The medicines that kill or stop the growth of the disease-causing microorganism are called antibiotic. Short Answer Question answers 1. What is meant by fermentation? To Study Chapter Notes - Micro-Organisms : Friend or Foe, Science, Class 8 for Class 8 this is your one stop solution. Sugar reduces the moisture content which inhibits the growth of bacteria which spoil food. Diseases in humans like common cold, tuberculosis, measles, chicken pox, polio, cholera, typhoid, hepatitis B, malaria, etc.
Answer: Some of the micro-organism present in the soil can fix nitrogen gas from the atmosphere to form nitrogen compounds. For example some bacteria in our gastrointestinal tract help in digestion. Users can download and print the worksheets on class 8 Science Microorganisms: Friend and Foe for free. These medicines kill or stop the growth of the disease-causing microorganisms. Microbial disease that can spread from an infected person to other healthy person through air, water, food, physical contact or by animals are called communicable diseases. Answer Micro-organisms cause diseases in animals.
How is dehydration helpful in food preservation? There are 10 trillion 10 x 1,000,000,000,000 or a million million cells in the average body. In humans, bacteria cause diseases such as cholera, common cold, chicken pox and tuberculosis etc. But once it is inside a host, it behaves like a living being, i. These days a number of antibiotics are being produced from bacteria and fungi. Diseases like malaria and giardia are protozoa. Some bacteria occur in the human intestine and intestine of other animals as well.
Name two common food preservatives used in our homes. Explain various methods through which communicable disease spread. Actually, some fungi like penicillium produce chemical substances called antibiotics. The process of circulation of nitrogen between the atmosphere, soil, plant and animals is called the nitrogen cycle. Apart from them certain food like curd, contain beneficial bacteria. They, however, reproduce only inside the cells of the host organism, which may be a bacterium, plant or animal.
A wrong dose of antibiotics makes the drug ineffective. What precautions must be taken while taking antibiotics? Some microorganisms decompose the organic waste and dead plants and animals into simple substances and clean up the environment. If suc h spoiled food is consumed it leads to food poisoning. When a disease causing microbe enters into our body, defense system produces 16. Recall that bacteria are alo used in the preparation of medicines. This air-free packing is called vacuum packing.
· it is used to preserve amla, raw mangoes, tamarind etc. They have different shapes — some look like balls, rods or spirals. You can see some Short Notes - Microorganisms: Friend and Foe, Science, Class 8 sample questions with examples at the bottom of this page. Short answers: What is pasteurization? Microbes are useful to mankind, justify the statement with any two suitable examples. Name the virus which uses bacteria as host. For example, fungus that grows on bread is so small that it can be seen only with the help of a magnifying glass or microscope.
The substance which is injected to trigger the body to develop its own defence mechanism by producing antibodies is called vaccine. Penicillin made it possible to treat many difficult diseases. Female Aedes mosquito acts as carrier of dengue virus. Microbes grow on food products and render them unfit for consumption. Some microbes are even found in extremely harsh conditions, e. There are number of antibiotics that are being produced by bacteria and fungi.
Question 3: Malaria is caused by which type of microbe? They can even cause diseases in animals and plants. Protozoa They mainly include organisms such as Amoeba, Plasmodium,etc. The dough rises and looks fluffy. Bacteria You cannot escape bacteria. So, if dead or weakened microbes are introduced in a healthy body, the body fights and kills them by producing suitable antibodies.
Q11: Name diseases caused by protozoa? Can microorganisms be seen with the naked eyes? During one of his experiments; Alexander Fleming observed that bacteria did not grow on culture where a fungus Penicillum notatum was present. Pulse Polio has been highly successful against eradication of polio. Cleaning the Environment: Many microbes feed on dead remains of plants and animals. A virus will hijack a cell in your body and change the instructions of the cell so that, instead of doing what it was designed to do, the cell begins to produce copies of the virus. Food poisoning is caused by microorganism. Name the microorganism which can fix atmospheric nitrogen in the soil.