Question 1

What is the primary use of Bt toxin produced by Bacillus thuringiensis?

Accepted Answer

Bt toxin is produced by a bacterium called Bacillus thuringiensis. Bt toxin genes have been cloned from the bacteria and been expressed in plants to provide resistance to insects without the need for insecticides; in effect created a biopesticide. Examples include Bt cotton, Bt corn, etc.

Question 2

Why does Bt toxin not kill the bacterium Bacillus thuringiensis that produces it?

Accepted Answer

Bt toxin protein exists as inactive protoxins in the bacterium. Once an insect ingests the inactive toxin, it is converted into an active form due to the alkaline pH of the gut, which solubilizes the crystals. Therefore, inside the neutral or acidic environment of the bacterium, it remains inactive

Question 3

Which nematode infects the roots of tobacco plants, causing a great reduction in yield?

Accepted Answer

Meloidogyne incognita is a nematode that parasitizes the roots of tobacco plants and causes a severe reduction in yield. RNA interference (RNAi) technology is used to create resistance against this nematode in tobacco plants.

Question 4

What is the mechanism behind RNA interference (RNAi)?

Accepted Answer

RNA interference (RNAi) involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA, thus silencing the specific gene expression.

Question 5

Genetically engineered human insulin is commercially known as:

Accepted Answer

Genetically engineered human insulin produced using rDNA technology by Eli Lilly company in 1983 is commercially known as Humulin. It consists of two short polypeptide chains (A and B) linked by disulfide bonds.

Biotechnology and its Applications