Take Class 8 Tuition from the Best Tutors
Search in
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
Viruses are tiny infectious agents that are smaller than bacteria and consist of genetic material (either DNA or RNA) surrounded by a protein coat called a capsid. They cannot replicate or carry out metabolic functions on their own and rely on infecting host cells to reproduce. Once inside a host cell, a virus hijacks the cell's machinery to replicate itself, often causing harm to the host cell in the process.
Some common diseases in humans caused by viruses include:
Influenza (Flu): Influenza viruses cause seasonal flu outbreaks, leading to symptoms such as fever, cough, sore throat, muscle aches, fatigue, and respiratory issues. There are several strains of influenza viruses, including influenza A, B, and C.
Common Cold: The common cold is caused by various viruses, including rhinoviruses, coronaviruses, and adenoviruses. It results in symptoms such as a runny or stuffy nose, sneezing, sore throat, cough, and mild fatigue.
Human Immunodeficiency Virus (HIV/AIDS): HIV is a retrovirus that attacks the immune system, specifically targeting CD4 T cells. If left untreated, HIV can lead to acquired immunodeficiency syndrome (AIDS), a condition characterized by a weakened immune system and an increased susceptibility to opportunistic infections and cancers.
Herpes Simplex Virus (HSV): HSV is a common virus that causes mouth herpes (cold sores) and genital herpes. It can lead to painful blisters or sores on the lips, mouth, genitals, or other areas of the body.
Human Papillomavirus (HPV): HPV is a sexually transmitted virus that can cause genital warts and various types of cancers, including cervical, and oropharyngeal cancers.
Varicella-Zoster Virus (VZV): VZV is responsible for causing chickenpox during childhood and can later reactivate to cause shingles (herpes zoster) in adulthood.
Hepatitis Viruses: Several viruses, including hepatitis A, B, C, D, and E viruses, can cause inflammation of the liver (hepatitis), leading to symptoms such as fatigue, jaundice, abdominal pain, and liver damage.
Ebola Virus: Ebola virus disease (EVD) is a severe and often fatal illness in humans. It is characterized by symptoms such as fever, severe headache, muscle pain, weakness, diarrhea, vomiting, and internal and external bleeding.
These are just a few examples of the many diseases caused by viruses in humans. Vaccination, antiviral medications, and other preventive measures are often used to manage and prevent viral infections.
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
The formation of curd from milk involves a process called "fermentation," which is primarily driven by the action of bacteria known as lactic acid bacteria. The key steps in this process are:
Inoculation: To initiate the fermentation process, a small amount of a starter culture containing lactic acid bacteria is added to the milk. Common strains of bacteria used for this purpose include Lactobacillus bulgaricus and Streptococcus thermophilus.
Incubation: After inoculation, the milk is left to incubate at a slightly elevated temperature, typically around 40-45°C (104-113°F). This warm environment provides optimal conditions for the growth and activity of the lactic acid bacteria.
Fermentation: As the lactic acid bacteria grow and multiply in the milk, they begin to ferment lactose, the natural sugar present in milk. During fermentation, the bacteria produce lactic acid as a byproduct of metabolism. This lactic acid causes the pH of the milk to decrease, leading to the coagulation of milk proteins, primarily casein.
Coagulation: The decrease in pH caused by the accumulation of lactic acid destabilizes the casein proteins in the milk, causing them to aggregate and form a gel-like structure. This process is what we observe as the milk transforming into curd or yogurt.
Maturation: After the curd has formed, it is typically allowed to undergo further maturation for a period of time, which can vary depending on the desired texture and flavor. During this maturation period, additional metabolic processes may occur, contributing to the development of characteristic flavors and textures in the curd.
The end result of this process is the transformation of liquid milk into a semi-solid curd with a tangy flavor and creamy texture. Curd is a nutritious dairy product rich in protein, calcium, and beneficial bacteria, making it a popular food choice in many cultures around the world.
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
Bacteria play numerous beneficial roles in various ecosystems and are essential for the functioning of many biological processes. Some of the beneficial effects of bacteria include:
Nutrient Recycling: Bacteria are critical for decomposing organic matter and recycling nutrients in ecosystems. They break down complex organic molecules into simpler forms that can be used by plants and other organisms, contributing to the cycling of carbon, nitrogen, and other essential elements.
Nitrogen Fixation: Certain bacteria, such as Rhizobium and Azotobacter, have the ability to convert atmospheric nitrogen into a form that plants can use. This process, known as nitrogen fixation, is crucial for supplying nitrogen to plants and maintaining soil fertility.
Food Production: Bacteria are used in various food production processes, including fermentation, cheese making, yogurt production, and pickling. They contribute to the development of flavor, texture, and preservation of food products, making them safe and nutritious for consumption.
Bioremediation: Some bacteria have the ability to break down or detoxify pollutants in the environment, a process known as bioremediation. These bacteria can degrade contaminants such as oil spills, pesticides, and industrial chemicals, helping to clean up contaminated sites and restore environmental quality.
Symbiotic Relationships: Bacteria form symbiotic relationships with plants and animals, providing benefits such as nutrient acquisition, protection against pathogens, and enhancement of immune function. For example, bacteria in the human gut microbiota help in digestion, vitamin synthesis, and regulation of immune responses.
Medical Applications: Bacteria have numerous medical applications, including the production of antibiotics, vaccines, and other pharmaceuticals. They are also used in genetic engineering techniques, such as recombinant DNA technology, to produce insulin, growth hormones, and other therapeutic proteins.
Soil Health: Bacteria play a vital role in maintaining soil health and fertility. They contribute to soil structure, nutrient cycling, and plant growth by decomposing organic matter, fixing nitrogen, and suppressing harmful pathogens.
Overall, bacteria are incredibly diverse and versatile organisms that perform essential functions in ecosystems, agriculture, industry, and medicine, making them invaluable to life on Earth.
Take Class 8 Tuition from the Best Tutors
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
The discovery of penicillin is attributed to Scottish bacteriologist Alexander Fleming in 1928. The discovery occurred serendipitously while Fleming was conducting experiments at St. Mary's Hospital in London, England.
Here's an overview of the discovery of penicillin:
Contamination of Petri dishes: Fleming was studying the bacteria Staphylococcus aureus in Petri dishes when he noticed that one of the dishes had become contaminated with mold. This mold was later identified as a strain of Penicillium notatum.
Observation of antibacterial properties: Upon closer examination, Fleming observed that the area around the mold on the Petri dish was free of bacterial growth. He noted that the mold appeared to produce a substance that inhibited the growth of bacteria.
Isolation of penicillin: Fleming conducted further experiments to isolate and characterize the antibacterial substance produced by the mold. He named this substance "penicillin" after the Penicillium mold from which it was derived.
Initial trials: Fleming conducted preliminary trials to test the effectiveness of penicillin in treating bacterial infections in animals. He found that penicillin was effective in treating various bacterial infections, including staphylococcal and streptococcal infections.
Limited production: Despite the promising results of his experiments, Fleming encountered challenges in producing penicillin in large quantities. The yield of penicillin from the Penicillium mold was low, and it was difficult to purify the substance for use in clinical applications.
Further development: The development of penicillin as a therapeutic agent was further pursued by other scientists, notably Howard Florey and Ernst Chain at the University of Oxford. They conducted extensive research to optimize penicillin production and conducted clinical trials to demonstrate its efficacy in treating bacterial infections.
Mass production and clinical use: With the onset of World War II, the need for effective antibiotics became urgent, leading to concerted efforts to mass-produce penicillin. By the early 1940s, penicillin was being produced on a large scale and was widely used to treat wounded soldiers during the war. Its success revolutionized the treatment of bacterial infections and ushered in the era of antibiotics.
The discovery of penicillin by Alexander Fleming marked a significant milestone in the history of medicine, leading to the development of antibiotics that have saved countless lives and transformed the treatment of infectious diseases.
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
Microorganisms can spoil food through various mechanisms, primarily by breaking down organic matter and producing harmful byproducts. The most common types of microorganisms involved in food spoilage include bacteria, molds, and yeast. Here's how these microorganisms spoil food:
Bacteria:
Molds:
Yeast:
Factors that contribute to microbial food spoilage include temperature, moisture content, pH, oxygen availability, and packaging conditions. To prevent food spoilage, it's essential to store food properly, maintain good hygiene practices, control temperature and humidity levels, and minimize exposure to contaminants. Additionally, preserving methods such as refrigeration, freezing, canning, drying, and pickling can help extend the shelf life of food and inhibit microbial growth.
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
Carriers of disease-causing microbes are individuals who harbor pathogens in their bodies and can transmit these pathogens to others without necessarily showing symptoms of the disease themselves. Carriers play a significant role in the spread of infectious diseases. Here are two examples of carriers of disease-causing microbes:
Asymptomatic Carriers: Some individuals can carry pathogenic microorganisms without exhibiting any symptoms of the associated disease. These asymptomatic carriers may unknowingly spread the pathogen to others through various means, such as direct contact, respiratory droplets, or contaminated surfaces. For example:
Convalescent Carriers: Convalescent carriers are individuals who have recovered from an infectious disease but continue to carry and shed the pathogen for an extended period after their symptoms have resolved. These individuals may no longer be contagious to the same extent as during the acute phase of the illness, but they can still transmit the pathogen to others. For example:
In both examples, carriers of disease-causing microbes can serve as sources of infection and contribute to the transmission of infectious diseases in communities. Identifying and managing carriers is crucial for controlling the spread of pathogens and preventing outbreaks of infectious diseases.
Take Class 8 Tuition from the Best Tutors
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
The nitrogen cycle is a biogeochemical process that describes the movement and transformation of nitrogen in various forms within ecosystems. Nitrogen is an essential element for the growth and survival of living organisms, as it is a component of proteins, nucleic acids, and other biomolecules. The nitrogen cycle involves several key processes, including nitrogen fixation, nitrification, denitrification, and ammonification. Here's an overview of the nitrogen cycle:
Nitrogen Fixation: Nitrogen fixation is the process by which atmospheric nitrogen gas (N2) is converted into a form that can be utilized by plants and other organisms. This conversion is primarily carried out by nitrogen-fixing bacteria, such as Rhizobium species in the roots of leguminous plants (e.g., peas, beans) and cyanobacteria in soil and aquatic environments. These bacteria possess the enzyme nitrogenase, which allows them to convert N2 gas into ammonia (NH3) or ammonium ions (NH4+), which can be assimilated by plants.
Ammonification: Ammonification is the process by which organic nitrogen compounds, such as proteins and nucleic acids from dead plant and animal matter, are broken down into ammonia (NH3) or ammonium ions (NH4+) by decomposer organisms, such as bacteria and fungi. These organisms release ammonia as a byproduct of their metabolic processes, making it available for uptake by plants in the soil.
Nitrification: Nitrification is a two-step process in which ammonia (NH3) or ammonium ions (NH4+) are converted into nitrite (NO2-) and then into nitrate (NO3-) by nitrifying bacteria. The first step is carried out by ammonia-oxidizing bacteria, such as Nitrosomonas species, which oxidize ammonia to nitrite. The second step is performed by nitrite-oxidizing bacteria, such as Nitrobacter species, which oxidize nitrite to nitrate. Nitrate is the primary form of nitrogen taken up by plants for growth and is also susceptible to leaching into groundwater.
Assimilation: Plants and other organisms assimilate nitrogen from the soil in the form of nitrate (NO3-) or ammonium ions (NH4+) to synthesize proteins, nucleic acids, and other nitrogen-containing compounds essential for growth and development.
Denitrification: Denitrification is the process by which nitrate (NO3-) is converted back into atmospheric nitrogen gas (N2) by denitrifying bacteria under anaerobic conditions. These bacteria reduce nitrate to nitrite (NO2-), nitric oxide (NO), nitrous oxide (N2O), and eventually to nitrogen gas (N2), which is released back into the atmosphere. Denitrification helps to balance the nitrogen cycle and prevent the accumulation of excess nitrogen in ecosystems
Atmospheric N2 (nitrogen gas) --> Nitrogen Fixation --> Ammonia (NH3) / Ammonium ions (NH4+)
|
v
Ammonification
|
v
Nitrification
|
v
Assimilation
|
v
Denitrification
|
v
Atmospheric N2 (nitrogen gas)
This diagram illustrates the flow of nitrogen through different forms and processes within the nitrogen cycle, demonstrating the interconnectedness of nitrogen in terrestrial and aquatic ecosystems.
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
Here are some common plant diseases along with their causative microorganisms and modes of transmission:
These are just a few examples of common plant diseases and their causative microorganisms, along with their modes of transmission. Effective management and control strategies, such as crop rotation, sanitation, and the use of resistant plant varieties or fungicides, are essential for minimizing the impact of these diseases on agricultural crops.
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
Bacteria, fungi, and algae are diverse groups of microorganisms that play important roles in various aspects of human life and the environment. Here are some of their key uses:
Bacteria:
Fungi:
Algae:
Overall, bacteria, fungi, and algae have diverse uses in agriculture, industry, medicine, and environmental management, highlighting their importance in human society and ecosystem functioning.
Take Class 8 Tuition from the Best Tutors
Answered on 21 Feb Learn Microorganisms: Friends or Foe
Sadika
Food preservatives are substances added to food products to prevent spoilage, extend shelf life, and maintain their quality, flavor, and safety. They inhibit the growth of microorganisms (such as bacteria, molds, and yeasts) and oxidative processes that can lead to food deterioration. Here are some common food preservatives along with brief explanations:
Salt (Sodium Chloride): Salt is one of the oldest and most commonly used food preservatives. It works by drawing moisture out of food, creating an environment where microorganisms cannot thrive. Salt is particularly effective in preserving meats, fish, and some vegetables.
Sugar: Sugar, in the form of sucrose, glucose, or fructose, acts as a preservative by reducing water activity in food, thereby inhibiting microbial growth. It is commonly used in jams, jellies, syrups, and other sweetened products to extend their shelf life.
Acetic Acid (Vinegar): Acetic acid, found in vinegar, is an organic acid that inhibits the growth of bacteria and molds. It is commonly used as a preservative in pickled vegetables, salad dressings, and condiments.
Ascorbic Acid (Vitamin C): Ascorbic acid is a natural antioxidant that helps prevent oxidative reactions, such as enzymatic browning and rancidity, in fruits and vegetables. It is often used as a preservative in processed fruits, fruit juices, and canned foods.
Sulfur Dioxide and Sulfites: Sulfur dioxide (SO2) and sulfites (such as sodium sulfite and sodium metabisulfite) are commonly used as preservatives in dried fruits, wine, and other foods. They inhibit microbial growth, prevent enzymatic browning, and act as antioxidants to maintain color and flavor.
Nitrites and Nitrates: Nitrites (such as sodium nitrite) and nitrates (such as potassium nitrate) are commonly used as preservatives in cured meats, such as bacon, ham, and hot dogs. They inhibit the growth of bacteria, particularly Clostridium botulinum, and impart a characteristic pink color and flavor to cured meats.
Sorbic Acid and Sorbates: Sorbic acid and sorbates (such as potassium sorbate and calcium sorbate) are synthetic preservatives commonly used in bakery products, cheese, and beverages. They inhibit the growth of molds and yeasts, extending the shelf life of these products.
Benzoic Acid and Benzoates: Benzoic acid and benzoates (such as sodium benzoate and potassium benzoate) are synthetic preservatives commonly used in acidic foods and beverages, such as soft drinks, fruit juices, and pickles. They inhibit the growth of bacteria, molds, and yeasts.
These are just a few examples of common food preservatives used to prevent spoilage and maintain the quality and safety of food products. It's important to note that while food preservatives can be effective in extending shelf life, their use should be regulated and their safety carefully evaluated to ensure they do not pose health risks to consumers.
UrbanPro.com helps you to connect with the best Class 8 Tuition in India. Post Your Requirement today and get connected.
Ask a Question
The best tutors for Class 8 Tuition Classes are on UrbanPro
The best Tutors for Class 8 Tuition Classes are on UrbanPro