Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

81.

The pyramid of energy-in a forest ecosystem is

  • always upright

  • always inverted

  • both (a) and (b)

  • none of the above


82.

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


83.

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

  • complementary gene

  • epistatic gene

  • hypostatic gene

  • supplementary gene


84.

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


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85.

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


86.

One of the following is sex-influenced character

  • Appearance of beard

  • Baldness in male

  • Docile behaviour of female

  • Low BMR in female


87.

Polymerase chain reaction is most useful in

  • DNA synthesis

  • DNA amplification

  • protein synthesis

  • amino acid synthesis


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88.

Sex factor in bacteria is

  • F-replicon

  • chromosomal replicon

  • RNA

  • sex pillies


A.

F-replicon

In bacteria, besides nuclear DNA, there is some extrachromosomal or extranuclear DNA which is known as plasmid. Term plasmid was given by Lederberg (1952). On the basis of their function, the plasmids are of 3 types :

(i) F or fertility factor : Responsible for transfer of genetic material

(ii) R or resistance factor Provides resistance against drugs.

(iii) Colicinogenic factor : Provides colicines which kill other bacteria (other than which produce these colicines).


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89.

Embryo sac is

  • microgametophyte

  • microsporangium

  • megagametophyte

  • megasporangium


90.

sprouting of potato can be prevented in storage by

  • maleic hydrazide

  • gibberellins

  • indole acetic acid

  • cytokinins


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