Selina solutions

Selina solutions

Grade 8

Disease and First Aid | Long Answer Questions (LA)

Question 1

Q1) What is Vaccination ? Mention the four ways in which vaccine's are prepared, giving the name of one disease for which each type of vaccine is used.

Solution :

Vaccination is the practice of artificially introducing germs or germ substances into the body for developing resistance against a particular diseases. Usually, the vaccine or germ is introduced into the body by injection and sometimes orally.

A vaccine can be prepared by any one of the following four methods:

  1. Using killed germs. E.g. TAB vaccine for typhoid, salk’s vaccine for poliomyelitis, and the vaccine for rabies.
  2. Using living weakened germs. The living germs are treated in such a way that they become very weak and as such, they cannot cause the disease. They can induce antibody formation in the body, e.g. the vaccine for measles, and the freeze-dried BCG vaccine for tuberculosis.
  3. Using fully virulent living germs. E.g. the vaccine for cowpox. In this vaccination, a person is inoculated with cowpox virus which is very similar to smallpox virus.
  4. Using toxoids. They are vaccines used for diphtheria and tetanus. The toxoids are extracts of toxins secreted by bacteria, and these poisons are made harmless by adding formalin, to retain the capacity to produce antibodies.

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subject-cta

Question 1

Q1) What is Vaccination ? Mention the four ways in which vaccine's are prepared, giving the name of one disease for which each type of vaccine is used.

Solution :

Vaccination is the practice of artificially introducing germs or germ substances into the body for developing resistance against a particular diseases. Usually, the vaccine or germ is introduced into the body by injection and sometimes orally.

A vaccine can be prepared by any one of the following four methods:

  1. Using killed germs. E.g. TAB vaccine for typhoid, salk’s vaccine for poliomyelitis, and the vaccine for rabies.
  2. Using living weakened germs. The living germs are treated in such a way that they become very weak and as such, they cannot cause the disease. They can induce antibody formation in the body, e.g. the vaccine for measles, and the freeze-dried BCG vaccine for tuberculosis.
  3. Using fully virulent living germs. E.g. the vaccine for cowpox. In this vaccination, a person is inoculated with cowpox virus which is very similar to smallpox virus.
  4. Using toxoids. They are vaccines used for diphtheria and tetanus. The toxoids are extracts of toxins secreted by bacteria, and these poisons are made harmless by adding formalin, to retain the capacity to produce antibodies.

Still have questions? Our expert teachers can help you out

Book a free class now

Want to top your biology exam ?

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subject-cta
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