Questions · Page 2 of 3

1 Marks Question

Question 511 Mark
Define mixotrophic nutrition.
Answer
Mode of nutrition in which organism derive nourishment from both autotropic and heterotrophic mechanisms,e.g., Euglena.
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Question 521 Mark
Give the name of the classes of kingdom-Plantae.
Answer
Algae, bryophytes, pteridophytes, gymnosperms and angiosperms.
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Question 531 Mark
Why are Plasmodium (malarial parasite)-like protozoans called sporozoans?
Answer
They have an infectious spore-like stage in their life cycle; hence, they are called sporozoans.
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Question 541 Mark
Suppose you accidentally find an old preserved permanent slide without a label. In your effort to identify it, you place the slide under microscope and observe the following features :-
  1. Unicellular
  2. Well defined nucleus
  3. Biflagellate–one flagellum lying longitudinally and the other transversely.
What would you identify it as? Can you name the kingdom it belongs to?
Answer
Dinoflagellates are unicellular eukaryotes. Most of them have two flagella; one lies longitudinally and the other transversely in a furrow between the wall plates. Dinoflagellates belongs to kingdom protista.
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Question 571 Mark
Which are the main groups of kingdom-Animalia?
Answer
Sponges, coelenterates, helminthes, annelids, arthropods, molluscs, Echinodermata, amphibian, reptiles, ayes and mammals.
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Question 581 Mark
What are coprophilous fungi?
Answer
The fungi, which grow on the dung of animals, are called coprophilous fungi.
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Question 591 Mark
What are the most common habitats of fungi?
Answer
Fungi are known to grow well in moist, dark and warm places so, they can be commonly seen in any habitat where organic matter and moisture are available.
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Question 601 Mark
How are lichens related to air pollution?
Answer
The decrease in lichen population of an area is indicative of air pollution particularly $\mathrm{SO}_2$ pollution.
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Question 611 Mark
Why are viruses described as obligate intracellular parasites?
Answer
It is because viruses can multiply inside their specific host cells only; outside the host cells, they are inert.
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Question 621 Mark
What is a eukaryote?
Answer
Eukaryotes are those living beings in which there is a well defined nucleus.
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Question 631 Mark
What is the basic difference between conidia and aplanospores?
Answer
Conidia are produced exogenously (outside on the conidiophores) while aplanospores are formed endogenously (within the sporangia).
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Question 661 Mark
Name the genetic material of:
  1. Tobacco mosaic virus.
  2. Bacteriophage.
Answer
  1. Single-stranded RNA.
  2. Double-stranded DNA.
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Question 691 Mark
  1. Name the specialised cells where nitrogen fixation occurs in the trichomes of certain cyanobacteria.
  2. Give two examples of cyanobacteria where such cells are present.
Answer
  1. Heterocysts.
  2. Nostoc, Anabaena.
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Question 701 Mark
Why are viruses not included in any of the kingdoms?
Answer
  1. They are non-cellular organisms.
  2. They have an inert crystalline structure outside their host cell.
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Question 711 Mark
What is the difference between virus and viroid?
Answer
Viroid is a free RNA; it lacks the protein coat that is found in viruses, hence the name viroid. The RNA of the viroid is of low molecular weight. Viroids are smaller than virus.
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Question 731 Mark
In the five kingdom system of Whittaker, how many kingdoms are eukaryotes?
Answer
In five kingdom system of classification given by Whittaker, four kingdoms include eukaryotes; Protista, Fungi, Plantae and Animalia.
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Question 741 Mark
What are acellular slime moulds?
Answer
Acellular slime moulds are consumer-decomposer protists which have a diploid somatic phase represented by Plasmodium, cellulose covered spores for dispersal and haploid swarm cells or myxoamoebae for sexual reproduction.
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Question 751 Mark
Write the names of two genera of fungi belonging to Basidiomycetes that are parasitic on plants and name the disease each of them uses in the plants.
Answer
  • Ustilago causes smut disease.
  • Puccinia causes rust disease.
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Question 761 Mark
Write the name of three parasitic protozoans.
Answer
  1. Plasmodium causes malaria.
  2. Entamoeba histolytica causes amoebic dysentery.
  3. Trypanosoma causes sleeping sickness.
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Question 771 Mark
Name the kingdom to which organisms with each of the following characteristics belong:
  1. Have cell wall made of polysaccharides and amino acids.
  2. Heterotrophs, multicellular with loose tissue and cells with a cell wall.
Answer
  1. Monera
  2. Fungi.
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Question 791 Mark
State the function of heterocyst in Nostoc.
Answer
It is the specialised cell in which atmospheric nitrogen is fixed by Nostoc.
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Question 801 Mark
What are the harmful effects of bacteria?
Answer
Bacteria cause several diseases in human.Some of them are as follows:
Tetanus, Tuberculosis, Cholera, etc.
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Question 821 Mark
Why were bacteria, cyanobacteria and fungi includedin plant kingdom, in the earlier classification systems?
Answer
Because they all have a cell wall.
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Question 831 Mark
Name the group of Monerans, which lacks a cell wall.OR
Name the smallest known prokaryote.
Answer
Mycoplasma.
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Question 841 Mark
What kind of nutrition occurs in a parasite?
Answer
Parasites have phagotrophic and absorptive type of nutrition.
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Question 851 Mark
Mention two uses of cilia to Paramoecium.
Answer
  1. Cilia help in locomotion.
  2. They also help in steering the water laden with food materials into the gullet, i.e. help in food capture.
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Question 881 Mark
How do halophiles prevent cellular dehydration?
Answer
Halophiles contain a chemical called halorhodopsin that pumps chlorides into the cells and prevents cellular dehydration.
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Question 891 Mark
Who discovered viroids? Name a plant disease caused by viroids.
Answer
  • T.O. Diener discovered viroids.
  • Potato spindle tuber disease.
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Question 931 Mark
Name the substance present in the cell wall of diatoms that makes them hard and indestructible.
Answer
Silica.
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Question 941 Mark
How does a nucleoid differ from a nucleus?
Answer
Nucleus is membrane bound structure located in centre of enkaryotic cell while necleoid is a membraneless structure found in prokaryotic cell (false nuleus).
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Question 951 Mark
What important ecological role do the chemosynthetic bacteria play?
Answer
They play an important role in the recycling of nutrients like nitrogen, iron, sulphur and phosphorus.
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Question 971 Mark
Euglena is both an autotroph and a heterotroph. Justify.
Answer
  • In the presence of sunlight, they are photosynthetic and autotrophs.
  • In the absence of sunlight, they are predators(heterotrophs) of other smaller organisms.
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Question 981 Mark
Why lichens are called dual organisms?
Answer
Lichens are dual organisms which contain a fungus or mycobiont and an alga or phycobiont.
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Question 991 Mark
In the five-kingdom classification of Whittaker, some acellular organisms are not included. What are these organisms?
Answer
Viruses and viroids.
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Question 1001 Mark
What are dolipores? In which class of fungi are these present?
Answer
Dolipores or central pores are barrel-shaped outgrowths present in septa of class-Basidiomycetes (club fungi).
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1 Marks Question - Page 2 - BIOLOGY STD 11 Science Questions - Vidyadip