step
(c) attack and kill plants as well as animals
(d) operate in relay terms, simplifying step by step the organic constituents of dead body
33. Mycorrhiza represents
(a) antagonism
(b) endemism
(c) symbiosis
(d) parasitism
34. The plasmid
(a) helps in respiration
(b) genes found inside nucleus
(c) is a component of cell wall of bacteria
(d) is the genetic part in addition to DNA in micro-organisms
35. Which of the following organism possesses characteristics of both a plant and an animal?
(a) Bacteria
(b) Euglena
(c) Mycoplasma
(d) Paramecium
36. The function of contractile vacuole, in protozoa, is
(a) locomotion
(b) food digestion
(c) osmoregulation
(d) reproduction
37. Macro and micronucleus are the characteristic feature of
(a) Paramecium and Vorticella
(b) Opelina and Nictothisus
(c) Hydra and Ballantidium
(d) Vorticella and Nictothirus
38. Excretion in Amoeba occurs through
(a) lobopodia
(b) uroid portion
(c) plasma membrane
(d) contractile vacuole
39. The organism, used for alcoholic fermentation, is
(a) Pseudomonas
(b) Penicillium
(c) Aspergillus
(d) Saccharomyces
40. Which of the following is not correctly matched?
(a) root knot disease – Meloidogyne javanica
(b) smut of bajra – Tolysporium penicillariae
(c) covered smut of barley – Ustilago nuda
(d) late blight of potato – Phytophthora infestans
41. The chemical compounds produced by the host plants to protect themselvesagainst fungal infection is
(a) phytotoxin
(b) pathogen
(c) phytoalexins
(d) hormone
42. White rust disease is caused by
(a) Claviceps
(b) Alternaria
(c) Phytophthora
(d) Albugo candida
43. Azotobacter and Bacillus polymyxa are the examples of
(a) symbiotic nitrogen-fixers
(b) non-symbiotic nitrogen-fixers
(c) ammonifying bacteria
(d) disease-causing bacteria
44. Sex factor in bacteria is
(a) Chromosomal replicon
(b) F-replicon
(c) RNA
(d) Sex-pilus
45. Influenza virus has
(a) DNA
(b) RNA
(c) both DNA and RNA
(d) only proteins and no nucleic acids.
46. In bacterial chromosomes, the nucleic acid polymers are
(a) linear DNA molecule
(b) circular DNA molecule
(c) of two types-DNA and RNA
(d) linear RNA molecule
47. Interferons are
(a) antiviral proteins
(b) antibacterial proteins
(c) anticancer proteins
(d) complex proteins
48. Which one of the following is not true about lichens?
(a) Their body is composed of both algal and fungal cells
(b) Some form food for reindeers in arctic regions
(c) Some species can be used as pollution indicators
(d) These grow very fast at the rate of about 2 cm per year
49. Mycorrhiza is
(a) a symbiotic association of plant roots and certain fungi
(b) an association of algae with fungi
(c) a fungus parasitising root system of higher plants
(d) an association of Rhizobium with the roots of lenguminous plants
50. The hereditary material present in the bacterium Escherichia coli is
(a) single stranded DNA
(b) deoxyribose sugar
(c) double stranded DNA
(d) single stranded RNA
51. The plasmids pesent in the bacterial cells are
(a) circular double helical DNA molecules
(b) circular double helical RNA molecules
(c) linear double helical DNA molecules
(d) linear double helical RNA molecules.
52. Which one of the following statements about viruses is correct?
(a) Viruses possess their own metabolic system
(b) Viruses contain either DNA or RNA
(c) Viruses are facultative parasites
(d) Viruses are readily killed by antibiotics
53. Most of the Lichens consist of
(a) blue-green algae and basidomycetes
(b) blue-green algae and ascomycetes
(c) red algae and ascomycetes
(d) brown algae and phycomycetes
54. Two bacteria found to be very useful in genetic engineering experiments are
(a) Escherichia and Agrobacterium
(b) Nitrobacter and Azotobacter
(c) Rhizobium and Diplococcus
(d) Nitrosomonas and Klebsiella
55. The main role of bacteria in the carbon cycle involves
(a) photosynthesis
(b) chemosynthesis
(c) digestion or breakdown of organic
compounds
(d) assimilation of nitrogenous compounds
56. A few organisms are known to grow and multiply at temperatures of 100–
105ºC. They belong to
(a) marine archaebacteria
(b) thermophilic sulphur bacteria
(c) hot-spring blue-green algae
(cyanobacteria)
(d) thermophilic, subaerial fungi
57. Transfer of genetic information from
one bacterium to another in the
transduction process is through [1998]
(a) Conjugation
(b) Bacteriophages released from the donor
bacterial strain
(c) Another bacterium
(d) Physical contact between donor and
recipient strain
58. Puccinia forms
(a) uredia and aecia on wheat leaves
(b) uredia and telia on wheat leaves
(c) uredia and aecia on barberry leaves
(d) uredia and pycnia on barberry leaves
59. Which one of the following microorganisms is used for production of citric acid in industries?
(a) Penicillium citrinum
(b) Aspergillus niger
(c) Rhizopus nigricans
(d) Lactobacillus bulgaris
60. Yeast Saccharomyces cerevisiae is
used in the industrial production of
(a) citric acid
(b) tetracycline
(c) ethanol
(d) butanol
61. Due to which of the following
organisms, yield of rice has been
increased?
(a) Anabaena
(b) Bacillus popilliae
(c) Sesbania
(d) Bacillus polymexa
62. Photosynthetic bacteria have
pigments in
(a) leucoplasts
(b) chloroplasts
(c) chromoplasts
(d) chromatophores
63. In prokaryotes, the genetic material is
(a) linear DNA with histones
(b) circular DNA with histones
(c) linear DNA without histones
(d) circular DNA without histones
64. A good green manure in rice fields is
(a) Aspergillus
(b) Azolla
(c) Salvinia
(d) Mucor
65. Enzymes are absent in
(a) Cyanobacteria
(b) Viruses
(c) Algae
(d) Fungi
66. A virus can be considered a living organism because it
(a) responds to touch stimulus
(b) respires
(c) reproduces (inside the host)
(d) can cause disease
67. In fungi stored food material is
(a) glycogen
(b) starch
(c) sucrose
(d) glucose
68. Black rust of wheat is caused by
(a) Puccinia
(b) Mucor
(c) Aspergillus
(d) Rhizopus
69. Industrial production of ethanol from starch is brought about by
(a) Saccharomyces
(b) Lactobacillus
(c) Azotobacter
(d) Penicillium
70. Interferons are synthesized in response to
(a) Mycoplasma
(b) Bacteria
(c) Viruses
(d) Fungi
71. Extra-nuclear inheritance occurs in
(a) Killer strain in Paramecium
(b) Colour blindness
(c) Phenylketonuria
(d) Tay sach disease
72. What is true for cyanobacteria?
(a) Oxygenic with nitrogenase
(b) Oxygenic without nitrogenase
(c) Non-oxygenic with nitrogen
(d) Non-oxygenic without nitrogenase
73. What is true for archaebacteria?
(a) All halophiles
(b) All photosynthetic
(c) All fossils
(d) Oldest living beings
74. Cauliflower mosaic virus contains
(a) ss RNA
(b) ds RNA
(c) ds DNA
(d) ss DNA
75. What is true for plasmid?
(a) Plasmids are widely used in gene transfer
(b) These are found in virus
(c) Plasmid contains gene for vital activities
(d) These are main party of chromosome
76. Plant decomposers are
(a) Monera and fungi
(b) Fungi and plants
(c) Protista and animalia
(d) Animalia and monera
77. Adhesive pad of fungi penetrates the host with the help of
(a) mechanical pressure and enzymes
(b) hooks and suckers
(c) softening by enzymes
(d) only by mechanical pressure
78. Some bacteria are able to grow in Streptomycin containing medium due to
(a) natural selection
(b) Induced mutation
(c) reproductive isolation
(d) genetic drift
79. Which bacteria is utilized in gober gas plant?
(a) Methanogens
(b) Nitrifying bacteria
(c) Ammonifying bacteria
(d) Denitrifying bacteria
80. In bacteria, plasmid is
(a) extra – chromosomal material
(b) main DNA
(c) non-functional DNA
(d) repetitive gene
81. Which statement is correct for bacterial transduction?
(a) Transfer of some genes from one
bacteria to another bacteria through virus
(b) Transfer of genes from one bacteria to
another bacteria by conjugation
(c) Bacteria obtained its DNA directly
(d) Bacteria obtained DNA from other
external source
82. Which of the following secretes toxins during storage conditions of crop plants?
(a) Aspergillus
(b) Penicillium
(c) Fusarium
(d) Colletotrichum
83. Which fungal disease spreads by seed and flowers?
(a) Loose smut of wheat
(b) Corn stunt
(c) Covered smut of barley
(d) Soft rot of potato
84. During the formation of bread it becomes porous due to release of CO2 by the action of
(a) Yeast
(b) Bacteria
(c) Virus
(d) Protozoans
85. The chief advantage of encystment to an Amoeba is
(a) the chance to get rid of accumulated waste products
(b) the ability to survive during adverse physical conditions
(c) the ability to live for sometime without ingesting food
(d) protection from parasites and predators
86. Viruses are no more ―alive‖ than isolated chromosomes because
(a) both require the environment of a cell to replicate
(b) they require both RNA and DNA
(c) they both need food molecules
(d) they both require oxygen for respiration
87. Chromosomes in a bacterial cell can be 1 – 3 in number and
(a) can be circular as well as linear within the same cell
(b) are always circular
(c) are always linear
(d) can be either circular or linear, but never both with in the same cell
88. Which one of the following statements about viruses is correct?
(a) Nucleic acid of viruses is known as capsid
(b) Viruses possess their own metabolic system
(c) All viruses contain both RNA and DNA
(d) Viruses are obligate parasites
89. Tobacco mosaic virus is a tubular filament of size
(a) 700 × 30 nm
(b) 300 × 10 nm
(c) 300 × 5 nm
(d) 300 × 20 nm
90. Lichens are well known combination of an alga and a fungus where fungus has
(a) a saprophytic relationship with the alga
(b) an epiphytic relationship with the alga
(c) a parasitic relationship with the alga
(d) a symbiotic relationship with the alga
91. Which one of the following pairs is not correctly matched?
(a) Streptomyces – Antibiotic
(b) Serratia – Drug addiction
(c) Spirulina – Single cell protein
(d) Rhizobium – Biofertilizer
92. Which of the following statements is not true for retroviruses?
(a) DNA is not present at any stage in the life cycle of retroviruses
(b) Retroviruses carry gene for RNAdependent DNA polymerase
(c) The genetic material in mature retroviruses is RNA
(d) Retroviruses are causative agents for certain kinds of cancer in man
93. The most thoroughly studied fact of the known bacteria-plant interactions is the
(a) cyanobacterial symbiosis with some aquatic ferns
(b) gall formation on certain angiosperms by Agrobacterium
(c) nodulation of Sesbania stems by nitrogen fixing bacteria
(d) plant growth stimulation by phosphatesolubilising bacteria
94. Viruses that infect bacteria, multiply and cause their lysis, are called
(a) lysozymes
(b) lipolytic
(c) lytic
(d) lysogenic
95. Auxopores and hormocysts are formed, respectively, by:
(a) Some diatoms and several cyanobacteria
(b) Some cyanobacteria and diatoms
(c) the ability to live for sometime without ingesting food
(d) protection from parasite and predators
96. All of the following statements concerning the Actinomycetes filamentous soil bacterium Frankia are correct except that Frankia:
(a) Can induce root nodules on many plant species
(b) Cannot fix nitrogen in the free-living state.
(c) Forms specialized vesicles in which the
nitrogenase is protected from oxygen by a chemical barrier involving triterpene hopanoids
(d) Like Rhizobium, it usually infects its host plant through root hair deformation and stimulates cell proliferation in the host‘s cortex
97. For retting of jute the fermenting microbe used is
(a) Methophilic bacteria
(b) Butyric acid bacteria
(c) Helicobactor pylori
(d) Streptococcus lactin
98. There exists a close association between the alga and the fungus within a lichen. The fungus
(a) provides protection, anchorage and absorption for the alga
(b) provides food for the alga
(c) fixes the atmospheric nitrogen for the alga
(d) releases oxygen for the alga
99. Which antibiotic inhibits interaction between RNA and mRNA during bacterial protein synthesis?
(a) Neomycin
(b) Streptomycin
(c) Tetracycline
(d) Erythromycin
100. Which of the following statements regarding cilia is not correct?
(a) Cilia are hair-like cellular appendages
(b) Microtubules of cilia are composed of tubulin
(c) Cilia contain an outer ring of nine doublet microtubules surrounding two single microtubules
(d) The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane
101. The thalloid body of a slime mould (Myxomycetes) is known as
(a) plasmodium
(b) fruiting body
(c) mycelium
(d) protonema
102. Which of the following environmental conditions are essential for optimum growth of Mucor on a piece of bread? A. Temperature of about 25°C B. Temperature of about 5° C C. Relative humidity of about 5% D. Relative humidity of about 95% E. A shady place F. A brightly illuminated place Choose the answer from the following options:
(a) A, D and E only
(b) B, D and E only
(c) B, C and F only
(d) A, C and E only
103. The causative agent of mad-cow disease is a
(a) Prion
(b) Worm
(c) Bacterium
(d) Virus
104. Which one of the following statements about mycoplasma is wrong?
(a) They are pleomorphic
(b) They are sensitive to penicillin
(c) They cause diseases in plants
(d) They are also called PPLO.
105. Which pair of the following belongs to Basidiomycetes
(a) puffballs and Claviceps
(b) peziza and stink borns
(c) Morchella and mushrooms
(d) birds nest fungi and puffballs.
106. Ergot of rye is caused by a species of
(a) uncimula
(b) ustilago
(c) claviceps
(d) phytophthora.
107. Which one of the following is a slime mould?
(a) Physarum
(b) Thiobacillus
(c) Anabaena
(d) Rhizopus
108. Which one of the following is linked to the discovery of Bordeaux mixture as a popular fungicide?
(a) Bacterial leaf blight of rice
(b) Downy mildew of grapes
(c) Loose smut of wheat
(d) Black rust of wheat
109. Bacterial leaf blight of rice is caused by a species of
(a) Xanthomonas
(b) Pseudomonas
(c) Alternaria
(d) Erwinia
110. 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?
(a) Archaea resemble eukarya in all respects
(b) Archaea have some novel features that are absent in other prokaryotes and eukaryotes
(c) Archaea completely differ from both prokaryotes and eukaryotes
(d) Archaea completely differ from prokaryotes
111. Thermococcus, Methanococcus and Methanobacterium exemplify:
(a) Archaebacteria that contain protein homologous to eukaryotic core histones
(b) Archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled
(c) Bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria
(d) Bacteria that contain a cytoskeleton and ribosomes
112. Which one is the wrong pairing for the disease and its causal organism?
(a) Black rust of wheat – Puccinia graminis
(b) Loose smut of wheat – Ustilago nuda
(c) Root-knot of vegetables – Meloidogyne sp
(d) Late blight of potato – Alternaria solani
113. Phylogenetic system of classification is based on:
(a) morphological features
(b) chemical constituents
(c) floral characters
(d) evolutionary relationships
114. Mannitol is the stored food in:
(a) Porphyra
(b) Fucus
(c) Gracillaria
(d) Chara
115. Single-celled eukaryotes are included in:
(a) Protista
(b) Fungi
(c) Archaea
(d) Monera
116. Ringworm in humans is caused by:
(a) Bacteria
(b) Fungi
(c) Nematodes
(d) Viruses
117.Which one of the following is a slime mould?
(a) Physarum
(b) Thiobacillus
(c) Anabaena
(d) Rhizopus
118. Virus envelope is known as:
(a) Capsid
(b) Virion
(c) Nucleoprotein
(d) Core
119. Which one of the following is not a biofertilizer?
(a) Agrobacterium
(b) Rhizobium
(c) Nostoc
(d) Mycorrhiza
120. Ethanol is commercially produced through a particular species of:
(a) Saccharomyces
(b) Clostridium
(c) Trichoderma
(d) Aspergillus
121. Which one of the following organisms is not an example of eukaryotic cells?
(a) Paramecium caudatum
(b) Escherichia coli
(c) Euglena viridis
(d) Pinus
126. Organisms called methanogens are most abundant in a:
(a) sulphur rock
(b) cattle yard
(c) polluted stream
(d) hot spring
127. Which one of the following pairs is wrongly matched while the remaining three are correct?
(a) Penicillium – Conidia
(b) Water hyacinth – Runner
(c) Bryophyllum – Leaf buds
(d) Agave – Bulbils
128. Consider the following four statements whether they are correct or wrong?
(A) The sporophyte in liverworts is more elaborate than that in mosses
(B) Salvinia is heterosporous
(C) The life cycle in all seed-bearing plants is diplontic
(D) In Pinus male and female cones are borne on different trees
(a) Statements (A) and (C)
(b) Statements (A) and (D)
(c) Statements (B) and (C)
(d) Statements (A) and (B)
129. Selaginella and Salvinia are considered to represent a significant step toward evolution of seed habit because:
(a) female gametophyte is free and gets dispersed like seeds
(b) female gametophyte lacks archaegonia
(c) megaspores possess endosperm and embryo surrounded by seed coat
(d) embryo develops in female gametophyte which is retained on parent sporophyte.
130. Compared with the gametophytes of the bryophytes the gametophytes of vascular plant are
(a) smaller but have larger sex organs
(b) larger but have smaller sex organs
(c) larger and have larger sex organs
(d) smaller and have smaller sex organs
131. The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the ones categorised as:
(a) Cyanobacteria
(b) Archaebacteria
(c) Chemosynthetic autotrophs
(d) Heterotrophic bacteria
132. The cyanobacteria are also referred to as
(a) protists
(b) golden algae
(c) Slime moulds
(d) blue green algae
133. Which statement is wrong for viruses
(a) All are parasites
(b) All of them have helical symmetry
(c) They have ability to synthesize nucleic
acids and proteins
(d) Antibiotics have no effect on them
134. Which one single organism or the pair of organisms is correctly assigned to its taxonomic group
(a) Paramoecium and Plasmodium belong to the same kingdom as that of Penicillium
(b) Lichen is a composite organism formed from the symbiotic association of an algae and a protozoan
(c) Yeast used in making bread and beer is a fungus
(d) Nostoc and Anabaena are examples of protista
135. How many organisms in the list given below are autotrophs? Lactobacillus, Nostoc, Chara, Nitrosomonas, Nitrobacter,
(a) Four
(b) Five
(c) Six
(d) Three
136. In the five-kingdom classification, Chlamydomonas and Chlorella have been included in
(a) protista
(b) algae
(c) plantae
(d) monera
137. Which one of the following sets of items in the options 1 – 4 are correctly categorized with one exception in it? Items- Category- Exception
(a) UAA, UAG, UGA -Stop codons -UAG
(b) Kangaroo, Koala, Wombat -Australian marsupials -Wombat
(c) Plasmodium, Cuscuta, Trypanosoma – Protozoan parasites- Cuscuta
(d) Typhoid, Pneumonia, Diphtheria -Bacterial diseases -Diphtheria
138. Which of the following are likely to be present in deep sea water?
(a) Eubacteria
(b) Blue-green algae
(c) Saprophytic fungi
(d) Archaebacteria
139. Which one of the following is true for fungi?
(a) They are phagotrophs
(b) They lack a rigid cell wall
(c) They are heterotrophs
(d) They lack nuclear membrane
140. Specialized cellsfor fixing atmospheric nitrogen in Nostoc are
(a) Akinetes
(b) Heterocysts
(c) Hormogonia
(d) Nodules
141. Satellite RNAs are present in some
(a) Plant viruses
(b) Viroids
(c) Prions
(d) Bacteriophages
142. The causal organism for African sleeping sickness is
(a) Trypanosoma cruzi
(b) T. rhodesiense
(c) T. tangela
(d) T. gambiense
143. The vector for sleeping sickness is
(a) House fly
(b) Tse-Tse fly
(c) Sand fly
(d) Fruit fly
144. Trypanosoma belongs to class
(a) Sarcodina
(b) Zooflagellata
(c) Ciliata
(d) Sporozoa
145. Malaria fever coincides with liberation of
(a) cryptomerozoites
(b) metacryptomerozoites
(c) merozoites
(d) trophozoites
146. A bite of Tse-Tse fly may pass to humans
(a) Leishmania donovani
(b) Trypanosoma gambiense
(c) Entamoeba histolytica
(d) Plasmodium vivax
147. The ineffective stage of malarial parasite Plasmodium that enters human body is
(a) merozoite
(b) sporozoite
(c) trophozoite
(d) minuta form
148. Lichens indicate SO2 pollution because they
(a) show association between algae and fungi
(b) grow faster than others
(c) are sensitive to SO2
(d) flourish in SO2 rich environment
149. Which one belongs to monera?
(a) Amoeba
(b) Escherichia
(c) Gelidium
(d) Spirogyra 150. The main difference in Gram (+)ve and Gram (–)ve bacteria resides in their
(a) cell wall
(b) cell membrane
(c) cytoplasm
150. The main difference in Gram (+)ve and Gram (–)ve bacteria resides in their
(a) cell wall
(b) cell membrane
(c) cytoplasm
(d) flagella
151. Genetic information in Paramecium is contained in
(a) micronucleus
(b) macronucleus
(c) both micronucleus and macronucleus
(d) mitochondria
152. DNA replication in bacteria occurs
(a) within nucleolus
(b) prior to fission
(c) just before transcription
(d) during S phase
153. Myxomycetes are
(a) saprobes or parasites, having mycelia, asexual reproduction by fragmentation.
(b) slimy mass of multinucleate protoplasm, having pseudopodia like structures for engulfing food, reproduction through fragmentation or zoospores.
(c) prokaryotic organisms, cellular or acellular, saprobes or autotrophic, reproduce by binary fission.
(d) eukaryotic, single-celled or filamentous, saprobes or autotrophic, asexual reproduction by division of haploid individuals, sexual reproduction by fusion of two cells or their nuclei.
154.Which one of the following statements is wrong?
(a) Eubacteria are also called false bacteria.
(b) Phycomycetes are also called algal fungi.
(c) Cyanobacteria are also called bluegreen algae.
(d) Golden algae are also called desmids
155.One of the following includes most closely linked organisms
(a) species
(b) genus
(c) family
(d) class
156.Bacterial cell wall is made up of
(a) xylan
(b) chitin
(c) cellulose
(d) murein
157. Which one is a wrong statement?
(a) Haploid endosperm is typical feature of Gymnosperms.
(b) Brown algae have chlorophyll a and c and fucoxanthin.
(c) Archegonia are found in Bryophyta,
Pteridophyta and Gymnosperms.
(d) Mucor has biflagellate zoospores.
158.Cell wall is absent in
(a) Mycoplasma
(b) Nostoc
(c) Aspergillus
(d) Funaria.
159.Which of the following shows coiled RNA strand and capsomeres?
(a) Polio virus
(b) Tobacco mosaic virus
(c) Measles virus
(d) Retrovirus
160.Binomial nomenclature refers to ………
(a) Two names of a species
(b) one specific and one local name of a species
(c) two words for the name of a species
(d) two life cycles of an organism
161.”Fairy rings” in lawns result from
outward, spreading circles of mycelia of mushrooms producing, at their periphery, fruiting bodies called
(a) ascocarps
(b) basidiocarps
(c) sorocarps
(d) pseudocarps
162.Which one single organism or the pair of organisms is correctly assigned to its or their named taxonomic group?
(a) Paramecium and Plasmodium belong to the same kingdom as that of Penicillium
(b) Lichen is a composite organism formed from the symbiotic association of an algae and a protozoan
(c) Yeast used in making bread and beer is a fungus
(d) Nostoc and Anabaena are examples of protista.
163.Two plants can be conclusively said to belong to the same species if they ……
(a) have more than 90% similar genes
(b) look similar and possess identical secondary metabolites
(c) have same number of chromosomes
(d) can reproduce freely with each other and form seeds
164.Which one of the following also acts as a catalyst in a bacterial cell?
(a) 5S rRNA
(b) snRNA
(c) hnRNA
(d) 23S RNA
165.Which one of the following is incorrectly matched?
(a) Root pressure guttation
(b) Puccinia – smut
(c) Root exarch protoxylem
(d) Cassiaimbricate Aestivation
166.The correct sequence of taxonomic categories is ……….
(a) class-phylum-tribe-order-family-genus-species
(b) phylum-order-class-tribe-family-genus-species
(c) division-class-order-family-tribe-genus-species
(d) division-class-family-tribe-order-genus-species
167.For retting of jute the fermenting microbe used is
(a) methanophilic bacteria
(b) butyric acid bacteria
(c) Helicobactor pylori
(d) Streptococcus lactin.
168.There exists a close association between the alga and the fungus within a lichen. The fungus
(a) provides protection, anchorage and
absorption for the algae
(b) provides food for the alga
(c) fixes the atmospheric nitrogen for the alga
(d) releases oxygen for the alga.
169.Tobacco mosaic virus is a tubular filament of size
(a) 300 × 10 nm
(b) 300 × 5 nm
(c) 300 × 20 nm
(d) 700 × 30 nm.
170.In five kingdom system, the main basis of classification is
(a) structure of nucleus
(b) mode of nutrition
(c) structure of cell wall
(d) asexual reproduction
171.Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the Kingdom
(a) Fungi
(b) Animalia
(c) Monera
(d) Protista
172.Which of the following are found in extreme saline conditions ?
(a) Eubacteria
(b) Cyanobacteria
(c) Mycobacteria
(d) Archaebacteria
173. Viroids differ from viruses in having;
(a) DNA molecules without protein coat
(b) RNA molecules with protein coat
(c) RNA molecules without protein coat
(d) DNA molecules with protein coat
174. Which among the following are the smallest living cells, known without a definite cell wall, pathogenic to plants as well as animals and can survive without oxygen ?
(a) Pseudomonas
(b) Mycoplasma
(c) Nostoc
(d) Bacillus
175. Which of the following organisms are known as chief producers in the oceans?
(a) Dinoflagellates
(b) Diatoms
(c) Euglenoids
(d) Cyanobacteria
176. Ciliates differ from all other protozoans in
(a) using flagella for locomotion
(b) having a contractile vacuole for removing excess water
(c) having two types of nuclei
(d) using pseudopodia for capturing prey
177. Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other?
(a) Hydrilla
(b) Yucca
(c) Viola
(d) Banana
178. Which among the following is not a prokaryote?
(a) Saccharomyces
(b) Mycobacterium
(c) Oscillatoria
(d) Nostoc
179. After karyogamy followed by meiosis, spores are produced exogenously in
(a) Neurospora
(b) Alternaria
(c) Saccharomyces
(d) Agaricus
180. Select the wrong statement :
(a) Cell wall is present in members of Fungi and Plantae
(b) Mushrooms belong to Basidiomycetes
(c) Mitochondria are the powerhouse of the cell in all kingdoms except Monera
(d) Pseudopodia are locomotory and feeding structures in Sporozoans
181. Which of the following statements is incorrect?
(a) Viroids lack a protein coat.
(b) Viruses are obligate parasites.
(c) Infective constituent in viruses is the protein coat.
(d) Prions consist of abnormally folded proteins.
182.Which is of the following statements is incorrect?
(a) Morels and truffles are edible delicacies.
(b) Claviceps is a source of many alkaloids and LSD.
(c) Conidia are produced exogenously and ascospores endogenously.
(d) Yeasts have filamentous bodies with long thread-like hyphae
183. Match Column – I Column – II
Column – I Column – II
(a) Saprophyte (i) Symbiotic association of fungi with plant roots
(b) Parasite (ii) Decomposition of dead organic materials
(c) Lichens (iii)Living on living plants or animals
(d) Mycorrhiza (iv) Symbiotic association of algae and fungi
Choose the correct answer from the option given below
(a) (b) (c) (d)
(1) (i) (ii) (iii) (iv)
(2) (iii) (ii) (i) (iv)
(3) (ii) (i) (iii) (iv)
(4) (ii) (iii) (iv) (i)
184. Which of the following is correct about viroids?
(a) They have DNA with protein coat
(b) They have free DNA without protein coat
(c) They have RNA with protein coat
(d) They have free RNA without protein coat
185. Which of the following hormone levels will cause release of ovum (ovulation) from the graffian follicle?
(a) Low concentration of LH
(b) Low concentration of FSH
(c) High concentration of Estrogen
(d) High concentration of Progesterone
186.Which of the following statements is correct ?
(a) Some of the organisms can fix atmospheric nitrogen in specialized cells called sheath cells
(b) Fusion of two cells is called Karyogamy
(c) Fusion of protoplasms between two motile on non-motile gametes is called plasmogamy
(d) Organisms that depend on living plants are called saprophytes
187. Match Column-I with Column-II.
Column-I Column-II
(a) Nitrococcus (i) Nitrococcus
(b) Rhizobium (ii) Conversion of ammonia to nitrite
(c) hiobacillus (iii) Conversion of nitrite to nitrate
(d) Nitrobacter (iv) Conversion of atmospheric nitrogen to ammonia
Choose the correct answer from options given
below.
(a) (b) (c) (d)
(1) (iv) (iii) (ii) (i)
(2) (ii) (iv) (i) (iii)
(3) (i) (ii) (iii) (iv)
(4) (iii) (i) (iv) (ii)
188. Match List – I with List – II
List I List II
(a) Metamerism (i) Coelenterata
(b) Canal system (ii) Ctenophora
(c) Comb plate (iii) Annelida
(d) Cnidoblasts (iv)Porifera
Choose the correct answer from the options given below.
(a) (b) (c) (d)
(1) (iv) (i) (ii) (iii)
(2) (iv) (iii) (i) (ii)
(3) (iii) (iv) (i) (ii) (4) (iii) (iv) (ii) (i)
Solutions :
1.Solution: (a)Trypanosoma is polymorphic i.e. it exists in different forms in the successive stages of its life cycle. These are Leishmania, Leptomonad, Crituidial and trypanosomal stages.
2.Solution: (c)Amoebiasis or amoebic dysentry is caused by a parasite Entamoeba histolytica present in the upper part of large intestine of human. It is caused due to ingesting contaminated food or water with cyst (trophozoite) of Entamoeba. It feeds on R.B.C of intestinal blood capillaries and damages intestinal mucosa secreting an enzyme – histolysin.
3.Solution: (c)Plasmodium belongs to class Sporozoa of protozoan profists. It is an endoparasite lacking any locomotony structure and contractile vacules. It reproduces through spore formation.
4.Solution: (c)Azotobacter is free living soil bacteria that are able to pick up dinitrogen from the soil and fixes it into organic nitrogenous material like aminoacid. Clostridium is anaerobic free living soil N2 fixing bacteria. Rhizobium is symbiotic N2 fixing bacteria.
5. Solution: (b)Fungi are nutritionally saprophytes, which grow on dead and decaying matter. They secrete enzyme to the external medium where digestion takes place and digested food absorbed by the body surface. They convert complex organic constituents of dead body into simple soluble forms. That is why Fungi are decomposers.
6.Solution: (c)Laveran discovered Plasmodium in R.B.C of human beings and concluded that malaria is caused by Plasmodium vivax. Sir Ronal Ross (1896) was the first to observe oocytes of Plamodium in female Anopheles.
7. Solution: (a)In human beings different types of malaria
are caused by 4 different species of
Plasmodium. They are:
1. Benign Tertian Malaria – Plasmodium vivax.
2. Malignant (Pernicious or cerebral)Tertian Malaria – Plasmodium falciparum.
3. Quartan Malaria – Plasmodium malariae.
4. Mild Tertian Malaria – Plasmodium ovale.
8.Solution: (a)Chemosynthetic bacteria does not require sunlight as a source of energy directly or indirectly. The energy for the synthesis of food is obtained by the oxidation of certain inorganic substances present in the medium. The chemical energy obtained from oxidation reaction is trapped in ATP molecules. The ATP is used in CO2 assimilation.
9.Solution: (c)I. African sleeping sickness disease also
Called as trypansomiasis common in western and central parts of African
continent.
II. The disease is caused by parasite Trypanosoma gambiense of class zooflagellata.
III. The parasite is transmitted (vector) through bite of Tse-Tse fly (Glossina palpalis).
IV. The disease appears when the causal organism enters into cerebrospinal fluid of human. V. Trypanosoma is an obligate parasite, Digenetic and Polymorphic organism.
10.Solution: (c)Contractile vacuole in Amoeba and Paramecium maintain the water balance of the cell. This is known as osmoregulation.
11.Solution: (a)In bacteria asexual reproduction through binary fission is the most common method of multiplication. Sexual reproduction which comprises of syngamy and meiosis is entirely absent. Hence no gamete formation takes place. In sexually reproducing organism alternation of generation occurs.
12.Solution: (a)Plasmodium vivax completes Sexual cycle or Gamogony in female Anopheles mosquito. Asexual cycle is passed in man (Schizogony).
13.Solution: (b)Lichens are composite organisms representing a symbiotic association between fungus and a algae. It can be Crustose, Foliose and Fruticose types. They are the pioneer organisms in a new habitat. Lichens used as indicator of air pollution. It pollution level is high, SO2 is strong air pollutant and lichens are very sensitive toSO2.
Solution: (b)Lichens are composite organisms representing a symbiotic association between fungus and a algae. It can be Crustose, Foliose and Fruticose types. They are the pioneer organisms in a new habitat. Lichens used as indicator of air pollution. It does grow in the environment where pollution level is high, SO2 is strong air pollutant and lichens are very sensitive to SO2.
14.Solution: (a)Escherichia coli, lives as a symbiont in human intestine.
15. Solution: (c) The bacterial genome/nucleoid is made of single circular double stranded DNAwithout histone protein as it is a prokaryotic organisms. The genome
contains some 100 chemical sites or loci. Each locus contains many genes. E coli contains about 4000 genes.
16. Solution: (d)Plasmodium transmitted through female Anopheles mosquito to Human and the most favourite dwelling place for Anopheles is water or moist places like ponds and puddles.
17.Solution: (c)Schizogont or Asexual stage occurs in human erythrocytes and liver cells.
18.Solution: (d)H. Temin and D. Baltimore (1970)discovered that tumor viruses contain RNA as genetic material and replicate by synthesizing complementary DNA. This process is called reverse transcription and it is carried by an RNA dependent DNA polymerase called as reverse transcriptase.
19.Solution: (b)All viruses are nucleoprotein (Nucleic acid + Protein) in the structure. The nucleic acid (DNA and RNA) is genetic material. In a particular virus either DNA or RNA is genetic material never both are present in a virus. Hence viruses are: (i) Double stranded DNA or ds DNA – Hepatitis B (ii) Single stranded DNA or ss DNA – coliphage (iii) Double stranded RNA or ds RNA – Reo virus, wound Tumor virus (iv) Single stranded RNA or ss RNA – Tobacco mosaic virus (TMV)
20.Solution: (a)Besides Nuclear DNA, bacteria possesses extranuclear DNA (outside the nucleoid region) called as plasmid which can replicate independently. Due to this property plasmid holds great importance in genetic engineering. Plasmid can be taken out of bacteria and made to combine with desired DNA segment. A lasmid carrying DNA of other organism now it is known as cosmid which can be introduced into any desired cells. This is the basis of genetic engineering.
21.Solution: (c)The term antibiotics was coined by Waksman but the first known antibiotic, penicillin was extracted from fungi Penicillium notatum by A Flemming 1944. Antibiotics are the chemicals that are produced from the living organisms, used to kill another living organisms. About 2300 antibiotics discovered so far e.g.
Streptomycin, Tetracycline etc.
22.Solution: (d)Some of the blue green algae can tolerate extremes of temperature due to presence of gelatinous sheath, and compactness of protein molecules in protoplasm.
23.Solution: (a)Azotobacter is nonsymbiotic, free living nitrogen fixing bacteria.
24.Solution: (c) Rickettsias are tiny obligate, intracellular parasites found in blood sucking insects like lices, mites, ticks. They were first observed by Ricketts 1909 but it was properly described by Rocha-lime 1916, who named them as Rickettsia. They have mucopeptide cell wall with DNA as genetic material and are independent entity produces diseases like Q-fever, typhus etc.
25.Solution: (b)Only some bacteria and Blue green algae (cynobacteria) has capacity to fix atmospheric nitrogen. • Bacteria:Azotobacter, Rhizobium, Frankia etc. •
Bluegreenalge, Nostoc , Oscillatoria, Anabaena etc.
26. Solution: (a)Protistans are eukaryotes and their genetic material is organised in form of nucleus.DNA is associated with histone protein.
27.Solution: (d)Pyrrhoea is caused by bacterial infections along with other factor, Diarrhoea by caused by rotavirus along with many other factor. Dysentery by Entamoeba histolytica.
28.Solution: (a)Members of kingdom Protista have diverse mode of nutrition. They are photosynthetic, saprophytic parasitic and ingestive. They are major heterotroph.
29. Solution: (d)Kingdom Protista includes flagellates (euglenophyceae), diatoms, dinoflagellates, slime moulds, sarcodines, ciliates,
sporozoans. They are photosynthetic, chemotrophic, heterotropic in mode of nutrition.
30..Solution: (d)Smut disease caused by Ustilago species of basidiomycetes fungi. It is characterised by formation of black coloured chlamydospores or teleutospores called smut spore due to which the affected part becomes black.
31.Solution: (c)The fungus that causes the disease ‗Ergot of Rye‘ is Claviceps purpurea. Itmany poisonous alkaloids. The hallucinogenic drug LSD is extracted from
this fungi. • Rust of wheat is used by Puccinia graminis. • Powdery Mildew of Pea is caused by Erysiphae.
32. Solution: (d)Decomposers act on dead bodies converting complex organic constituents into simple soluble form. They obtain their energy from dead organisms. Decomposers themselves are organisms (often fungi, earthworms, or bacteria) that break down organic materials to gain nutrients and energy. Decomposers accelerate the natural process of decomposition. They supply the required nutrients for other trophic levels. The fungi on the tree are decomposers.When an organism dies, it leaves behind nutrients that are locked tightly together. A scavenger might eat the carcass, but its feces would still contain a considerable amount of unused energy and nutrients. Decomposers will later induce further breakdown. This last step releases raw nutrients (such as nitrogen, phosphorus and magnesium) in a form usable to plants, which quickly incorporate the chemicals Into their own cells. This process greatly increases the nutrientload of an ecosystem,
in turn allowing for greater biodiversity.
33.Solution: (c)Mycorrhiza is symbiotic association between fungi and roots of higher plants. Mycorrhiza form wooly covering of fungal hyphae on the surface and remain in upper layers. It is of two types Ecto and Endomycorrhiza. In some endomycorrhiza, the fungal hyphae develop some organs called vesicles within the root cortical cells, such mycorrhizae are called VAM (vesicular arbuscular mycorrhizae). It is meant for phosphate nutrition.
34.Solution: (d)The term ‗plasmid‘ was introduced by Lederberg in 1952 for extragenomic DNA segment. It is a small circular molecule of DNA found in bacterial cell in addition to the larger circular bacterial DNA.
35. Solution: (b)The Euglena is an organism, which possesses both the characteristics of plants and animals, as it can move with a flagella and also contains chlorophyll. Its nutrition is mixotrophic.
36.Solution: (c)In protozoa, the function of contractile vacuole is the removal of excretory substances, carbon dioxide etc. It is very essential to regulate water content i.e., osmoregulation.
37.Solution: (a)The macronucleus lacks nuclear membrane and is formed of trophochromatin. It regulates the metabolic activities of the body and it is also known
as trophonucleus. The micronucleus has a definite nuclear membrane and controls the reproductive activities of Paramecium and Vorticella.
38.Solution: (d)The conractile vacuole is supposed to assist excertion in Amoeba, as its watery contents possess traces of carbon dioxide and urea. The CO2 diffuses directly through plasmalemma.
39.Solution: (d)Fermentation refers to the breakdown of organic substances, particularly carbohydrates, under anaerobic conditions.Saccharomyces cerevisiae is used for fermenting carbohydrate. The ethyl alcohol and carbon dioxide are formed at the end of the process.
40.Solution: (c)Covered smut of barley is caused by Ustilago hordei, not by Ustilago nuda. This disease is purely externally seed borned.
41.Solution: (c)Phytoalexins are non-specific antibiotic substances produced by plants in response to infection by a fungus.
42.Solution: (d)Albugo candida is an obligate parasite causing white rust on members of family Cruciferae and other hosts.
43.Solution: (b)Azotobacter and Bacillus polymyxa are the examples of non-symbiotic nitrogenfixers.
44. Solution: (b)Sex-factor or F-factor in bacteria results in high frequency conjugation. It allows bacteria to produce sex pilus necessary for conjugation.
45.Solution: (b)Influenza virus is a retrovirus wherein, the genetic material comprises of RNA. There are three genera of influenza virus, identified by antigenic ifferences in their nucleoprotein and matrix protein: • Influenza virus A are the cause of all flu pandemics and are known to infect humans, other mammals and birds (see also avian influenza). • Influenza virus B are known to infect humans and seals. • Influenza virus C are known to infect humans and pigs.
46. Solution: (b)Bacterial chromosomes comprise of circular DNA.
47.Solution: (a)Interferons are viru induced proteins produced by cells infected with viruses. They are antiviral in action.
48.Solution: (d)Lichens are composite dual organisms formed by the association between a fungus and a photosynthetic symbiont. The bulk of lichen body is formed of fungus
49.Solution: (a)Association of algae and fungi is referred to as lichen. Symbiotic association of Rhizobium with roots of leguminous plants is referred to as ymbiosis. Mycorrhiza is symbiotic association between fungi and roots of higher plants. The fungal partner of mycorrhiza obtains food from roots of the higher plant and in return supplies mineral elements to it.
50.Solution: (c)In any kind of Bacteria (E.coli) double stranded DNA is present.
51.Solution: (a)Plasmids are the extrachromosomal DNA.
52. Solution: (b)Viruses have either DNA or RNA as the genetic material. Viruses having RNA as the genetic material are known as Retroviruses.
53.Solution: (b)The lichen fungus is typically a member of the Ascomycota rarely a member of the Basidiomycota. The algal or cyanobacterial cells are photosynthetic, and as in higher plants they reduce atmospheric carbon dioxide into organic carbon sugars to feed both symbionts. Both partners gain water
and mineral nutrients mainly from the atmosphere through rain and dust. Thefungal partner protects the alga by retaining water, serving as a larger capture
area for mineral nutrients and, in some cases, provides minerals obtained from the substratum. If a cyanobacterium is present, as a primary partner or another
symbiont in addition to green alga as in certain tripartite lichens, they can fix atmospheric nitrogen, complementing the activities of the green alga.
54.Solution: (a)Escherichia and Agrobacterium are both used as vectors in genetic engineering. Nitrobactor converts nitrites to nitrates. Azotobacter is a free living nitrogen fixing bacteria. Nitrosomonas converts ammonia to nitrite. Rhizobium is a symbiotic nitrogen fixing bacteria living in the root nodules of leguminous plants Diplococcus pneumoniae causes pneumonia.
55.Solution: (c)Bacteria acts as decomposers in the carbon cycle.
56.Solution: (a)These are archaebacteria which can tolerate high temperature.
57.Solution: (b)Transfer of genetic information from one bacterium to another by physical contact is called conjugation while if it takes place by some other medium like virus than it is called transduction.
58.Solution: (b)Puccinia causes black rust of wheat. It completes its life cycle in two hostswheat and barberry. Two types of spores are produced on wheat – uredospores and teleutospores.
59.Solution: (b)Aspergillus niger is known as guinea pig of kingdom fungi. The main source of commercial preparation of citric acid is the fermentation of sugar with Aspergillus niger.
60.Solution: (c)Yeast performs alcoholic fermentation because of enzyme ‗Zymase‘. It is used in the production of ethyl alcohol or ethanol.
61.Solution: (a)Azolla is a freshwater fern harbouring a bluegreen alga – Anabaena in its leaf cavities. The alga fixes atmospheric nitrogen and releases nitrogenous
compounds in leaf cavities. This symbiotic system is the main source of algal biofertilizer in rice fields. When rice paddies are flooded in the spring, they can be
inoculated with Azolla, which then quickly multiplies to cover the water, suppressing weeds. As the plants die, they contribute nitrogen to the rice plants, and as the rice paddy dries out, the Azolla all eventually die, making an exceptional green manure.
62.Solution: (d)Chloroplasts, chromoplasts and leucoplasts are the types of plastids found in higher plants. Chloroplasts contain the green pigment chlorophyll. Chromoplasts contain coloured pigments. Leucoplasts are colourless and store starch granules.
63.Solution: (d) In prokayotes nucleoid consist of double stranded circular DNA without histone protein.
64.Solution: (b)Aspergillus is a fungus, Mucor is also a fungus. Azolla harbours blue-green algae Anabaena which fixes N2, increasing fertility.
65.Solution: (b)Enzymes are absent in viruses because they are unable to transmit their nucleic acid from one host cell to another.
66.Solution: (c)Virus is an ultra microscopic nucleoprotein entity which becomes active only inside a living cell. It resembles living beings due to presence of genetic material and reproduction.
67.Solution: (a)Glycogen is a glucosan Ohomopolysaccharide which is the major reserve food of animals, fungi and some bacteria is a also glucosan homopolysaccharide and is a major reserve food of plants. Sucrose is formed of one molecule of glucose and one molecule of fructose
68.Solution: (a)Black rust of wheat is caused by Puccinia graminis. The symptoms are seen in stem or leaf sheath as brownish spot. Yeast helps in ethyl alcohol formation.
69.Solution: (a)Lactobacillus is the milk bacteria while Azotobacter is the free living nitrogen fixing Penicillin.
70.Solution: (c)Interferons are virus induced proteins produced by cells infected with virus.
71.Solution: (a)Colour blindness follows sex-linked inheritance. Phenylketonuria is an in born error of metabolism.
72.Solution: (a)Cyanobacteria are oxygenic photoautotroph. Many members perform nitrogen fixation.
73.Solution: (d)Archaebacteria are the most ancient and halogenous group of bacteria and are called living fossils.
74.Solution: (c)Cauliflower mosaic virus contains double stranded DNA.
75.Solution: (a)Plasmids are small intranuclear circular DNAs which carry extra chromosomal genes in bacteria.
76.Solution: (a)Plant decomposers are Bacteria (Kingdom Monera) and Fungi.
77.Solution: (a)The fungal hyphae secrete enzymes which convert insoluble complex food material in the substratum to the soluble ones. The hyphae wall of intracellular hyphae come in contact with the host protoplasm and obtain food by direct diffusion.
78.Solution: (a)Prevention of mating between two natural populations of the same or different spaces due to presence of barriers to interbreeding
is called reproductive isolation. Genetic drift is the random change in the allele number and frequency in a gene pool. Natural selection is a type of force for
evolutionary processes. Here in this case it allows the growth of only those bacteria which have resistance towards streptomycin.
79.Solution: (a)Methanobacillus (methanogen) occurs in marshes and also in dung. It produces CH4 gas under anaerobic condition and is utilized in gobar gas plant.
80.Solution: (a)Plasmid is attached to mesosome in bacteria.
81.Solution: (a)Transduction experiments were carried out by Hershey and Chase.
82.Solution: (a)Aspergillus flavus produces carcinogenic fungus toxin (Aflatoxin) during storage condition of crop plant.
83. Solution: (a)Ustilago causes loose smut of wheat, as a result the grain and flower get converted into powdered mass.
84.Solution: (a)Yeast carry out fermentation, releasing CO2 making bread soft and porous. Hence Saccharomyces is referred to as baker‘s yeast.
85.Solution: (b)Encystment enables the zygote to survive under adverse or infavourable conditions wherein it lies dormant.
86Solution: (a).Viruses can live only inside the host cell,using their machinery for its own metabolism.
87.Solution: (b)Prokaryotes (bacteria) have only circular chromosomes.
88.Solution: (d)Virus is a nucleoprotein entity which becomes active only inside a living cells utilizing the latter machinery for multiplication. Capsid is the protein
covering around the genetic material.
89.Solution: (d)Tobacco mosaic virus is 300 nm long and 20 nm in diameter.
90.Solution: (d)Lichens are composite dual organisms formed by symbiotic association between a fungus and alga. A saprophyte is an organism feeding on dead, decaying organic matter. Epiphyte is a plant growing over another plant. Parasites live inside their host.
91.Solution: (b) Rhizobium is a symbotic nitrogen fixing bacteria. Streptomyces is source for streptomycin. Spirulina is a rich source of vitamin B1 and proteins.
92.Solution: (a)Retroviruses have RNA as the genetic material and hence they exhibit reverse transcription whereby DNA is synthesized on RNA template. They have reverse transcriptase as the enzyme.
93.Solution: (b)This phenomenon has been successfully used in genetic engineering to produce disease resistant varieties of plants.
94.Solution: (c)Viruses that get integrated with the bacterial host genome are called lysogenic. Virus which transmit its DNA into bacterial cell and divide within bacterial cell causing breakdown of bacterial cell wall are called lytic virus. Lysozymes are present in the lipolytic enzymes catalyses breakdown of
fats (Lipids).
95.Solution (d)Binary fission in diatoms reduces the sizeOf most daughters which is corrected hrough the development of auxospores. In some filamentous cyanobacterial forms unisexual reproduction occurs by hormogonia (hormocysts. They are dentified by presence of biconcave (one disk or separation disc between two adjacent cells e.g. Oscillatoria).
96.Solution: (b)Frankia, is a nitrogen fixing mycelial bacterium which is associated symbiotically (and not free living) with the root nodules of several non legume plants.
97.Solution: (b)Butyric acid bacteria, Clostridium butylicum causes the retting of fibres. Retting is a stage in the manufacturing of vegetable fibers, especially the bast fibers. It is the process of submerging plant stems such as flax, jute, hemp or kenaf in water, and soaking them for a period of time to loosen the fibers from the other
components of the stem. Retting can also be done by letting the cut crop stand in the fields in the wet fall, called ―dew retting‖. Bacterial action attacks pectin and lignin, freeing the cellulose fibres. The stems are then removed and washed and subject to mechanical processing to remove the soft tissue and then dried so that all that remains are the fibres.The process is caused by Closteridium butylicum.
98.Solution: (a)Lichens (coined by Theophrastus) are composite or dual organisms which are formed by a fungus partner or mycobiont (mostly ascomycetes) and an algal partner (mostly blue green algae). Fungus forms the body of lichen as well as its attaching and absorbing structures. Algae performs photosynthesis and provides food to the fungus.
99.Solution: (a)Neomycin is the antibiotic which inhibit the translation of bacterial cell so that it can not affect the host cell.
100.Solution: (a) Eukaryotic cilia are made up of tubulin protein. Cilia have a core of 2 microtubules and around there are 9 doublet microtubules. These are not at all hair like structures.
101.Solution: (a)The thalloid body of slime moulds is made up of multinucleated cell which lacks septa in between and hence it is a multinucleated
single celled mass called plasmodium.
102.Solution: (a)Mucor is a fungus and most of the fungi require the optimum temperature of about 15-30ºC, good moisture content in atmosphere and not very dark and not very lightened place. So the Mucor requires a temperature of about 25ºC, humidity about 95% and a shady place to grow fully.
103.Solution: (a)Mad cow disease is actually Bovine Spongiform Encephalopathy or BSE. In this disease cattles in Britain got their brain become spongy & ultimately gradual degradation of nervous system. It is caused by some virus like but nucleic acid devoid proteinaceous particles called prions (proteinaceous infectiousarticle).
104.Solution: (b)While working at the Rockefeller Institute, Brown reported isolation of a PPLO from human arthritic joint tissue in 1938. In 1949, Diennes reported to the 7th International Rheumatology Congress the isolation of PPLO from the genitourinary tracts of men afflicted with arthritis. In discussing the significance of this
observation, Brown reported successful treatment of arthritic patients in 1949 with a new antibiotic called aureomycin (Clark, 1997).
105.Solution: (d)The class Basidiomycetes includes those members that produce their basidia and basidiospores on or in a basidiocarp.
106.Solution: (c)Ergot of Rye is a plant disease that is caused by the fungus Claviceps purpurea.The so-called ergot that replaces the grain of the rye is a dark, purplish sclerotium, from which the sexual stage, of the life cycle will form after over wintering.
107.Solution: (a)Physarum polycephalum belongs to phylum Amoebozoa, infraphylum Mycetozoa, and class Myxogastrea. P. polycephalum, often referred to as the
―many-headed slime,‖ is a slime mold that inhabits shady, cool, moist areas, such as decaying leaves and logs.
108.Solution: (b)
109.Solution: (a)Bacterial leaf blight of rice is caused by a species of Xanthomonas. Mature rice plant infected by these bacteria, lesion begins as water soaked stripes on the leaf blades and eventually would increase in length and width becoming yellow to grayish-white until the entire leaf dries up.
110.Solution : (b)A domain of prokar organisms containing the archaebacteria including the methanogens, which produce methane; the thermoacidophilic bacteria, which live in extremely hot and acidic environments, & the halophilic bacteria, which can only function at high salt concentrations are abundant in the world‘s oceans.
111.Solution: (a)Thermococcus, Methanococcus and Methano bacterium exemplify archaebacteria that contain protein homologous to eukaryotic core histones.
112. Solution: (d)Late blight is caused by the fungus Phytophthora infestans. Late blight appears on potato or tomato leaves as pale green, water-soaked spots, often beginning at leaftips or edges. The circular or irregular leaf lesions are often surrounded by a pale yellowishgreen border that merges with
healthy tissue. Lesions enlarge rapidly and turn dark brown to purplish-black. During periods of high humidity and leaf wetness, a cottony, white mold growth is usually visible on lower leaf surfaces at the edges of lesions. In dry weather, infected leaf tissues quickly dry up and the white mold growth
disappears. Infected areas on stems appear brown to black and entire veins may be killed in a short time when moist weather persists.
113.Solution: (d)Phylogenetic system of classification is based on evolutionary relationships. This phylogenetic classification system names only clades-groups of organisms that are all descended from a common ancestor. Under a system of phylogenetic classification, we could name any clade on this tree. For
example, the Testudines, Squamata, Archosauria, and Crocodylomorpha all form clades.
114.Solution: (b)Mannitol is a food stored in Fucus. Fucus is a genus of brown alga in the class Phaeophyceae to be found in the intertidal zones of rocky seashores almost everywhere in the world. Primary chemical constituents of this plant include mucilage, algin,mannitol, betacarotene, zeaxanthin, iodine,
bromine, potassium, volatile oils, and many other minerals.
115.Solution: (a)Single celled eukaryotes are included in protista. Protista includes all unicellular and colonial eukaryotes except green and red algae. It is also known as kingdom of unicellular eukaryotes.
116.Solution: (b)Ring worm is a fungal disease caused by the dermatophyte fungi species of microsporum, trichophyton and epidermophyton.
117.Solution: (b)Membrane bound organelles are absent in Streptococcus. Streptococcus is a bacterium that is included under kingdomMonera. Monerans are prokaryotes which lack membrane bound E.R ,.organelle like mitochondria, Saccharomyces E. R Golgi etc. Saccharomyces, Chlamydomonas and plasmodium are eukaryotes that have membrane bound organelles.
118.Solution: (a)Virus envelope is known as capsid. The capsid is composed of protein subunits called capsomere.
119.Solution: (a)Agrobacterium is a soil borne pathogen responsible for affecting many higher species of plant. But Rhizobium, Nostoc and Mycorrhiza are biofertilizers.
120.Solution: (a)Saccharomyces cerevisiae is commercially used to produce ethanol. S. cerevisiae is a yeast which helps in alcoholic fermentation in which sugars such as glucose, fructose and sucrose are converted into cellular energy and produce ethanol.
121.Solution: (b) E. coli is a prokaryotic celled gram negative bacterium.
122.Solution: (a)Archegoniophore is the female sex organ of bryophytes (Marchantia) and pteridophytes. Its neck region is made up of 4-6 vertical rows of cells.
123.Solution: (a)Eubacteria are prokaryotic but eubacteria are enclosed by plasma membrane like eukaryotic cells.
124.Solution: (a)The gametophyte of bryophytes are smaller but have large sex organs.
125.Solution: (d)Gametophyte is not an independent free living generation in Pinus.
126.Solution: (b)Methanogens are archaebacteria abundant in cattle yard and paddy fields.
127. Solution: (b)Water hyacinth is a free floating perennial plant, can grow to a height of 3 feet.
128.Solution: (b)(A) Sporophyte is more developed in mosses rather than liverwort. (B) Pinus is monoecious in which male & female cones are borne on different branches.
129.Solution: (d)
130.Solution: (a)The gametophyte of bryophytes are smaller but have large sex organs.
131.Solution: (d)The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the heterotrophic bacteria. Lactobacillis bacteria convert milk into curd.
132.Solution: (d)Cyanobacteria are also referred as blue green algae, they perform oxygenic photosynthesis. They are most successful autotrophic organisms on arth which one found in all types of environment – fresh water, sea water, salt marshes, moist rocks, tree trunks, moist soils, hot springs, frozen waters.
133.Solution: (b)All the viruses are obligate parasite i.e. they remain inert outside the host cell. They have ability to syntheize nucleic acids and proteins by using host cellular machinery (ribosomes, tRNAs, aminoacids, energy). Three shapes are found in viruses helical (elongate body e.g. T.M.V) cuboidal (short broad body with rhombic rounded, polyhedral shape e.g. Poliomyelitis virus) and binal (with birth cuboidal and helical parts e.g. many bacteriophages like T2). Antibiotics have no effect on them, antiviral drugs can only kill them.
134.Solution: (c)Saccharomyces cervisiae is a yeast used in making bread (Baker‘s yeast) and commercial production of ethanol.Paramoecium & Plasmodium are of animal kingdom while pencillium is a fungi. Lichen is composite organism formed from the symbiotic association of an algae and a fungus. Nostoc & Anabaena are examples of kingdom monera.
135.Solution: (c)Autotrophs are those organisms that are able to make energy-containing organic molecules from inorganic raw material by using basic sunlight. Nostoc, Chara, Porphyra and Wolffia are photoautotrophs while Nitrosomonas and Nitrobacter are chemoautotrophs.
136. Solution: (b)Chlamydomonas & Chlorella have been included in algae. Algae are chlorophyllus, thalloid avascular plants with no cellular differentiation. Algae belong to thallophyta of plant kingdom.
137.Solution: (c)UAG is also a stop codon. Wombats are also Australian marsupials. They are shortlegged, muscular quadrupeds, approximately 1 metre (40 in) in length with a short, stubby tail. Diphtheria is an acute infectious disease caused by the bacteria Corynebacterium diphtheriae. Cuscuta, or Dodder plant, is not a
protozoan. It is a parasitic vine that wraps around other plants for nourishment.
138.Solution: (d)Archaebactera live in some of the most harsh habitats such as extreme salty areas (halophiles), hot springs (thermoacidophiles) and marshy areas
(methanogens) and in deep sea water.
139.Solution: (c)Fungi lack chlorophyll, hence, they do not prepare their food by photosynthesis. They can grow where organic material is available. So, they are heterotrophs that acquire their nutrient by absorption and store in the form of glycogen.
140.Solution: (b)Heterocysts are large sized, thick-walled specialised cells which occur in terminal, intercalary or lateral position in filamentous cyanobacteria, e.g., Nostoc. They have enzyme nitrogenase and specialised to perform biological nitrogen fixation.
141.Solution: (a)Plant viruses often contain parasites of their own, referred to as satellites. Satellite RNAs are dependent on their associated (helper) virus for both replication and encapsidation. Example—Tobacco Necrosis Virus (TNV). Viroids are infectious agents smaller than viruses. Bacteriophages are viruses that infect the bacteria. A prion is an infectious agent that is composed primarily of protein.
142.Solution: (d)African sleeping sickness disease also called trypanosomiasis common in Africa is caused by parasite Trypanosoma gambiense. The parasite is transmitted by Tse-Tse fly (Glossina palpalis).
143.Solution: (b)Vector for sleeping sickness is TseTse fly (Glossina palpalis). The parasite Trypanosoma is transmitted through the bite of this fly. Tse-tse have been
extensively studied because they are trypanosomiasis, deadly disease which include sleeping sickness in people and nagana in cattle. Tse-tse have existed in
the modern morphological form for at least 34 million years since fossil tse-tse have been recovered from the Florissant Fossil Beds in Colorado.
144.Solution: (b)Zooflagellata of Protozoan Protista. They have flagella and heterotrophic (Parasitic) mode of nutrition.
145.Solution: (c)Malarial parasite, (Plasmodium vivax),Protist of class Sporozoa, digenetic parasite causes malarial fever in human. The malarial parasite was discovered by Laveran (1880). Sir Ronald Ross (1898) discovered that Malaria disease is spread by mosquitoes. Its life cycle completes in two organisms-Primary host, female Anopheles mosquito and man (Intermediate or Secondary host). It enters into human begins with the release of merozoites in the liver cells, from RBC of human.
146.Solution: (b)Tse-Tse fly is vector of sleeping sickness disease and it transmits Trypanosoma gambiense through its bite.
147.Solution: (b)The infective stage of Plasmodium that enters human blood is sporozoite.
148.Solution: (c) Lichens typically grow in harsh nvironments in nature, most lichens, especially epiphytic fruticose species and those containing cyanobacteria, are
sensitive to manufactured pollutants. Hence, they have been widely used as pollution indicator organisms. Lichens are symbiotic associations of a fungus with a
photosynthetic partner (called a photobiont or phycobiont) that can produce food for the lichen from sunlight.
149.Solution: (b)Whittaker (1969) divided organisms into five kingdoms: Monera, Protista, Plantae, Fungi and Animalia. Kingdom Monera includes all prokaryotes – Mycoplasma, bacteria, actinomycetes, blue-green algae, archaebacteria, methanogens. Escherichia is bacteria, Amoeba, Gelidium come under Protista, Spirogyra is algae.
150.Solution: (a)Gram +(ve) and Gram –(ve) bacteria separates on the basis of their cell wall composition. Christian Gram on the basis of staining behaviour of the cell wall with Gram‘s stain, grouped bacteria into Gram +ve and Gram –ve type. The bacteria which retain blue or purple colour after staining are Gram +ve e.g. Bacillus subtilis and which loses blue colour is Gram –ve e.g. E. coli. In Gram –ve stain is washed due to high lipid content in the cell wall having thick wall, Gram +ve has single layered cell wall
151.Solution: (a)
152.(b) DNA replication in bacteria occurs prior to fission. Prokaryotes do not show well marked S-phase due to their primitive nature.
153.(b) Myxomycetes are slimy mass of multinucleate protoplasm, having seudopodia like structures for engulfing food, reproduction through fragmentation or zoospores.
154.(b) Eubacteria are true bacteria.
155.(a) species
156.(b) Bacterial cell walls are made of peptidoglycan , which is made from polysaccharide chains cross-linked by unusual peptides containing D-amino acids. Bacterial cell walls are different from the cell walls of plants and fungi which are made of cellulose and chitin.
157.(d) Mucor is a member of Zygomycetes (the conjugation fungi) in which motile cells e.g. zoospores, planogametes, etc. are absent. Asexual reproduction takes place by the formation of non-motile mitospores called sporangiospores. Sexual reproduction takes place by the formation of non-motile zygospores.
158.(a) Cell wall is absent in Mycoplasma which is a bacteria genus. The cell membrane is in them is not guarded by a cell wall.They remain unaffected by antibiotics that are common like penicillin or other antibiotics targeting the cell wall synthesis. They are one of the smallest bacteria cells that exist in the environment even surviving without oxygen. They can be found in many shapes in nature.
159.(b) Tobacco mosaic virus (TMV) is a positive-sense single-stranded RNA virus species in the genus Tobamovirus that infects a wide range of plants, especially tobacco and other members of the family Solanaceae. The capsomeres are known to be the subunits of capsid which are the outer protective covering of proteins and protect the genetic material of the virus.
160.(c) two words for the name of a species
161.(b) basidiocarps
162.(c) Yeast is a group of unicellular fungi of the phylum ascomycota. They occur as single cell or as a group or chain of cells. Yeast of the genus Saccharomy- ces ferments sugar and are used to make bread and beer.
163.(d) Two plants can be conclusively said to belong to the same species if they can reproduce freely with each other and form seeds
164.(d) 23 S Rna
165.(d) Puccinia not Smut. it’s Rust
166.(c) division-class-order-family-tribe-genus-species
167.(b) butyric acid bacteria
168(a) Lichen is a symbiotic association between a fungus and an algae. The fungal partner of lichen helps in the absorption of water and mineral to algal partner. It also provides protection and anchorage to algae partner of lichen. in exchange of this, the fungal partner absorbs prepared food material from algae partner. This food material is prepared by the algae partner of lichen through the process of photo synthesis.
169.(c) 300 nm long and 20 nm diameter. It is made of RNA and proteins.
170.(b)The five kingdom classification is a mode of classification based on the following criteria.- Complexity of cell structure – Complexity of body structure
– Modes of nutrition – Ecological life styles- Phylogenetic relationship
171.(d)All single celled eukaryotic organisms like chrysophytes [diatoms and desmids], euglenoids [Euglena], dinoflagellates and slimee moulds are included in kingdom-Protista
172 (d)Archaebacteria are one of the oldest living organisms (to be known) on Earth. They are classified as bacteria because many of their features resemble the bacteria when observed under a microscope. They belong to the kingdom Archaea and hence are named Archaebacteria.Archaebacteria encompass several distinct subgroups including methanogens, extreme halophiles, and various thermoacidophiles. The common characteristics of Archaebacteria known to date are these:
(1) the presence of characteristic tRNAs and ribosomal RNAs;
(2) the absence of peptidoglycan cell walls, with in many cases, replacement by a largely proteinaceous coat;
(3) the occurrence of ether linked lipids built from phytanyl chains and
(4) in all cases known so far, their occurrence only in unusual habitats.
173. (c)Viroids differ from viruses on six points :They exist inside the cells as RNA particles only, without capsid nor envelope.They have only one circular RNA strand which contains very little nucleotides.Their RNA do not code for any protein.Unlike certain viruses, viroids do not need the help of a virus to infect a cell.Unlike a virus of which the RNA can be copied in the cytoplasm or the nucleus, the viroids RNA is copied in the nucleus only..Special techniques must be used to detect their presence in the plant tissues.
174. (b)Mycoplasma is a genus of bacteria that lack a cell wall around their cell membranes. This characteristic makes them naturally resistant to antibiotics that target cell wall synthesis (like the beta-lactam antibiotics). They can be parasitic or saprotrophic.
175 (b)Diatoms are single-celled algae. Diatoms are algae that live in houses made of glass. They are the only organism on the planet with cell walls composed of transparent, opaline silica. Diatom cell walls are ornamented by intricate and striking patterns of silica.Diatoms are a major group of algae, specifically microalgae, found in the oceans, waterways and soils of the world.
176 (c)Protozoa (also protozoan, plural protozoans) is an informal term for a group of single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris The ciliates are a group of protozoans characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella.Ciliates differs from other protozoans in having two types of nuclei. eg. Paramoecium have two types of nuclei i.e. macronucleus & micronucleus.
177 (b)Yucca have an obligate mutualism with a species of moth i.e. Pronuba
178(a)Saccharomyces i.e. yeast is an eukaryote.A prokaryote is a cellular organism that lacks an envelope-enclosed nucleus
179 (d) spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa.In Agaricus (a genus of basidiomycetes), basidiospores or meiospores are produced exogenously.Neurospora (a genus of ascomycetes) produces ascospores as meiospores but endogenously inside the ascus.) Alternaria (a genus of deuteromycetes) does not produce sexual spores. Saccharomyces (Unicellular ascomycetes) produces ascospores, endogenously.
180 (d)Pseudopodia are locomotory structures in sarcodines (Amoeboid)
181 (c)The true infectious part of any virus is its nucleic acid, either DNA or RNA but never both.
182(d)Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. Yeast is an unicellular sac fungus. It lacks filamentous structure or hyphae.
183(d)Any organisms that live off or feed on other dead, decaying or decomposed organic matter are called saprophytes. Parasites are plants or animals that live in or on another living thing, getting their food from it while it is still alive. The organisms that they live on are called hosts. Hosts never benefit from parasites. A lichen is not a single organism; it is a stable symbiotic association between a fungus and algae and/or cyanobacteria. Like all fungi, lichen fungi require carbon as a food source; this is provided by their symbiotic algae and/or cyanobacteria, that are photosyntheti Mycorrhizae are symbiotic relationships that form between fungi and plants. The fungi colonize the root system of a host plant, providing increased water and nutrient absorption capabilities while the plant provides the fungus with carbohydrates formed from photosynthesis.
184(d)Viroids are the smallest infectious pathogens known. They are composed solely of a short strand of circular, single-stranded RNA that has no protein coating.
185 (c)Ovulation occurs when the level of hormones is as follows:
(a) High concentration of estrogens
(b) Low concentration of progesterone
(c) High concentration of LH
(d) High concentration of FSH
186 (d)In some blue-green algae specialised cells called heterocyst fixes atmospheric nitrogen into ammonia.
• Fusion of two nuclei is called Karyogamy.
• Organisms that depend on living plants are parasites, saprophytes grow on dead material.
• Fusion of protoplasts of two cells is called plasmogamy.
187 (b) (ii) (iv) (i) (iii)
188 (c) (iii) (iv) (i) (ii)
