Chapter 10 : Biotechnology and Its Applications

Class 12 Chapter 10 : Biotechnology and Its Applications Exercise Questions and Answers :

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

Answer : The meristem, specifically the apical and axillary meristems, is best suited for making virus-free plants. Even in infected plants, these meristems are free of the virus, allowing for virus-free plant regeneration through in vitro culture. This method has been successful for various plants like banana, sugarcane, and potato.

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

Answer : The major advantage of producing plants by micropropagation is the rapid and efficient generation of a large number of genetically identical plants in a short time. This technique allows for the mass production of plants, ensuring they are genetically identical to the original plant, which is crucial for preserving desirable traits in crops and other plants.

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

Answer : The medium for in vitro explant propagation typically are :

Carbon Source: Usually sucrose, providing energy.

Inorganic Salts: Essential minerals like nitrates and phosphates.

Vitamins: Such as B vitamins for growth.

Amino Acids: Important for protein synthesis.

Growth Regulators: Like auxins and cytokinins for growth control.

Solidifying Agent: Often agar to create a gel-like consistency.

pH Adjusting Agents: To maintain proper pH.

Plant Growth Regulators: To influence shoot and root development.

Antibiotics/Antifungal Agents: To prevent contamination.

Nutrient Supplements: Depending on plant needs.

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.

Answer : (c) toxin is inactive.

The crystals of Bt toxin produced by some bacteria exist in an inactive protoxin form. They do not kill the bacteria themselves. When an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the insect's gut, which solubilizes the crystals and activates the toxin.

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

Answer : Transgenic bacteria are bacteria that have been genetically modified by inserting foreign genes into their DNA. One example is the use of E. coli bacteria to produce human insulin. By inserting the human insulin gene into E. coli, these bacteria can synthesize human insulin. This biotechnology allows for the mass production of medically important proteins like insulin, benefiting individuals with diabetes.

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

Answer : The advantages and disadvantages of the production of genetically modified crops based on the provided information:

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

Answer : Cry proteins are insecticidal proteins produced by the bacterium Bacillus thuringiensis (Bt).

These proteins are toxic to specific insects such as lepidopterans, coleopterans, and dipterans.

Bt bacteria form protein crystals containing these toxins. The toxin remains inactive in the bacterium but becomes active in the alkaline pH of an insect's gut. Man has exploited this by isolating Bt toxin genes and incorporating them into crop plants like cotton and corn to create genetically modified crops that are toxic to insect pests, reducing the need for chemical pesticides.

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

Answer :  Gene therapy is a medical technique that aims to treat genetic disorders by introducing functional genes into a patient's cells. In the case of Adenosine Deaminase (ADA) deficiency, a disorder affecting the immune system, gene therapy involves introducing a functional ADA gene into the patient's lymphocytes using a retroviral vector. These modified cells are then returned to the patient, potentially offering a long-term or permanent cure for the disorder by restoring the production of the ADA enzyme.

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 ?

Answer :

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

Answer : Using rDNA technology to remove oil from seeds is not a common practice. This technology is typically used for genetic modification and biotechnology applications in crops rather than oil extraction. Traditional methods such as solvent extraction, mechanical pressing, or cold pressing are more suitable for separating oil from seeds. These methods involve physical and chemical processes rather than genetic manipulation.

11. Find out from internet what is golden rice.

Answer :  Golden Rice is a genetically modified rice variety engineered to produce beta-carotene, a precursor of vitamin A. It gets its name from the golden color of the rice grains due to this added nutrient. Golden Rice was developed to combat vitamin A deficiency, which can lead to blindness and other health issues, especially in developing countries where rice is a dietary staple. By providing an additional source of vitamin A through rice consumption, it aims to improve the nutritional status and health of communities that rely heavily on rice in their diets

12. Does our blood have proteases and nucleases?

Answer : No, our blood contains proteases and nucleases, but they are often in inactive forms or regulated by inhibitors to prevent unintended digestion of proteins and nucleic acids, maintaining the integrity of blood components and cells.

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

Answer : Making of Orally Active Protein Pharmaceuticals are :

(i) Modify the protein's structure to enhance stability and resistance to enzymatic degradation in the gastrointestinal tract.

(ii) Develop specialized formulations, such as nanoparticles or liposomes, to protect the protein from the harsh stomach environment and facilitate absorption in the intestines.

(iii) Use enteric coatings that dissolve in the less acidic environment of the intestines rather than the stomach to protect the protein.

(iv) Incorporate enzyme inhibitors into the formulation to reduce proteolytic degradation in the digestive system.

(v) Utilize specific transport mechanisms in the intestinal lining to enhance the uptake of the protein into the bloodstream.

Major Problem Encountered :

The primary challenge in developing orally active protein pharmaceuticals is the susceptibility of proteins to degradation by enzymes in the gastrointestinal tract. Proteases in the stomach and intestine can break down proteins, reducing their effectiveness and bioavailability when taken orally. Overcoming this enzymatic degradation is a major hurdle in the development of oral protein drugs.