Bacteria are classified regarding their shape and they are as follows:-
i. Spirilla:- spiral-shaped bacteria
ii. Cocci:- sphere-shaped bacteria
iii. Bacilli:- rod-shaped bacteria
iv. Vibrios:- curved-shaped bacteria
Our food can be contaminated by microorganisms. Food preservation is the process of making sure our food doesn't get contaminated by microorganisms. Food can be preserved in a number of ways. Some of food preservation methods are:
Drying: It reduces the moisture in food, which stops the growth of microorganisms.
Refrigeration and freezing: This growth of microorganisms is slowed by low temperatures. As a result, it is suitable for human consumption.
By oil and vinegar : Using oil and vinegar to preserve pickles minimizes spoiling since bacteria cannot survive in such an environment.
Using common salt and sugar: Dry salt is applied to meat and fish to prevent microbial growth. Sugar lowers moisture content, preventing the formation of microorganisms that ruin food.
(iii) What exactly are antibiotics? What precautions should be taken when using antibiotics?
Antibiotics are medications that are preferred during illness. They are used to treat bacterial infections in humans and animals. They either kill the bacteria or make it hard for the bacteria to grow and multiply. Precautions to take while using antibiotics include:
(i) They should only be used with the advice of a trained doctor.
(ii) The doctor-recommended course must be completed.
(iii) They should only be taken in the recommended doses.
(iv) Do not take these medications when they are unnecessary or in the incorrect dosage. It may make the drug less effective if you need it in the future.
(v) Unnecessary antibiotic use can kill beneficial microorganisms in the body.
(iv) Explain through a brief note Can microorganisms be harmful to humans?
Microorganisms can be harmful in a number of ways. Some microorganisms, for example, cause diseases in humans, other animals, and plants. Pathogens are microorganisms that cause disease. Pathogens can be bacteria, viruses, protozoa, or fungi, among other things.
Diseases caused by microorganisms include tuberculosis (TB), tetanus, diphtheria, whooping cough, cholera, typhoid, AIDS, food poisoning, malaria, smallpox, and chickenpox, etc..
Apart from causing disases some microorganisms contaminate food, clothing, and leather items.
5. Multiple Choice Questions (MCQ)
(1) Branch of science that involves the study of microorganisms is called
(IV) None of these
(2) Algae are
(III) Unicellular or Multicellular
(IV) None of these
(3) Which one of them is not an algae
(4) The Bread Mould
(5) Viruses that can infect bacteria
(I) Influenza virus
(II) Hepatitis virus
(6) Microorganisms which are used for medicines
(IV) All of them
(7) Which one of them is an example of viral disease
(II) Common cold
(8) Which one of them is not an example of communicable disease
(9) Which one of them is an example of plant disease
(I) Citrus canker
(10) The micro-organism which is capable of converting sugar into alcohol and carbon dioxide is :
This Class 8 science chapter 2 extra questions and Answers sheet is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.
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