Question
Select the wrong statement. [NEET 2018]
(a) Pseudopodia are locomotory and feeding structures in sporozoans
(b) Mushrooms belong to Basidiomycetes
(c) Cell wall is present in members of Fungi and Plantae
(d) Mitochondria are the powerhouse of the cell in all kingdoms except Monera
Answer/Explanation
Ans. (a)
Sporozoans are endoparasites. They lack locomotory organelles like cilia, flagella, pseudopodia, etc., e.g. Plosmodium. Pseudopodia are found in amoeboid protozoans, e.g., Amoeba, Entamoebo, etc. Therefore, statement (a) is wrong while rest of the statements are correct.
Question
Which of the following would appear as the pioneer organisms on bare rocks? [NEET 2016, Phase I]
(a) Liverworts
(b) Mosses
(c) Green algae
(d) Lichens
Answer/Explanation
Ans. (d)
In primary succession on rocks, lichens secrete acids to dissolve rock, helps in weathering and soil formation. So, lichens are pioneer species to colonise. the bare rock.
Question
One of the major components of cell wall of most fungi is [NEET 2016, Phase I]
(a) peptidoglycan
(b) cellulose
(c) hemicellulose
(d)chitin
Answer/Explanation
Ans. (d)
Cell wall of most fungi is made up of chitin. Chemically it is $\mathrm{N}$-acetyl glucosamine. It is also found in the exoskeleton of insects.
Question
Which one of the following is wrong for fungi?[NEET 2016, Phase II]
(a) They are eukaryotic
(b) All fungi possess a purely cellulosic cell wall
(c) They are heterotrophic
(d) They are both unicellular and multicellular
Answer/Explanation
Ans. (b)
In fungi, cell wall contains chitin or cellulose along with other polysaccharides, proteins and lipids. Only in some fungi, e.g. Phytophthora or other oomycetes a purely cellulosic cell wall is present. Hence, only option (b) is wrong, rest of the options are correct.
Concept Enhancer Chitin is chemically $\mathrm{N}$-acetyl glucosamine. The exoskeleton of insects also contains this chemical.
Question
Choose the wrong statement. [CBSE AIPMT 2015]
(a) Penicillium is multicellular and produces antibiotics
(b) Neurospora is used in the study of biochemical genetics
(c) Morels and truffles are poisonous mushrooms
(d) Yeast is unicellular and useful in fermentation
Answer/Explanation
Ans. (c)
All statements are correct, except statement (c), which can be corrected as Morels and truffles are edible and members of Ascomycetes in fungi.
Question
78 The imperfect fungi which are decomposers of litter and help in mineral cycling belong to [CBSE AIPMT 2015]
(a) Deuteromycetes
(b) Basidiomycetes
(c) Phycomycetes
(d) Ascomycetes
Answer/Explanation
Ans. (a)
The imperfecti fungi which are decomposers of litter and help in mineral cycling belong to Deuteromycetes. They are fungi which do not fit into the commonly established taxonomic classification of fungi. They include all those fungi in which the perfect stage (sexual stage) is not reported.
Question
79 The highest number of species in the world is represented by [CBSE AIPMT 2012]
(a) fungi
(b) mosses
(c) algae
(d) lichens
Answer/Explanation
Ans. (a)
Fungi represent the highest number of species in the world. Around 100000 species of fungi have been formally described by taxanomists but the global biodiversity of kingdom-Fungi is not fully understood.
Question
Which one of the following has haplontic life cycle? [CBSE AIPMT 2009]
(a) Funaria
(b) Polytrichum
(c) Ustilago
(d) Wheat
Answer/Explanation
Ans. (c)
Ustilogo has haplontic life cycle. In their sexual phase, only zygospore is diploid structure. All others are haploid, such a sexual cycle is termed as haploid or haplontic.
Question
Which one is the wrong pairing for the disease and its causal organism? [CBSE AIPMT 2009]
(a) Late blight of potato – Alternaria solani
(b) Black rust of wheat – Puccinia graminis
(c) Loose smut of wheat – Ustilago nuda
(d) Root-knot of vegetables – Meloidogyne sp.
Answer/Explanation
Ans. (a)
The causative agent of late blight of potato is fungus Phytophthora infestons, class-0omycetes, order-Peronosporales,
family-Pythiaceae. In India, the late blight of potato is a seed borne disease.
Question
Trichoderma harzianum has proved a useful microorganism for [CBSE AIPMT 2008]
(a) bioremediation of contaminated soils
(b) reclamation of wastelands
(c) gene transfer in higher plants
(d) biological control of soil-borne plant pathogens
Answer/Explanation
Ans. (d)
Some common fungal inhabitants of soil help to combat diseases caused by soil borne plant pathogens. These include Trichoderma harzianum which are found in damp soils. They have an inhibitory effect on the growth of the mycelium of Pythium. They serve to supress fungi causing damping off disease of the seedlings and thereby influence favourably the growth of crops.
Question
$\overline{\mathbf{8 3}}$ Cellulose is the major component of cell walls of [CBSE AIPMT 2008]
(a) Pythium
(b) Xanthomonas
(c) Pseudomonos
(d) Saccharomyces
Answer/Explanation
Ans. (a)
Cellulose does occur in cell walls of Oomycetes (e.g. Pythium) and Hyphochytridiomycetes. Fungal cell wall contains $80-90 \%$ carbohydrates, the remainder being proteins and lipids. The typical feature of fungal cell wall is presence of chitin.
Question
Which of the following is a slime mold? [CBSE AIPMT 2007]
(a) Rhizopus
(b) Physarum
(c) Thiobacillus
(d) Anabaena
Answer/Explanation
Ans. (b)
The genus Physarum with about 100 species is the largest and best-studied slime mold in the class-Myxomycetes.
Question
Ergot of rye is caused by a species of [CBSE AIPMT 2007]
(a) Phytophthora
(b) Uncinula
(c) Ustilago
(d) Claviceps
Answer/Explanation
Ans. (d)
The fungus Claviceps purpurea is responsible for ergot disease of rye which lowers the yield of rye plant.
Question
Which pair of the following belongs to Basidiomycetes? [CBSE AIPMT 2007]
(a) Birds nest fungi and puff balls
(b) Puff balls and Claviceps
(c) Pezizo and stink horns
(d) Morchello and mushrooms
Answer/Explanation
Ans. (a)
Birds nest fungi (Nidulariales) and puff ball fungi (Lycoperdales) belongs to Basidiomycetes. The common example of class-Basidiomycetes are smut, rusts, the mushrooms, the toad stools, the puff balls and the pore fungi.
Question
The thalloid body of a slime mold (Myxomycetes) is known as [CBSE AIPMT 2006]
(a) Plasmodium
(b) fruiting body
(c) mycelium
(d) protonema
Answer/Explanation
Ans. (a)
The thalloid body of a slime mould is known as Plasmodium. The members of Myxomycetes are called slime molds because they contain and secrete slime. They are included in lower fungi. Their somatic phase is a multinucleate, diploid holocarpic Plosmodium(a product of syngamyl.
In Plasmodium, propagation occurs through fission or thick walled cysts or sclerotium like structures.
Reproduction takes place by the formation of uninucleate, thick walled resting spores which are produced within minute fruiting bodies like structures, i.e. the sporangia.
Fruiting bodies and mycelium are absent in lower fungi. Protonema is not formed in fungi.
Question
$\overline{88}$ Which of the following environmental conditions are essential for optimum growth of Mucor on a piece of bread? [CBSE AIPMT 2006]
(i) Temperature of about $25^{\circ} \mathrm{C}$
(ii) Temperature of about $5^{\circ} \mathrm{C}$
(iii) Relative humidity of about $5 \%$
(iv) Relative humidity of about $95 \%$
(v) A shady place
(vi) A brightly illuminated place
Choose the answer from the following options
(a) (i) (iv)and (v) only
(b)(ii), (iv) and (v) only
(c)(ii), (iii) and (vi) only
(d)(i) (iii) and (v) only
Answer/Explanation
Ans. (a)
Mucor shows the best growth on a piece of bread at a temperature of about $25^{\circ} \mathrm{C}$, relative humidity of about $95 \%$ in a moist and shady place. Mucor is a saprophytic fungus belonging to the order-Mucorales and family-Mucoraceae and grows on decaying dung and on some food stuffs.
Question
There exists a close association between the alga and the fungus within a lichen. The fungus [CBSE AIPMT 2005]
(a) provides protection, anchorage and absorption for the alga
(b) provides food for the alga
(c) fixes the atmospheric nitrogen for the alga
(d) release oxygen for the alga
Answer/Explanation
Ans. (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 algal partner of lichen. In exchange of this, the fungal partner absorbs prepared food material from algal partner. This food material is prepared by the algal partner of lichen through the process of photosynthesis.
Question
90 Lichens are well known combination of an alga and a fungus where fungus has [CBSE AIPMT 2004]
(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
Answer/Explanation
Ans. (d)
Lichen is a symbiotic association between a fungus and an alga. The fungal part is called mycobiont while the algal part is called phycobiont. The fungi absorb mineral and water to algae and the algae synthesise food by photosynthesis.
Question
During the formation of bread it becomes porous due to the release of $\mathrm{CO}_2$ by the action of [CBSE AIPMT 2002]
(a) yeast
(b) bacteria
(c) virus
(d) protozoans
Answer/Explanation
Ans. (a)
Strains of Saccharomyces cerevisiae are extensively used for leavening of bread. During fermentation, the yeasts produce alcohol and $\mathrm{CO}_2$ which leaves the bread porous.
Question
Which fungal disease spreads by seed and flowers? [CBSE AIPMT 2002]
(a) Loose smut of wheat
(b) Corn stunt
(c) Covered smut of barley
(d) Soft rot of potato
Answer/Explanation
Ans. (a)
Fungal disease, loose smut of wheat spreads by seed and flowers. The causal organism of this disease is Ustilogo fungus. It is an internal parasite. It has a dikaryotic mycelium which remains within the intercellular spaces of the host tissue.
This fungus infects the ovary of the host flower as a result of which the masses of teliospores or brand spores are formed in place of grains.
Teliospores are not surrounded by any wall hence, called loose smut.
Question
Plant decomposers are [CBSE AIPMT 2001]
(a) Monera and Fungi
(b) Fungi and Plants
(c) Protista and Animalia
(d) Animalia and Monera
Answer/Explanation
Ans. (a)
Decomposers are living components chiefly the bacteria and fungi that breakdown the complex compounds of dead protoplasm of producers and consumers absorb some products and release others.
Question
Adhesive pad of fungi penetrates the host with the help of [CBSE AIPMT 2001]
(a) mechanical pressure and enzymes
(b) hooks and suckers
(c) softening by enzymes
(d) only by mechanical pressure
Answer/Explanation
Ans. (a)
Cell wall degrading enzymes (cellulolytic, pectolytic) as well as mechanical pressure of adhesive pad (appressorium) help the fungus in penetrating the host.
Question
In fungi stored food material is [CBSE AIPMT 2000]
(a) glycogen
(b) starch
(c) sucrose
(d) glucose
Answer/Explanation
Ans. (a)
Glycogen, also known as ‘animal starch’, is the chief storage polysaccharide of animal cells and most of the fungi (though food is also stored as oil globules in some fungi).
Starch is a complex water insoluble polysaccharide carbohydrate chiefly found in green plants as their principal energy (food) source. Glucose is the most widely distributed hexose sugar. It is an aldohexose reducing sugar. It is found in blood muscles and brain and works as energy fuel.
Sucrose is a non-reducing disaccharide consists of one glucose and one fructose molecules. It is one of the abundant transport sugar in plants.
Question
Black rust of wheat is caused by [CBSE AIPMT 2000]
(a) Puccinia
(b) Mucor
(c) Aspergillus
(d) Rhizopus
Answer/Explanation
Ans. (a)
Black rust of wheat is caused by Puccinia graminis tritici. This is the potential cause of enormous economic loss in all wheat growing regions of the world. Puccinia graminis tritici usually passes its life cycle on two different hosts, wheat and barbery.
Question
Which of the following is the use of lichens in case of pollution? [CBSE AIPMT 1999]
(a) Lichens are not related with pollution
(b) They act as bioindicators of pollution
(c) They treat the polluted water
(d) They promote pollution
Answer/Explanation
Ans. (b)
Growth of lichens on trees is inhibited by air pollution. Hence, atmospheric pollution causes decrease in their populations. So, lichens are biological indicators of pollution.
Question
Columella is a specialised structure found in the sporangium of [CBSE AIPMT 1999]
(a) Ulothrix
(b) Rhizopus
(c) Spirogyra
(d) None of these
Answer/Explanation
Ans. (b)
In Rhizopus, the central non-sporiferous region of sporangium is called columella.
Question
Puccinia forms [CBSE AIPMT 1998]
(a) uredia and aecia on wheat leaves
(b) uredia and telia on wheat leaves
(c) uredia and aecia on barbery leaves
(d) uredia and pycnia on barbery leaves
Answer/Explanation
Ans. (b)
Puccinia graminis tritici (fungus) causes black rust of wheat. It forms Urediospores(uredia) and teleutospores (telia) on wheat leaves.
Question
100 Most of the lichens consist of [CBSE AIPMT 1997]
(a) blue-green algae and Basidomycetes
(b) blue-green algae and Ascomycetes
(c) red algae and Ascomycetes
(d) brown algae and Phycomycetes
Answer/Explanation
Ans. (b)
Lichens consist of the fungal component mycobiont, mainly Ascomycotina (only a few Basidiomycotina and Deuteromycotina) and the algal component, phycobiont which are mostly blue-green algae (Nostoc, Scytonema) or green algae (Trebouxia, Trentophila, etc.)
Question
Which one of the following is not true about lichens? [CBSE AIPMT 1996]
(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 $2 \mathrm{~cm}$ per year
Answer/Explanation
Ans. (d)
Statement (d) is incorrect because lichens show very slow growth. Their size and slow rate of growth suggest that some lichens in the Arctic are 4000 years ago.
Question
Which of the following is not correctly matched? [CBSE AIPMT 1995]
(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
Answer/Explanation
Ans. (c)
Option ‘c’ is mismatched because the smuts in which sori are covered by the membranous covering or peridium are called covered smuts. These are caused by Ustilago hordei, in which the sorus or smut ball is covered by a peridium of host cells. Ustilogo nuda is responsible for causing loose smut of barley.
Question
The chemical compounds produced by the host plants to protect themselves against fungal infection is [CBSE AIPMT 1995]
(a) phytotoxin
(b) pathogen
(c) phytoalexins
(d) hormone
Answer/Explanation
Ans. (c)
Phytoalexins are chemical substances produced by plants in response to fungal infection and are toxic to fungi.
Question
White rust disease is caused by [CBSE AIPMT 1995]
(a) Claviceps
(b) Alternaria
(c) Phytophthora
(d) Albugo candido
Answer/Explanation
Ans. (d)
Albugo candida (Oomycetes) is an abligate parasite commonly found parastising a wide range of crucifers. It causes a disease called white rust or blister rust of crucifers resulting in economically significant losses in the yield of turnip, rape and mustard.
Question
Ustilago caused plant diseases are called smuts because [CBSE AIPMT 1994]
(a) they parasitise cereals
(b) Mycelium is black
(c) they develop sooty masses of spores
(d) affected parts become completely black
Answer/Explanation
Ans. (c)
The genus Ustillago (L. ustus = burnt) includes the group of fungi producing black, sooty powder mass of spores on the host plant parts imparting them a ‘burnt’ appearance, hence, the name, the black dusty masses of spores produced by these fungi resemble soot or smut, so these are also known as smut fungi.
Question
Mycorrhiza represents [CBSE AIPMT 1994, 96, 2003]
(a) antagonism
(b) endemism
(c) symbiosis
(d) parasitism
Answer/Explanation
Ans. (c)
Mycorrhiza $($ mykes $=$ mushroom $+$ rhiza $=$ root)represents a symbiotic association of fungi with the roots of higher plant. Mycorrhiza meaning fungus root is an infected root system arising from the rootlets of a seed plant. In ectomycorrhiza, the ultimate absorbing rootlets of the root system are completely surrounded by a distinct mantle or sheath of fungal tissue. In endomycorrhiza, there is no such sheath. Most of the fungus is within the root and may be intracellular as well as intercellular.
Question
Absorptive heterotrophic nutrition is exhibited by [CBSE AIPMT 1990]
(a) algae
(b) fungi
(c) bryophytes
(d) pteridophytes
Answer/Explanation
Ans. (b)
Fungi are heterotrophic, e.g. these require an organic source of carbon. also require some source of nitrogen, inorganic ions $\left(\mathrm{K}^{+}, \mathrm{Mg}^{+}\right)$, trace elements( $\mathrm{Fe}, \mathrm{Zn}, \mathrm{Cu})$ and growth factors like vitamins. Fungi may act as saprobes and parasites. They obtain nutrition from host by means of special structures called haustoria and exhibit absorptive or holophytic type of nutrition.
Question
Lichens indicate $\mathrm{SO}_2$ pollution because they [CBSE AIPMT 1989, 92]
(a) show association between algae and fungi
(b) grow faster than others
(c) are sensitive to $\mathrm{SO}_2$
(d) flourish in $\mathrm{SO}_2$ rich environment
Answer/Explanation
Ans. (c)
Lichens, the composite organisms consist of a specific fungus living in symbiotic association with one or sometimes, two species of algae. Lichens are world-wide in distribution. These are pioneer colonisers of barren rocks and mountains. Being extremely. sensitive to $\mathrm{SO}_2$, the lichens especially epiphytic lichens serve as bioindicators air pollution.