Model Paper 2 — BIOLOGY STD 12 Science — Question

Write a brief note on coral reef.

Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?

Write a note on the barrier method of family planning.

What do you understand by Red Data book? Explain briefly.

How are the cells of tapetum different from the cells of the other wall layers?

What is double fertilisation? Mention its significance.

How and why is the bacterium Thermus aquaticus employed in DNA technology? Explain.

Or

Name the source of the DNA polymerase used in PCR technique. Mention why it is used?

Or

Give the name of the organism from where the thermostable DNA polymerase is isolated. State its role in genetic engineering.

What is cleavage?

List any four factors which may lead to loss of biodiversity.

Difference between Down's syndrome and Turner's syndrome.