A researcher uses Agrobacterium tumefaciens to introduce a gene into a plant cell. Which of the following is NOT a crucial step in this process?
Infection of plant cells with the engineered Agrobacterium
Insertion of the gene of interest into the Ti plasmid
Ligation of the gene into a yeast expression vector
Regeneration of the transformed plant cells
Related Questions
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.
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.
Cry I endotoxins obtained from Bacillus thuringenisis are effective against?
Nematodes
Boll worms
Mosquitos
Flies
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.
Consider the following statements about Bt I. The bacteria Bacillus thuringiensis (Bt) are used to control butterfly catterpillers II. Fresh spores of Bt are mixed with water and sprayed on seeds such as brassicas and fruit trees III. Insect larvae, after eating these are killed by the toxin released in their gut IV. Bt toxin genes have been introduced into plants to provide resistance to pests Which of the statements given above are correct?
I and II only
II and III only
I, II and III only
I, II, III and IV
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.
What activates the protoxin of Bacillus thuringiensis into an active toxin within the gut of a bollworm?
Alkaline pH of the gut
Acidic pH of the gut
Presence of specific enzymes in the gut
Sunlight
The protein products of the following Bt toxin genes cry I Ac and cry II Ab are responsible for controlling
Bollworm
Roundworm
Moth
Fruit fly
I endotoxins obtained from Bacillus thuringiensis are effective against
Lepidoptera, Diptera and Coleoptera
Hymenoptera and Diptera
Coleoptera and Hymenoptera
Lepidoptera and Orthoptera
