Q4. Find out what the various components of the medium used for propagation of an explant in vitro are. (NCERT Exercise 3, page 186.)
A carbon source such as sucrose, inorganic salts, vitamins, amino acids, and growth regulators such as auxins and cytokinins; the explant is grown in this medium under sterile conditions (NCERT page 178).
Q5. Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil? (NCERT Exercise 10, page 187.)
One method, reasoned from this chapter: seed oil is made by the plant’s own enzymes, so a gene for an enzyme of oil synthesis can be silenced, as the nematode’s gene was silenced by RNAi, by introducing DNA that makes matching sense and anti-sense RNA with an Agrobacterium vector (NCERT page 180). The seeds should then make less oil (our reasoning). Note that seed oils are lipids, glycerol combined with fatty acids, rather than hydrocarbons in the strict sense (NCERT Class 11 Biology, Chapter 9); the method works either way, because it acts on the enzymes that build the oil.
Q6. Find out from the internet what golden rice is. (NCERT Exercise 11, page 187.)
NCERT names golden rice as Vitamin ‘A’ enriched rice, an example of GM food with enhanced nutritional value (page 179). Beyond the NCERT text: its grains have been engineered to build beta-carotene, from which the body makes vitamin A, and it is aimed at places where people get too little vitamin A from their food (Wikipedia, “Golden rice”, facts in our words).
Q7. What are the three critical research areas of biotechnology?
Providing the best catalyst, an improved organism (usually a microbe) or a pure enzyme; creating optimal conditions through engineering for the catalyst to act; and downstream processing technologies to purify the protein or organic compound (NCERT Chapter 10, Introduction, page 177).
Q8. Why could the Green Revolution’s methods not simply be extended for farmers in the developing world?
Its higher yields came mainly from better management and agrochemicals, which are often too expensive for these farmers, and further increases in yield with existing varieties are not possible by conventional breeding (NCERT page 178).