Class 12 Biology Chapter 8 Human Health and Disease

Class 12 Biology Chapter 8 Human Health and Disease The answer to each chapter is provided in the list so that you can easily browse through different chapters Assam Board HS 2nd Year Biology Chapter 8 Human Health and Disease Question Answer.

Class 12 Biology Chapter 8 Human Health and Disease

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Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 12 Biology Chapter 8 Human Health and Disease Solutions for All Subjects, You can practice these here.

Human Health and Disease

Chapter – 8


Very Short Answer Type Questions

Q.1. Blood circulation in human body was discovered by_____

Ans : William Harvey. 

Q.2. Typhoid fever could, be confirmed by ____ test.

Ans : Widal. 

Q.3. Common cold is a ___ disease. 

Ans : Viral. 

Q.4. Filariasis is caused by ____

Ans : Wuchereria. 

Q.5. AIDS can be diagnosed by ____

Ans : ELISA. 

Q.6. Heroin is obtained by _____ of morphine.

Ans : Acetylation. 

Q.7. Cocaine interfere with the transport of the neuro-transmitter _____

Ans : Dopamine. 

Q.8. The lymphoid tissue located within the lining of the respiratory, digestive and urogenital tracts is called_____

Ans : MALT (Mucosa-Associated Lymphoid Tissue)

(B). True or False : 

Q.1. Genetic diseases are inborn. 

Ans : True. 

Q.2. AIDS is a non-infectious disease. 

Ans : False. 

Q.3. Typhoid is caused by virus. 

Ans : False. 

Q.4. In common cold lung is infected. 

Ans : False. 

Q.5. A healthy person acquires ascariasis infection through blood transfusion.

Ans : False. 

Q.6. The genome of HIV is RNA. 

Ans : True. 

Q.7. Oncogenic viruses are cancer causing viruses. 

Ans : True.

Q.8. The chronic use of drugs and alcohol damage nervous system and liver. 

Ans : True.

(C). Very Short Answer Questions (1 Mark) 

Q.1. Define health. 

Ans : Health can be defined as a state of complete physical, mental and social well being. 

Q.2. How can you maintain good health? 

Ans : Regular exercise, personal hygiene and balanced diet are very important to maintain good health.

Q.3. What is disease? 

Ans : Disease is a state when the functioning of one or more organs or systems of the body is adversely affected, characterised by various signs and symptoms. 

Q.4. Write the biological name of the bacterium causing typhoid. 

Ans : Salmonella typhi.

Q.5. Why Mary Mallon was nicknamed as Typhoid Mary? 

Ans : Mary Mallon was nicknamed as Typhoid Mary because she was a cook and was a typhoid carries who continued to spread typhoid for several years through the food she prepared. 

Q.6. How a healthy person is infected by typhoid fever? 

Ans : A healthy person acquires the pathogen of typhoid fever through food and water and it enters the small intestine and migrate to other organs through food. 

Q.7. Name the bacteria which cause pneumonia in man. 

Ans : Streptococcus pneumonia.

Q.8. Which type of malaria is fatal to man? 

Ans : Malignant Malaria. 

Q.9. Why ringworm infections are prevalent in groin and other skin folds? 

Ans : Ring worm is ą infectious disease caused by fungi. Heat and moisture help these fungi to grow, which makes them thrive in skin folds such as those in the groin or between the toes. 

Q.10. In treating snake bite which type of immunisation is performed? 

Ans : Passive Immunization. 

Q.11. What type of immunity is responsible for graft rejection? 

Ans : Passive Immunization.

Q.12. What is the causative virus of AIDS? To which group of virus it belongs to? 

Ans : AIDS is caused by HIV virus (Human Immuno Deficiency Virus). It is a RNA virus belong to retrovirus. 

Q.13. What is cancer? 

Ans : Cancer is one of the most degraded diseases of human being and is a major cause of death all over the globe. 

Q.14. Define contact inhibition. 

Ans : The property of normal cells by virtue of which it contact with other cells inhibits their uncontrolled growth. 

Q.15. Name the drugs which are commonly abused. 

Ans : The drugs which are commonly abused are opioids, cannabinoids and coca-alkaloid. 

Q.16. Name the plant from which morphine is extracted. 

Ans : Morphine is extracted from the latex of poppy plant. 

Q.17. State the affects of heroin. 

Ans : Heroine is a depressant and slows down body functions. 

Q.18. What are cannabinoids? 

Ans : Cannabinoids are a group.of chemical which interact with cannabinoid receptors present principally in the brain. For example: ganja. 

Q.19. What is benign tumour? 

Ans : The tumours which remain confined in the organ affected and do not spread to other body parts. It is covered by a connective sheath and growth rate is very slow are called beriga tumour.

Q.20. Write the full form of ELISA. 

Ans : ELISH-Enzyme Linked Immuno Serbent Assay. 

Q.21. Name the property of normal cells by which uncontrolled growth of cell is inhibited. 

Ans : The growth of normal cells are regulated by certain regulatory mechanisms and they definite life span and mere adhesive.

(D). Short Answer Questions (2 Marks) 

Q.1. What are the two basic groups of diseases? Give one example of each group. 

Ans : Diseases can be broadly grouped into two types: 

(i) Infectious and (ii) Non-infectious 

(i) Infectious-eg. Pneumonia (ii) Non-infectious – eg. Allergy.

Q.2. Write a note on pathogens. 

Ans : Virus, bacteria, funges, protozoa parasite etc. disease causing organisms are known as pathogens. For eg- all parasites are therefore pathogens as they cause harm to the host by living in (or on) them. 

Q.3. State the symptoms of typhoid. 

Ans : Sustained high fever (39° C to 40°), weakness stomach pain, constipation, headache and loss of appetite are some of the common symptoms of typhoid. 

Q.4. Name four bacterial diseases of man. 

Ans : The four bacterial diseases of man are Typhoid, Pneumonia, Dysentery and Diphtheria. 

Q.5. How common cold disease spread from one to another person? 

Ans : Droplets resulting from cough or sneezes of an infected person are either inhaled directly or transmitted through contaminated objects such as pens, books, door, notes etc. and cause infection in a healthy person. 

Q.6. State the symptoms of common cold. 

Ans : Common cold disease is caused by Rhino viruses. This disease is characterised by nasal congestion and discharge, sore throat, hoarseness, cough, headache, tiredness etc. which casually last for 3-7 days. 

Q.7. “Malarial parasite is digenetic’, explain. 

Ans : ‘Malaria parasite is digenetic’ it is because it requires two hosts human and mosquitoes to complete its life cycle. Here female anopheles mosquito is the véctor also. 

Q.8. What are the main sources of infection of Entamoeba histolytica? 

Ans : Entamoeba histolytica causes amoebic dysentery in human beings. The symptoms of this disease include constipation, abdominal pain and cramps, stools with excess mucous and blood clots. 

Q.9. What is filariasis? State its symptoms. 

Ans : The filarial worm, hucheria cause a slowly developing chronic inflammation of the organs in which they live for many years, usually the Lymphatic vessels of the lower limbs and the disease is called filariasis or elephantiasis. 

The genital organs are also effected resulting in gross deformities. 

Q.10. Distinguish between the following pairs : 

(a) Humoral immunity and cell mediated immunity 

Ans :          

Humoral ImmunityCell Mediated Immunity
(i) Here antibodies are found in the blood, so known as humoral Immunity.(i) This type of immunity is due to the response from the cell.
(ii) Here T-lymphocytes help B-lymphocytes in the production of antibody.(ii) Here T-lymphocytes mediate cells.

(b) Innate Immunity and Acquired Immunity. 

Ans :        

Innate ImmunityAcquired Immunity
(i)  Innate Immunity is a non- specific type of defense.(i) Acquired Immunity is pathogen specific.
(ii) It is present at the time of birth.(ii) It is characterised by memory acquired in the life time.

(c) Passive immunity and Active Immunity. 

Ans :       

Active ImmunityPassive Immunity
(i) The process, when a host is exposed to antigens, antibodies are produced in the host body, is known as active Immunity.(i) When ready made anti- bodies are directly given to protect the body against foreign agents, is known as passive immunity.
(ii) For example- injecting the microbes during immunisation.(ii) The antibodies and immunity received by the foetus from their mother.

(d) T-lymphocyte and B-lymphocyte. 

Ans : 

(i) It produces secondary immune responses.(i) It produces primary immune  responses.
(ii) T-lymphocytes do not produce antibody but it helps to produce antibodies.(ii) B-Lymphocytes can B-Lymphocytes produce antibody from their own.

(e) Benign tumor and Malignant tumor. 

Ans :         

Benign tumorMalignant tumor
(i) It normally remain confined to their original location and do not spread.(i) There are a mass of proli- ferating cells grow very rapidly invading and damaging the surrounding normal tissues.
(ii) Its effects are negligible.(ii) There are harmful.

Q.11. What are the different types of barrier in innate immunity? 

Ans : Innate immunity consists of four types of barriers. These are – Physical barrier, Physiological barrier, Cellular barrier and cytokine barrier. 

Q.12. Define allergy. Name the antibody which is produced during allergy. 

Ans : The exaggerated response of the immune system to certain antigens present in the environment is called allergy. 

The antibody produced during allergy is IgE. 

Q.13. What is autoimmunity? Name an auto immune disease. 

Ans : Memory based acquired immunity evolved in higher vertebrates based on the ability to differentiate foreign organisms like pathogenes from self cells is known as auto-immunity. 

For example- Rheumatoid arthritis. 

Q.14. State how transmission of HIV infection occurs. 

Ans :Transmission of HIV- infection occurs by 

(a) Sexual contact with infected persons. 

(b) By transfusion of contaminated blood and blood products. 

(c) By sharing infected needles as in the case of intravenous drug abusers. and 

(d) From infected mother to her child through placenta. 

Q.15. Write the name of the plant and the plant parts from which cannabinoid can be obtained. 

Ans : Natural cannabinoids are obtained from the inflorescence of the plant Cannabis sativa. The flower tops, leaves and the resin of cannabis plant are used. 

Q.16. Define drug abuse. 

Ans : When drugs are taken in such a amount that impairs one’s physical, physiological or psychological functions, it constitutes drug abuse. 

Q.17. Which system is greatly affected by cannabinoids. 

Ans : Cannabinoids are a group of chemicals which interact with cannabinoid receptors present principally in the brain. 

Q.18. Describe the ill effects of smoking. 

Ans : Smoking is injurious to health. As a result of incomplete burning of Tobacco, nicotine is puffed into the lung which may cause lung cancer, throat cancer and mouth cancer. Excessive smoking make a man unstable and addicted. Passive smoking is more harmful compare to the active or direct smoking. 

Q.19. What is metastasis? 

Ans : Metastasis is the process of transference of cancerous cells from the site of origin to distant parts of the body. The most frequent sites of metastasis are lymph nodes, lungs, long bones, liver, skin and brain.

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