What is microbes?
Microorganisms include bacteria, fungi, protozoa and some algae. Viruses, though different from the above mentioned living organisms, are considered microbes.
CHAPTER 2 MICROORGANISMS FRIEND R AND FOE
Which pathogens cause serious diseases like dysentery and malaria?
Protozoans cause serious diseases likedysentery and malaria.
Why viruses are different from other microbes ?
Viruses are quite different from other microorganisms. They reproduce only inside the host organism: bacterium, plant or animal cell.
How to increase soil fertility by microorganisms ?
Some microorganisms reside in the root nodules of leguminous plants. They can fix nitrogen from air into soil and increase the soil fertility.
What is food poisoning ?
Some of the microorganisms grow on our food and cause food poisoning.
Food Preservation
A)Chemical MethodSalts and edible oils are the common chemicals generally used to check the growth of microorganisms. Thereforethey are called preservatives. We add salt or acid preservatives to pickles to prevent the attack of microbes. Sodiumbenzoate and sodium meta bisulphite are common preservatives 1)Preservation by Common SaltCommon salt has been used to preserve meat and …
Who was discovered the vaccine for smallpox ?
Edward Jenner discovered the vaccine for smallpox in 1798.
What is Nitrogen cycle?
Nitrogen cycleOur atmosphere has 78% nitrogen gas. Nitrogen is one of the essential constituents of all living organisms as part of proteins, chlorophyll, nucleic acids and vitamins. The atmospheric nitrogen cannot be taken directly by plants and animals. Certain bacteria and blue green algae present in the soil fix nitrogen from the atmosphere and convert …
What is preservatives?
Salts and edible oils are the common chemicals generally used to check the growth of microorganisms. Thereforethey are called preservatives. We add salt or acid preservatives to pickles to prevent the attack of microbes. Sodiumbenzoate and sodium meta bisulphite are common preservatives. These are also used in jams and squashes to checktheir spoilage.
What is pasteurisation ?
The milk is heated to about 70 degree C for 15 to 30 seconds and then suddenly chilled and stored. By doing so, it prevents the growth of microbes. This process was discovered by Louis Pasteur. It is called pasteurisation.