Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

41.

The quiescent centre in root meristem serves as a

  • Site for storage of food, which is utilised during maturation

  • Reservoir of growth hormones

  • Reserve for replenishment of damaged cells of the meristem

  • Region for absorption of water


42.

An example of the competitive inhibition of an enzyme is the inhibition of

  • Succinic dehydrogenase by malonic acid

  • Cytochrome oxidase by cyanide

  • Hexokinase by glucose-6-phosphate

  • Carbonic anhydrase by carbon dioxide


43.

In prokaryotes, chromatophores are

  • Specialised granules responsible for the colouration of cells

  • Structures responsible for organising the shape of the organism

  • Inclusion bodies lying free inside the cells for carrying out various metabolic activities

  • Internal membrane systems that may become extensive and complex in photosynthetic bacteria


44.

In the sieve elements, which one of the following is the most likely function of P-proteins?

  • Deposition of callose on sieve plates

  • Providing energy for active translocation

  • Autolytic enzymes

  • Sealing off mechanism on wounding


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45.

Which one of the following precedes re-formation of the nuclear envelope during M-phase of the cell Cycle?

  • Decondensation from chromosome and reassembly of the nuclear lamina

  • Transcription from chromosome and reassembly of the nuclear lamina

  • Formation of the contractile ring and formation of the phragmoplast

  • Formaltion of the contractile ring and transcription from chromosomes


A.

Decondensation from chromosome and reassembly of the nuclear lamina

At telophase stage, nuclear membrane vesicles associate with the surface of individual chromosomes and fuse to reform the nuclear membranes, which partially enclose clusters of chromosomes before coalescing to reform the complete nuclear envelope. During this process, the nuclear pores reassemble and the dephosphorylated reassociate to form the nuclear lamina) One of the lamina proteins (lamina-B) remains with the nuclear membrane fragments throughout mitosis and may help nucleate assembly. After the nucleus reforms, the pores pump in nuclear proteins, the chromosome decondense and RNA synthesis resume, causing the nucleolus to reappear.


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46.

Viruses that infect bacterial multiplication and cause their lysis, are called

  • Lysozymes

  • Lipolytic

  • Lytic

  • Lysogenic


47.

A plant requires magnesium (Mg) for

  • Holding cells together

  • Protein synthesis

  • Chlorophyll synthesis

  • Cell wall development


48.

Which one of the following pairs, is not correctly matched?

  • Abscisic acid - Stomatal closure

  • Gibberellic acid - Leaf fall

  • Cytokinin -  Cell division

  • IAA - Cell wall elongation


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49.

Two cells A and B are contiguous. Cell A has osmotic pressure 10 atm, turgor pressure-7 atm and diffusion pressure deficit 3 atm. Cell B has osmotic pressure 8 atm, turgor pressure 3 atm and diffusion pressure deficit 5 atm. The result will be

  • Movement of water from cell B to A

  • No movement of water

  • The equilibrium between the two

  • Movement of water from cell A to B


50.

In mammals, histamine is secreted by

  • Fibroblasts

  • Histocytes

  • Lymphocytes

  • Mast cells


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