Multiple Choice Questions

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Viroids have

  • single stranded RNA not enclosed by protein coat

  • single stranded DNA not enclosed by protein coat

  • double stranded DNA enclosed by protein coat

  • double stranded RNA enclosed by protein coat


A.

single stranded RNA not enclosed by protein coat

Viroids are a group of pathogens of some higher plants that are smaller or simpler than any of the known virus. They consist of single stranded linear or circular RNA molecules without a protein coat.


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Assertion : Smaller the organism higher is the rate of metabolism per gram weight.

Reason : The heart rate of a six month old baby is much higher than that of an old person.

  • If both Assertion and Reason are true and the reason is the correct explanation of the assertion

  • If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

  • If Assertion is true statement but Reason is false

  • If both Assertion and Reason are false statements


Plasmodesmata connections help in

  • cytoplasmic streaming

  • synchronous mitotic divisions

  • locomotion of unicellular organism

  • movement of substances between cells


Hill reaction occurs in:

  • high altitude plants

  • total darkness

  • absence of water

  • presence of ferricyanide


Which one of the following pairs is correctly matched?

  • Rhizobium - Parasite in the roots of leguminous plants

  • Mycorrhizae - Mineral uptake from soil

  • Yeast - Production of biogas

  • Myxomycetes - The disease ring worm


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The quiescent centre in root meristem serves as a

  • site for storage of food which is utilized during maturation

  • reservoir of growth hormones

  • reserve for replenishment of damaged cells of the meristem

  • region for absorption of water


Assertion : Severe Acute Respiratory Syndrome (SARS) originated in China.

Reason : China is the most populated country of the world.

  • If both Assertion and Reason are true and the reason is the correct explanation of the assertion

  • If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

  • If Assertion is true statement but Reason is false

  • If both Assertion and Reason are false statements


Azolla is used as a biofertilizer because it

  • multiplies very fast to produce massive biomass

  • has association of nitrogen - fixing Rhizobium

  • has association of nitrogen - fixing cyanobacteria

  • has association of mycorrhiza


Assertion : Rhoeo leaves contain anthocyanin pigments in epidermal cells.

Reason : Anthocyanins photosynthetic pigments.

  • If both Assertion and Reason are true and the reason is the correct explanation of the assertion

  • If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

  • If Assertion is true statement but Reason is false

  • If both Assertion and Reason are false statements


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Assertion : A cell membrane shows fluid behaviour.

Reason : A membrane is a mosaic or compositeof diverse lipids and proteins.

  • If both Assertion and Reason are true and the reason is the correct explanation of the assertion

  • If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

  • If Assertion is true statement but Reason is false

  • If both Assertion and Reason are false statements