12th Biology Study Material Chapter8(Human health and diseases) - Tamilyoungsters
CHAPTER 8 : HUMAN HEALTH AND DISEASES
IMPORTANT QUESTION
1.How do saliva and tear help to prevent bacterial infection?
Ans: -saliva and tear contain lysozymes. -Lysozymes are the enzymes which digest the cell wall of bacteria -By lysing the cell wall, they kill bacteria and prevent their infection.
2. What is vaccination?How does it help in producing immunity?
Ans:- Vaccination is the process of introducing a preparation of antigenic protein of the pathogens or weakened or killed pathogen into the body. -The vaccines include quick multiplication of B and T-lymphocytes;some of them are stored as memory cells -The B-lymphocytes quickly produced antibodies,which neutralize the antigen during infection.
3. Write the full form of ELISA.Give an example of the clinical application of ELISA?
Ans:-Enzyme Linked Immune Sorbent Assay. -ELISA test is used in the diagnosis of AIDS,hepatitis-B and other STDs
4 .What are the advantages of people being healthy ?
Ans-When people are healthy,
a)They are efficient at work which consequently increases productivity and brings economic prosperity
b)Health increases longevity.
c)It reduces infant and maternal mortality
5.a) Name the respective forms in which the malarial parasite gains entry into i) Human body and ii) Body of female Anopheles b) Name the hosts where the sexual and the asexual reproduction of malarial parasite occur respectively c) Name the toxin responsible for the appearance of symptoms of malaria in humans.Why do these symptoms occur periodically ?
Ans-(a) (i)-Sporozoite (ii)-Gametocyte (b) -sexual reproduction in mosquito -asexual reproduction in human body. (c) Haemozoin - Haemozoin is released when the RBCs rupture and release the pathogen -some cells of pathogen enter fresh RBCs and reproduce asexually and repeat the cycle; hence the symptoms appear periodically .
6. Define innate immunity. Name and explain the category of barrier which involves macrophages.
Ans. Innate immunity refers to all those defence elements with which a person is born and are always available to protect the body. -Macrophanges form part of the cellular barrier. -The cellular barrier includes the following specialized cells; (i) Polymorphonuclear leucocytes. (ii) Monocytes. (iii) Natural killer lymphocytes and (iv) Macrophages. - these cells phagocytose and destroy the invading microbes.
7. What is meant by writing H2L2 for an antibody? Name any four types of antibodies produced in our/human body?
Ans. - Each antibody molecule has four peptide chains. - Of them, two are small and called light chains (L) and two of them are longer and called heavy chains (H); hence written as H2L2. The four types of antibodies are IgA, IgE, IgG and IgM.
8(i) Explain metastasis. Why is it fatal? (ii) The lymphocytes are of two types B and T-cells. Why are they called so? (iii) A person was injured in a road accident and required an urgent immune response. What should be done?
Ans. (i) Metastasis is the property of tumor cells, which get separated from a tumor, spread to different sites in the body through body fluids and produce secondary tumors wherever they are lodged. Since secondary tumors are formed at several parts of the body, it is difficult to be diagnosed and treated; hence it is fatal. (ii) Those lymphocytes which undergo maturation in the bone marrow are called B-cells while those which undergo maturation in the thymus are called T-cells. (iii) Vaccine against Tetanus.
