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:
Explanation: NCERT Page No.208,(Topic-12.1 BIOTECHNOLOGICAL APPLICATIONS IN AGRICULTURE)
Statement I: Parenchyma is living but collenchyma is dead tissue.
Statement II: Gymnosperms lack xylem vessels but presence of xylem vessels is the characteristic of
angiosperms.
In the light of the above statements, choose the correct answer from the options given below:
Explanation:
In NCERT, parenchyma is living tissue at maturity, used for storage and photosynthesis. Collenchyma is also living with unevenly thickened cell walls, not dead; hence Statement I is false. Gymnosperms lack xylem vessels and have tracheids instead, while angiosperms have xylem vessels. Therefore, the statement βpresence of xylem vessels is the characteristic of angiospermsβ is true. So the correct choice is: Statement I is false and Statement II is true.
? Did You Know?
Collenchyma is living and provides flexible support; sclerenchyma is dead and provides rigid support. Xylem vessels are characteristic of flowering plants (angiosperms).
? NCERT Memory Line:
Parenchyma is living; collenchyma is living with thickened walls; sclerenchyma is dead. Angiosperms have xylem vessels; gymnosperms lack vessels and have tracheids.
