|microorganisms class 8 cbse questions|
1- microscope- an instrument that makes use of lens to make smaller objects appear larger is called a a microscope.
2- specimen- the object to be viewed under the microscope is called a a specimen.
3- microorganism / microbes- organism that are visible only through a microscope are called microorganism or microbes.
4- Fermentation- the process of convention of a sugar into on acid or an alcohol by the action of microorganism is called farmentation .
5- nitrogen cycle- A natural cycle process in which atmospheric nitrogen enters the soil and becomes a part of Living organism, before returning to the environment. is called nitrogen
6- nitrogen fixation- the process by which free atmospheric nitrogen is converted into nitrogen component it is called nitrogen fixation.
7- pathogens- microorganism that cause diseases in human being, animals and plants are called pathogens.
8- communicable diseases- diseases that can spread from one person to another uh are called communicable diseases.
9- food preservation- the process of treating and handling food with an I aim to stop or slow down. Its spoilage while maintaining if nutrients value, texture and flvour is called food preservation.
10- pasteurization- the food preservation method that invades heating a foodstuff to a high temperature and the the pulling it rapidly is called pasteurization.
Qus 1- what is microscope ?
Qus2- what are microorganism, name the five major group into which microorganism can be divided ?
ans- microorganism- organism that are visible only through a microscope are called microorganism.
* the five major group-
Qus-3- name any four medicinal uses of of microorganism?
ans- the name of four medicinal uses are-
(1) making antibodies = penicillin, straptomgcin
(2) making vaccines= polio, cholera
(3) making food supplement= chaorella
(4) in human body = Lactobacillus acidophilus
Qus-4- what is nitrogen fixation? How do do leguminous plant help in nitrogen fiction?
answer- nitrogen function is the the process by which free atmospheric nitrogen is convert into nitrogen compounds. In nature nitrogen is fixed during lighting or by nitrogen fixing bacteria and blue green algae. Nitrogen cycle is natural cycle process in which atmospheric nitrogen enter the soil and become a part of Living organism, before returning to the atmosphere,
Qus 5- what are the two to harmful effects of microorganism?
ans- harmful effect of microorganisms can be divided into two categories-
1- causing disease in human being animals
2- plant and food spoilage.
Qus-6- what are communicable diseases? Name any four communicable diseases of human being, animals, and plants ?
ans- communicable diseases- diseases that can spread from one person to another uh are called communicable diseases.
(1) human being- typhoid ,malaria
(2) animals- food and mouth diseases,
(3) plant- apple scab, loose smut.
Qus-7- list at least three things that help us direct that food is unfit consumption?
* foul odour
* slimy propose aur cotton like growth on the surface.
* surface discoloration.
* gas formation.
Qus-8- name the main conditions required for the growth of microorganism ?
answer- the main conditions required for the growth of these microorganism are a moderately warm temperature, air and moisture.
Qus9- what is the specimen? How does a coverslip help in making a slide? Write the basic steps for using a microscope?
ans- the object to be viewed under the microscope is referred to as the specimen.
* the basic steps to use a compound microscope are as follows.
(1) clean the mirror using a a soft, clean cloth if required.
(2) place the flight with the specimen on the stage.
(3) adjust the focus of the eyepiece and the objective lens with help up from your teacher.
(4) view the slide through the eye thepiece.
Qus-10- describe some commercial uses of microorganism in detail?
ans- some of commercial uses of microorganism are given below.
1- making curd and cheese-A bcterrium called led to basicallus, present in spoonful of curd added to the milk, converse the lactose sugar present in milk to lactic acid. The effort environment needed for casein coaugulation. The the production of cheese and paneer also involve the uses of bacteria like lactobacillus and straptococcus.
2- making alcoholic beverages- production of alcoholic beverages such as beer and wine involves formation of sugar present in barley and grapes etc. Bi a microscopic fungi called yeast. Fermentation by yeast product alcohol and carbon dioxide.
3- making bread- the process of making bread involves kneading a mixture of flour, salt, sugar, yeast cells and water into dough. yeast convert sugar to alcohol and carbon dioxide.
4- making vineger, coffee and tobacco- bacteria are used in the production of vinegar. It is also used in the processing of tea, coffee and tobacco.
5- making toothpaste- shell of diotoms(a type of algae) are used in toothpaste to give it a gritty texture that help in cleaning teeth.
Qus11- how can we prepare curd at home?ans-
* aim- to prepare curd
* malerials needed- milk (one glass) a teaspoon of curd, a bowl and lid.
(1) ask on adult to warm the milk.
(2) transfer the milk to the the bowl and add a a spoonful of call to it, stir well and cover the bawl without a lid. Leave the bowl undisturb overnight.
* observation- the milk transform into curd.
* conclusion- the bacterium lactobcillus present in the the spoonful of curd added to the milk convert milk into curd.
*note- adult supervision required.
Qus12- describe some medicinal uses of microorganism in detail ?
ans- some of the medicinal uses of microorganism are given below.
1- making antibiotics- certain bacteria and fungi used in the production of medicines called antibiotics that destroy certain diseases- causing microbes penicillin cobtained from the fungus penicillium.
2- making vaccines- a vaccine is a preparation of killed or weekend diseases- causing microbes.
3- making food supplements- microbes such as chlorella and spirulina(type of algae) are rich in protein and other nutrients and are used as good supplement.
4- In human body- bacteria such as lactobacillus acidophilus and Escherichia coil I live in human intestine, where they help to digest food and destroy diseases- causing microbes.
Q13- describe how nitrogen gets fixed in nature?
1- nitrogen fixation is the process by which free atmospheric nitrogen is converted into nitrogen compounds. In nature, nitrogen is fixed during light night or by nitrogen fixing bacteria and blue green algae.
2- leguminous plants it such as Pia and soyabean have the nitrogen fixing bacteria rhizobium present in their root nodules. The nitrogen fixed by this Bacteria is taken up by the plants and stored in their tissues as plant protein.
3- nitrogen cycle is a natural cycle process in which atmospheric nitrogen enters the soil and becomes a a part of Living organism, before returning to the atmosphere.
Q14- describe how pathogens are transmitted from one person to another ?
* in human beings- pathogens can enter the body of a healthy person through air, water and unclean or is spoiled food contains many pathogens. When a a healthy person consumes unclean water or spoiled food. The pathogens enter the body and cause diseases.
* Pathogens can also spread from an infected person to a helthy one.
* pathogens also spread from an infected person to a healthy one through insist such as the anopleks and aedes mosquitoes.