Few problems along with their solutions from this chapter are given follows:
Q. The transfer of genetic material from one bacterium to another through the mediation of a vector like virus is termed as
(a) Transduction
(b) Conjugation
(c) Transformation
(d)Ttranslation
Ans. (a) Transduction
Transduction is the process by which genetic material (DNA) is transferred from one bacterium to another through the mediation of a vector, like virus
Q. While isolating DNA from bacteria, which of the following enzymes is not used?
(a) Lysozyme
(b) Ribonuclease
(c) Deoxyribonuclease
(d) Protease
Ans. (c) Deoxyribonuclease
In the process of 'recombinant DNA technology' the first steps Isolation of DNA.
Since, the DNA is enclosed within the membranes; we have to break the cell open to release DNA along with other macromolecules such as RNA proteins, polysaccharides and also lipids.
This can be achieved by treating the bacterial cells/plant to animal tissue with enzymes such as lysozyme (bacteria), cellulase (plant cells) and chitinase (fungus).
Q. What would happen when one grows a recombinant bacterium in the bioreactor but forget to add antibiotic to the medium in which the recombinant is growing?
Ans. In the absence of antibiotic, there will be no pressure on recombinants to retain the plasmid (containing the gene of interest). Since, maintaining a high copy number of plasmids a metabolic burden to the microbial cells is required otherwise it will thus tend to lose the plasmid.
Q. Describe the role of Agrobacterium tumefaciens in transforming a plant cell.
Ans. A soil-inhabiting, plant pathogenic bacterium, Agrobacterium tumefaciens infects broad-leaved crops including tomato, soyabean, sunflower and cotton, but not the cereals. It causes tumors called crown galls.
Tumour formation is induced by its plasmid, which is, therefore called Ti-plasmid (Ti for tumour inducing). The Ti-plasmid integrates a segment of its DNA, termed T-DNA, into the chromosomal DNA of its host plant cells. The T-DNA causes tumors. As gene transfer occurs without human effort, the bacterium is known as natural genetic engineer of plants.
Class 12 Biology NCERT Exemplar Problems:
Class 12 Biology NCERT Exemplar problems are a very good resource for preparing the critical questions like Higher Order Thinking Skill (HOTS) questions. Every year, many questions from the NCERT Exemplar are directly asked in the board exams. Also, these are the kind of questions asked in the various competitive exams and Olympiad level tests. So, it’s very important for students to practice the NCERT exemplar problems to prepare well for the boards and the competitive exams.
Main topics discussed in Class 12 Biology, Chapter 11- Biotechnology: Principles and Processes, are:
- Principles of biotechnology
- Tools of recombinant dna technology
- Processes of recombinant dna technology.