Question 1

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

Accepted Answer

The meristematic tissue (apical meristem) of the plant is best suited for making virus-free plants because viruses do not invade this rapidly dividing tissue. Hence, plants regenerated from meristem culture are usually free from viruses. — Viruses generally do not infect the meristematic cells due to their rapid division and lack of vascular connections that viruses use to spread. Therefore, culturing the apical meristem allows production of virus-free plants.

Question 2

What is the major advantage of producing plants by micropropagation?

Accepted Answer

The major advantage of producing plants by micropropagation is the rapid multiplication of disease-free and genetically identical plants in a short period of time, independent of seasonal variations. — Micropropagation allows mass production of plants from a single explant under controlled conditions, ensuring uniformity and health of plants, which is not possible with traditional propagation methods.

Question 3

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

Accepted Answer

The medium used for in vitro propagation of an explant typically contains macronutrients (like nitrogen, phosphorus, potassium), micronutrients (like iron, manganese, zinc), vitamins (like thiamine), amino acids, carbon source (usually sucrose), plant growth regulators (auxins and cytokinins), and a gelling agent (like agar). — Each component supports the growth and development of the explant: macronutrients and micronutrients provide essential elements; vitamins and amino acids aid metabolism; sucrose acts as an energy source; growth regulators control differentiation; agar solidifies the medium.

Question 4

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.

Accepted Answer

The correct answer is (d) bacteria encloses toxin in a special sac.

Explanation: The Bt toxin is produced as crystalline inclusions inside the bacterial cells, which keeps it inactive and prevents it from harming the bacteria themselves. The toxin becomes active only when ingested by susceptible insect larvae. — Bt bacteria produce the toxin as crystals that are enclosed within the bacterial cell in a special sac, preventing self-toxicity. Upon ingestion by insects, the crystals dissolve in alkaline gut conditions, activating the toxin.

Question 5

What are transgenic bacteria? Illustrate using any one example.

Accepted Answer

Transgenic bacteria are bacteria that have been genetically engineered to contain and express foreign genes from other organisms. For example, Escherichia coli bacteria have been transformed with the human insulin gene to produce insulin protein for medical use. — By inserting a gene of interest into bacterial plasmids and introducing them into bacteria, these bacteria can produce proteins encoded by the foreign gene. This technology is widely used for producing pharmaceuticals like insulin.

Question 6

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

Accepted Answer

Advantages:
- Increased crop yield and quality.
- Resistance to pests, diseases, and herbicides.
- Reduced use of chemical pesticides.
- Enhanced nutritional content (e.g., Golden Rice).

Disadvantages:
- Potential environmental risks like gene flow to wild relatives.
- Development of resistance in pests.
- Ethical and biosafety concerns.
- High cost of seeds and technology.

Overall, genetically modified crops offer significant benefits but require careful regulation and assessment of risks. — GM crops can improve food security and reduce chemical inputs but may pose ecological and socio-economic challenges. Balancing benefits and risks is essential for sustainable use.

Question 7

What are Cry proteins? Name an organism that produce it. How has man exploited this protein to his benefit?

Accepted Answer

Cry proteins are insecticidal crystal proteins produced by the bacterium Bacillus thuringiensis (Bt). These proteins are toxic to certain insect larvae but harmless to humans and other animals.

Man has exploited Cry proteins by incorporating the Bt gene into crop plants (Bt crops) to confer resistance against insect pests, reducing the need for chemical insecticides. — Bt produces Cry proteins as crystalline inclusions that kill specific insects. Genetic engineering has allowed transfer of Bt genes into crops like cotton and maize, providing built-in pest resistance and improving crop protection.

Question 8

What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.

Accepted Answer

Gene therapy is a technique that involves inserting a normal gene into cells to correct a genetic disorder caused by a defective or missing gene.

In the case of adenosine deaminase (ADA) deficiency, which causes severe combined immunodeficiency (SCID), gene therapy involves introducing a functional ADA gene into the patient's bone marrow cells to restore immune function. — Patients with ADA deficiency lack an enzyme essential for lymphocyte function. By inserting the normal ADA gene into their cells using viral vectors, the enzyme production is restored, improving immunity.

Question 9

Digrammatically represent the experimental steps in cloning and expressing an human gene (say the gene for growth hormone) into a bacterium like E. coli?

Accepted Answer

The experimental steps are:
1. Isolation of the human growth hormone gene.
2. Insertion of the gene into a suitable vector (plasmid).
3. Introduction of the recombinant plasmid into E. coli cells (transformation).
4. Selection of transformed bacteria using antibiotic resistance markers.
5. Expression of the human growth hormone gene in bacteria.
6. Harvesting and purification of the expressed protein.

Diagrammatically, this involves gene isolation, vector insertion, transformation, selection, expression, and protein purification. — This process enables bacteria to produce human proteins for therapeutic use. Each step ensures the gene is correctly inserted and expressed in the host.

Question 10

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

Accepted Answer

One method is to genetically engineer seeds by using rDNA technology to suppress or knock out genes involved in oil biosynthesis pathways, thereby reducing oil content. Alternatively, genes encoding enzymes that degrade oil components could be introduced.

This approach requires understanding the biochemical pathways of oil synthesis and applying gene editing or silencing techniques to modify seed oil content. — By manipulating genes responsible for oil production or storage in seeds, it is possible to reduce or alter oil content. This can be achieved through transgenic approaches or gene editing tools like CRISPR.

Question 11

Find out from internet what is golden rice.

Accepted Answer

Golden rice is a genetically modified variety of rice that has been engineered to produce beta-carotene, a precursor of vitamin A, in the edible parts of rice. It aims to combat vitamin A deficiency in populations dependent on rice as a staple food. — Golden rice contains genes from daffodil and a bacterium that enable the biosynthesis of beta-carotene in the rice endosperm, providing a dietary source of vitamin A.

Question 12

Does our blood have proteases and nucleases?

Accepted Answer

Yes, our blood contains proteases and nucleases. Proteases help in breaking down proteins during processes like blood clotting and immune response, while nucleases degrade nucleic acids and help in clearing extracellular DNA and RNA. — Proteases and nucleases are enzymes present in blood plasma and cells to regulate various physiological processes including defense mechanisms and maintaining homeostasis.

Question 13

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

Accepted Answer

Orally active protein pharmaceuticals are made by protecting the protein drugs from degradation in the digestive tract, for example by encapsulation in nanoparticles, use of enzyme inhibitors, or formulation with absorption enhancers.

The major problem encountered is that proteins are usually degraded by stomach acids and digestive enzymes, which reduces their bioavailability when taken orally. — Proteins are sensitive to the harsh conditions of the gastrointestinal tract. Strategies to protect them and enhance absorption are essential for effective oral delivery.

Question 14

Which of the following is NOT one of the three critical research areas of biotechnology?

Accepted Answer

Developing synthetic chemical fertilizers for agriculture — The three critical research areas of biotechnology include (i) providing the best catalyst in the form of improved organisms or pure enzymes, (ii) creating optimal conditions through engineering for catalysts to act, and (iii) downstream processing technologies to purify proteins or organic compounds. Developing synthetic chemical fertilizers is not a biotechnology research area but an agrochemical approach.

Question 15

Which of the following best describes 'totipotency' in plant tissue culture?

Accepted Answer

The ability of any plant cell or explant to regenerate into a whole plant under suitable conditions — Totipotency is the capacity of any plant cell or explant to regenerate into a whole plant when cultured under sterile conditions with appropriate nutrient media. This is the foundational principle of tissue culture and micropropagation.

Biotechnology and Its Applications

Biotechnology and Its Applications — Study Notes

Biotechnology and Its Applications

10.1 Biotechnological Applications in Agriculture

Production of Pest Resistant Plants: Bt Cotton

Practice Questions — Biotechnology and Its Applications

All 13 Chapters in Biology