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Some of the characteristics of Bt cotton are 

  • long fibre and resistance of aphids

  • medium yield, long fibre and resistance to beetle pests

  • high yield and production of toxic protein crystals which kill dipteran pests

  • high yield and production of toxic protein crystals which kill dipteran pests


D.

high yield and production of toxic protein crystals which kill dipteran pests

Bacillus thuringiensis forms crystals containing a toxic insecticidal protein. Bt toxin protein exists as an inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut, which solubilises the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores the cause cell swelling and lysis and eventually cause the death of the insect. Specific Bt toxin genes were isolated from B. thruingiensis and incorporated into the several plants such as cotton. The toxin is coded by the gene name cry. There is a number of them, eg, the proteins encoded by the genes cry IAc a cry II Ab control the cotton bollworms, that of cry IAB control corn borers.

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Farmers in a particular region were concerned that pre-mature yellowing of leaves of a pulse crop might cause decrease in the yield. Which treatment could be most beneficial to obtain maximum seed yield?

  • Frequent irrigation of the crop

  • Treatment of the plants with cytokinins alongwith a small dose of nitrogenous fertilizer

  • Removal of all yellow leaves and spraying the remaining green leaves with 2,4,5- trichlorophenoxy acetic acid

  • Removal of all yellow leaves and spraying the remaining green leaves with 2,4,5- trichlorophenoxy acetic acid


Microbes found to be very useful in genetic engineering are

  • Escherichia coli and Agrobacterium tumefaciens

  • Vibrio cholerae and a tailed bacteriophage

  • Diplococcus sp. and Pseudomonas sp

  • Diplococcus sp. and Pseudomonas sp


Read the following four statements (I - IV) about certain mistakes in two of them
I .The first transgenic buffalo, Rosie produced mile which was human alpha - lactal bumin enriched
II. Restriction enzymes are used in isolation of DNA from another macro -molecules.
III. downstream processing is one of the steps of R-DNA technology.
IV. Disarmed pathogen vectors are also used in the transfer of R - DNA into the host. 
Which are the two statements having mistakes?

  • Statement (II) and (III)

  • Statements (III) and (IV)

  • Statements (I) and (III)

  • Statements (I) and (III)


Which one of the following proved effective for biological control of nematodal diseases in plants?

  • Pisolithus tinctorius

  • Pseudomonas cepacin

  • Gliocladium virens

  • Gliocladium virens


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