Get, detailed solutions to the questions of the chapter Biotechnology Principle and Processes from NCERT textbooks. The objective is to helping students regarding the pattern of answering the question as per the cbse latest marking scheme.Cbse.jagranjosh.com provided you NCERT solutions for classes 12th math and science subjects.
Some questions of this chapter are given here.
Q. From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
Answer. Proteins are made from amino acids which is joined through peptide bonds. In nature 20 different kinds of amino acids are found. Avg. Protein length is around 300residues of amino acids. Some of like actin are made up of thousand actin molecules. DNA is made up of polymers of nucleotides. DNA polymers can be enormous molecules containing million of nucleotides. Like human chromosome is made up of 220 millions base pairs. So, DNA is bigger in molecular size.
Q. Do eukaryotic cells have restriction endonucleases? Justify your answer.
Answer. Eukaryotic cells do not have restriction nuclease. Restriction enzymes restrict the infection of bacteria by some viruses like bacterio phages by degrading the viral DNA without affecting viral DNA.
Q. Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?
Answer. Stirred tank bioreactors provide a better agitation system, oxygen delivery system, foam system, pH control system, temperature control system and provide a better provision for cleaning and sterilization.
Q. 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?
Answer. There are many methods of introducing the ligated DNA into recipient cells, after making them ―component‖ to receive and take up DNA present in its surrounding. So if a recombinant DNA bearing gene for resistance to an antibiotic is transferred into E.coli cells, the host cells become transformed into ampicillin resistant cells. Since due to ampicillin resistance gene,one is able to select a transformed call in the presence of ampicillin. When we insert a piece of alien DNA into a cloning vector and transfer it into a bacterial, plant or animal cell, the alien DNA gets multiplied. The whole process involves the use of restriction endonucleases, DNA ligase, appropriate plasmid or viral factors to isolate and ferry the foreign DNA into host organisms.