Engineering Life: Miracles in Biotechnology Class 9 Question Answer Advanced Science Chapter 10

Students can use NCERT Class 9 Advanced Science Solutions Chapter 10 Engineering Life: Miracles in Biotechnology Question Answer to understand complex concepts with ease.

Engineering Life: Miracles in Biotechnology Class 9 Questions and Answers

Engineering Life: Miracles in Biotechnology Question Answer Class 9

Quick Check

Question 1.
What is biotechnology?
Answer:
It is the judicious use of living organisms (like microbes) or their cellular components to produce substances beneficial to humans.

Question 2.
Give two examples from your daily life demonstrating the use of biotechnology.
Answer:

1. Making curd from milk using bacteria.
2. Making bread or fermented drinks like kanji using yeast.

Question 3.
Why are microorganisms important in biotechnology?
Answer:
Microorganisms are important because:

• They help in fermentation processes
• They produce useful substances like antibiotics, enzymes and vitamins
• They are easy to grow and multiply quickly
• They help improve food quality and produce industrial products

Question 4.
Complete the difference between traditional and modern biotechnology.

Traditional biotechnology	Modern biotechnology
Uses natural microbial processes.	Uses _______ techniques
Used since _______  times	Developed in _______  times.
Example: Making curd and bread	Example: Production of _______ using bacteria
Has limited control over _______	Provides greater control over _______
Does not involve gene transfer.	Involves _______  modification.

Answer:

Traditional biotechnology	Modern biotechnology
Uses natural microbial processes.	Uses advanced techniques
Used since ancient times	Developed in modern times.
Example: Making curd and bread	Example: Production of insulin using bacteria
Has limited control over processes.	Provides greater control over processes.
Does not involve gene transfer.	Involves genetic modification.

Question 5.
Why is temperature control important in fermenters?
Answer:
Temperature control is important in fermenters because:

1. Microorganisms produce heat during growth, which can increase temperature.
2. Enzymes in microbes work best at an optimum temperature; high temperature can denature them.
3. Excess heat can kill microorganisms, stopping the process.
4. Proper temperature ensures good yield and quality of the desired product.

Question 6.
What happens if contamination occurs?
Answer:
If contamination occurs in a fermenter:

1. Unwanted microbes compete for nutrients, reducing product yield.
2. They may produce toxins or harmful substances that inhibit or kill useful microbes.
3. The final product becomes impure and unsafe.
4. The entire batch may be wasted, causing economic loss.

Question 7.
Explain sterilisation and its importance in microbial growth.
Answer:
Sterilisation is the process of removing or killing’all microorganisms (including bacteria, fungi and spores) from equipment and media. 0
Importance in microbial growth:

1. It prevents contamination by unwanted microbes.
2. It ensures growth of only the desired microorganism (pure culture).
3. It helps in obtaining pure and safe products.
4. It increases the efficiency and yield of the process.

Check Your Understanding

Question 1.
Define biotechnology. Explain how microorganisms act as “life’s engineers”, giving two examples.
Answer:
Biotechnology is the use of living organisms or their components (like cells, enzymes or genes) to develop useful products and processes for human welfare. Microorganisms act as “life’s engineers” because they carry out processes like fermentation and synthesis of useful substances.
Examples:

• Lactobacillus converts milk into curd through fermentation.
• Yeast produces alcohol and carbon dioxide in bread making.

Question 2.
Differentiate between traditional biotechnology and modern biotechnology using suitable examples.
Answer:

Traditional Biotechnology	Modern Biotechnology
Uses natural organisms and their processes with­out genetic modification	Uses genetic engineering and advanced techniques to modify organisms
Based on simple methods like fermentation	Involves complex meth­ods like recombinant DNA technology
Less precise and slower	More precise and faster
Example: Making curd, bread and wine using yeast or bacteria	Example: Production of insulin using genetically modified bacteria, Bt cotton

Question 3.
Why are fermenters used instead of open containers for industrial production of useful substances? Give any two reasons.
Answer:
Fermenters are used instead of open containers for industrial production because:

1. They provide sterile (contamination-free) conditions, preventing unwanted microorganisms from affecting the product.
2. They allow controlled conditions like tempetature, pH, oxygen supply and nutrients, which help in efficient and high-quality production.

Question 4.
Explain the importance of maintaining sterility inside a fermenter. What problems may arise if sterility is not maintained?
Answer:
Maintaining sterility inside a fermenter is essential because it ensures that only the desired microorganism grows and produces the required product efficiently. It helps in obtaining pure, high-quality products and prevents interference from unwanted microbes.

If sterility is not maintained, contamination may occur. Unwanted microorganisms can grow faster, compete for nutrients and may even produce harmful or undesired substances. This can reduce yield, spoil the product and lead to economic loss in industrial production.

Question 5.
Study the diagram of a fermenter given below and answer the questions.

A. Identify any two parts responsible for maintaining microbial growth.
B. What is the function of the stirrer in a fermenter? ID
C. Why is oxygen supply important in some fermenters?
Answer:
A. Two parts responsible for maintaining microbial growth:

• Temperature control system – maintains optimum temperature for growth
• Nutrient inlet (medium supply) – provides nutrients required for microorganisms

B. The stirrer mixes the contents of the fermenter uniformly, ensuring even distribution of nutrients, oxygen and microorganisms, which helps in efficient growth and production.

C. Oxygen is important in some fermenters because many microorganisms require it for aerobic respiration, which helps in energy production and faster growth, leading to higher yield of useful products.

Question 6.
The following data shows the number of microorganisms growing in a fermenter.

Time (hours)	Number of organisms
0	20
2	30
4	70
6	140
8	145
10	140
12	90

Answer the following:
(a) During which time period does rapid microbial growth occur?
(b) Identify the stationary phase from the data.
(c) Suggest one reason why the microbial population decreases after a certain time.
Answer:
(a) Rapid growth occurs between 2 to 6 hours (from 30 to 140), where the population increases quickly.
(b) The stationary phase is around 6 to 8 hours, where the number remains nearly constant (140 to 145).
(c) The microbial population decreases after a certain time due to depletion of nutrients or accumulation of toxic waste products, which affects their survival.

Question 7.
Microbes are used in food production, medicine and environmental protection. Analyse how biotechnology helps improve human life using any three examples.
Answer:
Biotechnology improves human life in many ways through the use of microorganisms:

1. Food Production: Microbes such as bacteria and yeast are used to make foods such as curd, bread and cheese. This improves food quality, taste and shelf life.
2. Medicine: Microorganisms are used to produce antibiotics, vaccines and insulin, which help in treating diseases and saving lives.
3. Environmental Protection: Microbes help in waste decomposition and sewage treatment, reducing pollution and keeping the environment clean.

Question 8.
A scientist wants to produce insulin using bacteria. Explain how modern biotechnology makes this possible. Why has traditional biotechnology not achieved this?
Answer:
Modern biotechnology makes it possible to produce insulin using bacteria through genetic engineering (recombinant DNA technology). Scientists isolate the human insulin gene and insert it into a bacterial cell like E. coli. The bacteria then multiply and start producing insulin, which is later collected and purified for medical use.

Traditional biotechnology cannot achieve this because it relies on natural processes like fermentation without altering genetic material. Since bacteria do not naturally produce human insulin, traditional methods cannot produce such specific and advanced products.

Question 9.
Biotechnology has helped increase food production, but some people have ethical concerns regarding GM crops. Evaluate both advantages and concerns.
Answer:
Biotechnology, especially genetically modified (GM) crops, has both advantages and ethical concerns.
Advantages:

• GM crops can give higher yields, helping to meet food demands.
• They can be made pest-resistant (e.g., Bt crops), reducing the use of pesticides.
• Some are nutritionally enhanced and can grow in harsh conditions like drought or poor soil.

Ethical Concerns:

• There is a risk of ecological imbalance, as GM crops may affect non-target organisms or biodiversity.
• Development of superweeds (herbicide-resistant weeds) due to gene transfer or overuse.
• Economic issues, as farmers may depend on expensive patented seeds.
• Possible health concerns and lack of long-term studies.

Question 10.
Design a simple biotechnology product that can help solve an environmental problem in your community. Describe:
(i) The microorganism or enzyme you would use
(ii) The problem it solves
(iii) How it benefits society?
Answer:
Biotechnology Product: Biodegradable Waste Decomposer

1. Microorganism used: A mixture of decomposer bacteria and fungi (such as Bacillus and Aspergillus species)
2. Problem it solves: In many communities, kitchen waste and organic waste accumulate and cause bad smell, pollution and attract pests. This product helps in rapid decomposition of organic waste.
3. Benefits to the society:
   • Converts waste into useful compost (manure) for plants
   • Reduces land pollution and garbage load
   • Minimises bad odour and spread of diseases
   • Promotes eco-friendly waste management

Question 11.
Which of the following is an example of traditional biotechnology?
(A) Production of insulin using bacteria
(B) Preparation of curd from milk
(C) Development of disease-resistant crops
(D) Gene transfer between organisms
Answer:
Option (B) is correct.
Explanation: Traditional biotechnology involves using natural processes without genetic modification. Making curd from milk uses natural fermentation by bacteria such as Lactobacillus, which is a traditional method. The other options involve genetic engineering and modern biotechnology techniques.

Question 12.
Which microorganism is commonly used in bread making?
(A) Bacteria
(B) Virus
(C) Yeast
(D) Algae
Answer:
Option (C) is correct.
Explanation: Yeast is commonly used in bread making because it carries out fermentation, converting sugars into carbon dioxide and alcohol. The carbon dioxide gas makes the dough rise, giving bread its soft and fluffy texture.

Question 13.
Which of the following conditions is necessary for proper functioning of a fermenter?
(A) Contamination
(B) Controlled temperature
(C) Open environment
(D) Absence of nutrients
Answer:
Option (B) is correct.
Explanation: A fermenter requires a controlled temperature to maintain optimal conditions for microbial growth and product formation. Uncontrolled temperature can slow down or stop microbial activity, reducing efficiency.

Question 14.
Genetic engineering mainly involves:
(A) mixing different foods
(B) transfer of genes between organisms
(C) increasing natural microbial growth
(D) removing microorganisms from food
Answer:
Option (B) is correct.
Explanation: Genetic engineering involves the transfer or modification of genes from one organism to another to obtain desired traits. This allows scientists to produce useful products like insulin or develop improved crops, which is not possible through simple natural growth or food mixing.

Question 15.
During which phase do microorganisms show maximum growth?
(A) Lag phase
(B) Log phase
(C) Stationary phase
(D) Death phase
Answer:
Option (B) is correct.
Explanation: During the log (exponential) phase, microorganisms multiply rapidly and show maximum growth rate because conditions like nutrients and space are optimal. In the lag phase, cells adjust; in the stationary phase, growth equals death; and in the death phase, cells start dying.

Question 16.
Assertion (A): Sterility must be maintained inside a fermenter.
Reason (R): Contamination by unwanted microorganisms can reduce product quality.
(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is not the correct explanation of A.
(C) A is true but R is false.
(D) A is false but R is true.
Answer:
Option (A) is correct.
Explanation: Maintaining sterility in a fermenter is essential because contamination by unwanted microorganisms can compete for nutrients, spoil the product and reduce quality. Thus, the reason correctly explains the assertion.

Question 17.
Assertion (A): Modern biotechnology allows production of insulin using bacteria
Reason (R): Modern biotechnology involves genetic modification techniques.
(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is not the correct explank-, tion of A.
(C) A is true but R is false.
(D) A is false but R is true.
Answer:
Option (A) is correct.
Explanation: Modern biotechnology enables the production of insulin using bacteria through genetic modification techniques, where the human insulin gene is inserted into bacteria such as E. coli. Therefore, the reason correctly explains how insulin production is possible.

Engineering Life: Miracles in Biotechnology Class 9 Extra Questions and Answers

Short Answer Type Questions

Question 1.
Distinguish between Traditional and Modern Biotechnology based on the methods used and the level of scientific intervention.
Answer:
The two forms of biotechnology differ as follows: Traditional Biotechnology relies on the natural activity of microorganisms and has been used since ancient times for simple processes like baking bread, making wine, or fermenting household foods.

Modern Biotechnology involves deliberate genetic modification using advanced molecular techniques. It specifically uses recombinant DNA technology to “cut” and “paste” genes between organisms to create products like insulin or disease-resistant crops.

Question 2.
Explain how the American company Eli Lilly used recombinant DNA technology to overcome the challenge of producing mature human insulin in 1983.
Answer:
The major challenge in producing human insulin using bacteria is that E. coli cannot process the pro¬hormone to remove the C-peptide. To solve this:

1. Eli Lilly prepared two separate DNA sequences corresponding to chain A and chain B of human insulin.
2. These sequences were inserted into plasmids of E. coli to produce the two chains separately.
3. After extraction, the A and B chains were combined in a laboratory setting by creating disulphide bonds to form mature, functional human insulin (Humulin).

Question 3.
State two ways in which biotechnological processing enhances the nutritional value and safety of food products.
Answer:
Biotechnological processing improves food in the following ways:

1. Enhances Nutrition: Controlled fermentation by microorganisms like probiotics supports gut health and can increase the vitamin content of the food.
2. Improves Safety and Shelf Life: The process prevents the growth of harmful, spoilage-causing microbes, allowing food to be stored safely for longer periods.

Question 4.
Describe the different phases that microorganisms pass through during their growth in a fermenter, and explain why the population remains constant during the stationary phase.
Answer:
During growth in a fermenter, microorganisms follow a distinct growth curve consisting of four main phases:

1. Lag Phase: The initial adaptation stage where microbes adjust to the new environment; metabolic activity begins, but there is little to no cell division.
2. Log (Exponential) Phase: The most productive stage where microbes divide rapidly at their maximum rate, leading to a sharp population increase and maximum product formation.
3. Stationary Phase: The survival stage where the population stabilises and remains constant. This happens because nutrients start running out and toxic waste products accumulate, causing the rate of new cell growth to become exactly equal to the rate of cell death.
4. Decline (Death) Phase: The final stage where depletion of nutrients and high toxicity cause the microorganisms to die rapidly, decreasing the overall population.

Question 5.
Explain the ethical principles of Beneficence and Non-maleficence in biotechnology, providing one example for each.
Answer:
Beneficence (Doing Good): This principle states that biotechnology should be used to actively benefit humanity and society by improving health, food production, and quality of life. Example: Gene therapy or GMO crops designed to fight malnutrition.

Non-maleficence (Do No Harm): This principle ensures that biotechnological advancements do not cause unintended harm, risks, or negative side effects to humans, animals, or the environment. Example: Strict regulations on cloning or gene drives to avoid ecological imbalance.

Question 6.
Define biotechnology’s role in environmental protection through bioremediation and biofuels, and explain how each process contributes to a more sustainable environment.
Answer:
Biotechnology provides eco-friendly solutions to environmental challenges through two primary processes:
Bioremediation: This involves using microorganisms like bacteria (e.g., Pseudomonas) and fungi to break down harmful pollutants such as oil spills, heavy metals, and industrial waste. It is sustainable because it restores polluted environments naturally, converting toxic substances into less harmful forms without the use of dangerous chemicals.

Biofuels: Biotechnology uses microbes to convert organic biomass into renewable energy sources like ethanol, biodiesel, and biogas. This contributes to sustainability by reducing our dependence on fossil fuels and lowering greenhouse gas emissions. Additionally, using organisms like algae helps absorb carbon dioxide during the production process.

Question 7.
Given below is a diagram of a bioreactor with some of its parts labelled P and Q.

(a) Which type of organisms can MOST likely be used if part P is not made a part of the bio-reactor? Why?
(b) Identify the name and purpose of part Q.
(c) How does the thermal jacket help in the process?
Answer:
(a) Anaerobic organisms
Reason: As the aerator ensures a supply of oxygen for aerobic organisms to respire and function, anaerobic organisms will not need this to carry out life processes.

(b) Q: Stirrer/agitator
Purpose: The stirrer facilitates even mixing and oxygen availability throughout the bioreactor.

(c) To maintain optimum temperature throughout the process

Long Answer Type Questions

Question 1.
The provided graph illustrates the different phases of microbial growth over a period of 14 hours.

(a) Identify and describe the characteristics of the four distinct phases shown in the graph.
(b) Based on the data points provided (Number of Microorganisms), calculate the net increase in the
microbial population during the Log Phase.
(c) Explain why the population begins to drop after 12 hours.
Answer:
(a) The four phases of the Microbial Growth Curve are:

• Lag Phase (0-2 h): This is the adaptation period. Microorganisms adjust to the new environment and prepare for division. As shown in the graph, there is very little increase in number (from 10 to 12).
• Log Phase (2-8 h): Also known as the Exponential Phase. Microbes divide rapidly at their maximum rate. The graph shows a steep upward curve as the population jumps from 12 to 120.
• Stationary Phase (8-12 h): The growth rate slows down and becomes equal to the death rate. The population reaches its peak (125) and levels off because nutrients begin to deplete and waste accumulates.
• Death Phase (12-14 h): Toxic waste buildup and lack of nutrients cause the microbes to die rapidly. The graph shows a sharp decline in the number of living organisms (from 123 down to 90).

(b) Calculation of Net Increase during Log Phase:

• Population at the start of Log Phase (2 h) = 12
• Population at the end of Log Phase (8 h) = 120
• Net Increase = 120 – 12 = 108 microorganisms.

(c) Reason for population drop after 12 hours:
After the 12-hour mark, the microbes enter the Death Phase. The environment in the fermenter or culture becomes “toxic” because the microorganisms have consumed most of the available nutrients and have released a high concentration of metabolic waste products. These conditions can no longer support life, leading to a rapid decrease in the number of viable cells.

Question 2.
Biotechnology has revolutionised the cleaning industry through the introduction of bio-enzymes. Based on the text provided, answer the following:
(a) Define bio-enzymes and identify their biological sources.
(b) Discuss the “specific action” of bio-enzymes by categorising how different enzymes target various types of household stains.
(c) Evaluate the environmental and economic advantages of using bio-enzyme-based detergents over traditional harsh chemical cleaners.
Answer:
(a) Definition and Sources: Bio-enzymes are natural proteins that act as biological catalysts, speeding up the chemical breakdown of stains and dirt. They are primarily produced by microorganisms such as bacteria and fungi.

(b) Specific Action on Stains: Bio-enzymes are highly specific, meaning different enzymes target different chemical structures in stains:

• Proteases: These enzymes break down protein-based stains, such as blood, sweat, or grass marks.
• Amylases: These target starch-based stains, which are commonly found in food residues.
• Lipases: These are used to break down organic fats, oils, and grease.

(c) Environmental and Economic Advantages:

• Energy Efficiency (Economic): Bio-enzymes work efficiently even at low temperatures. This allows households to save energy by using cold water for washing rather than heating it.
• Eco-friendliness (Environmental): These products are biodegradable and reduce chemical pollution. They safely break down organic waste without damaging plumbing systems and are generally safer for human skin, making them a sustainable alternative to harsh synthetic chemicals.

Case-Based MCQs

I. Bt Cotton is a genetically modified (GM) crop that has transformed modern agriculture by providing a biological solution to pest management. Scientists developed this variety by incorporating specific genes from the soil bacterium Bacillus thuringiensis (Bt) into the cotton plant’s genome. This bacterium naturally produces crystalline protein (Cry) toxins, which are lethal to certain insect pests like the cotton bollworm.

In the plant, these toxins exist as inactive protoxins. When a susceptible insect ingests the plant tissue, the protoxin enters its midgut. Because the insect’s gut provides an alkaline pH, the crystals are solubilised and converted into an active form. This active toxin binds to the surface of the midgut epithelial cells, creating pores that cause cell swelling and lysis. This ultimately leads to the insect’s death, significantly reducing the need for synthetic chemical pesticides and promoting a more sustainable farming environment.

Question 1.
The “Bt” in Bt cotton refers to which of the following?
(A) Bio-transformed cotton
(B) Bacillus thuringiensis
(C) Biotechnological toxin
(D) Bollworm-terminator
Answer:
Option (B) is correct.
Explanation: Bt stands for Bacillus thuringiensis, the soil bacterium from which the insecticidal genes are extracted.

Question 2.
Why does the Bt toxin not harm the cotton plant itself?
(A) The plant has a specialised immune system.
(B) The toxin is only present in the roots.
(C) The toxin exists in an inactive “protoxin” form within the plant.
(D) The plant’s cells are naturally acidic.
Answer:
Option (C) is correct.
Explanation: The toxin is synthesised as an inactive protoxin, which only becomes lethal when it undergoes specific chemical changes inside an insect.

Question 3.
Which specific condition in the insect’s gut is required to activate the Bt toxin?
(A) Highly acidic pH
(B) Extremely low temperature
(C) Presence, of specific enzymes only
(D) Alkaline pH
Answer:
Option (D) is correct.
Explanation: The alkaline pH of the insect’s midgut is the trigger that solubilises the protein crystals and activates the toxin.

Question 4.
What is the primary mechanism that leads to the death of the insect after ingesting Bt cotton?
(A) Dehydration due to high salt content
(B) Creation of pores in the midgut leading to cell lysis
(C) Total paralysis of the nervous system
(D) Blockage of the respiratory tract
Answer:
Option (B) is correct.
Explanation: Once activated, the toxin binds to the midgut lining and creates pores, causing the cells to swell and burst (lysis), which kills the insect.

Case-Based Subjective Questions

I. The provided image illustrates the process of Recombinant DNA Technology used to produce human insulin. The process begins by using restriction enzymes to “cut” the specific insulin gene from human DNA and to open a bacterial plasmid. These two pieces are then joined together using another enzyme (ligase) to create a recombinant plasmid. This modified DNA is reinserted into a bacterium, which acts as a biological factory. When these bacteria reproduce rapidly inside a bioreactor, they express the human gene and mass-produce insulin for medical use.

Question 1.
What is the specific role of restriction enzymes as shown in the initial steps of the diagram?
Answer:
Restriction enzymes act as “molecular scissors” that cut and isolate the human insulin gene and open the bacterial plasmid at specific sites.

Question 2.
Why are the modified bacteria grown inside a bioreactor?
Answer:
Bacteria are grown in bioreactors to provide a controlled environment that allows them to reproduce rapidly and produce insulin on a large industrial scale.

Question 3.
Describe the three main stages of producing human insulin as depicted in the flowchart, identifying the key components involved in each stage.
Answer:
The process can be divided into the following three stages:

1. Isolation and Cutting: The human insulin gene is identified and isolated from human DNA, and a bacterial plasmid (circular DNA) is extracted from a bacterium. Both are cut using restriction enzymes to create compatible ends.
2. Ligation (Joining): The human insulin gene is inserted into the opened bacterial plasmid. A joining enzyme (DNA ligase) helps these two different DNA sources bond together through base pairing to form a recombinant plasmid.
3. Transformation and Multiplication: The recombinant plasmid is inserted back into a host bacterium. These modified bacteria are then cultured in bioreactors, where they multiply quickly and begin synthesising human insulin according to the instructions in the newly added gene.

II. Industrial fermentation in biotechnology is a highly structured process for the large-scale production of valuable biological substances. It begins with critical groundwork: preparing and thoroughly sterilising the culture medium and all equipment to eliminate contamination. Next, a pure inoculum of carefully selected microorganisms is introduced. The heart of the process is the controlled growth of these microbes within a specialised fermenter, where environmental conditions are precisely managed to maximise productivity. Following this biological factory phase, the final steps involve extracting and purifying the desired product from the fermentation broth and ensuring the responsible treatment of waste materials. The entire sequence is designed to move systematically from raw materials to a purified, ready-to-use biological product.

Question 1.
Define inoculum in the context of the fermentation process.
Answer:
Inoculum refers to the pure microbial culture prepared to be added to the fermenter to initiate the microbial growth and production phase.

Question 2.
Which phase of the microbial growth curve is often considered the most productive for forming antibiotics or enzymes?
Answer:
The Log Phase (or Exponential Phase) is the most productive for product formation, as microorganisms divide rapidly and produce the target substances.

Question 3.
Briefly explain two critical control measuresimplemented in the “Growth of Microorganisms in a Fermenter” step to optimise production.
Answer:
Two critical control measures are:

1. Maintaining optimal physical conditions: Continuous monitoring and automated adjustment of parameters like temperature, pH, and oxygen levels to provide the ideal environment for a specific microbe’s metabolism.
2. Nutrient regulation: Often, additional nutrients are supplied or waste products are monitored (e.g., in fed- batch systems) during the fermentation run to prevent early entry into the stationary or decline phases before maximum product yield is achieved.

Engineering Life: Miracles in Biotechnology Class 9 MCQ

Question 1.
Which of the following processes describes the use of microorganisms like Pseudomonas to naturally clean up industrial waste?
(A) Carbon sequestration
(B) Bioremediation
(C) Fermentation
(D) Biofuel synthesis
Answer:
Option (B) is correct.
Explanation: Bioremediation is a sustainable process where microorganisms such as bacteria and fungi are used to break down harmful pollutants in the environment. Microbes like Pseudomonas have the specific ability to degrade hydrocarbons found in industrial waste, converting toxic substances into simpler, less harmful forms. This allows for the restoration of polluted soil and water without the need for additional harmful chemicals.

Question 2.
In large-scale industrial biotechnology, why is “sterilisation” of a bioreactor essential before starting the production process?
(A) To ensure the vessel can hold up to 1,00,000 litres of medium.
(B) To increase the C02 absorption rate of the microorgan-isms.
(C) To prevent contamination by unwanted microbes that could spoil the product.
(D) To convert the inoculum into a nutrient-rich medium.
Answer:
Option (C) is correct.
Explanation: Bioreactors provide an ideal environment with controlled temperature, pH, and nutrients for the growth of specific microorganisms. If the vessel and materials are not sterilised, unwanted microbes may enter the system. These contaminants can compete with the desired culture, reduce the efficiency of the reaction, and ultimately spoil the final product, such as medicines, enzymes, or biofuels.

Question 3.
Match the Column A with Column B

Column A (Application)	Column B (Function/Component)
(i) Golden Rice	(1) Uses Lactobacillus for fermentation
(ii) Bio-enzymes	(2) Beta-carotene for Vitamin A
(iii) Lipases	(3) Biological catalysts for stains
(iv) Food Processing	(4) Breakdown of fats and oils

(A) (i)-2, (ii)-3, (iii)-4, (iv)-1
(B) (i)-1, (ii)-4, (iii)-3, (iv)-2
(C) (i)-2, (ii)-1, (iii)-4, (iv)-3
(D) (i)-4, (ii)-3, (iii)-2, (iv)-1
Answer:
Option (A) is correct.
Explanation: Golden Rice is biofortified with beta-carotene to combat Vitamin A deficiency. Bio-enzymes act as biological catalysts in cleaning products to speed up the breakdown of dirt. Specifically, Lipases are the enzymes that target and break down fats and oils. Finally, Food Processing (such as making yoghurt or cheese) relies on microorganisms like Lactobacillus to carry out controlled fermentation, improving the quality and nutrition of the food.

Question 4.
Analyse the following statements regarding the structure of insulin and choose the correct option:
Statement I: Mature functional insulin consists of two short polypeptide chains, chain A and chain B, linked together by hydrogen bonds.
Statement II: In mammals, insulin is synthesised as a pro-hormone which contains an extra stretch called the C-peptide.
(A) Statement 1 is correct but Statement II is incorrect.
(B) Statement I is incorrect but Statement II is correct.
(C) Both Statement 1 and Statement II are incorrect.
(D) Both Statement I and Statement II are correct.
Answer:
Option (B) is correct
Explanation: Statement I is incorrect because the two polypeptide chains (A and B) of mature functional insulin are linked together by disulphide bonds, not hydrogen bonds.

Statement II is correct because in humans and other mammals, insulin is initially synthesised as a pro¬hormone (pro-insulin). This precursor contains an additional polypeptide segment called the C-peptide, which is removed during the maturation process to produce functional insulin.

Question 5.
Examine the following statements regarding Bt Cotton:
Statement I: Bt cotton is a transgenic crop created by inserting genes from the bacterium Bacillus thuringiensis into the cotton genome.
Statement II: The Bt toxin is produced in the plant in an active, lethal form that immediately kills any insect that touches the leaves.
Statement III: The toxin becomes active in the insect’s gut due to the alkaline pH, which solubilises the protein crystals.
Statement IV: Once activated, the toxin creates pores in the midgut epithelial cells, leading to cell swelling, lysis, and eventually the death of the insect.
Which of the following combinations is correct?
(A) I, II, and III only
(B) I, III, and IV only
(C) II, III, and IV only
(D) All of the statements are correct
Answer:
Option (B) is correct.
Explanation: Statement II is incorrect because the Bt toxin is produced as an inactive protoxin. It does not harm the plant or kill insects on contact. The toxin only becomes lethal after an insect (such as a bollworm) ingests the plant tissue. In the insect’s midgut, the alkaline pH triggers the conversion of the protoxin into its active form. This active toxin then binds to the surface of midgut epithelial cells, creating pores that cause the insect to stop feeding and eventually die.

Question 6.
Which of the following correctly states the purpose of steam in a bioprocessor?
(A) Helps organisms grow faster.
(B) Adds to the water content.
(C) Maintains sterility.
(D) Steam is not required in a bio-processing unit.
Answer:
Option (C) is correct.
Explanation: In bioprocessing, steam is primarily used to sterilise equipment and the environment. This ensures that unwanted micro-organisms do not contaminate the culture medium, thereby maintaining a sterile environment essential for the growth of specific microbes used in the bioprocess.

Assertion-Reason Questions

Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
(A) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.

Question 1.
Assertion (A): The caterpillar stops feeding shortly after consuming plant foliage containing the Bt toxin.
Reason (R): The Bt toxin binds to specific receptors in the caterpillar’s gut, disrupting normal gut function and causing the gut wall to break down.
Answer:
Option (A) is correct.
Explanation: The Assertion is true because a caterpillar cannot continue to eat after ingesting Bt proteins. The Reason correctly explains why this happens: once consumed, the toxin immediately binds to specific receptors in the insect’s midgut cells. This binding causes cellular disruption, halts feeding, and breaks down the gut wall, allowing microbes to flood the body cavity and eventually cause fatal blood poisoning (septicaemia). Thus, the structural breakdown of the gut directly accounts for the immediate cessation of feeding.

Question 2.
Assertion (A): Recombinant DNA (rDNA) technology can be used to mass-produce human hormones, such as insulin, within other host organisms.
Reason (R): Genetic engineering allows specific genes to be extracted from one organism and inserted into another to express desired traits and enhance the production of industrially significant substances.
Answer:
Option (A) is correct.
Explanation: The Assertion is true because producing therapeutic hormones like insulin in foreign host organisms (like bacteria) is a primary application of biotechnology. The Reason is also true and perfectly explains the assertion by defining the core mechanism of recombinant DNA technology: extracting a specific gene of interest and placing it into another organism so that the host can efficiently manufacture the desired protein or hormone.

Question 3.
Assertion (A): During the home fermentation activity, frothing and bubbles are observed after mixing yeast with a warm sugar solution.
Reason (R): Yeast breaks down sugar in the absence of oxygen, producing ethanol and releasing carbon dioxide gas as a byproduct.
Answer:
Option (A) is correct.
Explanation The Assertion is true because visible frothing and bubbles are the direct physical observation when yeast is activated in a sugar solution. The Reason is also true and correctly explains the assertion: yeast undergoes anaerobic respiration (fermentation) to break down the sugar. This chemical process generates ethanol (which causes the pungent smell) and carbon dioxide gas. It is the accumulation and release of this carbon dioxide gas that physically forms the bubbles and froth in the mixture.

Question 4.
Assertion (A): A bioreactor provides the optimal conditions for achieving the desired product by providing optimum growth conditions.
Reason (R): The most commonly used bioreactors are of stirring type. G CD
Answer:
Option (B) is correct.
Explanation: Bioreactors are vessels used for the large- scale production of biological products such as enzymes, antibiotics and hormones. They provide controlled conditions such as temperature, pH, oxygen supply and nutrient availability to ensure optimal microbial or cell growth and product formation. Stirring-type bioreactors, also called stirred-tank bioreactors, are widely used due to their efficient mixing, aeration and ability to maintain uniform conditions throughout the culture medium. However, while stirring bioreactors are common, they are not the sole reason why bioreactors provide optimal conditions.