MP Board Class 12th Biology Solutions Chapter 11 Biotechnology : Principles And Processes
Biotechnology : Principles And Processes NCERT Text Book Questions and Answers
Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).
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 products it produces.
The substrate DNA on which a restriction enzyme acts :
From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
DNA is bigger in molecular size than enzymes. Because DNA is a long double-stranded molecule which can go up to a few meters in length when stretched end to end but enzymes although variable in size, would still be smaller than the DNA.
What would be the molar concentration of human DNA in a human cell? Consult your teacher.
Calculate molar concentration by finding the weight of DNA in a cell and the weight of the whole cell.
Do eukaryotic cells have restriction endonucleases? Justify your answer.
No. of Eukaryotic cells do not have restriction endonucleases. All the restriction endonucleases have been isolated from die various strains of bacteria and they are also turned according to the genus and species of prokaryotes. The first letter of the enzyme comes from the genus and the second two letters come from the species of the prokaryotic cell from which they have been isolated.
Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?
Foam control system, a temperature control system, pH control system and sampling port to take small volume of culture periodically are some other advantages of stirred tank bioreactors.
Collect 5 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base-pair rules.
Some palindromic DNA sequences and the restriction enzymes which act on them are:
Can you recall meiosis and indicate at what stage recombinant DNA is made?
A recombinant DNA is made in the pachytene stage of prophase I by crossing over during meiosis cell division. Recombination nodules are visible in a synaptonemal complex in the pachytene sub-stage. Crossing over occurs in this time between chromatids than recombinant DNA is formed.
Can you think and answer how a reporter enzyme can be used to monitor the transformation of host cells by foreign DNA in addition to a selectable marker?
Reporter enzyme can differentiate recombinants from non-recombinants on the basis of their ability to produce a specific colour in the presence of a chromogenic substrate. DNA is inserted within the coding sequence of the enzyme β-galactosidase. This result into the inactivation of the enzyme which is referred to as insertional inactivation.
The presence of a chromogenic substrate gives blue-coloured colonies if the plasmid in the bacteria does not have an insert The presence of the insert results in insertional inactivation of β-galactosidase and the colonies do not produce any colour. These are identified as recombinant colonies.
Describe briefly the followings:
(a) Origin of replication
(c) Downstream processing.
(a) Origin of replication: Origin of replication (ori) is a sequence on the chromosome, from where replication starts, and any place of DNA when linked to this sequence can be made to replicate within the host cells.
This sequence also controls the copy number of the linked DNA.
So, if we want to recover many copies of the target DNA it should be linked to the ‘ori’ site and should be cloned in a vector whose origin supports a high copy number.
(b) Bioreactors: Bioreactors are large vessels in which raw materials are biologically converted into specific products, individual enzymes, etc., using microbial, plant, animal or human cells.
A bioreactor provides the optimal conditions for achieving the desired production levels by providing optimum growth conditions of temperature, pH, substrate, salts, vitamins, oxygen, etc.
(c) Downstream processing: Downstream processes include separation and purification, formulation with suitable preservatives, etc, which are collectively referred to as downstream processing.
Such formulation has to undergo thorough clinical trials as in the case of drugs.
Strict quality control testing for each product is also required. The downstream processing and quality control testing vary from product to product.
(b) Restriction enzymes and DNA
(a) PCR : PCR stands for polymerase chain reaction; a method of amplifying fragments of DNA. This method can make multiple copies of even asingle DNA fragment or the gene of interest, in a test tube. The reaction mixture requires.
- Double-stranded DNA fragment (gene of interest).
- Primers-small chemically synthesized oligonucleotides that are complementary to the regions of this DNA.
- The special thermostable DNA polymerase (isolated from a bacterium, Thermus aquaticus), does not denature and remain active even at high temperatures.
The unwinding of two strands of DNA by heating the sample at 92-94°C helps primers to get positioned on the exposed nucleotides as per base-pairing rules. DNA polymerase recognizes primes as ‘start’ tags and begins to extend the primes using the free nucleotides provided in the reaction and the genomic DNA as a template. With each round of reactions, the DNA doubles.
(b) Restriction enzymes and DNA: These enzymes are used in genetic engineering to cut the large DNA molecule into smaller fragments.
When DNA from two different sources are cut by the same restriction enzyme, the resultant DNA fragments have the same kind of sticky ends and these can be joined together (end-to-end) using DNA ligases.
This new DNA created by joining fragments, from two different sources/genomes together is recombinant DNA.
(c) Chitinase: Chitinase is an enzyme that breaks down chitin, a component of the fungal cell wall. It is useful for isolating the fungal cell DNA.
Discuss with your teacher and find out how to distinguish between :
(a) Plasmid DNA and Chromosomal DNA.
(b) RNA and DNA.
(c) Exonuclease and Endonuclease.
(a) Distinguish between Plasmid DNA and Chromosomal DNA :
(b) Distinguish between DNA and RNA:
(c) Distinguish between Exonuclease and Endonucleases:
Exonucleases are nucleases which cut off the nucleotides from the 5′ or 3′ ends of a DNA molecule, whereas endonucleases are nucleases which cleave the DNA duplex at any point except at the ends.
Biotechnology: Principles And Processes Other Important Questions and Answers
Biotechnology: Principles And Processes Objective Type Questions
1. Choose the Correct Answers :
Exchange between genetic material in artificial is called:
(a) Gene recombination
(b) Gene transfer
(c) (a) and (b)
(d) None of these.
(c) (a) and (b)
When was DNA recombinant technique discovered:
(a) In 1971
(b) In 1972
(c) In 1973
(d) In 1974.
(b) In 1972
Which recombinant technique was given by H. Harris and J.F. Watkins:
(d) Protoplast recombination.
(d) Protoplast recombination.
An artificial gene is made by scientists of California which capacity was:
(a) For making of Insulin
(b) For making of artificial gene
(c) For protection of pests
(d) For production of food nutrients.
(a) For making of Insulin
The process in which a gene of interest is located and copied out of DNA extracted is called:
(a) Animal cloning
(b) Gene cloning
(c) DNA cloning
(d) RNA cloning.
(b) Gene cloning
An organism, produced a sexually from one ancestor are called:
(d) None of these.
Which is used as molecular scissors in genetic engineering :
(a) DNA Polymerase
(b) DNA Ligase
(d) Restriction endonuclease.
(d) Restriction endonuclease.
Transgenic expression of transgene in target tissue is determined by :
First restriction endonuclease is :
(b) Hind II
(c) Hind III
(d) Taq I.
(b) Hind II
Cloning vector pBR322 showing restriction site by which :
(c) Both (a) and (b)
(d) None of these.
(c) Both (a) and (b)
DNA segment (T-DNA) of Agrobacterium tumefaciens is caused the disease in plant cells:
(d) None of these.
2. Fill in the Blanks :
- ………………………. is the process by which information from a gene is used in the synthesis of a functional gene product.
- Man made insulin is …………………………….
- ……………………….. in RNA replaces thymine in DNA.
- Formation of m-RNA from DNA is called …………………………
- Gene that effects more than one character is called …………………………
- Gene expression
3. Match the Following:
4. Answer in One Word/Sentence :
- Name the plant in which sequence of nucleotide in DNA was read for the first time.
- Stickyudy of structural and functional aspects of genome.
- Name the scientist who has discovered DNA finger- printing technique.
- DNA having similar nucleotide sequence.
- Organism in which gene of other organism is inserted.
- Where does CCMB situated?
- Name of the first cloned animal.
- Medical system by which disturbed genes can be replaced by normal genes.
- Biomolecule that destroy viruses and produce immunity in human beings.
- Source of Ti plasmid.
- Alec Jeffrey
- Repetitive DNA
- Gene therapy
- Agrobacterium tumefaciens.
Biotechnology: Principles And Processes Very Short Answer Type Questions
Which enzyme is used for the isolation of the target gene?
Restriction endonuclease is used for isolation of target gene.
What is biotechnology?
It is a branch of science that deals with techniques of using live organisms or enzymes from organisms, to produce products and processes useful to humans.
Name three Restriction endonuclease enzymes.
- Hindi II
- Hind III.
Name the first restriction endonuclease discovered.
Hind II is the first restriction endonuclease.
What is Bacteriophage?
Viruses that are infected with bacteria are called Bacteriophage.
What acts as “molecular scissors” in biotechnology.
Restriction enzyme “endonuclease” acts as molecular scissors in biotechnology.
What are molecular scissors?
A restriction enzyme is called molecular scissors.
Name the substance used as the medium in gel electrophoresis.
Agarose is the substance used in gel electrophoresis.
What are the functions of sticky ends?
It helps enzyme DNA ligase.
Name the enzymes used to digest the cell wall of bacteria and fungi for genetic engineering.
- Bacteria -Lysozyme
- Fungi – Chitinase
How does ethidium bromide cause DNA to fluorescein electrophoresis?
The most commonly used stain for detecting DNA is ethidium bromide.
Name any 4 products of Recombinant technology.
Human insulin (Humulin). Human growth hormone (HGH) Chorionic gonadotropin Blood dotting factors VIII and IX Erythropoietin Platelet growth factor Interferon (α,β,γ) (any 4)
Give the function Of circular DNA which is found in the bacterial cell.
It works as a vector.
Why does a cloning vector requires a selectable marker?
Because it helps in identifying and selecting the recombinants and eliminating the non-recombinants.
Name two antibiotic restriction gene which found in plasmid pBR322
Ampicillin and Tetracycline.
Biotechnology: Principles And Processes Short Answer Type Questions
What is genetic engineering?
It is the process of attaining the DNA in an organism’s genome. Genetic engineering is used by scientists to enhance the characteristics of an individual organism.
Give any two purposes of genetic engineering.
- It is a set of technologies used to change the genetic makeup of cells.
- Transfer of genes within and across species boundaries to produce improved organisms.
What is a bacteriophage?
Bacteriophages are composed of proteins that encapsulate a DNA genome and may have a relatively simple structure.
What is restriction endonuclease?
An enzyme produced chiefly by certain bacteria, that has the property of cleaving DNA molecules at or near a specific sequence of basis.
What is vector?
A vector is a quantity or phenomenon that has two independent properties. It used to transfer gentic material to a target cell.
Write the four characters of vector.
- The plasmid DNA act as vectors to transfer the piece of DNA.
- Have compatible restriction site for insertion of DNA molecule.
- It should be capable of self reptication.
- It is not dergadate in host cell.
What is plasmid?
A plasmid is a small DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.
Name any two cloning vectors. Describe the features required to facilitate cloning into a vector.
- Presence of origin of replication (Ori)
- Selectable marker for identifying recombinant from non-recombinant
- Single site recognition site for cloning
What is C-DNA?
C-DNA is a single-stranded RNA. C-DNA is often used to clone eukaryotic genes in prokaryotes.
Name the organism from where the thermostable DNA polymerase is isolated. Write the importance of this enzyme is genetic engineering.
Thermits acquaticus. This enzyme can remain active even during the high temperature-induced denaturation of the double-stranded DNA occurs.
Name of the first clone of the world.
Dolly was a female domestic sheep and the first mammal cloned.
List 4 steps to isolate DNA from a bacterial cell. (AI 2008, 2009)
- The bacterial cell is treated with lysozyme to break open the cell.
- The RNAs associated with the DNA are removed by treatment with ribonuclease (RNases)
- The proteins are removed by treatment with proteases
- The purified DNA is precipitated with chilled ethanol.
What is gene manipulation or genetic engineering? Explain it.
Genetic engineering also called genetic modification is the direct manipulation of an organism’s genes using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes and across species boundaries to produce improved organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesizing the DNA.
It may also mean extracting DNA from another organism’s genome and combining it with the DNA of that individual. Genetic engineering is used by scientists to enhance or modify the characteristics of individual organisms genetic engineering can be used to produce plants that have a higher nutritional value or can tolerate exposure to herbicides.
Write application of genetic engineering to crop improvement.
Genetic engineering has played an important role in the improvement of plant production. There are the following applications of genetics in plant improvement.
- Production of polyploidy crops.
- Hybridization: Hybridization is used to produce plants with desirable traits.
- Transgenic plants: It helps a lot in improving the yield and Questionualify of crops.
- Insect and herbicides resistant plants are engineered.
Write the uses of animal cloning.
Applications of Animal cloning:
- By this techniQuestionue desired genotypes of any organism can be conserved.
- It produces organisms with better characters.
- Endangered plant and animal species can be conserved by this techniQuestionue.
- Animals with good Questionuality of milk and protein can be produced.
Write applications of genetic engineering in the medical field.
- Hereditary diseases like color-blindness, hemophilia are caused by recessive genes therapy. .
- Substances like vitamins, hormones, amino acids and antibiotics can be synthesized in bacteria by introducing the genes which code these substances.
- Production of insulin: It is a medicine used for the treatment of diabetes. It is produced by gene splicing.
- Hepatitis – B vaccine: Hepatitis-B is a viral disease of the liver, today this vaccine is prepared with the help of genetic engineering.
What do you understand by gene bank? What are its significances?
Gene bank: The institution which conserves the genes of the organisms is called a gene bank. The genetic material (DNA) found in the cells of organisms are conserved in gene banks. The best measure of conserving genes is to conserve endangered organisms. The tissues or cells of organisms is also conserved in gene banks.
Significance: Genes stored in gene banks are used for the production of improved varieties of species and for scientific tests.
What do you understand by gene cloning? What is its significance?
What is gene cloning? Write its importance.
Gene cloning: It is a process in which the DNA of an organism is cut into smaller DNA fragments by the use of restriction endonuclease enzymes. Each DNA fragment is introduced into a bacterial, yeast, insect, plant, or animal cell. The cells are grown on a suitable medium under suitable conditions. Each ceil containing a particular DNA fragment multiplies to give rise a group of cells, all containing the same foreign DNA.
These groups of cells are known as clones of cells. These copies of DNA resulting from the multiplication or recombinant DNA are called cloned DNA and the process is known as gene cloning.
- Useful hereditary characters are obtained by this process.
- Many diseases are cured by this process.
- Many medicines are synthesized with the help of this process.
- This process should also be used in eugenics.
Biotechnology: Principles And Processes Long Answers Type Questions
Describe the useful and harmful effects of genetic engineering.
Describe the utility of genetic engineering.
Describe the Genetic engineering. Write the importance of it in human life.
The branch of molecular genetics in which we can manipulate or transplant the genes or the genetic material or DNA according to our will is called gene manipulation or genetic engineering. The main objective of genetic engineering is to synthesize recombinant DNA (formed of the DNA segments of two different organisms).
The useful and harmful effects of genetic engineering are as follows :
(A) Useful effects or Utility :
1. Industrial uses : Various types of substances such as vitamins, hormones and antibiotics can be synthesized in bacteria by introducing genes that code these substances. In this way, bacteria can function as living factories for the synthesis of these substances. Humulin (human insulin) is synthesized by this method.
2. Treatment of diseases : A new system of medicines, gene therapy may develop to cure several genetic disorders such as haemophilia, colour-blindness, etc. Also many inborn metabolic disorders due to defective genes such as alkaptonuria, phenylketonuria, etc. can be cured.
3. Use in agriculture : The genes for N2 fixation found in symbiotic bacteria Rhizobium leguminosarum or blue-green algae may be transferred to the major food crops, increases food production without using expensive fertilizers. Thus, we can save millions of rupees spent otherwise on fertilizers and manures to boost food production.
4. Changes in the structure and expression of genes : We can obtain new plants, animals having traits tailored according to our will.
(B) Harmful effects:
- Normal harmless bacteria can be transformed into cancer causing forms thus ushering a new era of biological warfare.
- During experiments, it is Questionuite possible to obtain super viruses for which we might have no defence.
- By the use of recombinant DNA, the bacteria may be made resistant to antibiotics.
Explain the mechanism of recombinant DNA technology in genetic engineering by using plasmid as carrier of genes.
Mechanism of Recombinant DNA Technology: Mechanism of recom-binant DNA technology involves the following steps
1. Isolation of desired gene or fun¬ctional DNA segment : From the eukaryotic cell desired DNA segment is isolated with the help of enzyme restriction endo¬nuclease. Now this segment of DNA is known as foreign DNA.
2. Transfer of DNA segment from one organism to other : Plasmid is an extra chromosomal circular DNA found mostly in bacteria over and above the main genome. When bacteria multiplies the plasmid DNA also multiplies along with the chromosomal DNA. These plasmids can be easily isolated from the bacterial cell with the help of restriction endonu¬cleases. Plasmid serves as a vector for transferring the foreign DNA into a suitable recipient.
Foreign DNA and plasmid sliced with the help of endonucleases has free sticky ends through which they join each other with complementary base pairing with the help of enzyme DNA ligase. Thus, a recombinant DNA is formed,
Such a recombinant DNA when introduced into a recipient bacterium (transformation), it replicates and expresses itself, within the bacterial cell, the recombinant DNA molecule replicates along with the endogenous DNA of the host cell and produces copies of cloned DNA. This process is known as gene cloning. The cloned recombinant DNA produced in large Questionuantities can be isolated, purified and analysed.
Describe the role of genentic engineering in artificial synthesis of human insulin.
- Aldric and his supporter prepared two DNA seQuestionuences corresponding to the A and B chains of human insulin.
- Sticky ends were produced in the E.coli plasmid and the insulin gene by treating them both with the same restriction endonucleases.
- These two are then joined together by the enzyme DNA ligase.
- The bacteria are then grown in sterilised bioreactors in the appropriate growth medium.
- The chain A and B are produced separately, extracted and purified.
In a bacterial culture, some of the colonies produced blue colour in the presence of a chromogenic substrate and some did not due to the presence or absence of an insert (r DNA) in the coding sequence of (3 – galactosidase).
(a) Mention the mechanism and the steps involved in the above experiment.
(b) How is it advantageous over simultaneous plating on two plates having different antibiotics.
(a) The mechanism involved is called insertional inactivation, the phenomenon in which the enzyme becomes inactivated when a recombinant DNA is inserted within the coding sequence of that enzyme.
Steps in the process:
- A recombinant DNA is inserted into the DNA sequence coding for the enzyme galactosidase, it results in the inactivation of the enzyme.
- In case of the recombinants, when the plasmid has an insert, there is no blue color produced in the presence of a chromogenic substrate in the medium.
- In the case of nonrecombinants/non- transformants i.e. when the plasmid has no insert, the blue colour is produced in the presence of a chromogenic substrate in the medium.
The simultaneous plating method is quite cumbersome as it requires two plates whereas this method is simple and easy.