Interferons are chemicals secreted by host cells against different types of viruses.They play an important role in protecting the organism from viral infection and also bacterial and parasitic pathogens.These chemicals signal the other cells to release out another kind of interferons that protect the unaffected cells from the viral infection.

The serum is an antitoxin-rich blood preparation used against a specific disease. This is yellowish and obtained when a blood sample is allowed to clot (coagulation). The sample is then centrifuged to remove the clot and blood cells, and the resulting liquid supernatant is serum. It consists of 90% water with dissolved hormones, proteins, minerals, and carbon dioxide. The serum is injected into the person against the specific disease. The antibodies present in the serum neutralise the antigens.

The microorganisms which cause diseases in humans, animals, and plants are known as pathogens. Bacteria, Viruses, Fungi, Protozoan, and Helminthes are different types of microorganisms that cause infectious diseases.

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A New Approach to I.C.S.E. Biology>Chapter 17 - Health and Hygiene>Exercises

Exercises

Author:Dr. S.K. Aggarwal

Dr. S.K. Aggarwal Biology Solutions for Exercises

Simple step-by-step solutions to Exercises questions of Health and Hygiene from A New Approach to I.C.S.E. Biology. Also get 3D topic explainers, cheat sheets, and unlimited doubts solving on EMBIBE.