Microorganisms Friends And Foe Class 8 Science Chapter 2 Extra Questions and answers are available here. These extra questions and answers have been created by the subject experts of our website CBSE Wale.
Microorganisms Friends And Foe Class 8 Science Chapter 2 Extra Questions And Answers
Question 1: What are microorganisms or microbes, and why are they significant?
Answer: Microorganisms, also known as microbes, are tiny living organisms that are too small to be seen with the naked eye. Despite their size, they play crucial roles in various ecosystems, including nutrient cycling, decomposition, and symbiotic relationships with other organisms.
Question 2: What is the observable effect of microorganisms on bread during the rainy season?
Answer: During the rainy season, moist bread can become spoiled, exhibiting greyish-white patches on its surface. These patches are indicative of microbial growth.
Question 3: What are the tiny black rounded structures observed on moist bread through a magnifying glass?
Answer: The tiny black rounded structures observed on moist bread through a magnifying glass are likely to be spores or reproductive structures of certain types of fungi, such as mold.
Question 4: Where do the greyish-white patches on moist bread come from?
Answer: The greyish-white patches on moist bread are the result of the growth and proliferation of microorganisms, particularly fungi, which thrive in damp environments. These fungi release enzymes that break down the bread, leading to spoilage.
Question 5: What can be observed when a drop of water from the beaker containing moist soil is observed under a microscope?
Answer: When observing a drop of water from the beaker containing moist soil under a microscope, one may observe various microorganisms such as bacteria, protozoa, and possibly fungal spores, depending on the composition of the soil.
Question 6: Are tiny organisms observed when water from a pond is examined under a microscope?
Answer: Yes, when water from a pond is examined under a microscope, one can typically observe a variety of tiny organisms moving around. These organisms may include algae, protozoa, and small aquatic invertebrates.
Question 7: Why are some microorganisms visible with just a magnifying glass, while others require a microscope?
Answer: Some microorganisms, such as the fungus that grows on bread, are larger and can be seen with a magnifying glass due to their size. However, many microorganisms are so small that they cannot be seen without the aid of a microscope, hence the term “microorganisms” or “microbes.”
Question 8: What are the four major groups into which microorganisms are classified?
Answer: Microorganisms are classified into four major groups: bacteria, fungi, protozoa, and some algae.
Question 9: How do viruses differ from other microorganisms?
Answer: Viruses are also microscopic but differ from other microorganisms in that they reproduce only inside the cells of a host organism, which can be a bacterium, plant, or animal.
Question 10: What are some common ailments caused by viruses?
Answer: Common ailments caused by viruses include cold, influenza (flu), and most coughs.
Question 11: Can you provide examples of serious diseases caused by viruses?
Answer: Serious diseases caused by viruses include polio and chickenpox.
Question 12: Which diseases are caused by protozoa and bacteria, respectively?
Answer: Diseases like dysentery and malaria are caused by protozoa (protozoans), whereas typhoid and tuberculosis (TB) are bacterial diseases.
Question 13: What are the two main forms microorganisms can take in terms of cellular structure?
Answer: Microorganisms can be single-celled, like bacteria, some algae, and protozoa, or multicellular, such as many algae and fungi.
Question 14: In what types of environments can microorganisms be found?
Answer: Microorganisms inhabit a wide range of environments, including ice-cold climates, hot springs, deserts, marshy lands, and even inside the bodies of animals, including humans.
Question 15: How do microorganisms vary in terms of their relationship with other organisms?
Answer: Some microorganisms grow on other organisms in a symbiotic or parasitic relationship, while others exist freely in the environment.
Question 16: Can you provide examples of microorganisms that live inside the bodies of animals, including humans?
Answer: Examples of microorganisms that live inside the bodies of animals, including humans, include certain bacteria in the gut microbiota and various types of fungi and protozoa.
Question 17: What is the significance of the diverse habitats inhabited by microorganisms?
Answer: The ability of microorganisms to thrive in diverse habitats underscores their ecological versatility and importance in various ecosystems. Additionally, understanding their adaptability to different environments is essential for studying their roles in processes such as decomposition, nutrient cycling, and disease transmission.
Question 18: What roles do microorganisms play in our lives?
Answer: Microorganisms play various important roles in our lives, including aiding in digestion, nutrient cycling, decomposition, and production of foods such as yogurt and cheese. They are also involved in processes like fermentation and sewage treatment.
Question 19: How do beneficial microorganisms contribute to human life?
Answer: Beneficial microorganisms provide numerous benefits, such as producing antibiotics, aiding in the digestion of food, synthesizing vitamins, and participating in environmental processes like nitrogen fixation in soil.
Question 20: What are some examples of harmful microorganisms?
Answer: Harmful microorganisms include pathogens that cause diseases such as bacteria (e.g., Escherichia coli), viruses (e.g., influenza virus), fungi (e.g., Candida albicans), and protozoa (e.g., Plasmodium falciparum causing malaria).
Question 21: How do harmful microorganisms cause diseases?
Answer: Harmful microorganisms cause diseases by invading the body, damaging tissues, and producing toxins. They can also trigger immune responses that lead to symptoms like fever, inflammation, and tissue damage.
Question 22: What are some examples of food products that are prepared using microorganisms?
Answer: Microorganisms are used in the preparation of various food products, including curd, bread, and cake. In the case of curd, bacteria such as Lactobacillus are used to ferment milk and produce yogurt.
Question 23: In what ways are microorganisms used in environmental cleanup?
Answer: Microorganisms play a crucial role in environmental cleanup by breaking down organic wastes, such as vegetable peels, animal remains, and feces, into harmless and usable substances. Bacteria are particularly effective in this process.
Question 24: Besides food production and environmental cleanup, how else are microorganisms utilized in medicine?
Answer: Microorganisms, especially bacteria, are used in the preparation of medicines such as antibiotics. Certain bacteria produce compounds that inhibit the growth of harmful bacteria or fungi, making them valuable for treating infections.
Question 25: How are microorganisms employed in agriculture to increase soil fertility?
Answer: In agriculture, microorganisms, particularly certain types of bacteria, are used to increase soil fertility by fixing nitrogen. Nitrogen-fixing bacteria convert atmospheric nitrogen into a form that plants can use, thereby enhancing plant growth and soil fertility.
Question 26: What role does the bacterium Lactobacillus play in the formation of curd?
Answer: Lactobacillus promotes the formation of curd by multiplying in milk and converting it into curd through fermentation.
Question 27: How are bacteria involved in the making of cheese, pickles, and other food items?
Answer: Bacteria play a crucial role in the making of cheese, pickles, and various other food items through processes such as fermentation, which contributes to flavor development and preservation.
Question 28: Why is curd an important ingredient in dishes like rava idlis and bhaturas?
Answer: Curd is an important ingredient in dishes like rava idlis and bhaturas because it helps in fermentation, which results in soft and fluffy textures in the final product.
Question 29: What happens when yeast is added to flour, sugar, and warm water mixture, and allowed to sit for two hours?
Answer: When yeast is added to the mixture of flour, sugar, and warm water and allowed to sit for two hours, it reproduces rapidly and produces carbon dioxide during respiration. This process causes the dough to rise as the gas bubbles fill the dough, increasing its volume.
Question 30: How is yeast utilized in the baking industry?
Answer: Yeast is utilized in the baking industry for making breads, pastries, and cakes by leavening the dough or batter through the production of carbon dioxide gas, which causes the dough to rise and results in a light and airy texture in the final baked products.
Question 31: What are some commercial products produced using microorganisms?
Answer: Microorganisms are used in the large-scale production of alcohol, wine, and acetic acid (vinegar).
Question 32: Which microorganism is commonly used for the commercial production of alcohol and wine?
Answer: Yeast is commonly used for the commercial production of alcohol and wine.
Question 33: How is yeast utilized in the production of alcohol and wine?
Answer: Yeast is grown on natural sugars present in grains like barley, wheat, rice, crushed fruit juices, etc., to produce alcohol through fermentation.
Question 34: What is fermentation, and who discovered it?
Answer: Fermentation is the process of converting sugar into alcohol by microorganisms such as yeast. It was discovered by Louis Pasteur in 1857.
Question 35: What are antibiotics, and how are they used in medicine?
Answer: Antibiotics are medicines that kill or inhibit the growth of disease-causing microorganisms. They are commonly prescribed by doctors to treat bacterial infections in humans and animals.
Question 36: What is the source of antibiotics?
Answer: Microorganisms, such as bacteria and fungi, are the source of antibiotics. These microorganisms produce compounds that have antibacterial properties.
Question 37: Can you provide examples of commonly known antibiotics and their sources?
Answer: Some commonly known antibiotics and their sources include penicillin (from Penicillium fungi), streptomycin (from Streptomyces bacteria), tetracycline (from Streptomyces bacteria), and erythromycin (from Saccharopolyspora erythraea bacteria).
Question 38: How are antibiotics manufactured?
Answer: Antibiotics are manufactured by growing specific microorganisms in large-scale fermentation processes. The microorganisms produce the antibiotic compounds, which are then isolated, purified, and formulated into various dosage forms such as tablets, capsules, or injections.
Question 39: What is the significance of antibiotics in modern medicine?
Answer: Antibiotics have revolutionized modern medicine by providing effective treatments for bacterial infections. They have saved countless lives and continue to be essential tools in healthcare for combating infectious diseases. However, overuse and misuse of antibiotics have led to the development of antibiotic resistance, posing a significant public health challenge.
Question 40: Who discovered penicillin, and what led to its discovery?
Answer: Penicillin was discovered by Alexander Fleming in 1929. He noticed the growth of a little green mould (Penicillium) in one of his culture plates containing disease-causing bacteria. He observed that the presence of the mould prevented the growth of bacteria and even killed many of them.
Question 41: What was Alexander Fleming working on when he made the discovery of penicillin?
Answer: Alexander Fleming was working on a culture of disease-causing bacteria when he discovered penicillin.
Question 42: How did the presence of the green mould affect the bacteria in Alexander Fleming’s culture plates?
Answer: The presence of the green mould (Penicillium) in Alexander Fleming’s culture plates prevented the growth of bacteria and also killed many of them.
Question 43: What is the significance of Alexander Fleming’s discovery of penicillin?
Answer: Alexander Fleming’s discovery of penicillin marked a major milestone in medicine. Penicillin became the first widely used antibiotic, revolutionizing the treatment of bacterial infections and saving countless lives.
Question 44: How was penicillin prepared after its discovery by Alexander Fleming?
Answer: After the discovery of penicillin by Alexander Fleming, the mould was isolated and cultivated in large-scale fermentation processes to produce penicillin in sufficient quantities for medical use.
Question 45: How are antibiotics used in agriculture?
Answer: Antibiotics are mixed with the feed of livestock and poultry to prevent and control microbial infections in animals, thereby promoting animal health and productivity.
Question 46: What is the purpose of mixing antibiotics with livestock and poultry feed?
Answer: Mixing antibiotics with livestock and poultry feed helps prevent and control microbial infections in animals, reducing the spread of diseases and promoting growth and overall health.
Question 47: What are some examples of plant diseases that antibiotics are used to control?
Answer: Antibiotics are used to control various plant diseases caused by bacteria and fungi, such as bacterial leaf spot, fire blight, and fungal infections like powdery mildew and damping-off.
Question 48: What are the potential implications of using antibiotics in agriculture?
Answer: The use of antibiotics in agriculture can contribute to the development of antibiotic-resistant bacteria, which may pose risks to human health and the environment. Additionally, there are concerns about the presence of antibiotic residues in food products and the potential for antibiotic resistance to spread from agricultural settings to clinical settings.
Question 49: Why is it important to take antibiotics only on the advice of a qualified doctor?
Answer: It is important to take antibiotics only on the advice of a qualified doctor because they can determine whether antibiotics are necessary based on the type and severity of the infection. Taking antibiotics unnecessarily can contribute to antibiotic resistance and may not effectively treat the infection.
Question 50: What precaution should be taken regarding the completion of the prescribed antibiotic course?
Answer: It is essential to complete the prescribed antibiotic course as instructed by the doctor, even if symptoms improve before the course is finished. Failure to complete the course can lead to incomplete eradication of the infection and potentially contribute to antibiotic resistance.
Question 51: What are the consequences of taking antibiotics when not needed or in incorrect doses?
Answer: Taking antibiotics when not needed or in incorrect doses can make the drug less effective when it is genuinely needed in the future. Additionally, it may kill beneficial bacteria in the body, leading to imbalances and potential health issues.
Question 52: Why are antibiotics not effective against cold and flu?
Answer: Antibiotics are not effective against cold and flu because these illnesses are caused by viruses, not bacteria. Antibiotics specifically target bacteria and do not have any effect on viruses.
Question 53: What is the significance of understanding the limitations of antibiotics?
Answer: Understanding the limitations of antibiotics helps prevent misuse and overuse, which can contribute to antibiotic resistance—a major public health concern. It also encourages appropriate use of antibiotics, preserving their effectiveness for treating bacterial infections when they are truly needed.
Question 54: How does the body defend itself against disease-causing microbes?
Answer: When a disease-carrying microbe enters the body, the immune system produces antibodies to fight the invader. These antibodies target and neutralize the microbe, helping the body to eliminate the infection.
Question 55: What happens to the body’s immune response after encountering a microbe for the first time?
Answer: After encountering a microbe for the first time, the body “remembers” how to fight the microbe if it enters again. This memory response allows the immune system to mount a faster and more effective defense upon subsequent exposures.
Question 56: How does a vaccine work to prevent disease?
Answer: A vaccine works by introducing dead or weakened microbes into a healthy body. This stimulates the immune system to produce antibodies against the microbe without causing illness. These antibodies remain in the body, providing protection against future infections by the disease-causing microbe.
Question 57: Can you provide examples of diseases that can be prevented by vaccination?
Answer: Several diseases, including cholera, tuberculosis, smallpox, and hepatitis, can be prevented by vaccination.
Question 58: What is the long-term benefit of vaccination?
Answer: The long-term benefit of vaccination is the establishment of immunity against specific diseases, thereby reducing the risk of infection, transmission, and outbreaks within communities. Vaccination programs have been instrumental in eradicating or controlling many infectious diseases worldwide.
Question 59: Who discovered the vaccine for smallpox, and in which year?
Answer: Edward Jenner discovered the vaccine for smallpox in 1798.
Question 60: What is the purpose of vaccination during childhood?
Answer: Vaccination during childhood is essential to protect children against several diseases by stimulating their immune system to produce antibodies against specific pathogens, thereby preventing illness and promoting overall health.
Question 61: Where can necessary vaccines be obtained for children?
Answer: Necessary vaccines for children are available in nearby hospitals, clinics, and healthcare centers. Health authorities often provide vaccination services through routine immunization programs.
Question 62: What is the Pulse Polio Programme, and what vaccine is administered under this program?
Answer: The Pulse Polio Programme is a public health initiative aimed at eradicating polio by vaccinating all children under a certain age against the poliovirus. Polio drops, administered orally, are given to children as part of this program.
Question 63: How are vaccines like polio drops beneficial in protecting children against diseases?
Answer: Vaccines like polio drops contain weakened or killed forms of the disease-causing microorganism. When administered to children, they stimulate the immune system to produce antibodies against the pathogen, providing immunity and protection against the disease.
Question 64: What is the status of smallpox worldwide due to vaccination campaigns?
Answer: Smallpox has been eradicated from most parts of the world as a result of widespread vaccination campaigns.
Question 65: How are vaccines produced to protect humans and animals from diseases?
Answer: Vaccines are produced on a large scale from microorganisms to protect both humans and animals from various diseases. These vaccines stimulate the immune system to produce antibodies against specific pathogens, providing immunity and protection against the diseases they cause.
Question 66: What is the significance of producing vaccines on a large scale?
Answer: Producing vaccines on a large scale allows for widespread distribution and administration, helping to prevent and control the spread of infectious diseases on a global scale. It contributes to public health efforts to reduce illness, disability, and mortality caused by preventable diseases.
Question 67: How have vaccines impacted public health?
Answer: Vaccines have had a profound impact on public health by preventing the spread of infectious diseases, reducing morbidity and mortality rates, and contributing to the eradication or control of many deadly diseases. They are considered one of the most effective and cost-effective public health interventions.
Question 68: Can you provide examples of diseases for which vaccines are made to protect humans and animals?
Answer: Vaccines are made to protect against a wide range of diseases, including but not limited to measles, mumps, rubella, polio, hepatitis, influenza, tetanus, diphtheria, pertussis, rabies, and various bacterial and viral infections in animals.
Question 69: How do some bacteria contribute to increasing soil fertility?
Answer: Some bacteria are capable of fixing nitrogen from the atmosphere, converting it into a form that plants can use. By doing so, these bacteria enrich the soil with nitrogen, which is essential for plant growth, and increase its fertility.
Question 70: What is the term used to describe bacteria that can fix nitrogen from the atmosphere?
Answer: Bacteria that can fix nitrogen from the atmosphere are commonly referred to as biological nitrogen fixers.
Question 71: Why is nitrogen important for soil fertility?
Answer: Nitrogen is a crucial nutrient for plant growth and development. It is a major component of chlorophyll, which is essential for photosynthesis, and is involved in the synthesis of proteins, nucleic acids, and other important molecules in plants.
Question 72: How does nitrogen fixation by bacteria benefit plants?
Answer: Nitrogen fixation by bacteria benefits plants by providing them with a readily available source of nitrogen, which is essential for their growth and development. This can lead to increased crop yields and overall plant health.
Question 73: Can you provide examples of crops or plants that benefit from biological nitrogen fixation?
Answer: Leguminous plants, such as beans, peas, soybeans, and clover, often form symbiotic relationships with nitrogen-fixing bacteria in their root nodules. These bacteria supply the plants with nitrogen, reducing the need for synthetic fertilizers and improving soil fertility.
Question 74: What process occurred to convert the collected waste into manure?
Answer: The collected waste decomposed over time due to the action of microorganisms like bacteria, fungi, and other decomposers. This decomposition process breaks down organic matter into simpler compounds, eventually forming nutrient-rich manure.
Question 75: Why is the decomposition of organic waste important for making manure?
Answer: Decomposition of organic waste is important for making manure because it breaks down complex organic molecules into simpler compounds that are readily available as nutrients for plants. This process transforms waste into a valuable resource for enhancing soil fertility and plant growth.
Question 76: How does the decomposition of organic waste contribute to cleaning the environment?
Answer: Decomposition of organic waste helps clean the environment by reducing the accumulation of waste materials and converting them into useful products like manure. Additionally, it prevents the release of harmful gases and leachates that can pollute soil and water bodies.
Question 77: What role do microbes play in the conversion of plant waste into manure?
Answer: Microbes play a crucial role in the conversion of plant waste into manure by breaking down the organic matter present in the waste into simpler compounds. This process releases nutrients that can be used by plants for growth and development.
Question 78: How does the inability of microbes to act on non-organic materials contribute to environmental management?
Answer: The inability of microbes to act on non-organic materials, such as polythene bags and plastic items, highlights the importance of proper waste management practices. Non-biodegradable materials like plastics can accumulate in the environment, leading to pollution and ecological damage. Therefore, it is important to reduce, reuse, and recycle such materials to minimize their environmental impact.
Question 79: What happens to the substances produced by the decomposition of dead organic matter?
Answer: The substances produced by the decomposition of dead organic matter are recycled and used by other plants and animals. These substances provide essential nutrients for the growth and development of living organisms.
Question 80: How do microorganisms help clean up the environment?
Answer: Microorganisms degrade harmful and smelly substances by decomposing organic waste. By breaking down these substances into simpler compounds, microorganisms help clean up the environment and recycle nutrients for reuse by other organisms.
Question 81: Why is the decomposition of dead organic matter important for ecosystem functioning?
Answer: The decomposition of dead organic matter is essential for ecosystem functioning because it recycles nutrients and energy back into the ecosystem. This process helps maintain soil fertility, nutrient cycling, and the overall balance of ecosystems. Additionally, it helps remove organic waste, preventing the buildup of dead material and minimizing the risk of pollution.
Question 82: What are some of the harmful effects of microorganisms?
Answer: Microorganisms can be harmful in various ways, including causing diseases in humans, plants, and animals, as well as spoiling food, clothing, and leather.
Question 83: What term is used to describe microorganisms that cause diseases?
Answer: Microorganisms that cause diseases are called pathogens.
Question 84: How do pathogenic microorganisms affect human health?
Answer: Pathogenic microorganisms can cause a wide range of diseases in humans, ranging from mild infections to serious illnesses. Common examples include bacteria such as Escherichia coli and Staphylococcus aureus, viruses such as influenza virus and human immunodeficiency virus (HIV), fungi such as Candida albicans, and protozoa such as Plasmodium falciparum.
Question 85: Besides causing diseases, how else can microorganisms be harmful?
Answer: Microorganisms can spoil food, clothing, and leather by causing decomposition, mold growth, and unpleasant odors. This can lead to economic losses and health hazards if contaminated food or materials are consumed or used.
Question 86: What measures can be taken to prevent the harmful effects of microorganisms?
Answer: To prevent the harmful effects of microorganisms, it is important to practice good hygiene, sanitation, and food safety measures. This includes proper handwashing, food handling and storage practices, disinfection of surfaces, and regular cleaning of clothing and other materials. Additionally, vaccination and use of antimicrobial agents can help prevent the spread of infectious diseases.
Question 87: How do pathogens typically enter the human body?
Answer: Pathogens can enter the human body through various routes, including the air we breathe, the water we drink, or the food we eat. They can also be transmitted through direct contact with an infected person or carried by animals.
Question 88: What term is used to describe diseases that spread from an infected person to a healthy person through various means?
Answer: Diseases that spread from an infected person to a healthy person through air, water, food, or physical contact are called communicable diseases.
Question 89: Can you provide examples of communicable diseases caused by microbial pathogens?
Answer: Examples of communicable diseases caused by microbial pathogens include cholera, the common cold, chickenpox, and tuberculosis.
Question 90: How does the transmission of communicable diseases occur?
Answer: The transmission of communicable diseases occurs when pathogens are transferred from an infected individual to a susceptible individual through various means such as respiratory droplets (airborne transmission), contaminated food or water, direct physical contact, or vectors like mosquitoes or ticks.
Question 91: What measures can be taken to prevent the spread of communicable diseases caused by microbial pathogens?
Answer: To prevent the spread of communicable diseases, it is important to practice good hygiene, such as washing hands frequently, covering mouth and nose when coughing or sneezing, and avoiding close contact with sick individuals. Vaccination, proper sanitation, safe food and water practices, and public health interventions like quarantine and isolation also play important roles in controlling the spread of communicable diseases.
Question 92: How are viruses spread when a person suffering from the common cold sneezes?
Answer: When a person suffering from the common cold sneezes, fine droplets of moisture containing thousands of viruses are expelled into the air.
Question 93: How can the virus enter the body of a healthy person and cause infection?
Answer: The virus can enter the body of a healthy person when they breathe in the air contaminated with the virus-laden droplets expelled during a sneeze. Once inside the body, the virus can infect cells in the respiratory tract and cause illness.
Question 94: What is the primary mode of transmission for the common cold virus?
Answer: The primary mode of transmission for the common cold virus is through respiratory droplets expelled when an infected person coughs or sneezes. The virus can also spread through direct contact with contaminated surfaces or objects.
Question 95: What precautions can be taken to reduce the risk of contracting the common cold virus?
Answer: Precautions to reduce the risk of contracting the common cold virus include practicing good hygiene, such as washing hands frequently with soap and water, avoiding close contact with individuals who are sick, and covering the mouth and nose when coughing or sneezing.
Question 96: How does understanding the transmission of the common cold virus help in preventing its spread?
Answer: Understanding how the common cold virus is transmitted helps individuals and communities implement preventive measures to reduce its spread. By following proper hygiene practices and avoiding close contact with sick individuals, the risk of contracting and spreading the virus can be minimized.
Question 97: How do houseflies act as carriers of disease-causing microbes?
Answer: Houseflies can act as carriers of disease-causing microbes by picking up pathogens from garbage and animal excreta, which stick to their bodies. When these flies land on uncovered food, they may transfer the pathogens, potentially causing illness in individuals who consume the contaminated food.
Question 98: What precaution is advised to prevent the transmission of pathogens by houseflies?
Answer: It is advisable to always keep food covered to prevent houseflies from contaminating it with disease-causing microbes. Avoiding consumption of uncovered items of food can help reduce the risk of illness.
Question 99: Provide examples of diseases transmitted by mosquitoes.
Answer: Mosquitoes can transmit various diseases to humans, including malaria (caused by the Plasmodium parasite), dengue fever (caused by the dengue virus), Zika virus infection, chikungunya fever, and yellow fever.
Question 100: How can the spread of malaria or dengue be controlled?
Answer: The spread of malaria or dengue can be controlled through a combination of mosquito control measures and public health interventions. This includes:
- Mosquito control: Implementing measures to reduce mosquito breeding sites, such as eliminating standing water where mosquitoes breed, using larvicides, and using insecticides to kill adult mosquitoes.
- Vector surveillance: Monitoring mosquito populations and their infection rates to guide control efforts.
- Personal protection: Using insect repellents, wearing long-sleeved clothing, and using mosquito nets to prevent mosquito bites.
- Community education: Educating communities about the importance of eliminating mosquito breeding sites, protecting against mosquito bites, and seeking prompt medical care for suspected cases of malaria or dengue.
- Treatment and prevention: Providing prompt diagnosis and treatment of malaria and dengue cases, as well as implementing vaccination programs where available (e.g., for dengue).
Question 101: Why is it important to control the spread of malaria or dengue?
Answer: Controlling the spread of malaria or dengue is crucial to protect public health and reduce the burden of these diseases on affected populations. Malaria and dengue can cause significant illness, disability, and death if left untreated, and they can also have socioeconomic impacts by affecting productivity and healthcare costs. Additionally, preventing the transmission of these diseases helps to maintain the effectiveness of treatments and reduce the risk of outbreaks.
Question 102: What is the primary breeding habitat for mosquitoes, and why is it important to eliminate stagnant water?
Answer: Mosquitoes breed in stagnant water, making it essential to eliminate any sources of standing water, such as coolers, tires, flower pots, and other containers. Stagnant water provides an ideal breeding environment for mosquitoes, leading to increased mosquito populations and the spread of diseases like malaria.
Question 103: How can individuals prevent mosquito breeding in their surroundings?
Answer: Individuals can prevent mosquito breeding in their surroundings by regularly emptying and cleaning containers that may collect water, such as coolers, buckets, flower pots, and tires. By keeping the surroundings clean and dry, mosquitoes are deprived of breeding sites, reducing their population and the risk of disease transmission.
Question 104: What measures can be taken to avoid the spread of malaria?
Answer: To avoid the spread of malaria, individuals can take various measures, including using mosquito repellents, installing screens on windows and doors, sleeping under insecticide-treated mosquito nets, wearing protective clothing, using mosquito coils or mats indoors, applying mosquito larvicides to water bodies, seeking prompt medical attention for malaria symptoms, and following preventive measures during travel to malaria-endemic areas.
Question 105: Why is it important to seek medical attention promptly for suspected cases of malaria?
Answer: It is important to seek prompt medical attention for suspected cases of malaria because early diagnosis and treatment are crucial for preventing severe illness and complications. Delayed treatment can result in serious health consequences and even death in some cases, especially in areas where access to healthcare services is limited.
Question 106: How can community education contribute to malaria prevention efforts?
Answer: Community education plays a vital role in malaria prevention efforts by raising awareness about the importance of eliminating mosquito breeding sites, using mosquito repellents, seeking medical care for malaria symptoms, and following preventive measures during travel. By educating communities, individuals can take proactive steps to protect themselves and their families from malaria and contribute to overall malaria control efforts.
Question 107: What types of plants can be affected by diseases caused by microorganisms?
Answer: Various types of plants, including wheat, rice, potato, sugarcane, orange, apple, and others, can be affected by diseases caused by microorganisms.
Question 108: How do diseases caused by microorganisms impact crop yields?
Answer: Diseases caused by microorganisms can significantly reduce crop yields by affecting plant health, growth, and productivity. Infected plants may experience stunted growth, reduced fruit or grain production, and even death, leading to economic losses for farmers and food shortages.
Question 109: How can diseases caused by microorganisms in plants be controlled?
Answer: Diseases caused by microorganisms in plants can be controlled using certain chemicals known as pesticides or fungicides. These chemicals are designed to kill or inhibit the growth of the microbes responsible for the diseases. Additionally, cultural practices such as crop rotation, planting disease-resistant varieties, and maintaining proper sanitation can help manage plant diseases.
Question 110: What are some examples of plant diseases caused by microorganisms?
Answer: Examples of plant diseases caused by microorganisms include wheat rust, rice blast, potato blight, sugarcane smut, citrus canker, apple scab, and many others.
Question 111: Why is it important to control diseases caused by microorganisms in plants?
Answer: It is important to control diseases caused by microorganisms in plants to protect crop yields, ensure food security, and maintain the economic viability of agriculture. By controlling plant diseases, farmers can minimize losses and maximize productivity, ultimately contributing to global food production and supply.
Question 112: How can microorganisms contribute to food poisoning?
Answer: Microorganisms that grow on food can sometimes produce toxic substances, making the food poisonous when consumed. These toxic substances can cause serious illness and even death in individuals who consume the contaminated food.
Question 113: Why is it important to preserve food to prevent it from spoiling?
Answer: It is important to preserve food to prevent it from spoiling because spoiled food can become contaminated with harmful microorganisms that produce toxins. By preserving food properly through methods such as refrigeration, proper storage, and timely consumption, the growth of harmful microorganisms can be inhibited, reducing the risk of food poisoning.
Question 114: What are some measures individuals can take to prevent food poisoning?
Answer: Individuals can prevent food poisoning by following proper food handling and storage practices, including washing hands before handling food, cooking food thoroughly, storing food at proper temperatures, avoiding cross-contamination between raw and cooked foods, and consuming perishable foods before they spoil. Additionally, practicing good hygiene in food preparation environments and avoiding consuming food from questionable sources can help reduce the risk of food poisoning.
Question 115: What are preservatives, and why are they used in food?
Answer: Preservatives are chemicals added to food to prevent or slow down the growth of microorganisms, thus extending the shelf life of the food and preventing spoilage. They help maintain the quality, safety, and freshness of food products.
Question 116: Give examples of common chemicals used as preservatives in food.
Answer: Common chemicals used as preservatives in food include salts (such as sodium chloride) and edible oils. Specific chemical preservatives include sodium benzoate and sodium metabisulphite.
Question 117: How are salt and acid used as preservatives in food?
Answer: Salt and acid are used as preservatives in food to create an environment that is inhospitable to the growth of microorganisms. In pickles, for example, salt or acid preservatives are added to prevent the attack of microbes and inhibit spoilage.
Question 118: In what types of food products are sodium benzoate and sodium metabisulphite commonly used as preservatives?
Answer: Sodium benzoate and sodium metabisulphite are commonly used as preservatives in various food products, including pickles, jams, and squashes. They help prevent spoilage and extend the shelf life of these products.
Question 119: What is the purpose of using preservatives in jams and squashes?
Answer: In jams and squashes, preservatives such as sodium benzoate and sodium metabisulphite are used to prevent spoilage by inhibiting the growth of microorganisms. This helps maintain the quality and freshness of the products, allowing them to be stored for longer periods without deterioration.
Question 120: How has common salt been traditionally used for preservation?
Answer: Common salt has been used for ages to preserve meat and fish. In this method, meat and fish are covered with dry salt to inhibit the growth of bacteria, thereby extending their shelf life.
Question 121: What is the process of preservation by salting?
Answer: In preservation by salting, meat, fish, or other food items are coated with dry salt. The salt draws moisture out of the food, creating an environment where bacteria cannot thrive, thus preventing spoilage and extending the food’s preservation.
Question 122: Besides meat and fish, what other food items can be preserved using common salt?
Answer: Common salt can also be used to preserve other food items such as amla (Indian gooseberry), raw mangoes, tamarind, and various fruits and vegetables. These items are typically treated with dry salt to inhibit microbial growth and prolong their shelf life.
Question 123: Why is salting an effective method of preservation?
Answer: Salting is an effective method of preservation because salt draws moisture out of the food, creating an environment that is inhospitable to the growth of bacteria. Without moisture, bacteria cannot survive or multiply, thus preventing spoilage and extending the shelf life of the food.
Question 124: How is sugar used for preservation in food products like jams, jellies, and squashes?
Answer: Sugar is used for preservation in jams, jellies, and squashes by reducing the moisture content of the food. This reduction in moisture inhibits the growth of bacteria, which helps prevent spoilage and extends the shelf life of these products.
Question 125: What role does sugar play in preserving food products like jams and jellies?
Answer: Sugar acts as a preservative in jams and jellies by creating an environment with low water activity. This environment makes it difficult for bacteria to grow and reproduce, thereby inhibiting spoilage and prolonging the shelf life of the products.
Question 126: Why are jams, jellies, and squashes preserved with sugar?
Answer: Jams, jellies, and squashes are preserved with sugar because sugar helps maintain the quality, flavor, and texture of the products while also preventing spoilage. The high sugar content reduces the water activity, making it less favorable for microbial growth.
Question 127: How does sugar inhibit the growth of bacteria in preserved food products?
Answer: Sugar inhibits the growth of bacteria in preserved food products by reducing the water activity, or water availability, in the product. Bacteria require water to grow and reproduce, so by lowering the water activity through the addition of sugar, the growth of bacteria is slowed down or prevented.
Question 128: How are oil and vinegar used for preservation?
Answer: Oil and vinegar are used for preservation by creating an environment that inhibits the growth of bacteria. When foods are submerged in oil or vinegar, the low moisture content and acidic or anaerobic conditions make it difficult for bacteria to thrive, thus preventing spoilage.
Question 129: What types of foods can be preserved using oil and vinegar?
Answer: Various types of foods, including vegetables, fruits, fish, and meat, can be preserved using oil and vinegar. This method is commonly used for pickling, as well as for preserving other perishable items.
Question 130: How does the use of oil and vinegar prevent spoilage in pickles?
Answer: The use of oil and vinegar in pickles prevents spoilage by creating an environment that is inhospitable to bacteria. The acidity of the vinegar and the presence of oil form a barrier that inhibits bacterial growth, thus preserving the pickles and extending their shelf life.
Question 131: Why are oil and vinegar preferred for preserving certain foods?
Answer: Oil and vinegar are preferred for preserving certain foods because they offer effective protection against spoilage while also enhancing flavor and texture. Additionally, these ingredients are readily available and have been used for preservation purposes for centuries.
Question 132: How does heat treatment, such as boiling, contribute to food preservation?
Answer: Heat treatment, such as boiling, contributes to food preservation by killing many microorganisms present in the food. Boiling milk, for example, helps eliminate harmful bacteria and other pathogens, reducing the risk of foodborne illnesses.
Question 133: What is the role of low temperature in preserving food?
Answer: Low temperature inhibits the growth of microbes by slowing down their metabolic processes. Storing food in the refrigerator helps maintain a cold environment that prevents or slows down microbial growth, thus extending the shelf life of perishable foods.
Question 134: How does pasteurization contribute to milk preservation?
Answer: Pasteurization contributes to milk preservation by heating the milk to about 70°C for 15 to 30 seconds, followed by rapid chilling. This process kills harmful microorganisms present in the milk while preserving its nutritional value and flavor. Pasteurized milk can be consumed without further boiling as it is free from harmful microbes.
Question 135: Who discovered the process of pasteurization, and what does it entail?
Answer: The process of pasteurization was discovered by Louis Pasteur. It involves heating a liquid, such as milk, to a specific temperature (around 70°C) for a short period (15 to 30 seconds) and then rapidly chilling it to prevent the growth of microbes while preserving the quality of the product.
Question 136: What are the advantages of pasteurized milk over raw milk?
Answer: Pasteurized milk offers several advantages over raw milk, including:
- Safety: Pasteurization eliminates harmful bacteria and pathogens present in raw milk, reducing the risk of foodborne illnesses.
- Extended shelf life: Pasteurized milk has a longer shelf life compared to raw milk, as it is free from spoilage-causing microorganisms.
- Convenience: Pasteurized milk can be consumed directly without the need for boiling, making it more convenient for consumers.
- Nutritional quality: Pasteurization helps preserve the nutritional value and quality of milk while ensuring its safety for consumption.
Question 137: Why are dry fruits and vegetables often sold in sealed, airtight packets?
Answer: Dry fruits and vegetables are often sold in sealed, airtight packets to prevent the attack of microbes. This packaging helps maintain the freshness and quality of the products by creating a barrier that prevents microbial contamination and extends shelf life.
Question 138: How does sealed, airtight packaging contribute to food preservation?
Answer: Sealed, airtight packaging contributes to food preservation by creating a barrier that prevents the entry of oxygen, moisture, and microbial contaminants. This helps maintain the freshness, flavor, and nutritional quality of the food products while extending their shelf life.
Question 139: How does sealed packaging protect food items from microbial attack?
Answer: Sealed packaging protects food items from microbial attack by creating a barrier that prevents the entry of microbes, such as bacteria, molds, and yeast. Without access to air and moisture, which are essential for microbial growth, the growth and proliferation of microbes are inhibited, helping to maintain the safety and quality of the food products.
Question 140: What are some examples of other food items commonly sold in sealed, airtight packaging?
Answer: In addition to dry fruits and vegetables, other food items commonly sold in sealed, airtight packaging include grains, cereals, snacks, beverages, meats, and dairy products. These packaging formats help ensure the freshness, safety, and quality of the products for consumers.
Question 141: What is nitrogen fixation, and how is it important for plant growth?
Answer: Nitrogen fixation is the process by which atmospheric nitrogen (N2) is converted into ammonia (NH3) or other nitrogen compounds that can be utilized by plants. It is important for plant growth because nitrogen is an essential nutrient required for the synthesis of proteins, DNA, and chlorophyll, which are vital for plant growth and development.
Question 142: Describe the role of the bacterium Rhizobium in nitrogen fixation.
Answer: The bacterium Rhizobium forms a symbiotic relationship with leguminous plants (pulses) by living in the root nodules of these plants. Within the root nodules, Rhizobium converts atmospheric nitrogen into ammonia through the process of nitrogen fixation. This ammonia is then used by the host plant for its growth and development.
Question 143: How does nitrogen fixation benefit leguminous plants?
Answer: Nitrogen fixation benefits leguminous plants by providing them with a readily available source of nitrogen in the form of ammonia. This nitrogen is essential for the synthesis of proteins and other vital compounds necessary for plant growth, allowing leguminous plants to thrive even in nitrogen-deficient soils.
Question 144: Besides the bacterium Rhizobium, how else can nitrogen fixation occur?
Answer: Nitrogen fixation can also occur through non-biological processes, such as the action of lightning. Lightning can convert atmospheric nitrogen into reactive nitrogen species, which can then combine with other elements to form nitrogen compounds that are accessible to plants.
Question 145: Despite the process of nitrogen fixation, why does the amount of nitrogen in the atmosphere remain constant?
Answer: The amount of nitrogen in the atmosphere remains constant because nitrogen fixation is balanced by other processes, such as denitrification and nitrogen loss through leaching and runoff. Additionally, nitrogen fixation by Rhizobium and other organisms, as well as abiotic processes like lightning, contribute to maintaining the equilibrium of nitrogen in the atmosphere.
Question 146: What is the significance of nitrogen for living organisms?
Answer: Nitrogen is essential for all living organisms as it is a constituent of proteins, chlorophyll, nucleic acids, and vitamins. These compounds are vital for various biological processes, including growth, development, and reproduction.
Question 147: Why can’t plants and animals directly utilize atmospheric nitrogen?
Answer: Plants and animals cannot directly utilize atmospheric nitrogen (N2) because it is in a stable and inert form that cannot be assimilated by most organisms. Atmospheric nitrogen must be converted into usable compounds, such as ammonia (NH3) or nitrates (NO3-), before it can be utilized by plants and animals.
Question 150: How do certain bacteria and blue-green algae contribute to the nitrogen cycle?
Answer: Certain bacteria and blue-green algae present in the soil fix atmospheric nitrogen by converting it into compounds of nitrogen, such as ammonia and nitrates. This process, known as nitrogen fixation, makes atmospheric nitrogen accessible to plants and other organisms, thus contributing to the nitrogen cycle.
Question 151: Describe how nitrogen from the soil is utilized by plants.
Answer: Plants absorb nitrogen from the soil through their root systems in the form of nitrates, nitrites, or ammonium ions. Once absorbed, nitrogen is utilized by plants for the synthesis of proteins, enzymes, chlorophyll, and other essential compounds necessary for growth and development.
Question 152: How do animals obtain nitrogen for their nutritional needs?
Answer: Animals obtain nitrogen for their nutritional needs by consuming plants or other organisms that have assimilated nitrogen from the soil. Proteins and other nitrogen-containing compounds obtained from plant-based or animal-based food sources provide animals with the nitrogen necessary for their growth, metabolism, and cellular functions.
Question 153: How do bacteria and fungi contribute to the recycling of nitrogen from dead plants and animals?
Answer: Bacteria and fungi present in the soil play a crucial role in the recycling of nitrogen from dead plants and animals. They decompose the nitrogenous wastes of these organisms and convert them into nitrogenous compounds, such as ammonia, nitrites, and nitrates, which can be utilized by plants for growth and development.
Question 154: What happens to nitrogenous compounds produced from the decomposition of dead plants and animals?
Answer: The nitrogenous compounds produced from the decomposition of dead plants and animals can be utilized by plants for their growth and development. However, some of these compounds may also be converted back into nitrogen gas by certain bacteria. This nitrogen gas returns to the atmosphere, contributing to the maintenance of the nitrogen cycle.
Question 155: How does the recycling of nitrogen contribute to the maintenance of nitrogen levels in the atmosphere?
Answer: The recycling of nitrogen through decomposition and nitrogen fixation helps maintain the balance of nitrogen levels in the atmosphere. While some nitrogenous compounds are utilized by plants, others are converted back into nitrogen gas by bacteria. This process ensures that the percentage of nitrogen in the atmosphere remains relatively constant over time.
Question 156: Why is it important for nitrogen levels in the atmosphere to remain constant?
Answer: It is important for nitrogen levels in the atmosphere to remain constant because nitrogen is an essential element for living organisms. Maintaining a stable concentration of atmospheric nitrogen ensures that plants have an adequate supply of nitrogen for growth and development, which in turn supports ecosystems and food webs.
Question 157: What role do bacteria play in the conversion of nitrogenous compounds to nitrogen gas?
Answer: Certain bacteria possess the ability to carry out denitrification, a process in which they convert nitrogenous compounds, such as nitrates, into nitrogen gas (N2). This process releases nitrogen gas back into the atmosphere, completing the nitrogen cycle and contributing to the maintenance of nitrogen levels in the environment.