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Practical: Study of Nostoc

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 Practical: Study of Nostoc Nostoc is a filamentous, photosynthetic cyanobacterium. It commonly occurs in freshwater, moist soil, wet rocks and other damp habitats. Colonies are usually gelatinous because numerous filaments remain embedded in a mucilaginous matrix. Materials Required Fresh or preserved Nostoc material, clean glass slide, cover slip, dropper, dissecting needle, water, blotting paper and compound microscope. Procedure Take a small quantity of Nostoc colony with the help of a dissecting needle and place it on a clean glass slide. Add one or two drops of water and gently tease the material so that the filaments become separated. Place a cover slip carefully over the material without trapping air bubbles. Remove excess water with blotting paper. First observe the preparation under low power and then under high power of the compound microscope. Observations The plant body of Nostoc is thalloid and usually forms a soft, jelly-like colony. A colony contains numerous ...
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Biological Science Practice SET

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  1. Evolutionary homology is similarity due to common ancestry. Which of the following characters are evolutionary homologies? a) wing of a bird and a bat b) beak of a vulture and an eagle c) fin of a fish and a whale d) webbed feet of a duck and a frog   2. Locus   A in a diploid   organism has two alleles A 1 and A 2 , where A1 is dominant over A 2 . Additionally A 2   is deleterious in the homozygous condition. Allele A 2 takes a long time to get eliminated from the population because a) A 1 is harbored in the heterozygotes b) A 1 is harbored in the homozygotes c) A 2 is harbored in the heterozygotes d) A 2 is harbored in the homozygotes   3. In a population of 100 diploid individuals, the frequency of neutral alleles A 1 and A 2 are 0.4 and 0.6 respectively. Assuming Hardy-Weinberg equilibrium and no change in population size, the frequency of heterozygotes after five generations is: a) 0.36     ...
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BIOLOGICAL SCIENCE MCQ 13.07.2021 Practice set

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  BIOLOGICAL SCIENCE MCQ  13.07.2021 Practice set 1. All eukaryotic unicellular organisms belong to a. Monera b. Protista c. Fungi d. Bacteria 2. The five kingdom classification was proposed by a. R.H. Whittaker b. C.Linnaeus c. A. Roxberg d. Virchow 3. Organisms living in salty areas are called as a. Methanogens b. Halophiles c. Heliophytes d. Thermoacidophiles 4. Naked cytoplasm, multinucleated and saprophytic are the characteristics of a. Monera b. Protista c. Fungi d. Slime molds 5. An association between roots of higher plants and fungi is called a. Lichen b. Fern c. Mycorrhiza d. BGA 6. A dikaryon is formed when a. Meiosis is arrested b. The two haploid cells do not fuse immediately c. Cytoplasm does not fuse d. None of the above 7. Contagium vivum fluidum was proposed by a. D.J. Ivanowsky b. M.W. Beijerinek c. Stanley d. Robert Hook 8. Mycobiont and Phycobiont are found in a. Mycorrhiza b. Root c. Lichens d. BGA 9. Difference between Virus and Viroid is a. Absence of pr...
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MCQ BIOLOGY BIOMOLECULES 12.07.2021

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  1.The mature erythrocyte contains a) Cytochromes                          b) TCA – enzymes c) Pyruvic kinase                        d) ATP – ase 2. Hemoglobin is responsible for what percentage of carbondioxide transport by the blood ? a) 90                    b) 50                    c) 10                    d) 5 3. Christmas factor is synonymous with a) Proconvertin                 ...
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