A person trapped in a swamp is advised to lie down because as the area increases, the pressure decreases (A). When lying down, the person's weight is distributed over a larger surface area, reducing the pressure exerted on the swamp's surface. Option (A) accurately explains the reason behind this adRead more
A person trapped in a swamp is advised to lie down because as the area increases, the pressure decreases (A). When lying down, the person’s weight is distributed over a larger surface area, reducing the pressure exerted on the swamp’s surface. Option (A) accurately explains the reason behind this advice. Options (B) and (C) are incorrect as they do not reflect the relationship between pressure and area accurately. Option (D) is also incorrect as it suggests that all options are valid, which is not the case. Therefore, option (A) provides the most appropriate explanation for why a person trapped in a swamp should lie down, as it describes the physical principle of pressure distribution and its effect on sinking in soft surfaces like swamps.
Milk becomes sour primarily due to the action of bacteria. Specifically, lactic acid bacteria such as Lactobacillus and Streptococcus ferment the lactose (milk sugar) present in the milk, converting it into lactic acid. This acidification changes the pH of the milk, leading to the sour taste and cauRead more
Milk becomes sour primarily due to the action of bacteria. Specifically, lactic acid bacteria such as Lactobacillus and Streptococcus ferment the lactose (milk sugar) present in the milk, converting it into lactic acid. This acidification changes the pH of the milk, leading to the sour taste and causing the proteins in the milk to coagulate, forming curds. These bacteria are naturally present in milk and other dairy products, and their activity is essential in the production of sour milk, yogurt, and cheese. The fermentation process not only changes the flavor and texture of the milk but also increases its shelf life by inhibiting the growth of spoilage organisms. While bacteria are the primary agents of milk souring, the other options, such as protozoa, viruses, and nematodes, do not play a significant role in this process.
Lactobacillus is the microorganism that plays a crucial role in the process of making curd. When added to milk, it begins a fermentation process where it converts lactose, the natural sugar in milk, into lactic acid. This change in the milk's composition leads to the thickening of the milk and the fRead more
Lactobacillus is the microorganism that plays a crucial role in the process of making curd. When added to milk, it begins a fermentation process where it converts lactose, the natural sugar in milk, into lactic acid. This change in the milk’s composition leads to the thickening of the milk and the formation of curd. The lactic acid also gives curd its distinct sour taste, which many people find appealing. This bacterium is naturally found in milk and dairy products, so it serves as an effective starter culture for curd production. Aside from its role in curd making, Lactobacillus also contributes to the health benefits of curd, as it is known to be beneficial for gut health and digestion. The process is simple and has been practiced for centuries, making curd a staple food in many cultures.
Refrigeration helps in food preservation by reducing the rate of biochemical reactions. By lowering the temperature, refrigeration slows down the growth and activity of bacteria and other microorganisms that can cause spoilage and foodborne illnesses. This method also slows down the rate of enzyme aRead more
Refrigeration helps in food preservation by reducing the rate of biochemical reactions. By lowering the temperature, refrigeration slows down the growth and activity of bacteria and other microorganisms that can cause spoilage and foodborne illnesses. This method also slows down the rate of enzyme activity in foods, which can affect flavor, texture, and overall quality. By keeping the food at a lower temperature, refrigeration helps maintain freshness and extend shelf life. While refrigeration does not necessarily kill bacteria, it inhibits their reproduction, allowing food to be safely stored for a longer period. Additionally, refrigeration can help prevent the growth of mold and yeast on perishable items. Properly storing food in the refrigerator is an effective way to preserve its nutritional value and prevent waste.
Azotobacter is a free-living bacterium that increases the yield of paddy in the soil. It is known for its ability to fix atmospheric nitrogen into ammonia, which enriches the soil and provides a valuable nutrient source for paddy plants. This process helps to improve soil fertility and enhances cropRead more
Azotobacter is a free-living bacterium that increases the yield of paddy in the soil. It is known for its ability to fix atmospheric nitrogen into ammonia, which enriches the soil and provides a valuable nutrient source for paddy plants. This process helps to improve soil fertility and enhances crop growth and yield. Unlike Rhizobium, which forms symbiotic relationships with legumes, Azotobacter does not require a plant host and can thrive independently in the soil. Acetobacter is known for its role in the production of acetic acid and is not directly related to paddy cultivation. Anabaena is a genus of cyanobacteria that can also fix nitrogen but is more commonly associated with aquatic environments rather than soil. Therefore, Azotobacter is the most effective free-living bacteria for increasing paddy yield in soil.
Tuberculosis is caused by bacteria. Specifically, it is caused by the bacterium Mycobacterium tuberculosis. This disease primarily affects the lungs but can also impact other parts of the body. Symptoms of tuberculosis include a persistent cough, chest pain, fever, and night sweats. The disease is tRead more
Tuberculosis is caused by bacteria. Specifically, it is caused by the bacterium Mycobacterium tuberculosis. This disease primarily affects the lungs but can also impact other parts of the body. Symptoms of tuberculosis include a persistent cough, chest pain, fever, and night sweats. The disease is transmitted through the air when an infected person coughs or sneezes. Early diagnosis and appropriate antibiotic treatment are crucial for managing tuberculosis and preventing its spread. Jaundice is a symptom rather than a disease and can result from various underlying conditions, including liver disease. Smallpox is caused by the variola virus, and mumps is caused by the mumps virus. Both of these viral diseases have largely been controlled through vaccination programs. Therefore, of the options provided, only tuberculosis is caused by bacteria.
Leghemoglobin plays a crucial role in nitrogen fixation by absorbing oxygen. It is a protein found in the root nodules of leguminous plants that forms a complex with oxygen, similar to the function of hemoglobin in animal blood. By absorbing oxygen, leghemoglobin maintains a low-oxygen environment iRead more
Leghemoglobin plays a crucial role in nitrogen fixation by absorbing oxygen. It is a protein found in the root nodules of leguminous plants that forms a complex with oxygen, similar to the function of hemoglobin in animal blood. By absorbing oxygen, leghemoglobin maintains a low-oxygen environment in the root nodules, which is essential for the nitrogen-fixing enzyme nitrogenase to function effectively. Nitrogenase is sensitive to oxygen and cannot operate efficiently in its presence. By keeping oxygen levels low, leghemoglobin ensures that nitrogenase can fix atmospheric nitrogen into ammonia, which the plant uses for growth. This process is vital for the plant’s nutrition and contributes to soil fertility. Additionally, the presence of leghemoglobin gives the root nodules a red or pink color, indicating active nitrogen fixation.
Beans are helpful in nitrogen fixation. They belong to the legume family, which forms a symbiotic relationship with nitrogen-fixing bacteria such as Rhizobium in their root nodules. These bacteria convert atmospheric nitrogen into ammonia, a form of nitrogen that the plant can use for growth. This pRead more
Beans are helpful in nitrogen fixation. They belong to the legume family, which forms a symbiotic relationship with nitrogen-fixing bacteria such as Rhizobium in their root nodules. These bacteria convert atmospheric nitrogen into ammonia, a form of nitrogen that the plant can use for growth. This process enriches the soil with nitrogen, benefiting both the legume crop and subsequent crops grown in the same soil. By improving soil fertility, beans play a vital role in sustainable agriculture and crop rotation practices. The ability of beans to fix nitrogen reduces the need for synthetic nitrogen fertilizers, promoting more environmentally friendly farming methods. In contrast, rice, wheat, and corn do not have the same nitrogen-fixing abilities as beans. Therefore, beans are an excellent choice for enhancing soil health and supporting agricultural productivity.
If one bacterial cell divides every 20 minutes, then in two hours (which is equal to 120 minutes), it will divide a total of six times. This is calculated by dividing the total time (120 minutes) by the time it takes for one division (20 minutes): 120 / 20 = 6 divisions. Each division doubles the nuRead more
If one bacterial cell divides every 20 minutes, then in two hours (which is equal to 120 minutes), it will divide a total of six times. This is calculated by dividing the total time (120 minutes) by the time it takes for one division (20 minutes): 120 / 20 = 6 divisions.
Each division doubles the number of bacteria. Starting with one bacterial cell, the first division produces two cells, the second division produces four cells, the third division produces eight cells, the fourth division produces sixteen cells, the fifth division produces thirty-two cells, and the sixth division produces sixty-four cells.
Therefore, in two hours, one bacterial cell will form 64 bacteria. The correct answer is [D] 64.
Antibiotics are mostly obtained from bacteria and fungi. These microorganisms naturally produce antibiotics as a defense mechanism against other microbes. From bacteria, a variety of antibiotics like streptomycin, tetracycline, and erythromycin are derived. Similarly, fungi, such as Penicillium, proRead more
Antibiotics are mostly obtained from bacteria and fungi. These microorganisms naturally produce antibiotics as a defense mechanism against other microbes. From bacteria, a variety of antibiotics like streptomycin, tetracycline, and erythromycin are derived. Similarly, fungi, such as Penicillium, produce penicillin, one of the first and most widely used antibiotics. Antibiotics from these sources have been instrumental in treating various bacterial infections in humans and animals. Research and development in microbiology have led to the discovery of many antibiotics that have revolutionized medicine and increased life expectancy. While most antibiotics come from bacteria and fungi, some plant-derived compounds also exhibit antimicrobial properties, but they are less common in mainstream antibiotic use. The continuous search for new antibiotics from natural sources remains crucial in combating antibiotic-resistant bacteria and emerging infectious diseases.
A person trapped in a swamp is advised to lie down because
A person trapped in a swamp is advised to lie down because as the area increases, the pressure decreases (A). When lying down, the person's weight is distributed over a larger surface area, reducing the pressure exerted on the swamp's surface. Option (A) accurately explains the reason behind this adRead more
A person trapped in a swamp is advised to lie down because as the area increases, the pressure decreases (A). When lying down, the person’s weight is distributed over a larger surface area, reducing the pressure exerted on the swamp’s surface. Option (A) accurately explains the reason behind this advice. Options (B) and (C) are incorrect as they do not reflect the relationship between pressure and area accurately. Option (D) is also incorrect as it suggests that all options are valid, which is not the case. Therefore, option (A) provides the most appropriate explanation for why a person trapped in a swamp should lie down, as it describes the physical principle of pressure distribution and its effect on sinking in soft surfaces like swamps.
See lessBy which of the following milk becomes sour?
Milk becomes sour primarily due to the action of bacteria. Specifically, lactic acid bacteria such as Lactobacillus and Streptococcus ferment the lactose (milk sugar) present in the milk, converting it into lactic acid. This acidification changes the pH of the milk, leading to the sour taste and cauRead more
Milk becomes sour primarily due to the action of bacteria. Specifically, lactic acid bacteria such as Lactobacillus and Streptococcus ferment the lactose (milk sugar) present in the milk, converting it into lactic acid. This acidification changes the pH of the milk, leading to the sour taste and causing the proteins in the milk to coagulate, forming curds. These bacteria are naturally present in milk and other dairy products, and their activity is essential in the production of sour milk, yogurt, and cheese. The fermentation process not only changes the flavor and texture of the milk but also increases its shelf life by inhibiting the growth of spoilage organisms. While bacteria are the primary agents of milk souring, the other options, such as protozoa, viruses, and nematodes, do not play a significant role in this process.
See lessWhich of the following microorganisms is used in making curd?
Lactobacillus is the microorganism that plays a crucial role in the process of making curd. When added to milk, it begins a fermentation process where it converts lactose, the natural sugar in milk, into lactic acid. This change in the milk's composition leads to the thickening of the milk and the fRead more
Lactobacillus is the microorganism that plays a crucial role in the process of making curd. When added to milk, it begins a fermentation process where it converts lactose, the natural sugar in milk, into lactic acid. This change in the milk’s composition leads to the thickening of the milk and the formation of curd. The lactic acid also gives curd its distinct sour taste, which many people find appealing. This bacterium is naturally found in milk and dairy products, so it serves as an effective starter culture for curd production. Aside from its role in curd making, Lactobacillus also contributes to the health benefits of curd, as it is known to be beneficial for gut health and digestion. The process is simple and has been practiced for centuries, making curd a staple food in many cultures.
See lessRefrigeration helps in food preservation by
Refrigeration helps in food preservation by reducing the rate of biochemical reactions. By lowering the temperature, refrigeration slows down the growth and activity of bacteria and other microorganisms that can cause spoilage and foodborne illnesses. This method also slows down the rate of enzyme aRead more
Refrigeration helps in food preservation by reducing the rate of biochemical reactions. By lowering the temperature, refrigeration slows down the growth and activity of bacteria and other microorganisms that can cause spoilage and foodborne illnesses. This method also slows down the rate of enzyme activity in foods, which can affect flavor, texture, and overall quality. By keeping the food at a lower temperature, refrigeration helps maintain freshness and extend shelf life. While refrigeration does not necessarily kill bacteria, it inhibits their reproduction, allowing food to be safely stored for a longer period. Additionally, refrigeration can help prevent the growth of mold and yeast on perishable items. Properly storing food in the refrigerator is an effective way to preserve its nutritional value and prevent waste.
See lessWhich is the free-living bacteria that increases the yield of paddy in the soil?
Azotobacter is a free-living bacterium that increases the yield of paddy in the soil. It is known for its ability to fix atmospheric nitrogen into ammonia, which enriches the soil and provides a valuable nutrient source for paddy plants. This process helps to improve soil fertility and enhances cropRead more
Azotobacter is a free-living bacterium that increases the yield of paddy in the soil. It is known for its ability to fix atmospheric nitrogen into ammonia, which enriches the soil and provides a valuable nutrient source for paddy plants. This process helps to improve soil fertility and enhances crop growth and yield. Unlike Rhizobium, which forms symbiotic relationships with legumes, Azotobacter does not require a plant host and can thrive independently in the soil. Acetobacter is known for its role in the production of acetic acid and is not directly related to paddy cultivation. Anabaena is a genus of cyanobacteria that can also fix nitrogen but is more commonly associated with aquatic environments rather than soil. Therefore, Azotobacter is the most effective free-living bacteria for increasing paddy yield in soil.
See lessWhich of the following diseases is caused by bacteria?
Tuberculosis is caused by bacteria. Specifically, it is caused by the bacterium Mycobacterium tuberculosis. This disease primarily affects the lungs but can also impact other parts of the body. Symptoms of tuberculosis include a persistent cough, chest pain, fever, and night sweats. The disease is tRead more
Tuberculosis is caused by bacteria. Specifically, it is caused by the bacterium Mycobacterium tuberculosis. This disease primarily affects the lungs but can also impact other parts of the body. Symptoms of tuberculosis include a persistent cough, chest pain, fever, and night sweats. The disease is transmitted through the air when an infected person coughs or sneezes. Early diagnosis and appropriate antibiotic treatment are crucial for managing tuberculosis and preventing its spread. Jaundice is a symptom rather than a disease and can result from various underlying conditions, including liver disease. Smallpox is caused by the variola virus, and mumps is caused by the mumps virus. Both of these viral diseases have largely been controlled through vaccination programs. Therefore, of the options provided, only tuberculosis is caused by bacteria.
See lessWhat is the function of Leghemoglobin in nitrogen fixation?
Leghemoglobin plays a crucial role in nitrogen fixation by absorbing oxygen. It is a protein found in the root nodules of leguminous plants that forms a complex with oxygen, similar to the function of hemoglobin in animal blood. By absorbing oxygen, leghemoglobin maintains a low-oxygen environment iRead more
Leghemoglobin plays a crucial role in nitrogen fixation by absorbing oxygen. It is a protein found in the root nodules of leguminous plants that forms a complex with oxygen, similar to the function of hemoglobin in animal blood. By absorbing oxygen, leghemoglobin maintains a low-oxygen environment in the root nodules, which is essential for the nitrogen-fixing enzyme nitrogenase to function effectively. Nitrogenase is sensitive to oxygen and cannot operate efficiently in its presence. By keeping oxygen levels low, leghemoglobin ensures that nitrogenase can fix atmospheric nitrogen into ammonia, which the plant uses for growth. This process is vital for the plant’s nutrition and contributes to soil fertility. Additionally, the presence of leghemoglobin gives the root nodules a red or pink color, indicating active nitrogen fixation.
See lessWhich of the following crops is helpful in nitrogen fixation?
Beans are helpful in nitrogen fixation. They belong to the legume family, which forms a symbiotic relationship with nitrogen-fixing bacteria such as Rhizobium in their root nodules. These bacteria convert atmospheric nitrogen into ammonia, a form of nitrogen that the plant can use for growth. This pRead more
Beans are helpful in nitrogen fixation. They belong to the legume family, which forms a symbiotic relationship with nitrogen-fixing bacteria such as Rhizobium in their root nodules. These bacteria convert atmospheric nitrogen into ammonia, a form of nitrogen that the plant can use for growth. This process enriches the soil with nitrogen, benefiting both the legume crop and subsequent crops grown in the same soil. By improving soil fertility, beans play a vital role in sustainable agriculture and crop rotation practices. The ability of beans to fix nitrogen reduces the need for synthetic nitrogen fertilizers, promoting more environmentally friendly farming methods. In contrast, rice, wheat, and corn do not have the same nitrogen-fixing abilities as beans. Therefore, beans are an excellent choice for enhancing soil health and supporting agricultural productivity.
See lessIf one bacterial cell divides every 20 minutes, then how many bacteria will be formed from the bacteria in two hours?
If one bacterial cell divides every 20 minutes, then in two hours (which is equal to 120 minutes), it will divide a total of six times. This is calculated by dividing the total time (120 minutes) by the time it takes for one division (20 minutes): 120 / 20 = 6 divisions. Each division doubles the nuRead more
If one bacterial cell divides every 20 minutes, then in two hours (which is equal to 120 minutes), it will divide a total of six times. This is calculated by dividing the total time (120 minutes) by the time it takes for one division (20 minutes): 120 / 20 = 6 divisions.
Each division doubles the number of bacteria. Starting with one bacterial cell, the first division produces two cells, the second division produces four cells, the third division produces eight cells, the fourth division produces sixteen cells, the fifth division produces thirty-two cells, and the sixth division produces sixty-four cells.
Therefore, in two hours, one bacterial cell will form 64 bacteria. The correct answer is [D] 64.
See lessAntibiotics are mostly obtained from
Antibiotics are mostly obtained from bacteria and fungi. These microorganisms naturally produce antibiotics as a defense mechanism against other microbes. From bacteria, a variety of antibiotics like streptomycin, tetracycline, and erythromycin are derived. Similarly, fungi, such as Penicillium, proRead more
Antibiotics are mostly obtained from bacteria and fungi. These microorganisms naturally produce antibiotics as a defense mechanism against other microbes. From bacteria, a variety of antibiotics like streptomycin, tetracycline, and erythromycin are derived. Similarly, fungi, such as Penicillium, produce penicillin, one of the first and most widely used antibiotics. Antibiotics from these sources have been instrumental in treating various bacterial infections in humans and animals. Research and development in microbiology have led to the discovery of many antibiotics that have revolutionized medicine and increased life expectancy. While most antibiotics come from bacteria and fungi, some plant-derived compounds also exhibit antimicrobial properties, but they are less common in mainstream antibiotic use. The continuous search for new antibiotics from natural sources remains crucial in combating antibiotic-resistant bacteria and emerging infectious diseases.
See less