Q. No.The bacterium Bacillus thuringiensis is widely used in contemporary biology as a/an:
1. indicator of water pollution
2. insecticide
3. agent for production of dairy products
4. source of industrial enzyme
What is true about Bt toxin?
| 1. | the inactive protoxin gets converted into active form in the insect gut |
| 2. | Bt protein exists as active toxin in the Bacillus |
| 3. | The activated toxin enters the ovaries of the pest to sterilize it and thus prevent its multiplication |
| 4. | the concerned Bacillus has antitoxins |
Bacillus thuringiensis forms protein crystals which contain insecticidal protein. This protein:
| 1. | does not kill the carrier bacterium which is itself resistant to this toxin |
| 2. | binds with epithelial cells of the midgut of the insect pest ultimately killing it |
| 3. | is coded by several genes including the gene cry. |
| 4. | is activated by acid pH of the foregut of the insect pest. |
Bt cotton is not
1. a GM plant
2. insect resistant
3. a bacterial gene expressing system
4. resistant to all pesticides
A protoxin is
1. a primitive toxin
2. a denatured toxin
3. toxin produced by Protozoa
4. inactive toxin
The trigger for activation of toxin of Bacillus thuringiensis is
1. acidic pH of stomach
2. high temperature
3. alkaline pH of gut
4. mechanical action in the insect gut
| Statement I: | Bt toxins are insect group specific and coded by a gene cry IAc. |
| Statement II: | Bt toxin exists as inactive protoxin in B. thuringiensis. However, after ingestion by the insect, the inactive protoxin gets converted into active form due to acidic pH of the insect gut. |
In the light of the above statements, choose the correct answer from the options given below:
1. Both Statement I and Statement II are False
2. Statement I is True but Statement II is False
3. Statement I is False but Statement II is True
4. Both Statement I and Statement II are True
| 1. | Bt toxin requires acidic pH for activation |
| 2. | Bacillus has protective mechanism against it |
| 3. | In Bacillus, it is present in an inactive state and once insects ingests it, it is converted to active form |
| 4. | The protoxin requires protein conjugate for its activation |
Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (BT) is resistant to:
2. Plant nematodes
3. Insect predators
4. Insect pests
What triggers the activation of protoxin to active Bt toxin of Bacillus thuringiensis in bollworms?
1. Acidic pH of the stomach
2. Body temperature
3. Moist surface of midgut
4. Alkaline pH of the gut
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