Bihar Board Class 12 Biology Solutions Chapter 11 Biotechnology: Principles and Processes Textbook Questions and Answers, Additional Important Questions, Notes.
BSEB Bihar Board Class 12 Biology Solutions Chapter 11 Biotechnology: Principles and Processes
Bihar Board Class 12 Biology Biotechnology: Principles and Processes Text Book Questions and Answers
Can you list 10 recombinant proteins which are used in medical practice? Find where they are used as therapeutics (use the internet).
|Recombinant Proteins||Therapeutic use|
|1. Human insulin||: → Diabetes|
|2. Insulin-like growth factor||: Childhood growth anabolic effects in adults.|
|3. Interferon||: Treatment of infectious diseases, multiple sclerosis|
|4. Glucocerebrosidase||: Gaucher’s disease|
|5. DNAse||: MucovisCidosis|
|6. Tissue plasminogen activator||: Myocardial infarction|
|8. alpha-galactosidase A||: Enzyme replacement therapy|
|9. Interleukin||: Cancer|
|10. Erythropoietin||: Stimulation of production of erythrocytes|
|11. Human growth hormone(HGH)||: Dwarfism|
Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cots DNA and the product it produces.
From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
Proteins are made up of amino acids. There are 20 amino acids which are joined through peptide bonds. The average protein length is around 300 residues of amino acids. Some like actin filaments are made up of thousand actin molecules.
DNA polymers are made up of nucleotides. There are four | nucleotides which are joined together by phosphodiester bonds. DNA polymers can be enormous molecules containing millions of nucleotides. For instance the largest human chromosome is 220 million base pairs long.
What would be the molar concentration of human DNA in a human cell? Consult your teacher.
Students are advised to discuss it with their teacher.
Do eukaryotic cells have restriction endonucleases? Justify your answer.
Restriction enzymes restrict the infection of bacteria by some viruses like bacteriophages by degrading the viral DNA without affecting viral DNA. These are present in some bacterias. Eukaryotic cells do not have restriction endonucleases.
Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?
Stirred tank bioreactors provide a better agitation system, an oxygen delivery system, a foam control system, a temperature control system, pH control system, sampling ports to withdraw small volumes of culture, and better provision for cleaning and sterilization.
Collect 5 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base-pair rules.
Palindromic are group of letters that form the same words when read both forward and backward. The palindrome in DNA is a sequence of base pairs that reads same as the two strands when orientation of reading is kept the same.
5′ – GAATTC – 3′
3′ – CTTAAC – 5′
Note: For examples consult your school teacher.
Can you recall meiosis and indicate at what stage a recombinant DNA is made?
The linking of antibiotic resistance gene with the plasmid vector with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends. This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.
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?
There are several methods of introducing the ligated DNA into recepient cells, after making them ‘competent 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-resistant gene, one is able to select a transformed cell 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 ferny the foreign DNA into host organisms.
Describe briefly the followings :
(a) Origin of replication
(c) Downstream processing
(a) Origin of replication: When a piece of DNA gets integrated into the genome of the recipient, it may multiply and be inherited along with the host DNA. This happens because the alien piece of DNA has become part of a chromosome, which has the ability to replicate. In a chromosome, there is a specific DNA sequence called the origin of replication, which is responsible for initiating replication. Hence, for the multiplication of any alien piece of DNA in an organism, it needs to be a part of a chromosome(s) which has a specific sequence known as ‘origin of replication. Thus, an alien DNA is linked with the origin of replication, so that, this alien piece of DNA can replicate and multiply itself in the host organism.
(b) Bioreactors: Bioreactors are 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 product by providing optimum growth conditions (temperature, pH, substrate, salts, vitamins, oxygen).
(c) Downstream processing: After the biosynthetic stage, the product are subjected through a series of processes, such as separation and purification, before it is ready for marketing as a finished product. These processes are referred to as downstream processing.
(b) Restriction enzymes and DNA
(a) PCR: PCR stands for Polymerase Chain Reaction. In this reaction, multiple copies of the gene (or DNA) of interest is synthesised in vitro using two sets of primers and the enzyme DNA polymerase. The enzyme extends the primers using the nucleotides provided in the reaction and the genomic DNA as template. The segment of DNA can be amplified to approximately billion times if the process of replication of DNA is repeated many times.
(b) Restriction enzymes and DNA: Restriction enzymes are also called molecular scissors. With the help of restriction enzymes it is possible to cut a DNA sequence. The restriction enzyme will act on both the strands and produce a break. If the vector and the source DNA are cleared using the same restriction enzyme they with have the same kind of sticky ends which are joined by DNA ligases to produce a recombinant vector.
When restriction enzymes make a cut in the DNA strand, it will leave single-stranded portions at the ends. These are overhanging, called sticky ends. Sticky ends can form hydrogen bonds with their complementary cut counterparts by DNA ligases.
(c) Chitinase: Chitinase is a type of enzyme which is treated with plant or animal tissue to break the cell open to release DNA along with other macromolecules such as RNA, proteins, polysaccharides and also lipids.
Discuss with your class teacher and find out how to distinguish between:
(a) Plasmid DNA and Chromosomal DNA
(A) RNA and DNA
(c) Exonuclease and Endonuclease
(a) Plasmid DNA are double-stranded, circular DNA molecules which can self replicate. The plasmid DNA carry genes for sexuality, antibiotic resistance etc., but not any vital genes. The cell can survive without them. They can replicate independently of main genome and being small, can easily come out or get into a cell. Chromosomal DNA acts as agentic factor. These DNA gives us detail account of the chromosomes present in the cell.
(b) RNA and DNA: DNA (Deoxyribonucleic acid) is a nucleic acid found in iiving systems. It acts as a genetic material in most of the organisms.RNA (Ribonucleic acid) also acts as a genetic material but in some viruses. It mostly functions as a messenger. It has additional roles as well. It functions as adapter, structural, and in some cases as a catalytic molecule.
(c) Exonuclease and Endonuclease: Exonucleas’es remove nucleotides from the ends of the DN A whereas, endonucleases make cuts at specific positions within the DNA.
Bihar Board Class 12 Biology Biotechnology: Principles and Processes Additional Important Questions and Answers
Very Short Answer Type Questions
Name three enzymes of industrial importance.
Proteases, Amylases and Renin.
Name two types of fermentation processes.
Batch process and continuous process.
Biotechnology is the controlled use of biological agents, such a$ micro-organisms or cellular components like enzymes for the benefit of organisms.
Name a few important products of biotechnology.
Alcohols, organic acids, enzymes, vitamins, steroids, mono-clonal antibodies, insulin etc.
What are the areas which are responsible for advancement in biotechnology?
Agriculture, medicine, food industry, fermentation, genetic engineering, environmental engineering.
What is genetic engineering?
It is the process by which manipulation in genetic material of an organism is done.
Which enzymes are used for releasing macromolecules (DNA) from cell envelope?
Lysozyme for bacteria, cellulase for plant cell and chitinase for fungus.
Why were restriction enzymes named so?
Because they restrict infection of bacteria from some viruses by degrading the viral DNA without affecting the bacterial DNA.
What are bacteriophages?
These are viruses which infect bacteria, e.g. phage X.
What are structural genes?
The genes which code for a polypeptide.
Name the types of restriction enzymes?
Restriction endonucleases and Restriction exonucleases.
What are various kinds of cloning vehicles?
Plasmids, Phages, Cosmid and phasmid vectors.
What are sticky end?
These are Single-stranded hanging DNA fragments which are formed as a result of restriction enzyme activity.
What is the best method for separation of DNA fragments?
Agarose gel electrophoresis.
What is an origin of replication?
A sequence from where replication begins. It is inserted with foreign DNA fragment to be able to self replicate inside the host cell.
What does PCR stands for?
Polymerase chain reaction (PCR), with it any piece of DNA can be quickly amplified.
What is a bioreactor?
Bioreactor is a large vessel in which raw materials are biologically converted into specific products using microbes or enzymes or plant or animal cells.
What is teminism?
It is reverse transcription.
What are retroviruses?
Viruses which are capable of reverse transcription.
What is a promoter gene?
Promoter gene makes the site at which transcription of mRNA starts.
Short Answer Type Questions
Define cleaning. What are its advantages?
The production of one individual organism or a group of organisms of identical genotype or cells that have been derived from a single parental organism or cell. Cloning is of two types: gene cloning and organism cloning. Cloning is very beneficial in DNA fingerprinting, DNA-probe, gene therapy and genetic engineering.
What is therapeutic cloning? Write its some uses?
Therapeutic cloning is used to repair damaged tissues and diseased organs. Its uses are :
- In the production of cloned embryos and harvesting of their stem cells to repair damaged or defective tissue in the DNA donor,
- Human embryonic cells can be transformed into insulin-producing cells,
- Mature nerve cells can be created from human embryonic stem cells,
- Human embryos can be created from stem cell is through cloning.
What is genetic engineering?
Generic engineering is the science which deals with the synthesis of artificial genes, repair of genes, combining of genes from two organisms (recombinant DNA) and manipulation of the artificial genes for improvement of living beings.
How antibiotics are produced? What are their properties?
Antibiotics are produced by lichens, fungi, actinomycetes and eubacteria. According to their effect, they may be specific antibiotics or broad-spectrum antibiotics. They have following properties :
- The antibiotic should be able to destroy all the strains of the parasite,
- It should not produce any allergic reactions or toxic to the host,
- The antibiotic should not be harmful to natural and useful microbial flora of the host,
- It should have broad-spectrum application beside being specific for a particular pathogen,
- Antibiotics kill the pathogen by breaking a vital link in the metabolism of the pathogen.
Which steps are involved in genetic engineering?
Genetic engineering process has several steps :
- Gene isolation: The desired gene is cut with restriction enzymes and joined by ligases to host DNA.
- Synthesis of gene: The nucleotides are synthesized chemically.
- Transformation: The DNA is incorporated into genome of a cell.
- Transduction: The DNA is carried from a donor bacterium to a recipient bacterium with the help of bacteriophages. It results in changing the recipient’s genotype.
- Gene cloning: It is a technique for producing new combination of genetic material in bacterial cells. The DNA is inserted in the vector, where it produces copies of itself.
According to EFB (European Federation of Biotechnology) “Biotechnology is the integrated use of biochemistry, microbiology and engineering sciences in order to achieve technological application of the capabilities of micro-organisms, cultured tissues/ cells and parts their of.”
What are stem cells? What is stem cell therapy?
The cells of young embryo (approx.40) are called stem cells. They are capable of transforming into any of the 220 cell types human body, they are pluripotent. These are used in therapy called stem cell therapy. For example, if injected into various organs, stem cells can rejuvenate them like stem cells transformed to islet cells can cure diabetes, stem cells that form nerve cells can cure spinal cord injuries. Alzheimer etc.
What are monoclonal antibodies? Write down their characteristics.
In 1970, Georges K6hler and Cesar Milstein developed the technique of producing monoclonal antibodies by fusing normal antibody-producing cells with cells from cancerous tumours. Their main characteristics are : (i) Monoclonal antibodies are pure and highly specific for specific antigens, (ii) These can be easily cultured outside the body, (iii) These antibodies are more effective and ideal for diagnosis of specific diseases. Their most effective clinical application is immune suppression for kidney transplantation.
What are plasmids, why they are suitable for use as a vehicle DNA?
Plasmids are circular, double-stranded DNA molecules which occurs as extrachromosomal material and can replicate independently. They serve as vectors or cloning vehicles in prokaryotes like bacteria.
The ideal plasmid vector has three properties for suitable use as cloning vector :
- low molecular weight, it makes handling easy;
- ability to confer readily with selectable phenotypic traits on host cells;
- single sites for a large number of restriction enzymes.
Diagrammatically show the construction of a chimeric plasmid.
Chimeric or recombinant plasmids have an additional foreign fragment of DNA. It can be shown like this :
What are DNA libraries? How they are made?
A complete library of genome fragments is a set of independent clones, that contains the entire genome among the recombinant DNA molecules. Genomic libraries are also called gene banks. Construction of cDNA library involves following steps :
- the generation of DNA segments,
- introduction of DNA fragments into a cloning vector-like plasmid, cosmid or virus,
- introduction of cloned DNA into a bacterium like E.Coli.
What are second-generation vaccines?
With the help of genetic engineering vaccines of immense importance are synthesized, called second-generation vaccines. These consist of a few antigens present on the surface of the infecting agents rather than the whole inactivated organism (first-generation vaccine). The surface antigens are produced in large quantities with the help of recombinant DNA technique. These are injected in safer dozes to healthy individuals for development of immunity. These are more uniform in quality and have less side effects than first-generation vaccines. For example, vaccine for Hepatitis B.
Show diagrammatically “how monoclonal antibodies are produced.
Long Answer Type Questions
Write short notes on following :
(i) Cloning vectors
(ii), Production of monoclonal antibodies
(iii) Applications of biotechnology
(i) The cloning of a foreign fragment of DNA, in bacteria is made possible with the help of cloning vectors or carriers, which are additional sequences of DNA and do not affect the normal functioning of the cell.
These are various kinds :(a) Plasmids: Plasmids are most commonly used vectors for genetic engineering. They are circular, double-stranded extrachromosomal DNA with self reply- eating system. A cut is made in plasmid DNA by restriction enzyme, the desired segment of DN A is introduced and joined by DNA ligases. This reforms a circular hybrid or chimeric plasmid. The chimeric: plasmid is transferred to a bacteria like E.Coli where it replicates and expresses itself.
(b) Phages are viruses which infect bacteria. For example X (Lamda) phage. They have sites for restriction enzymes and can easily enter inside bacteria and insert their genome.
(c) Cosmid and phasmid vectors: Cosmids are plasmid vectors containing a fragment of X phage DNA. They provide an efficient means of cloning large fragments of foreign DNA. They are used in constructing DNA libraries of eukarya otes.
Phasmids are also plasmid vectors containing a fragment of phage DNA. They have the advantages of both plasmids and phages. Plasmid may insert into phage DNA in the same way by which phage DNA „ enters in bacterial chromosome during lysogenic
(ii) Production of monoclonal antibodies: It involves following steps –
(a) First a mouse or other animal is injected with specific antigen.
(b) The animal will develop an immune response and produces antibodies against the antigen in B-lymphocyte cells in spleen.
(c) The spleen of the animal is taken out and its B-lymphocyte cells are isolated.
(d) In the same way, the cells producing bone marrow cancer (myeloma cells) are isolated. These cells should not be able to synthesise their own nutrients.
(e) Both the myeloma cells and antibody-producing cells are made to fuse together in cultures. The fused cells are named hybridomas.
(f) The unfused myeloma cells are separated from fused myeloma cells by growing them on nutrient-deficient medium (needed by myeloma cells)
(g) The surviving fused myeloma (hybridoma) cells are grown separately and each clone is tested for production of antibody.
(h) The clones which show positive results are isolated and cultured for large scale production of antibody.
(iii) Applications of biotechnology :
(a) Food: The important foods employing micro-organisms during their preparation are Bread, Idli, Dosa, Acid Porridge, Shoyu, Soy Sauce, Miso, Koji Tempeh, Ontjom, etc.
(b) Dairy Products: Yogurt (= yoghurt), Curd, Kefir (Russian), Cheese and butter require specific strains of micro-organisms during their preparation or maturation.
(c) Alcoholic Beverages: Beers, Wines, Whisky, etc. are produced through fermentation of different foods by suitable micro-organisms.
(d) Nonalcoholic Beverages: Curing of coffee beans and Tea leaves is a microbial process.
(e) Sewage Treatment: Different types of bacteria, fungi and algae take part in removal of organic matter in the sewage.
(f) Biogas (Gobar Gas): Cowdung, farm refuse, garbage, etc. are placed in biogas plants where anaerobic conditions allow methane bacteria to produce methane and other fuel gases. The organic remains of the biogas plants are used as manure.
(g) Biofertilizers: They are mostly nitrogen-fixing micro-organisms which may live free in the soil or form associations with plants. Special strains of these organisms are now inoculated to soil or seeds.
(h) Organic Acid: A number of organic acids (acetic acid, lactic acid, citric acid, gluconic acid) and amino acids are obtained through biotechnology.
(i) Enzymes: Enzymes required for industrial and medicinal use are available from microbial processes.
(j) Vitamins: Some vitamins are still manufactured with the help of microorganisms. Others are synthesised chemically. Food yeast is rich in both proteins and vitamins.
(k) Antibiotics: Only a few are synthetic. All others are products of micro-organisms.
(l) Vaccines: They are employed for providing immunity against important diseases. Vaccines contain attenuated or killed pathogens or their antigens.
(m) Monoclonal Antibodies: Antibodies against pathogens can now be obtained in form from clonal cultures.
(n) Hormones: Insulin, growth hormone and other hormones are presently synthesised through the use of microbes and genetic engineering.
(o) Tissue culture: This is an important tool for improvement of agriculture, forestry introduction of mutations and resistance, synthesis of specific biochemicals, etc.
(p) Genetic engineering: Recombinant DNA technology is applied to several biotechnological processes in obtaining particular biochemicals, improvement of genetic make-up of organism and fighting genetic defects.
(q) Transplants: Test-tube babies and embryo transplants are now being routinely undertaken for production of offspring of desired parents.
(r) Steroids: Micro-organisms are employed for transformation of one type of steroids with other types. Steroids and some other products are regularly employed in antifertility formations.
(i) Give a schematic representation of construction of DNA library.
(ii) Role of biotechnology in diagnosis of diseases.
(i) Construction of DNA library :
Isolation of mRNA from tissue
(ii) Now-a-day$ biotechnology is contributing a lot to medicines, both in the diagnosis of diseases and in the development of pharmaceutical products. Its main purpose is to identify the genes whose mutation causes genetic diseases All diseases involve changes in gene expression within the affected cells, and within the patient’s immune system. By comparing gene expression in healthy and diseased cells, biotechnologists may identify genes which are turned on or off in particular diseases.
(a) Polymerase chain reaction (PCR) is a technique by which any piece of DNA can be copied many times in short period. If the source of DNA is impure it can be amplified to using PCR technique. Amplification makes DNA identification much easier. For example the sequence of HIV DNA is known, its amplification by PCR can help to detect HIV DNA in blood or tissue samples.
DNA from single embryonic cells is amplified by PCR for rapid prenatal (before birth) diagnosis of genetic disorders. DNA technology can help to identify individuals with genetic disorders before the appearance of symptoms or carriers of potentially harmful recessive alleles.
(b) Pharmaceutical products: With the help of genetic engineering the gene for a desired protein is transferred into bacteria or yeast and a large amount of protein can be produced in short time or the gene is directly inserted inside the host cells to avoid purifications. Some pharmaceutical products like:(i) Hormones: Mammalian hormones are produced by DNA technology, e.g. Human growth hormone (HGH), insulin etc.
(ii) Immunomodulation: These fight with certain diseases where traditional drug therapy does not work.
(iii) Antisense nucleic acids: These are single-stranded DNA or RNA with pairs with mRNA and block translation and inhibit the propagation of diseases like cancer.
(iv) Genetically engineered proteins: They mimic or block the surface receptors of cell membranes. For example one such protein mimics the HIV receptor protein as a result the HIV virus binds to this protein and fails to enter the white blood cell. Recombinant DNA technology is also helpful in the production of vaccines.
(v) Interferons: These are proteins which limit the cell-to-cell spread of viruses inside the host. Interferons can be produced in large amounts by recombinant DNA technology.
(c) Gene therapy: It may help scientists to replace the defective genes with normal genes. This new system of medicine is called gene therapy.
One Word Type Questions
What are organic compounds produced by a micro-organism that inhibits the growth of or kill another micro-organism called?
Which enzyme is most commonly used for the crop- improvement in genetic engineering?
What does EFB stands for?
European Federation of Biotechnology.
To produce multiple copies of a gene which technique is used?
PCR: Polymerase Chain Reaction.
What are molecular scissors?
Who made the first recombinant DNA?
1972, Stanley Cohen and Herbert Boyer.
Name the specific base sequence where restriction enzymes cut
Name the DNA sequence of base pairs that reads the same on two strands if the orientation is kept same.
In an agarose gel electrophoresis, DNA will move in which direction?
Towards anode (positive electrode).
How large productions of biochemical compounds is done?