NCERT Solutions for Class 12 Biology Chapter 8
NCERT Solutions for Class 12 Biology Chapter 8 Human Health and Diseases to Study Online without downloading or download in PDF format for academic session 2020-21 for all boards using NCERT Books 2020-21.
NCERT Books based on latest Curriculum 2020-2021 is also available to download. Ask Your Questions or Reply to your friends by answering their questions via discussion forum.
NCERT Solutions for Class 12 Biology Chapter 8
Class: | 12 |
Subject: | Biology |
Chapter 8: | Human Health and Diseases |
Chapter 8 Human Health and Diseases Solutions
Class 12 Biology Chapter 8 Solutions in English
NCERT Solutions for Class 12 Biology Chapter 8 Human Health and Diseases are given here to free download. NCERT Solutions 2020-21 are updated according to NCERT Books 2020-21 following latest CBSE Syllabus 2020-2021. Join the discussion forum to ask your doubts and reply to questions asked by other users.
What is meant by Vaccination?
A preparation of weakened or attenuated pathogen is introduced in the human body. Antibodies are formed against the pathogen. B and T memory cells are generated that recognises the pathogen quickly on subsequent exposure a kills it with quick and massive production of antibodies.
Define the type of types of Immunities?
Two types of Immunities.
Innate immunity: inherited by the organism from the parents and present at the time of birth.
Acquired Immunity: Acquired by a person after birth by vaccination or contacting the disease.
Important Terms related to Chapter 8
1. Addiction: A psychological attachment to effects like euphoria and temporary well-being associated with drugs and alcohol.
2. Interferon: The glycoproteins produced by our body cells in response to a viral infection.
3. Incubation Period: The time period between infection and tire appearance of symptoms.
4. Metastasis: The property in which the cancer cells spread to different sites through blood and develop secondary tumours.
5. Oncogenes: Viral genome which causes cancer/Cancer causing genes.
6. Retrovirus: A virus having RNA as genetic material and forms DNA by reverse transcription and then replicate e.g., Human Immunodeficiency Virus (HIV).
7. Withdrawal Syndrome: If a drug dependent person stop taking drugs then his body stop functioning normally and he feels severe physical and psychological disturbance called withdrawal syndrome.
8. Contact Inhibition: It is a property of normal cells in which the cells stop dividing when comes in contact with its surrounding cells.
Infectious Diseases
Viral Diseases e.g., polio, common cold, measles, rabies
Bacterial diseases e.g., Typhoid, Pneumonia, Diptheria, Tetanus.
Fungal diseases e.g., Ring worm & Scabies
Helminthic diseases e.g. Ascariasis, Filariasis, Taeniasis
Protozoan diseases e.g. Malaria, Amoebiasis.
Prevention of Dengue and Chikungunya: Protection against mosquitoes by wearing long sleeves and full pants. Window and doors should have wire gauze screens, use mosquito repellents and there should be no stagnant water nearby.
Allergens
Substances to which immune system shows exaggerated response. e.g. mites in dust, pollens, animal dander, perfume, wool, nail polish and drugs.
Lymphoid Organs: Organs where lymphocytes are formed proliferate and mature are called lymphoid organs.
Bone Marrow: It is a primary lymphoid organs. Lymphocytes maturing here are called B-lymphocytes.
Thymus: Lymphocyte which mature in thymus are called T-lymphocyte.
Important Questions on 12th Biology Chapter 8
Secondary lymphoid organs are the spleen, lymph nodes, tonsils, Peyer’s patches of small intestine, and appendix.
It has the following modes of transmission:
Unprotected sexual contact with an infected person.
Transfusion of blood from a healthy to an infected person.
Sharing infected needles and syringes.
From an infected mother to a child through the placenta.