CBSE Class 11th Biology – 2 Biological Classification MCQs
There exists a close association between the alga and fungus within a lichen. The fungus
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.
Yeast is divided under the class
True yeast bear asci which are not organized into ascocarps. e.g., Schizosaccharomyces, Saccharomyces, Saccharomycodes, Zygosaccharomyces, Nematospora. Therefore, yeast are classified under ascomycetes.
When fungi feed on dead organic matter, they are known as
When fungi feed on dead organic matter, they are known as saprophytes.
Shell of Diatom is made up of:
Cell wall of diatom is deposited with silica. After the death of diatoms, cell wall is resistant to decomposition, piles up at the floor of water body and forms diatomaceous earth.
Enzymes are absent in
viruses do not have well defined structure and enzymes for replication. They grow in host cell.They produce enzymes when they infect host cell.
Plant decomposers
Plant decomposers are Bacteria (Kingdom Monera) and Fungi
Lichens indicate SO2 pollution because they
Lichens typically grow in harsh environments 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.
"What is true for archaebacteria? "
Archaebacteria are the most ancient and halogenous group of bacteria and are called living fossils.
Decomposers are organisms that
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 breakdown 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 faces 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 nutrient-load of an ecosystem, in turn allowing for greater biodiversity.
Comma' shaped bacteria are known as
Bacteria posses various forms and shapes and are of 4 different types - coccus (round), bacillus (rod shaped), vibrio (comma shaped) and spirillum (spiral like cork screw). When the shape of a bacteria is like a comma then it is said to be vibrio, e.g., Vibrio cholerae.
Bacteria are considered plant because they :
Bacterial cell wall is peculiar in being made up of a compound called Peptidoglycan. Peptidoglycan ® Heteropolysaccharide alternative amino-sugar molecules ® N-acetyl glucosamine and N-acetyl muramic acid. Chains of peptidoglycan are cross linked by short chains of peptides.
Name the organisms which do not derive energy directly or indirectly from sun
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.
Escherichia coli is used extensively in biological research as it is
Escherichia coli, lives as a symbiont in human intestine. It is often preferred organism in reserch laboratories as, it is easy to grow.
Mycorrhiza is
Association of algae and fungi is referred to as lichen. Symbiotices association of Rhizobium with roots of leguminous plants is referred to as symbiosis. Mycorrhiza is symbiotic association between fungi and roots of higher plants. The fungal partner of mycorrhiza obtains food from roots of the higher plants and in return supplies mineral elements to it.
Which one belongs to Monera?
Whittaker (1969) divided organisms into five kingdoms: Monera, Protista, Fungi, Plantae and Animalia. Kingdom Monera includes all prokaryotes - Mycoplasma, bacteria, actinomycetes, blue-green algae, archaebacteria, methanogens. Escherichia coli is bacteria, Amoeba, Gelidium come under Protista, Spirogyra is algae.
Virus envelope is known as :
Virus envelope is known as capsid. The capsid is composed to protein subunits called capsomere.
Fungi are always
Plants which can make their own food are autotrophic. Plants which can not make their own food and depend on others are heterotrophic. Parasitic and saprophytic are types of heterotrophic plants. Parasites depend on living organisms and saprophytes depend on dead and decaying matter. Fungi can not make their own food and depend on dead and decaying matters.
Mycorrhiza represents
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 nycorrhizae are called VAM (vesicular arbuscular mycorrhizae). It is meant for phosphate nutrition.
Whittaker is famous for -
Which bacteria is utilized in gober gas plant?
Methanobacillus (methanogen) occurs in marshes and also in dung. It produces CH4 gas under anaerobic condition and is utilized in gobar gas plant.
Absorptive heterotrophic nutrition is exhibited by
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.
In Amoeba and Paramoecium osmoregulation occurs through
Contractile vacuole in Amoeba and Paramoecium maintain the water balance of the cell. This is known as osmoregulation.
Photosynthetic bacteria have pigments in
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.
What is true for cyanobacteria?
Cynobacteria are oxygenic photoautotroph. Many members perform nitrogen fixation.
Bacteria lack alternation of generation because there is
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.
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