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NEET Questions / Botany / Biotechnology and Its Applications
A scientist is attempting to develop a transgenic crop resistant to a specific lepidopteran pest. Which gene would be the LEAST suitable candidate for transfer?
A gene encoding a Bt toxin
A gene conferring resistance to a bacterial pathogen
A gene involved in photosynthesis
A gene encoding a protein that disrupts insect gut function
Which type of pest is the primary target of the Bt toxin produced by Bt cotton?
Coleopteran insects
Lepidopteran insects
Dipteran insects
Hymenopteran insects
Statement I: Bt toxins are specific to certain insect groups and are encoded by the cry gene family, such as cryIAc.
Statement II: Bt toxin is initially inactive (protoxin) within Bacillus thuringiensis. Upon ingestion by an insect, the alkaline pH of the gut activates the protoxin.
Choose the correct answer:
Both Statement I and Statement II are true.
Statement I is true but Statement II is false.
Statement I is false but Statement II is true.
Both Statement I and Statement II are false.
The cryIAc gene codes for a Bt toxin that targets specific insect groups. Which of the following is TRUE regarding the activation of this toxin?
It is activated by the acidic pH of the insect gut.
It is activated by the alkaline pH of the insect gut.
It is activated by enzymes in the insect's saliva.
It is always active and does not require activation.
Which of the following describes the mechanism of action of Bt toxin coded by the cry gene?
Active toxin is ingested and directly kills the insect.
Inactive protoxin is ingested and activated by the alkaline pH of the insect gut.
Active toxin is ingested and deactivated by the gut pH, then reactivated later.
Inactive protoxin is ingested and activated by enzymes in the insect's saliva.
Why doesn't the Bt toxin produced by Bacillus thuringiensis harm the bacterium itself?
The bacterium has a special enzyme that degrades the toxin.
The bacterium's cell wall is impermeable to the toxin.
It exists as an inactive protoxin within the bacterium.
The bacterium produces an antitoxin that neutralizes the Bt toxin.
A farmer uses a biopesticide containing Bacillus thuringiensis to control a pest insect. Which of the following best describes the fate of the Bt toxin after it is ingested by the insect?
It remains inactive in the gut and is excreted.
It is activated in the alkaline gut and binds to receptors, causing cell death.
It is deactivated by gut enzymes and has no effect.
It stimulates the insect's immune system, providing resistance.
A bt prototoxin is
A toxin produced by protozoa
Inactive toxin
An active toxin
Primitive toxin
A bt prototoxin is
A toxin produced by protozoa
Inactive toxin
An active toxin
Primitive toxin
Pest resistant Bt cotton crop has been developed by transferring a gene from
Agro bacterium
Meloidogyne incognita
Bacillus thuringiens is
E.Coli
