Multiple Choice Questions

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In the lactose operon of Escherichia coli what is the function of promoter

  • Binding of Gyrase enzyme

  • Binding of RNA polymerase

  • Codes for RNA polymerase

  • Processing of messenger RNA


B.

Binding of RNA polymerase

Promoters contain specific DNA sequences such as response elements that provide a secure initial binding site for RNA polymerase and for proteins called transcription factors that recruit RNA polymerase.


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9: 3: 3: 1 ratio is modified to 9 : 7 ratio due to

  • complementary gene

  • epistatic gene

  • hypostatic gene

  • supplementary gene


Lichens are important in the studies on atmospheric pollution because they

  • can grow in polluted atmosphere

  • can readily multiply in polluted atmosphere

  • efficiently purify the atmosphere

  • are very sensitive to pollutants like sulphur dioxide


The map distance between the genes A and B is 3 units, between B and C is 10 units and between C and A is 7 units. The order of the genes in a linkage map constructed on the above data would perhaps be

  • A, B, C 

  • A, C, B

  • B, C, A

  • B, A, C


Sex factor in bacteria is

  • F-replicon

  • chromosomal replicon

  • RNA

  • sex pillies


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sprouting of potato can be prevented in storage by

  • maleic hydrazide

  • gibberellins

  • indole acetic acid

  • cytokinins


Polymerase chain reaction is most useful in

  • DNA synthesis

  • DNA amplification

  • protein synthesis

  • amino acid synthesis


The pyramid of energy-in a forest ecosystem is

  • always upright

  • always inverted

  • both (a) and (b)

  • none of the above


One of the following is sex-influenced character

  • Appearance of beard

  • Baldness in male

  • Docile behaviour of female

  • Low BMR in female


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Embryo sac is

  • microgametophyte

  • microsporangium

  • megagametophyte

  • megasporangium