Multiple Choice Questions

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Assertion: Plant growth regulators (PGRs) are very important for plant growth and development.

Reason: Auxins do not induce flowering in gymnosperms

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

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

  • If assertion is true but reason is false. 

  • If both assertion and reason are false.


B.

If both assertion and reason are true but reason is not the correct explanation of assertion. 

Plant growth regulators (PGRs) are small, simple molecules of diverse chemical composition, which in low concentration regulate growth, differentiation and development by promoting or inhibiting the same. One type of plant growth regulators are plant hormones or phytohormones. Auxins are the phytohormones. They do not induce flowering in gymnosperms.


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Which of the following genes do not occur naturally in living organisms

  • Bt genes

  • RNAi genes

  • Cry genes

  • Endogeneous cytoplasmic defence genes


The phenomenon that operates in the formation of root or shoot in a callus culture is

  • differentiation

  • re-differentiation

  • de-differentiation

  • re-juvenation


Vernalisation is subjected to plants growing in

  • tropical areas

  • sub tropical areas

  • temperate areas

  • hot areas/arctic region.


Assertion: Yeasts are unicellular fungi that are used in bakery and brewery industries.

Reason: Potato spindle tuber disease is caused by viroids

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

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

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


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Assertion: No secondary growth takes place in monocots.

Reason: Secondary growth is not related with cambium.

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

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

  • If assertion is true but reason is false. 

  • If both assertion and reason are false.


One hormone hastens maturity period in juvenile conifers, a second hormone controls xylem differentiation, while the third hormone increases the tolerance of plants to various stresses. They are respectively

  • Gibberellin, Auxin, Ethylene

  • Auxin, Gibberellin, Cytokinin

  • Gibberellin, Auxin, ABA

  • Auxin, Gibberellin, ABA


DNA and RNA comprise of

  • sugar, phosphate, base

  • sugar, phosphate

  • base, phosphate

  • sugar, base


Assertion: A correct concentration of auxin and cytokinin is required for the development of root and shoot in a callus.

Reason: When the ratio of kinetin to auxin is high, then only shoots develop. But when the ratio is low then only roots develop.

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

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

  • If assertion is true but reason is false. 

  • If both assertion and reason are false.


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Gibberellins can promote seed germination because of their influence on

  • rate of cell division

  • production of hydrolysing enzymes

  • synthesis of abscisic acid

  • absorption of water through hard seed coat.


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