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Ncert Solutions For Class 12 Biology Chapter 11_30.1
Ncert Solutions For Class 12 Biology Chapter 11

Ncert Solutions For Class 11 Biology Chapter 11 Pdf Download

Adda 247 provides NCERT Solutions for Class 12 Biology Chapter 11. NCERT solutions which is for the students who want to go ahead in life and achieve great marks in their examinations. The NCERT Solutions for class 12 are provided by the teachers who are experts of their subjects. The solutions are set according to the rules formulated by the NCERT class 12 biology and in the language that can be understood by every student. By these reading the solutions students can build up a strong base easily. The NCERT class 12 Biology solutions covers the chapters 1 to 16 with the important questions and the answers in a detailed way.

Examinations can be threatening for some people, a proper learning of the concepts is the key to crack the examination. Students rely on the solutions of the NCERT provided by Adda 247. The solutions are formulated by the experts of the subjects who have tremendous knowledge in their subjects.

These NCERT Solutions of class 12 chapter 11 help the students to get familiarized with the textbooks. The students can access the solutions anywhere while browsing the web easily. The solutions are very precise and accurate.


NCERT Solutions for Class 12 Biology Chapter 11– Biotechnology: Principles and Processes


The chapter provides information about Biotechnology: Principles and Processes. Biotechnology deals with the techniques of using living organisms or enzymes from organisms to produce products useful to humans. The processes like in vitro fertilization leading to a ‘test-tube’ baby, synthesizing a gene and using it, developing a DNA vaccine or correcting a defective gene, are all parts of biotechnology. Biotechnology can be defined as- ‘The integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services’.

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Features of the NCERT Solutions for Class 12 Biology Chapter 11 – Microbes in Human Welfare


NCERT Solutions for class 12 biology chapter 11 have been answered based on the important information on the question.

  • The columns are used wherever necessary.
  • Solutions are solved point wise and accurately answered point to point.


Important Question of Ncert Solutions for Class 12 Biology Chapter 11

Question 1. Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).


Answer:  Recombinant proteins are obtained from the recombinant DNA technology. This technology involves the transfer of specific genes from an organism into another organism using vectors and restriction enzymes as molecular tools.

Ten recombinant proteins used in medical practice are −

Recombinant protein Therapeutic use
Insulin Treatment for type I diabetes mellitus
Interferon-α Used for chronic hepatitis C
Interferon -β Used for herpes and viral enteritis
Coagulation factor VII Treatment of haemophilia A
Coagulation factor IX Treatment of haemophilia B
DNAase I Treatment of cystic fibrosis
Anti-thrombin III Prevention of blood clot
Interferon B. For treatment of multiple sclerosis
Human recombinant growth hormone For promoting growth in an individual
Tissue plasminogen activator Treatment of acute myocardial infection


Question 2.  Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and the product it produces.


Answer:  The name of the restriction enzyme is Bam H1.

The substrate for BamH1 enzyme is GGATCC. BAM H1 enzyme can make cut or nick on the G nitrogen base of restriction site and produces cut with sticky ends.


Question 3.  From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?


Answer: DNA possesses all the genetic information of an organism. This genetic information can be transcripted in the form of proteins, multiprotein complexes, enzymes etc. Thus, we can conclude that DNA is bigger in size than enzyme because for the synthesis of enzyme only a fragment of DNA called gene is sufficient however DNA is  a larger molecule responsible for containing instructions for development and functioning of cell.


Question 4. What would be the molar concentration of human DNA in a human cell? Consult your teacher.


Answer:  The molar concentration of human DNA in a human cell can be given as:

6.023 x 1023 x Total number of chromosomes

6.023 x 1023 x 46

2.77 x 1023 moles

Therefore, 2.77 x 1023 moles is the molar concentration of DNA in each of the diploid cell in humans


Question 5. Do eukaryotic cells have restriction endonucleases? Justify your answer.


Answer:   No. They do not have restriction endo nucleases. The eukaryotic cells have some other means of defence against viral infection i.e., immune system.


Question 6. Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?


Answer:  Stirred tank bioreactors have several advantages over shake flasks:

(1) Small volumes of culture can be taken out from the reactor for sampling or testing.


(2) It has a foam breaker for regulating the foam.


(3) It has a control system that regulates the temperature and pH.


Question 8. Can you recall meiosis and indicate at what stage a recombinant DNA is made?


Answer:  Pachytene is marked by completion of lateral pairing of homologous chromosomes along the


entire length of chromosome and crossing over. Crossing over is the process of exchange of genetic material between non-sister chromatids of homologous chromosomes to produce new genetics combinations or variations. The chromosomes after crossing over contain new genetic combinations and represent rDNA.


Question 9.  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:  A reporter gene can be used to monitor the transformation of host cells by foreign DNA. They act as a selectable marker to determine whether the host cell has taken up the foreign DNA or the foreign gene gets expressed in the cell. The researchers place the reporter gene and the foreign gene in the same DNA construct. Then, this combined DNA construct is inserted in the cell. Here, the reporter gene is used as a selectable marker to find out the successful uptake of genes of interest (foreign genes). An example of reporter genes includes lac Z gene, which encodes a green fluorescent protein in a jelly fish.


Question 10. Describe briefly the following:

(a) Origin of replication

(b) Bioreactors

(c) Downstream processing



(a) Origin of replication (ori): One of the major components of a plasmid is a sequence of bases where replication starts. It is called origin of replication (on). This is a specific portion of plasmid genome that serves as start signal for self-replication (to make another copy of itself). Any piece of DNA when linked to this sequence can be made to replicate within the host cells. This property is used to make a number of copies of linked DNA (or DNA insert).


(b) Bioreactors: Bioreactors are vessels in which raw materials are biologically converted into specific products by microbes, plant and animal cells and their enzymes. They are allowed to synthesize the desired proteins which are finally extracted and purified from cultures. Small volume cultures are usually employed in laboratories for research and production of less quantities of products. However, large scale production of the products is carried out in ‘ bioreactors’. The most commonly used bioreactors are of stirring type that have a provision for batch culture or continuous culture. In continuous culture, the culture medium is added and the product is taken out continuously.


(c) Downstream processing: After the formation of the product in the bioreactors, it undergoes through some processes before a finished product is ready for marketing. The processes include separation and purification of products which are collectively called the downstream processing. The product is then subjected to quality control testing and kept in suitable preservatives. A proper quality control testing for each product is also needed. The downstream process and quality control test are different from product to product.


Question 11. Explain briefly

(a) PCR

(b) Restriction enzymes and DNA

(c) Chitinase



(a) PCR : PCR stands for Polymerase chain reaction. In this reaction multiple copies of the gene (DNA) of interest is synthesized in vitro using two sets of primers (small chemically synthesized oligonucleotides that are complementary to the region of DNA) and the enzyme DNA polymerase. The enzyme extends the primers using the nucleotides provided in the reaction and the genomic DNA as template. Then the process of replication of DNA is repeated many times i.e. one billion copies are made.


(b) Restriction enzyme:  The enzymes which are responsible for ‘ restricting the growth of bacteriophage in Escherichia coli are called restriction enzymes. One of this enzyme is added to the methyl groups of DNA, while the other cut DNA. This enzyme is known as restriction endonuclease enzyme. The first restriction endonuclease is Hind II. Now more than 900 restriction enzymes have been isolated from over 230 strains of bacteria.


(c) Chitinase: It is an enzyme obtained from fungus Trichoderma which is specialised to digest chitin of fungal cell walls. The enzyme is used both as an effective fungicide as well as dissolving fungal cell walls to obtain their protoplasts for separation of DNA is genetic engineering.


Frequently Asked Questions on NCERT Solutions for Class 12 Biology Chapter 11


What are the advantages of referring NCERT Solutions for class 12 Biology chapter 11?

Students referring the ncert solutions for class 12 biology chapter 11 pdf download by Adda 247 find the solutions helpful during the exams. The solutions are prepared by the experts in an interactive manner keeping in mind the students. The students’ perspective is kept in mind while preparing the solutions. It helps in completing the syllabus on time and also provides notes for the revision prior to the exam.


What are the advantages of referring NCERT in competitive exams like JEE and AIPMT?


Most of the competitive exams like NEET, JEE etc. follow the basic NCERT books for designing their question papers. NCERT serves as the base for every book prepared for NEET and JEE. The competitive exams are based on the CBSE syllabus applied in XI and XII classes and NCERT books strictly follow CBSE syllabus. In addition to this, NCERT books play an important role in clearing out the theoretical concepts. Every topic given in NCERT books is explained in such a way to help students make their basics and fundamentals strong and clear.


How To Use NCERT Solutions For Class 12 Biology?

i) Study the chapter topic wise and understand the various concepts

ii) First, try to solve the questions by yourself and then look at the solutions.

iii) Use them as a reference guide while revising the chapter.

iv) If you get stuck at any question, you can check the step by step solution from the PDF from ncert solutions for class 12 biology chapter 11 pdf download by Adda 247.



Is it mandatory to solve all the NCERT questions mentioned at the end of each chapter?


The questions and answers mentioned in NCERT textbooks at the end of each chapter are quite important not only for examination but also for understanding the concepts in a better way. These questions aim to test the students’ understanding and learning over the topics that they have learned in the chapter.

Solving the NCERT exercise problems will help to

  • clear all the concepts and formulae you learned in a chapter
  • get comfortable with different types of questions that might be asked in exams
  • get enough practice which is key to succeed in Mathematics exam
  • improve your accuracy and speed


What are the important concepts covered in the Chapter 11 of NCERT Solutions for Class 12 Biology?


The concepts involved in the chapter 11 of NCERT Solutions are –

11.1 – Principles of Biotechnology

11.2 – Tools of Recombinant DNA Technology

11.3 – Processes of Recombinant DNA Technology

These concepts are created by the faculty at Adda 247. The solutions are available at Adda 247 in the PDF format which can be downloaded by the students.

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