16. Which of the following is not true about the nurse or conditioned medium?

A. It is liquid removed from the suspension of fast-growing cells
B. It contains uncharacterized growth factor released by growing cells
C. It is used in the culture of regenerating protoplast
D. it is removed aseptically from the culture and is autoclaved before use

17. Very high sugar concentration (40-100 g/l) have been used

A. in specialized secondary metabolite production
B. to adjust the osmotic potential of the media in short term treatment for regeneration
C. Both (a) and (b)
D. none of these

18. What is ‘nurse’ or conditioned medium?

A. It is the media full of growth factors used for the growth of cells
B. It is the medium added to nurse the callus culture
C. Both (a) and (b)
D. It is the liquid medium removed from the suspension of fast-growing cells

19. What are the macronutrients used in plant cell culture medium?

A. N, P, K, S, Na
B. N, P, K, Ca, Cl
C. N, P, K, S, Ca
D. N, P, Ca, Na, Cl

20. Neutralized activated charcoal is occasionally added to young regenerating cultures to

A. remove toxic phenolics produced by the stressed plant cell
B. help to remove plants growth regulators introduced at an earlier stage
C. both (a) and (b)
D. maintain the pH of the medium