Last updated on June 28th, 2023 at 11:09 pm
Q: What are some examples of communicable diseases?
Common cold, cholera, tuberculosis, and chickenpox are examples of communicable diseases.
Q: How do houseflies and mosquitoes contribute to the spread of diseases?
Houseflies can act as carriers of disease-causing microbes by transferring pathogens from garbage and animal excreta to uncovered food. Female Anopheles mosquito carries the parasite of malaria, while female Aedes mosquito carries the dengue virus.
Q: What measures can be taken to control the spread of malaria or dengue?
To control the spread of malaria or dengue, it is essential to eliminate the breeding sites of mosquitoes by removing stagnant water from around the house and using mosquito nets and repellents.
Q: What are the ways in which microorganisms can spoil food?
Microorganisms can spoil food by producing toxic substances, making it poisonous and causing illness or even death. Spoiled food emits bad smell, has a bad taste, and changes color.
Q: How can we prevent spoilage of food by microorganisms?
Preservatives such as salt, sugar, sodium benzoate, sodium metabisulphite, and vinegar are commonly used to prevent spoilage of food by inhibiting the growth of microbes. Dry salting is a common method used to preserve meat and fish. Jams, jellies, and squashes are preserved by sugar. Oil and vinegar are used to prevent spoilage of pickles.
Q: What is pasteurization, and how does it prevent the growth of harmful microbes in milk?
Pasteurization is a process that involves heating and cooling milk to prevent the growth of harmful microbes. By heating the milk, the harmful microbes are killed, and then cooling the milk prevents the growth of any remaining microbes.
Q: How do certain bacteria and blue-green algae in the soil convert atmospheric nitrogen into compounds of nitrogen, which can be used by plants?
Certain bacteria and blue-green algae present in the soil fix nitrogen from the atmosphere and convert it into compounds of nitrogen. Once nitrogen is converted into these usable compounds, it can be utilized by plants from the soil through their root system.
Q: What are bacteria?
Bacteria are unicellular living organisms that can be found in air, water, soil, and living organisms. They grow and multiply quickly, producing two bacteria in 10 to 30 minutes.
Q: Define algae.
Algae are microorganisms that resemble plants and contain cell walls and chlorophyll. They can be unicellular or multicellular.
Q: How are microorganisms useful?
Microorganisms are useful in making food, alcohol, medicines (such as antibiotics), and other products.
Q: Define virus.
A virus is a tiny microorganism that can only grow inside the cells of a host, such as animals or plants. They are smaller than bacteria and lack many of the features of living organisms.
Q: Define protozoa.
Protozoa are single-celled microorganisms that can cause diseases such as dysentery and malaria.
Q: What is fermentation?
Fermentation is the process of converting sugar into alcohol using yeast.
Q: Define vaccine.
A vaccine is a type of medication that provides protection against a specific illness by triggering an immune response in the body.
Q: What is vaccination? What vaccine is given to children?
Vaccination is the practice of administering a vaccine to prevent specific illnesses. Children are commonly vaccinated against diseases such as polio, smallpox, cholera, typhoid, hepatitis, tuberculosis, tetanus, measles, and diphtheria.
Q: What are communicable diseases? Give examples.
Communicable diseases are illnesses that can spread from one person to another through air, water, food, or physical contact. Examples include the common cold, cholera, chickenpox, tuberculosis, malaria, and AIDS.
Q: Which mosquito carries dengue in humans?
The Aedes mosquito is the carrier of the dengue virus, which can spread the disease from person to person.
Q: What is food poisoning?
Food poisoning is an illness caused by the presence of harmful microorganisms or compounds in food.
Q: What are the symptoms of food poisoning?
The most common symptoms of food poisoning include vomiting, diarrhea, abdominal pain, headache, and fever.
Q: What is preservation? What are the methods of food preservation?
Preservation is the process of treating food to prevent spoilage. Methods of food preservation include sun-drying, heating, cooling, deep freezing, adding salt, sugar, mustard oil, and vinegar, using chemical preservatives, and pasteurization.
Q: What is nitrogen fixation?
Nitrogen fixation is the process of converting nitrogen gas from the environment into nitrogen compounds.
Q: Define the Nitrogen Cycle.
The nitrogen cycle is the movement of nitrogen through living things and the non-living environment in nature.
