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What are Cry proteins? - Biology

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प्रश्न

What are Cry proteins?

लघु उत्तरीय

उत्तर

Cry protein is a toxic protein coded by the cry gene. There are many types of cry proteins; for example, the proteins coded by the genes cryIAc and cryIIAb control cotton budworm, while cryIAb controls corn borer. 

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अध्याय 12: Biotechnology and its Applications - Exercises [पृष्ठ २१६]

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एनसीईआरटी Biology [English] Class 12
अध्याय 12 Biotechnology and its Applications
Exercises | Q 4 | पृष्ठ २१६

वीडियो ट्यूटोरियलVIEW ALL [3]

संबंधित प्रश्न

Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because −


List any five possible advantages of a GMO to a farmer.


In the following questions/statements has four suggested answers. Rewrite the correct answer

Bt cotton is resistant to:

(A) Insects

(B) Herbicides

(C) Salt

(D) Drought


How has the use of Agrobacterium as vectors helped in controlling Meloidogyne incognita infestation in tobacco plants? Explain in the correct sequence.


Answer the following question.
How is a continuous culture system maintained in bioreactors and why?


Answer the following question.
List one advantage and one disadvantage of an apomictic crop. 


Answer the following question.
List any four ways by which GMOs have been useful for enhanced crop output.


Answer the following question.
Write the desirable characters a farmer looks for in his sugarcane crop.


GM crops especially Bt crops are known to have higher resistance to pest attacks. To substantiate this an experimental study was conducted in 4 different farmlands growing Bt and non Bt-Cotton crops. The farm lands had the same dimensions, fertility and were under similar climatic conditions. The histogram below shows the usage of pesticides on Bt crops and non-Bt crops in these farm lands.

  1. Which of the above 4 farm lands has successfully applied the concepts of Biotechnology to show better management practices and use of agrochemicals? If you had to cultivate, which crop would you prefer (Bt or Non- Bt) and why?
  2. Cotton Bollworms were introduced in another experimental study on the above farm lands wherein no pesticide was used. Explain what effect would a Bt and Non Bt crop have on the pest.

Bt toxin obtained from ______.


Assertion (A): In Bt cotton, B. thuringiensis produces a toxic insecticidal crystalline protein which destroys bollworms.

Reason (R): B. thuringiensis produces this toxic protein in an inactive form, but when an insect ingests this inactive protein, it is converted into active form of toxin due to the alkaline pH of gut which solubilises the crystals, which is responsible for the death of bollworm. 


Silencing of a gene could be achieved through the use of ______.


Many proteins are secreted in their inactive form. This is also true of many toxic proteins produced by microorganisms. Explain how the mechanism is useful for the organism producing the toxin?


Bt cotton is resistant to pest, such as lepidopteron, dipterans and coleopterans. Is Bt cotton also resistant to other pests as well?


Insects in the Lepidopteran group lay eggs on maize crops. The larvae on hatching feed on maize leaf and tender cob. In order to arrest the spread of three such Lepidopteran pests, Bt maize crops were introduced in an experimental field.
A study was carried out to see which of the three species of lepidopteran pests was most susceptible to Bt genes and its product.
The lepidopteran pests were allowed to feed on the same Bt-maize crops grown on 5 fields (A-E).
The graph below shows the leaf area damaged by these three pests after feeding on maize leaves for five days.

Key for lepidopteran insect pest species

Species I
Species II
Species III

Insect gut pH was recorded as 10, 8 and 6 respectively for Species I, II and III respectively.

(a) Evaluate the efficacy of the Bt crop on the feeding habits of the three species of stem borer and suggest which species is least susceptible to Bt toxin.

(b) Which species is most susceptible to Bt-maize, and explain why?

(c) Using the given information, suggest why a similar effect was not seen in the three insect species.


Certain specific bacterial spores are mixed in water and sprayed over Brassica crop to control butterfly caterpillars.

Name this bacterium and its mode of action on the butterfly caterpillars.


Compare and contrast the disadvantages of production of genetically modified crops.


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