Download App

Biotechnology and its Applications — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYBiotechnology and its Applications3 Marks
Question
How has the study of biotechnology helped in developing pest resistant cotton crop? Explain.

Or

One of the major contribution of biotechnology is to develop pest resistant varieties of cotton plants. Explain how it has been made possible.

✓

Answer

The pests that destroy the cotton balls are cotton bollworms and cotton borer. Bt cotton is created by using some strains of a bacterium, Bacillus thuringiensis (Bt is short form).
  1. This bacterium produces protein that kills certain insects such as lepidopterans (tobacco budworm and armyworm), coleopterans (beetles) and dipterans (flies and mosquitoes).
  2. Bacillus thuringiensis forms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein.
  3. Bt toxin protein exists as inactive protoxins in bacteria, but once an insect ingests this inactive toxin, it is converted into an active form due to the alkaline pH of the gut, which solubilises the crystals.
  4. The activated toxin binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis leading to death of insect.
  5. Specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into several crop plants.
  6. Most Bt toxins are insect-group specific. The toxin is coded by a gene named cry. For example, the proteins encoded by the genes cry IAc and cry IAD control the cotton bollworms and cry IAb controls corn borer.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Biotechnology and its Applications→Biotechnology and its Applications — all question types→BIOLOGY STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

In relation to energy transfer in ecosystem, explain the statement "10kg of deer's meat is equivalent to 1kg of lion's flesh".
→
How does $\beta$-galactosidase coding sequence act as a selectable marker? Explain. Why is it a preferred selectable marker to antibiotic resistance genes?
→
Name the source of streptokinase. How does this bioactive molecule function in our body?
→
Represent schematically the decomposition cycle in a terrestrial ecosystem.
→
On world population day, Rohit and his friends arranged an awareness campaign on population explosion programme in their locality. Some elderly people tried to stop the children and asked them not to talk on such things in public. The children convinced the elders about the need for the programme and on understanding their point of view, the elders also joined the campaign.
  1. Why is such awareness programme necessary?
  2. What role has the government played in controlling population explosion?
  3. When were reproductive health programmes initiated in India?
  4. What values did Rohit and his friends show on the occasion?
→
Give three reasons as to why the prokaryotes are not given any figures for their diversity by the ecologists.
→
  1. Why does DNA replication occur in small replication forks and not in its entire length?
  2. Why is DNA replication continuous and discontinuous in a replication fork?
  3. Explain the importance of origin of replication' in a replication fork.
→
Write the characteristics of Ramapithecus, Dryopithecus and Neanderthal man.
→
A couple where both husband and wife are producing functional gametes, but the wife is still unable to conceive, is seeking medical aid. Describe any one method that you can suggest to this couple to become happy parents.
→
Why should biodiversity be conserved? Explain giving three reasons.
→