Central Board of Secondary Education
Class – XII (Year 2011)
Subject – Biology - (Set - 2)
All Questions are compulsory.
Wherever necessary, the diagrams drawn should be neat and
Q.1 Write the unit used for measuring ozone thickness.
Q.2 Name the event during cell division cycle that
results in the gain or loss of chromosome.
Q.3 How can bacterial DNA be released from the bacterial
cell for biotechnology experiments ?