List of top Biology Questions on Biotechnology asked in CBSE CLASS XII

The picture given below shows:


(a) Roots of a typical control tobacco crop plant (infected).
(b) Transgenic tobacco plant showing healthy roots even after deliberate infection by nematode.
Explain how this transformation was achieved in the tobacco plant.

(a) (i) Why should a cell be made competent to take up an alien DNA? How can a bacterial cell be made competent using calcium ions? Explain.
(ii) (1) State the importance of gel electrophoresis in biotechnology.
(2) Explain the principle on which this technique works.
(3) Mention why ethidium bromide is used in this technique.
OR
(b) (i) How was Bt cotton, the genetically modified crop, has greatly helped the cotton farmers to increase their crop yield?
(ii) Describe the mechanism that leads to the death of bollworms feeding on Bt cotton plants.

Write the role of ’ori’ and restriction site in the cloning vector pBR322.

Assertion (A): Specific enzymes are used to degrade the cell wall in organisms to isolate the DNA from the cell.
Reason (R): Fungal cell wall is degraded by the enzyme cellulase.

Which one of the following pairs is not correctly matched?

What are transgenic animals?

Name the first transgenic cow and state its importance.

Explain how it is ensured that the orchid $\textit{Ophrys is pollinated by a specific species of bee.}$
 

Mention any two applications of this technique.

Name and write two characteristics of the type of DNA that forms the basis of DNA fingerprinting technique.

Assertion (A): Agrobacterium tumefaciens is a pathogen of several monocot plants.
Reason (R): It is able to deliver a piece of DNA known as ‘T-DNA’ to transform normal plant cells into a tumor.

Assertion (A): Indian Government has set up an organisation known as GEAC to decide the validity of GM research.
Reason (R): Genetic modification of organisms has no effect when such organisms are introduced into the ecosystem.

Describe briefly the followings:

1. Origin of replication
2. Bioreactors
3. Downstream processing

Discuss with your teacher and find out how to distinguish between

1. Plasmid DNA and chromosomal DNA
2. RNA and DNA
3. Exonuclease and Endonuclease

Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?

Can you recall meiosis and indicate at what stage a recombinant DNA is made?

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

Do eukaryotic cells have restriction endonucleases? Justify your answer.

What would be the molar concentration of human DNA in a human cell? Consult your teacher.

From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?

Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (Use the internet).