Multiple Choice Questions

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Restriction endonucleases are enzymes which

  • make cuts at specific positions within the DNA molecule

  • recognize a specific nucleotide sequence for binding of DNA ligase

  • restrict the action of the enzyme DNA polymerase

  • restrict the action of the enzyme DNA polymerase


A.

make cuts at specific positions within the DNA molecule

Restriction endonucleases recognise a specific DNA base sequence (recognition sequence of the recognition site, restriction sequence or restriction site) and cleave both the strands of DNA at or near the site. The enzyme cuts are DNA, generating restriction fragments wit overhanging ends or blunt ends.

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Cu ions released from copper -releasing Intra Uterine Devices (IUDs)

  • make uterus unsuitable for implantation

  • increase phagocytosis of sperms

  • suppress sperm motility 

  • suppress sperm motility 

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The first movements of the foetus and appearance of hair on its head are usually observed during which month of pregnancy?

  • Fourth month

  • Fifth month

  • Sixth month

  • Sixth month

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The common nitrogen -fixer in paddy field is 

  • Rhizobium

  • Azopirillum

  • Oscillatoria

  • Oscillatoria

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The figure given below is a diagrammatic representation of the response of organisms to abiotic factors. What do A, B, and C represent respectively?


  • A
    B
    C

    Conformer

    Regulator

    Partial regulator 

  • A

    B

    C

    Regulator

    Partial regulator

    Conformer

  • A
    B
    C

    Partial regulator

    regulator conformer
  • A
    B
    C

    Partial regulator

    regulator conformer
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Which two of the following changes (1-4) usually tend to occur in the plain dwellers when they move to high altitudes (3500 m or more)?

1) Increase in red blood cell size
2) Increase in red blood cell production
3) Increase in breathing rate
4) Increase in thrombocytes count

Changes occurring are

  • (2) and (3)

  • (3) and (4)

  • (1) and (4)

  • (1) and (4)

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The permissible use of the technique amniocentesis is for

  • detecting the sex of the unborn foetus

  • artificial insemination

  • transfer of embryo into the uterus of a surrogate mother

  • transfer of embryo into the uterus of a surrogate mother

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DNA and RNA segment tagged wit  a radioactive molecule is called

  • vector

  • probe

  • clone

  • clone

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Darwin's finches are a good example of 

  • industrial melanism

  • connecting link

  • adaptive radiation

  • adaptive radiation

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The signals for parturition originate from

  • placenta only

  • placenta as well as the fully developed foetus

  • oxytocin released from the maternal pituitary

  • oxytocin released from the maternal pituitary

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