Set-II: Past Entrance Papers

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(b) All unicellular eukaryotic organisms like diatoms, desmids (chrysophytes), euglenoids, dinoflagellates, and slime mould are included in Protista.

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(d) In chrysophytes, the cell walls form two thin overlapping shells held together. The body of Diatoms appears like soap box due to overlapping shells.

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(b) Chlarrydomonas & Chlorella have been included in algae. Algae are chlorophylus, thalloid avascular plants with no cellular differentiation. Algae belong to thallophyta of the plant kingdom.

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(b) E. coli is a prokaryotic gram negative bacterium.

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(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 the kingdom of unicellular eukaryotes.

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(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.

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(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.

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(d) Binary fission in diatoms reduces the size of most daughters which is corrected through the development of auxospores.
In some filamentous cyanobacterial forms, unisexual reproduction occurs by hormogonia (hormocysts). They are identified by the presence of biconcave (one disk or separation disc between two adjacent cells e.g. Oscillatoria).

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(c) Contractile vacuole in Amoeba and Paramecium maintain the water balance of the cell. This is known as osmoregulation.

It was previously known as the pulsatile or pulsating vacuole.

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(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.
Euglena is a genus of single cell flagellate eukaryotes. It is the best known and most widely studied member of the class Euglenoidea. Species of Euglena are found in both freshwater and salt water.

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(c) In protozoa, the function of the contractile vacuole is the removal of excretory substances, carbon dioxide, etc. It is very essential to regulate water content i.e., osmoregulation.

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(a) The macronucleus lacks nuclear membrane and is formed of trophochromatin. It regulates the body’s metabolic activities and is also known as trophonucleus. The micronucleus has a definite nuclear membrane and controls the reproductive activities of Paramecium and Vorticella.

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(d) The conractile vacuole is supposed to assist excertion in Amoeba, as its watery contents possess traces of carbon dioxide and urea. The $\mathrm{CO}_{2}$ diffuses directly through plasmalemma.

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(a) Protistans are eukaryotes and their genetic material is organised in form of nucleus. DNA is associated with histone protein.

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(a) Members ofkingdom Protista have diverse mode of nutrition. They are photosynthetic, saprophytic, parasitic and ingestive. They are major heterotrophs.

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(d) Kingdom Protista includes flagellates (euglenophyceae), diatoms, dinoflagellates, slime moulds, sarcodines, ciliates, sporozoans. They have photosynthetic, chemotrophic, heterotropic mode of nutrition.

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(c) I. African sleeping sickness disease also called as trypansomiasis is 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 through bite of Tse-Tse fly (vector 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.

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(a) Paramecium has two nuclei Macronucleus and Macronucleus. 

Micronucleus
– Small having two sets of chromosomes (diploid)
– Concerned with reproduction i.e. stores genetic information

Macronucleus
-Larger having many sets of chromosomes
-Concerned with the functioning of the cell

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(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.

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(c) Plasmodium belongs to the class Sporozoa of protozoan protists. It is an endoparasite lacking any locomotory structure and contractile vacules. It reproduces through spore formation.

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(d) African sleeping sickness disease also called trypanosomiasis, that is common in Africa which is caused by parasite, Trypanosoma gambiense. The parasite is transmitted by Tse-Tse fly (Glossina palpalis).

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(b) Vector for sleeping sickness is Tse-Tse fly (Glossina palpalis). The parasite Trypanosoma is transmitted through the bite of this fly. Tse-tse has been extensively studied because they are biological vectors of the African trypanosomiasis, a deadly disease that includes sleeping sickness in people and nagana in cattle. Tse-tse has 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.

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(b) Zooflagellata of Protozoan Protista. They have flagella and heterotrophic (Parasitic) mode of nutrition.

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(b) Tse-Tse fly is vector of sleeping sickness disease and it transmits Trypanosoma gambiense through its bite.

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(b) The infective stage of Plasmodium that enters human blood is sporozoite.

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(d) Trypanosoma, Noctiluca, Monocystis & Giardia are unicellular protists i.e. unicellular eukaryotes.

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(d) Yeast is a unicellular sac fungi. It lacks filamentous structure or hyphae.

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(a) A cell wall is a rigid structural layer, which provides protection and structural support to the cells. The composition of cell wall varies from one species to another. In fungi, the cell wall is composed of strong covalent linkages of chitin, glucans, and glycoproteins. Alternatively, in case of land plants, the cell wall is composed of cellulose and hemicellulose. Archean cell walls consists of peptidoglycans.

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(c) Eubacteria are the true bacteria.
Eubacteria are prokaryotic organisms, characterized by the lack of a membrane-enclosed nucleus, predominantly unicellular, with DNA in a single circular chromosome, and have peptidoglycan on the cell wall when present. They include most of the familiar bacteria of medical and economic importance such as \(E\). coli.

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(a) Alternaria belongs to the class – Deuteromycetes, which lack sexual reproduction. Asexual reproduction takes place by conidia produced on conidiophores.

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(d) Anabaena is a cyanobacteria that lack a true nucleus because of the absence of a nuclear membrane.

Znabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities, and they form symbiotic relationships with certain plants, such as the mosquito fern.

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(d) Class- deuteromycetes comprises of imperfect fungi which play role in decomposition of organic wastes.

The imperfect fungi, also known as Deuteromycota, are fungi that do not fit into the commonly established taxonomic classifications of fungi that are based on biological species concepts or morphological characteristics of sexual structures because their sexual form of reproduction has never been reported.

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(b) Morel and truffles are used as food and they are members of Ascomycetes fungi.

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(b) Several mushrooms such as Amanita muscaria, Psilocybe Mexicana, and Panaeolus spp. secrete hallucinogenic substances like psilocybin and psilocin. These substances may destroy brain cells and the power of perception in human beings.

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(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 them in the form of glycogen.

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(b) Membrane bound organelles are absent in Streptococcus. It is a bacterium that is included under kingdom Monera. Monerans are prokaryotes that lack membrane bound organelles like mitochondria, E.R, Golgi, etc.
Saccharomyces, Chlamydomonas, and Plasmodium are eukaryotes that have membrane bound organelles.

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(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 yellowish-green 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.

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(d) The class Basidiomycetes includes those members that produce their basidia and basidiospores on or in a basidiocarp.

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(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.

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(a) Mucor is a fungus and most of the fungi require the optimum temperature of about 15 \(30^{\circ} \mathrm{C}\), good moisture content in the atmosphere, and not very dark and not very lightened place. So Mucor requires a temperature of about \(25^{\circ} \mathrm{C}\), humidity about \(95 \%\), and a shady place to grow fully.

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(c) Viruses that get integrated with the bacterial host genome are called lysogenic. Virus which transmit its DNA into the bacterial cell and divide within bacterial cell causing the breakdown of bacterial cell wall are called lytic virus. Lysozymes are lipolytic enzymes that catalyse breakdown of fats (lipids).

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(c) Mycorrhiza is a 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.

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(a) Aspergillus flavus produces carcinogenic fungus toxin (Aflatoxin) during storage condition of crop plant.

Aflatoxins are poisonous carcinogens and mutagens that are produced by certain molds (Aspergillus flavus and Aspergillus parasiticus) which grow in soil, decaying vegetation, hay, and grains.

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(a) Ustilago causes loose smut of wheat, as a result, the grain and flower get converted into powdered mass.

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(a) Plant decomposers are bacteria (Kingdom Monera) and fungi.

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(a) The fungal hyphae secrete enzymes that convert insoluble complex food material in the substratum to the soluble ones. The hyphae wall of intracellular hyphae comes in contact with the host protoplasm and obtain food by direct diffusion.

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(b) Aspergillus is a fungus, Mucor is also a fungus. Azolla harbors blue-green algae Anabaena which fixes \(\mathrm{N}_{2}\), increasing fertility.
Azolla is unique because it is one of the fastest-growing plants on the planet – yet it does not need any soil to grow. Unlike almost all other plants, Azolla is able to get its nitrogen fertilizer directly from the atmosphere. Azolla is able to do this because it has a unique mutually beneficial ‘symbiotic relationship’ with a cyanobacterium (blue-green alga) called Anabaena.

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(a) Glycogen is a glucosan homopolysaccharide that is the major reserve food of animals, fungi, and some bacteria. Starch is also glucosan homopolysaccharide and is the major reserve food of plants. Sucrose is formed of one molecule of glucose and one molecule of fructose.

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(a) Black rust of wheat is caused by Puccinia graminis. The symptoms are seen in stem or leaf sheath as brownish spots.

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(b) Puccinia causes black rust of wheat. It completes its life cycle in two hosts-wheat and barberry. Two types of spores are produced on wheat – uredospores, and teleutospores.

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(a) Association of algae and fungi is referred to as lichen. Symbiotic association of Rhizobium with roots of leguminous plants is referred to as symbiosis. Mycorrhiza is a symbiotic association between fungi and roots of higher plants. The fungal partner of mycorrhiza obtains food from the roots of the higher plant and in return supplies mineral elements to it.

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(c) Covered smut of barley is caused by Ustilago hordei, not by Ustilago nuda. This disease is purely externally seed borne.

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(c) Phytoalexins are non-specific antibiotic substances produced by plants in response to infection by a fungus.

Phytoalexins are antimicrobial and often antioxidative substances synthesized de novo by plants that accumulate rapidly in areas of pathogen infection. They are broad-spectrum inhibitors and are chemically diverse in a particular plant species.

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(d) Albugo candida is an obligate parasite causing white rust on members of the family Cruciferae and other hosts.