NCERT Solutions Class 12 Biology Chapter 10 Biotechnology and Its Applications

Biotechnology and Its Applications explains how genetic engineering, tissue culture, GM crops, recombinant insulin, gene therapy and transgenic animals improve human life.
These NCERT Solutions help Class 12 Biology students write accurate answers on agriculture, medicine, molecular diagnosis and ethical issues.

Chapter 10 is one of the most application-based chapters in Class 12 Biology. It moves beyond definitions and asks students to understand how laboratory techniques solve real problems, such as pest attacks in crops, insulin production for diabetes, early disease diagnosis and hereditary disorders like ADA deficiency. Students should focus on process-based answers, especially Bt toxin activation, RNA interference, recombinant insulin production and gene therapy steps. These NCERT Solutions Class 12 Biology Chapter 10 keep each concept linked to its practical use, making it easier to write accurate answers in CBSE 2026 board exams and biology revision tests.

Key Takeaways

  • Micropropagation: Thousands of genetically identical plants can be produced through tissue culture.
  • Bt cotton: Bt toxin genes from Bacillus thuringiensis protect cotton from specific insect pests.
  • Gene therapy: Functional genes are inserted into cells to correct genetic defects.
  • Biopiracy: Unauthorised use of bio-resources and traditional knowledge without compensation is called biopiracy.

NCERT Solutions Class 12 Biology Chapter 10 Structure 2026

Exercise Type Topic Covered Question Count
Short Answers Tissue culture, Bt toxin, transgenic bacteria 7
Application Answers GM crops, gene therapy, rDNA steps 3
Research-based Answers Golden rice, blood enzymes, oral protein drugs 3

NCERT Solutions for Class 12 Biology Chapter 10 Exercise

Biotechnology and Its Applications questions need correct examples and process-based clarity. Answers should use NCERT terms such as explant, totipotency, somaclones, cry genes, RNAi, recombinant therapeutics, ADA deficiency and biopiracy.

Q1. Which part of the plant is best suited for making virus-free plants and why?

Answer: The meristem, especially apical and axillary meristem, is best suited for making virus-free plants.

Even if a plant is infected with a virus, the meristem is usually free from viral infection. Scientists remove the meristem and grow it under sterile in vitro conditions to obtain healthy virus-free plants.

This method has been used in plants such as banana, sugarcane and potato.

Q2. What is the major advantage of producing plants by micropropagation?

Answer: The major advantage of micropropagation is the production of a large number of genetically identical plants in a short time.

Micropropagation is done through tissue culture. Plants produced by this method are genetically identical to the parent plant and are called somaclones.

This technique is useful for commercial production of crops such as tomato, banana and apple.

Q3. Find out what the various components of the medium used for propagation of an explant in vitro are.

Answer: The medium used for in vitro propagation of an explant must contain nutrients and growth regulators.

The major components are:

  1. Carbon source such as sucrose.
  2. Inorganic salts.
  3. Vitamins.
  4. Amino acids.
  5. Growth regulators such as auxins and cytokinins.
  6. Water.
  7. Solidifying agent such as agar, when a solid medium is required.

The medium must be sterile because contamination can destroy the tissue culture.

Q4. Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because:

(a) bacteria are resistant to the toxin
(b) toxin is immature
(c) toxin is inactive
(d) bacteria encloses toxin in a special sac

Answer: (c) toxin is inactive

Explanation: Bt toxin exists as an inactive protoxin inside Bacillus thuringiensis. When an insect ingests it, the alkaline pH of the insect gut solubilises the crystals and converts the protoxin into active toxin.

The active toxin binds to midgut epithelial cells, creates pores, causes cell swelling and lysis, and finally kills the insect.

Class 12 Biology Chapter 10 Biotechnology and Its Applications Short Answers

Short answers in this chapter often test biotechnology terms and examples. Use organism names, gene names and direct applications wherever possible.

Q5. What are transgenic bacteria? Illustrate using any one example.

Answer: Transgenic bacteria are bacteria whose DNA has been genetically modified by introducing a foreign gene.

A common example is transgenic E. coli used for producing human insulin. In 1983, Eli Lilly prepared two DNA sequences corresponding to the A and B chains of human insulin and introduced them into plasmids of E. coli.

The bacteria produced the two insulin chains separately. These chains were extracted and joined by disulfide bonds to form functional human insulin.

Q6. Compare and contrast the advantages and disadvantages of production of genetically modified crops.

Answer: Genetically modified crops are crops whose genes have been altered through genetic engineering.

Advantages of GM Crops Disadvantages of GM Crops
They can tolerate abiotic stresses such as cold, drought, salt and heat. Their long-term ecological effects need careful monitoring.
They reduce dependence on chemical pesticides. Gene flow to wild relatives may create ecological concerns.
They can reduce post-harvest losses. They may affect non-target organisms if not tested properly.
They increase mineral-use efficiency in plants. Farmers may become dependent on patented seeds.
They can improve nutritional value, such as golden rice. Ethical, biosafety and patent-related issues may arise.

GM crops are useful, but their release must be regulated through proper biosafety checks.

Q7. What are Cry proteins? Name an organism that produces them. How has man exploited this protein to his benefit?

Answer: Cry proteins are insecticidal crystal proteins produced by Bacillus thuringiensis.

During a particular phase of growth, Bacillus thuringiensis forms protein crystals containing Bt toxin. These toxins are insect-group specific. For example, cryIAc and cryIIAb control cotton bollworms, while cryIAb controls corn borer.

Humans have isolated Bt toxin genes from Bacillus thuringiensis and introduced them into crop plants. These genetically modified plants produce Bt toxin and become resistant to specific insect pests.

Examples include Bt cotton, Bt corn, rice, tomato, potato and soybean.

Q8. What is gene therapy? Illustrate using the example of adenosine deaminase deficiency.

Answer: Gene therapy is a method of treating genetic disorders by inserting functional genes into a person’s cells and tissues.

It corrects a defective gene by delivering a normal gene that compensates for the non-functional gene.

Example: ADA deficiency

Adenosine deaminase or ADA deficiency is caused by deletion of the gene coding for the ADA enzyme. This enzyme is essential for immune system function.

The first clinical gene therapy was given in 1990 to a 4-year-old girl with ADA deficiency.

Steps involved are:

  1. Lymphocytes are taken from the patient’s blood.
  2. These lymphocytes are grown in culture outside the body.
  3. Functional ADA cDNA is introduced into the lymphocytes using a retroviral vector.
  4. The genetically engineered lymphocytes are returned to the patient.
  5. Periodic infusion is required because these lymphocytes are not immortal.

A permanent cure may be possible if the ADA gene from marrow cells is introduced into cells at early embryonic stages.

Biotechnology and Its Applications Class 12 Questions and Answers

Application-based questions need process diagrams, examples and scientific logic. Write steps in sequence for rDNA and gene expression answers.

Q9. Diagrammatically represent the experimental steps in cloning and expressing a human gene, such as the gene for growth hormone, into a bacterium like E. coli.

Answer: The cloning and expression of a human gene in E. coli can be represented through these steps:

Step 1: Isolation of human gene
The desired human gene, such as the growth hormone gene, is isolated from human DNA.

Step 2: Cutting of gene and plasmid
The human gene and bacterial plasmid are cut using the same restriction endonuclease.

Step 3: Formation of recombinant DNA
The human gene is inserted into the plasmid using DNA ligase. This forms recombinant DNA.

Step 4: Transformation of E. coli
The recombinant plasmid is introduced into E. coli cells.

Step 5: Selection of transformed cells
The bacterial cells carrying the recombinant plasmid are selected using suitable markers.

Step 6: Expression of human gene
The transformed E. coli expresses the human gene and produces the required protein.

Step 7: Downstream processing
The protein is extracted, purified and processed for use.

Flow representation:
Human gene isolation → plasmid isolation → restriction digestion → ligation → recombinant plasmid → transformation into E. coli → selection → expression → protein purification

Q10. Can you suggest a method to remove oil from seeds based on your understanding of rDNA technology and chemistry of oil?

Answer: A possible rDNA-based method is to silence or modify genes involved in oil biosynthesis in seeds.

Oil in seeds is mainly stored as lipids. If the genes coding for key enzymes of fatty acid or lipid biosynthesis are identified, their expression can be reduced using RNA interference or gene silencing.

A suitable construct can be introduced into the plant through a vector such as Agrobacterium. This construct can produce complementary RNA that silences the target mRNA of oil biosynthesis enzymes.

As a result, the seed may produce less oil. This method must be tested carefully because oil is important for seed germination and energy storage.

Q11. Find out what golden rice is.

Answer: Golden rice is a genetically modified rice variety enriched with Vitamin A precursor, beta-carotene.

It is called golden rice because the grains have a yellow-golden colour due to beta-carotene. The aim of golden rice is to improve nutritional value and help reduce Vitamin A deficiency.

NCERT mentions golden rice as an example of a GM crop with enhanced nutritional value.

Q12. Does our blood have proteases and nucleases?

Answer: Yes, blood has proteases and nucleases in regulated forms.

Proteases are enzymes that break down proteins. Blood contains protease systems involved in processes such as blood clotting, fibrinolysis and complement activation.

Nucleases are enzymes that break down nucleic acids. Small amounts of nucleases are present in blood and help degrade extracellular DNA and RNA.

These enzymes do not normally digest blood proteins or nucleic acids randomly because they are tightly regulated.

Q13. Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?

Answer: Orally active protein pharmaceuticals can be made by protecting the protein drug from digestion and helping it cross the intestinal barrier.

Possible approaches include:

  1. Encapsulating the protein in protective nanoparticles.
  2. Using enteric coating to prevent breakdown in stomach acid.
  3. Adding enzyme inhibitors to reduce protease action.
  4. Using absorption enhancers for intestinal uptake.
  5. Designing protein analogues that resist digestive enzymes.
  6. Using carrier systems such as liposomes or polymer-based delivery systems.

The major problem is that protein drugs are digested by proteases in the stomach and intestine. They are also large molecules, so they cannot easily cross the intestinal epithelium.

This is why many protein pharmaceuticals, such as insulin, are usually given by injection.

NCERT Solutions Class 12 Biology Biotechnology and Its Applications: Important Concepts

Biotechnology and Its Applications connects genetic engineering with real-world use in agriculture, medicine, diagnosis and industry. These concepts help students write better CBSE answers.

Biotechnological Applications in Agriculture

Biotechnology helps increase food production through tissue culture, genetically modified crops and pest-resistant plants.

The three broad approaches for increasing food production are:

  1. Agrochemical-based agriculture.
  2. Organic agriculture.
  3. Genetically engineered crop-based agriculture.

GM plants can tolerate abiotic stresses, reduce pesticide use, lower post-harvest losses, improve mineral-use efficiency and enhance nutritional value.

Tissue Culture and Totipotency

Tissue culture is the growth of plant cells, tissues or organs under sterile conditions in a nutrient medium.

The ability of a plant cell or explant to regenerate a whole plant is called totipotency. The plant part taken out and grown in vitro is called an explant.

Micropropagation uses tissue culture to produce thousands of genetically identical plants in a short time.

Somatic Hybridisation

Somatic hybridisation is the fusion of protoplasts from two different plant varieties.

Scientists first remove cell walls to obtain naked protoplasts. Protoplasts from two plants with desirable traits are fused. The hybrid protoplast is grown into a new plant.

A tomato and potato protoplast fusion produced pomato, but it did not have all the desired commercial traits.

Bt Cotton

Bt cotton is a genetically modified cotton plant that contains Bt toxin genes from Bacillus thuringiensis.

Bt toxin is produced as inactive protoxin. When an insect eats it, the alkaline gut pH activates the toxin. The toxin binds to the midgut epithelial cells, creates pores and kills the insect.

Specific cry genes target specific insects. cryIAc and cryIIAb control cotton bollworms.

Pest-resistant Plants and RNA Interference

RNA interference or RNAi is a method of silencing specific mRNA.

In tobacco plants, the nematode Meloidogyne incognita infects roots and reduces yield. Scientists introduced nematode-specific genes into host plants using Agrobacterium vectors.

The introduced DNA produced both sense and antisense RNA. These formed double-stranded RNA and triggered RNAi. The nematode mRNA was silenced, so the parasite could not survive in the transgenic plant.

Genetically Engineered Insulin

Human insulin was earlier extracted from cattle and pigs, but animal insulin could cause allergy or immune reactions.

Human insulin has two polypeptide chains, A and B, linked by disulfide bonds. In humans, insulin is first produced as proinsulin, which contains an extra C-peptide. The C-peptide is removed during maturation.

In 1983, Eli Lilly produced human insulin using E. coli. DNA sequences for A and B chains were inserted into E. coli. The chains were produced separately, extracted and joined by disulfide bonds.

Molecular Diagnosis

Molecular diagnosis helps detect diseases before symptoms become severe.

Important techniques are:

  1. Recombinant DNA technology.
  2. Polymerase Chain Reaction or PCR.
  3. Enzyme Linked Immunosorbent Assay or ELISA.

PCR detects very low concentrations of pathogen DNA or RNA by amplification. It is used to detect HIV in suspected AIDS patients and mutations in suspected cancer patients.

ELISA is based on antigen-antibody interaction. It detects infection by identifying antigens or antibodies.

Transgenic Animals

Transgenic animals have DNA manipulated to possess and express a foreign gene.

Transgenic mice, rats, rabbits, pigs, sheep, cows and fish have been produced. More than 95% of existing transgenic animals are mice.

They are used to study normal physiology, disease development, biological products, vaccine safety and chemical safety.

Ethical Issues in Biotechnology

Genetic manipulation needs regulation because modified organisms may affect ecosystems and public health.

In India, GEAC evaluates the validity of GM research and the safety of introducing GM organisms for public use.

Biopiracy is another concern. It refers to the use of bio-resources by companies or organisations without proper authorisation and compensation.

The patenting of Basmati rice by an American company and attempts to patent uses of turmeric and neem show why countries must protect traditional knowledge.

Class 12 Biology Chapter 10 Exercise Answers: Important Terms

Important terms in this chapter are useful for one-mark answers and quick revision. Learn each term with its application.

Term Meaning Example
Explant Plant part grown in vitro Meristem culture
Totipotency Ability to regenerate whole plant Tissue culture
Micropropagation Rapid production of many plants Banana tissue culture
Somaclones Genetically identical tissue culture plants Tomato plants
GMO Organism with altered genes Bt cotton
Cry protein Bt insecticidal protein cryIAc in cotton
RNAi mRNA silencing mechanism Nematode-resistant tobacco
Gene therapy Correction of genetic defect ADA deficiency
Transgenic animal Animal with foreign gene Rosie cow
Biopiracy Unauthorised use of bio-resources Basmati patent issue

Biotechnology and Its Applications NCERT Solutions: Agriculture Chart

Agriculture-based applications are frequently asked in board exams. This chart links technique, example and benefit.

Technique Example Benefit
Tissue culture Banana, sugarcane, potato Virus-free plants
Micropropagation Tomato, banana, apple Rapid clonal multiplication
Somatic hybridisation Pomato Combines traits from two plants
Bt technology Bt cotton Insect resistance
RNA interference Tobacco against nematode Pest resistance
Nutritional enhancement Golden rice Vitamin A enrichment

NCERT Class 12 Biology Chapter 10 Solutions: Medicine Chart

Medical biotechnology improves diagnosis, treatment and production of safe therapeutics. These examples are important for CBSE answers.

Application Method Example
Recombinant therapeutics rDNA technology Human insulin
Gene therapy Functional gene insertion ADA deficiency
Molecular diagnosis PCR HIV detection
Antigen-antibody test ELISA Infection diagnosis
Biological products Transgenic animals Alpha-lactalbumin milk from Rosie

Useful Links for Class 12 Biology

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Revision Notes CBSE Class 12 Biology Revision Notes
Important Questions CBSE Important Questions Class 12 Biology
Syllabus CBSE Class 12 Biology Syllabus
NCERT Books NCERT Books for Class 12

Q.1 Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?

Ans-

I would carry some fresh homemade yogurt/ curd because ‘Lactic acid bacteria’ (LAB) for example Lactobacillus grows in milk and converts it into curd. A small amount of curd contains millions of LAB and these can be easily observed under a microscope.

Method to observe LAB under the microscope:

  1. Make a thin smear of curd on a glass slide.
  2. Stain the smear according to the procedure for the Gram stain or with methylene blue.
  3. View the stained smear at 400x to determine the characteristic features of Lactobacillus like rod-shaped cells.
  4. Observe the morphology. LABs the rod- shaped bacteria will stain blue.

Q.2 Give examples to prove that microbes release gases during metabolism.

Ans-

Microbes produce different types of gaseous end-products during growth and metabolism. The type of gas produced depends upon the microbes and the organic substrates they utilise.

  1. Microbes found in the dough of idli, dosa or for making bread release CO2 during fermentation. The idli batter after being kept overnight becomes very fluffy with small bubbles. If the batter is mixed hard it flattens down because the entrapped air (carbon dioxide) escapes.
  2. Some microbes which grow anaerobically on cellulosic material produce a large amount of methane along with CO2 and H2. These bacteria are collectively called methanogens, and one such common bacterium is Methanobacterium. These bacteria reside in the stomach of cattle and help these animals to digest the cellulose. Cattle dung is rich in these bacteria and is used in the production of biogas, which can be used for cooking food and generating electricity.

Q.3 In which food would you find lactic acid bacteria? Mention some of their useful applications.

Ans-

Lactic Acid Bacteria (LAB) can be found in curd. LAB converts milk into curd. Lactobacillus (LAB) is also used for commercial and industrial production of lactic acid. Casein, an important milk protein, is soluble at a neutral pH, but insoluble in acid. When milk turns sour, casein precipitates leading to the thickening of the product.

Lactose (milk sugar) + Lactobacillus → Lactic acid

This lactic acid causes casein to curdle and form the curd.

Q.4 Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes.

Ans-

Wheat: Bread, kulchas and bhaturas

Rice: Dosa and idli

Bengal Gram: Dhokla and khandvi

Explanation: The microbes that ferment these batters are found naturally on urad dal which is used for making the batter hence, no inoculums are required to start the fermentation unlike in bread where yeast inoculum is used to initiate fermentation.

Q.5 In which way have microbes played a major role in controlling diseases caused by harmful bacteria?

Ans-

Microbes such as fungi and bacteria produce antibiotics which are chemical substances that can kill or retard the growth of other (disease-causing) microbes. Antibiotics can be used to treat potentially life threatening diseases like pneumonia to relatively mild conditions such as acne. Antibiotics have greatly improved our ability to treat deadly diseases such as plague, whooping cough (kali khansi), diphtheria (gal ghotu) and leprosy (kusht rog), which used to kill millions of people all over the world.

Q.6 Name any two species of fungus, which are used in the production of the antibiotics.

Ans-

Fungus Antibiotic
Penicillium notatum Penicillin
Streptomyces griseus Streptomycin

Q.7 What is sewage? In which way can sewage be harmful to us?

Ans-

Municipal wastewater that contains human excreta and effluent from the kitchen and bathrooms is collectively called sewage. Sewage contains large amounts of organic matter and also microbes some of which can be harmful to humans and other living beings. Sewage water is a major source of water pollution. Therefore, it is important and mandatory to collect, treat and dispose of sewage responsibly.

Q.8 What is the key difference between primary and secondary sewage treatment?

Ans-

Primary Sewage Treatment Secondary Sewage Treatment
Mechanical, inexpensive and simple process Biological, expensive and complicated process
Involves simple filtration and sedimentation of sewage for the removal of debris Involves the use of microbes to breakdown the organic matter in the sewage

Explanation: Before being drained into water bodies like rivers and lakes, sewage needs to be treated to remove the organic matter. This is carried out in two stages:

Primary Sewage Treatment: The initial phase of sewage treatment involves physical removal of particles. These are removed in two stages;

  1. Sequential filtration for removing floating debris
  2. Sedimentation for removing grit (soil and small pebbles)

All the solids that settle form the primary sludge and the supernatant forms the effluent. The effluent from the primary settling tank is taken for secondary treatment.

Secondary sewage treatment or Biological treatment: This is also carried out in stages before the water can be returned to natural water sources.

  1. Aeration tank: The primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and air is pumped into it. This allows vigorous growth of useful aerobic microbes into flocs (masses of bacteria associated with fungal filaments to form mesh-like structures). While growing, these microbes consume the major part of the organic matter in the effluent. This significantly reduces the BOD (biochemical oxygen demand) of the effluent. BOD refers to the amount of the oxygen that would be consumed if all the organic matter in one litre of water is oxidised by bacteria. The sewage water is treated till the BOD is sufficiently reduced after which the effluent is then passed into a settling tank.
  2. Settling tank: Here the bacterial ‘flocs’ are allowed to sediment. This sediment is called activated sludge. A small part of the activated sludge is pumped back into the aeration tank to serve as the inoculum. The remaining major part of the sludge is pumped into large tanks called anaerobic sludge digesters.

Anaerobic sludge digesters: Here anaerobic bacteria digests the bacteria and fungi in the sludge. The effluent from the secondary treatment plant is generally released into natural water bodies like rivers and streams.

Q.9 Do you think microbes can also be used as source of energy? If yes how?

Ans-

Yes, microbes can be used as a source of energy. One of the most common examples of microorganisms being used for obtaining energy is biogas.

Biogas: Methanogens are anaerobic bacteria that breakdown cellulosic material producing large amounts of methane along with carbon dioxide and hydrogen. These bacteria reside in the stomach of cattle and help the animal to digest the cellulose. Cattle dung is rich in these bacteria and is used in the production of biogas. The biogas plant consists of a concrete tank (10-15 feet deep) into which biowastes are collected and the slurry of dung is fed. A floating cover is placed over the slurry, which keeps on rising as the gas is produced in the tank due to the microbial activity. The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses.

Q.10 Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.

Ans-

The chemical fertilisers and pesticides used in agricultural practices these days pose several health hazards to humans and also create an imbalance in the natural ecosystem. To decrease the use of these chemicals, microbes have been employed through various methods like:

Biopesticides: Biological control of pests and diseases relies on using the natural pest-predator relationship to control diseases. Some microbes have proven to be effective biological control agents and have shown to have no impact on other useful plants or animals. For examples:

  • Trichoderma species is a fungus that is commonly found in the root ecosystem. They are effective biocontrol agents of several plant pathogens.
  • Bacillus thuringiensis is the most widely used species of bacteria for biological control of insects.
  • Baculoviruses are pathogens that attack insects and other arthropods.

Biofertilisers: They add nutrients through the natural processes of nitrogen fixation, solubilising phosphorus, and stimulating plant growth through the synthesis of growth-promoting substances. They can be applied to seed, plant surfaces, or soil. They colonise the interior of the plant and promote growth by increasing the supply or availability of primary nutrients to the host plant. For examples:

  • Azotobacter can be used with crops like wheat, maize, mustard, cotton, potato, and other vegetable crops.
  • Azospirillum inoculations are recommended mainly for sorghum, millets, maize, sugarcane, and wheat.
  • Blue-green algae fix atmospheric nitrogen and are used as inoculations for paddy crop.

Q.11 Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labeled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8 mg/L and 400 mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

Ans-

BOD refers to the amount of the oxygen that would be consumed if all the organic matter in one litre of water is oxidised by bacteria. The BOD test measures the rate of uptake of oxygen by micro-organisms in a sample of water and thus, indirectly, BOD is the measure of the organic matter present in the water. The greater the BOD of waste water more is its polluting potential.

Sample BOD values Water sample types
A 20 mg/L Secondary effluent This is the effluent that has been treated before disposing into the natural water bodies.
B 8 mg/L River water This sample has the least amount of organic matter. Therefore, it can be considered the river water.
C 400 mg/L Untreated sewage water This is the municipal sewage that is collected for treatment in the STP.

Q.12 Find out the name of the microbes from which Cyclosporin A (an immunosuppressive drug) and Statins (blood cholesterol lowering agents) are obtained.

Ans-

Cyclosporin A An immunosuppressive drug Tolypocladium inflatum (fungus)
Statins

Lovastatin

Simvastatin

 Blood cholesterol lowering agents Monascus purpureus (fungus)

Aspergillus terreus (fungus)

Q.13 Find out the role of microbes in the following and discuss it with your teacher.
(a) Single cell protein (SCP)
(b) Soil

Ans-

(a) Single Cell Protein (SCP)

SCP refers to the dried microbial cells or total protein extracted from pure microbial cell culture (algae, bacteria, filamentous fungi, yeasts), which can be used as food supplement for humans (food grade) or animals (feed grade). SCP, a non-conventional protein source can help solve the problem of malnutrition, food and feed shortage in the developing countries. The production of ‘Single Cell Protein’ can be done using waste materials as the substrate, specifically agricultural wastes such as wood shavings, sawdust, corn cobs, etc. and culturing yeast, bacteria, algae or fungi. Spirulina algae, is a good resource as it can be mass cultivated easily and is fast growing with high nutritional content.

(b) Soil

Microorganisms in soil are important because they affect the structure and fertility of different soils. Soil microorganisms can be classified as bacteria, actinomycetes, fungi, algae, and protozoa. Each of these groups has different functions in the soil they inhabit. Some examples of microbes, which are beneficial for soil quality are as follows:

Microorganisms Species Function
Bacteria Nitrobacter Turns nitrite into nitrate, which results in the gain of oxygen and is also known as oxidation
Pseudomonas Metabolises a wide range of chemicals and fertilisers
Anabaena, Nostoc, Oscillatoria Nitrogen fixation
Azospirillum and Azotobacter Fixes atmospheric nitrogen
Algae Blue-green algae Nitrogen fixation
Fungi Glomus Absorption of phosphorus

Q.14 Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas, Citric acid, Penicillin and Curd

Ans-

Entity Importance in society
1 Penicillin The first antibiotic and is used for the treatment of several life-threatening bacterial infections.
2 Biogas A clean, environmentally friendly, sustainable source of energy made of biological waste product. Biogas production can be carried out by unskilled people and is not expensive. It provides energy for cooking and generating electricity in the areas with limited resources.
3 Citric Acid The dominant use of citric acid is as a flavouring agent and preservative in food and beverages. Industrial-scale production of citric acid began during world war I.
4 Curd Curd has many health benefits for humans. It is a natural probiotic which keeps the microflora of the gut healthy and balanced. Curd is also a source of nutrients like calcium, vitamin-B12, etc.

Q.15 How do biofertilisers enrich the fertility of the soil?

Ans-

Biofertilisers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilisers are bacteria, fungi, and cyanobacteria. Biofertilisers can enrich the fertility of the soil in the following ways:

  1. Nitrogen enrichment – Bacteria like Azospirillum and Azotobacter are free-living in the soil and can fix atmospheric nitrogen thus increasing the nitrogen content of the soil. Rhizobium another nitrogen-fixing bacteria forms nodules on the plant roots and lives symbiotically. Cyanobacteria are widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen, e.g. Anabaena, Nostoc, Oscillatoria, etc. In paddy fields, cyanobacteria serve as an important biofertiliser.
  2. Phosphorous enrichment – Fungus like Glomus form Mycorrhiza live symbiotically with a plant and help in absorbing phosphorus for the plant.

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Related Chapters

Chapter 1 - Reproduction in Organism

Chapter 2 - Sexual Reproduction in Flowering Plants

Chapter 3 - Human Reproduction

Chapter 4 - Reproductive Health

Chapter 5 - Principles of Inheritance and Variation

Chapter 6 - Molecular Basis of Inheritance

Chapter 7 - Evolution

Chapter 8 - Human Health and Disease

Chapter 9 - Strategies for Enhancement in Food Production

Chapter 11 - Biotechnology: Principles and Processes

Chapter 12 - Biotechnology and its Applications

Chapter 13 - Organisms and Populations

Chapter 14 - Ecosystem

Chapter 15 - Biodiversity and Conservation

Chapter 16 - Environmental Issues

FAQs (Frequently Asked Questions)

Biotechnology and Its Applications explains the use of genetically modified organisms, tissue culture, rDNA technology, gene therapy, molecular diagnosis and transgenic animals in agriculture and medicine.

The meristem is used because it is usually free from viral infection even when the rest of the plant is infected. It can be grown in vitro to produce healthy plants.

Bt toxin becomes active in the alkaline gut of insects. It binds to midgut epithelial cells, forms pores, causes cell swelling and lysis, and kills the insect.

RNA interference is a cellular defence mechanism in which double-stranded RNA silences a specific mRNA. It has been used to protect tobacco plants from nematodes.

GEAC evaluates GM research and decides the safety of introducing genetically modified organisms for public use in India.