Boost Your Preparation for Class 12 Biology Human Health and Disease Exam with NCERT Solutions
The NCERT Solutions of Class 12 Biology are reliable study materials that will help the students to secure good marks in the exam. Highly experienced teachers at Vedantu have prepared the Class 12 chapter 8 NCERT Solutions. The Chapter 12 Human Health and Diseases NCERT Solutions comprises comprehensive answers, with relevant diagrams and explanations, for all the questions given in the exercise of the chapter. Students can download the NCERT Solutions and refer to them offline, for absolutely free of cost from Vedantu.
The NCERT Solutions of Human Health and Disease will help the students to get a clear idea of all the topics covered in the chapter.
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Human Health and Diseases Chapter at a Glance - Class 11 NCERT Solutions
Human Health and Diseases
Health is defined as a state of complete physical, mental and social well-being. It simply does not mean ‘absence of disease’ or ‘physical fitness’.
A disease is an abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not due to any immediate external injury.
Diseases can be congenital or acquired. Acquired diseases can further be differentiated into communicable and non-communicable diseases.
Human body has a very efficient in-built defense mechanism which provides immunity to our body. Immunity is of two types innate and acquired. Acquired immunity comprises cell mediated immunity controlled by T cells and humoral immunity controlled by B cells.
The immune cells of the body are formed in lymphoid organs. There are primary lymphoid organs such as bone marrow and thymus and secondary lymphoid organs such as tonsils, Peyer’s patches, MALT.
One of the most important non-communicable diseases is cancer. Cancer results due to tumor formation due to uncontrolled cell division. There are various cancer-causing agents called carcinogens responsible for occurrence of this disease.
Cancer is curable if detected early. There are various diagnostic techniques such as CT scan, MRI. The treatment for this disease includes chemotherapy, radiotherapy and surgery.
AIDS is one of the most fatal communicable diseases which is caused by HIV. It can be transferred through infected blood transfusion and from infected mother to foetus. There is no permanent cure of this disease.
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1. What are the various public health measures you would suggest as a safeguard against infectious diseases?
Ans: Public health measures are preventive measures that are taken to check the spread of various infectious diseases. These measures should be taken to reduce contact with infectious agents. Some of these methods are:
(1) Personal and Public Hygiene Should be Maintained: One of the most important methods of preventing infectious diseases is the maintenance of personal and public hygiene. Personal hygiene involves maintaining a clean body, consumption of healthy and nutritious food, drinking clean water, etc. Whereas public hygiene involves proper disposal of waste material, excreta, periodic cleaning, and disinfection of water reservoirs.
(2) Isolation of Infected Persons: To prevent the spread of air-borne diseases such as pneumonia, chickenpox, tuberculosis, etc., it is essential to keep the infected person in isolation to reduce the chances of spreading these diseases.
(3) Vaccination: The protection of the body from communicable diseases by administering some agent that mimics the microbe inside the body is known as vaccination. It provides both active and passive immunization to the body. Various vaccines are available for the treatment of many diseases such as tetanus, polio, measles, mumps, etc.
(4) Vector Eradication: Many diseases such as malaria, filariasis, dengue, and chikungunya spread through vectors. By providing a clean environment and preventing the breeding of mosquitoes these diseases can be prevented easily. By not allowing water to stagnate around residential areas, the breeding of mosquitoes can be prevented. To keep our environment healthy, regular cleaning of coolers should be done, also the use of mosquito nets, and insecticides such as malathion in drains, ponds, etc. should be considered. Fish such as Gambusia are introduced in ponds to control the breeding of mosquito larvae in stagnant water.
2. In which way has the study of biology helped us to control infectious diseases?
Ans: In the field of biology, various advancements once a person starts taking alcohol or drugs have helped us in gaining a better understanding to fight against various infectious diseases. Biology has helped us in studying the life cycle of various parasites, pathogens, and vectors along with their modes of transmission and controlling measures. Vaccination programs against several infectious diseases such as smallpox, chickenpox, tuberculosis, etc. have helped nearly eradicate these diseases. In the preparation of newer or safer drugs and vaccines, biotechnology has helped a lot. In treating infectious diseases the antibiotics have also played a very important role.
3. How does the transmission of each of the following diseases take place?
(a) Amoebiasis
(b) Malaria
(c) Ascariasis
(d) Pneumonia
Ans:
4. What measure would you take to prevent water-borne diseases?
Ans: Water-borne diseases like cholera, typhoid, hepatitis B, etc. spread by drinking contaminated water. By ensuring proper disposal of sewage, excreta, and periodic cleaning habits we can prevent ourselves from water-borne diseases. Along with these, measures such as disinfecting community water reservoirs, boiling and filtering drinking water, etc. should also be observed.
5. Discuss with your teacher what ‘a suitable gene’ means, in the context of DNA vaccines.
Ans: In the context of DNA vaccines, a ‘suitable gene’ refers to a specific DNA segment that can be injected into the cells of the host body to produce specific proteins. The specific proteins kill the specific disease-causing organism in the body of the host and it also provides immunity to the host body.
6. Name the primary and secondary lymphoid organs.
Ans: The names of primary and secondary lymphoid organs are as follows:
(a) Primary lymphoid organs - The bone marrow and the thymus.
(b) Secondary lymphoid organs - The spleen, lymph nodes, tonsils, Peyer’s patches of the small intestine, and appendix.
7. The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form:
(a) MALT
(b) CMI
(c) AIDS
(d) NACO
(e) HIV
Ans: The abbreviations with their full forms are as follows:
(a) MALT – Mucosa – Associated Lymphoid Tissue
(b) CMI – Cell-Mediated Immunity
(c) AIDS – Acquired Immunodeficiency Syndrome
(d) NACO – National AIDS control organization
(e) HIV – Human Immunodeficiency Virus
8. Differentiate the following and give examples of each:
(a) Innate and acquired immunity
Ans:
(b) Active and passive immunity
Ans:
9. Draw a well-labelled diagram of an antibody molecule.
Ans: A well-labelled diagram of an antibody molecule is drawn below.
In diagram
(a) Antigen binding site
(b) Light chain
(c) Disulphide bridges
(d) Constant region
(e) Heavy chain
(f) Variable region of light chain
(g) Constant region of light chain
(h) Disulphide bonds
10. What are the various routes by which transmission of the human immunodeficiency virus takes place?
Ans: AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV). The various modes of transmission of this virus are:
Making unprotected sexual contact with an infected person.
Transfusion of an infected person’s blood to a healthy person.
Sharing of infected needles and syringes.
Through the placenta from an infected mother to a child.
11. What is the mechanism by which the AIDS virus causes deficiency of the immune system of the infected person?
Ans: AIDS (Acquired Immunodeficiency Syndrome) is caused by the human immunodeficiency virus (HIV) through sexual or blood-blood contact. After entering the human body, HIV attacks and enters the macrophages. The RNA of the virus replicates with the help of enzyme reverse transcriptase and gives rise to viral DNA, inside the macrophages. After this, the viral DNA is incorporated into the host DNA and directs the synthesis of virus particles. Simultaneously, HIV enters into the helper T-lymphocytes. There it replicates and produces viral progeny. Now, these newly formed progeny viruses get released into the blood, attacking other healthy helper T lymphocytes in the body. As a result, the number of T-lymphocytes in the body of an infected person decreases progressively and hence decreases the immunity of a person.
12. How is a cancerous cell different from a normal cell?
Ans: The differences are given below in the table.
13. Explain what is meant by metastasis.
Ans: Metastasis Property is exhibited by malignant tumours. and it is the pathological process of spreading cancerous cells to the different parts of the body. These cells divide uncontrollably, forming a mass of cells called tumours. From the tumour, some cells get sloughed off and enter into the bloodstream. Through the bloodstream, these cells reach different parts of the body, and therefore, by dividing actively at their position they begin the formation of new tumours
14. List the harmful effects caused by alcohol/drug abuse.
Ans: Alcohol and drugs have several adverse effects on the individual, his family, and society. The list of harmful effects is given below:
(A) Effects of alcohol:
(a) Effects on the Individual: Alcohol harms the body of an individual. The consumption of excess alcohol by an individual causes damage to the liver and the nervous system. This results in the appearance of other symptoms such as depression, fatigue, aggression, loss of weight, and appetite in the individual. Sometimes, extreme levels of alcohol consumption may also lead to heart failure, resulting in coma and death. Also, pregnant women should avoid alcohol as it may inhibit the normal growth of the baby.
(b) Effects on the Family:
Consumption of excess alcohol by any family member is having devastating effects on the family. It may lead to several domestic problems such as quarrels, frustrations, insecurity, etc.
(c) Effects on Society:
(i) Rash behavior
(ii) Malicious mischief and violence
(iii) Deteriorating social network
(iv) Loss of interest in social and other activities
(B) Effects of Drugs: An individual who is addicted to using drugs can create several problems not only for himself but also for his family too.
Effects on the Individual: Drugs harm the central nervous system of an individual which results in the malfunctioning of several other organs of the body such as the kidney, liver, etc. In these individuals, the spread of HIV is most common because they share common needles while injecting drugs into their bodies. On both males and females drugs have long-term side effects which include increased aggressiveness, mood swings, and depression.
Effects on the Family and Society: A person addicted to drugs creates problems for his family and society too. That person becomes frustrated, irritated, and anti-social.
15. Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
Ans: Yes, I think that friends can highly influence a person to take drugs or alcohol. Following steps should be taken by a person for protecting himself/herself against drug abuse:
(a) Increase your willpower to stay away from alcohol and drugs. For curiosity and fun, one should not experiment with alcohol.
(b) Avoid the company of drug-taking friends.
(c) Seek help from parents and peers.
(d) Take proper knowledge and counseling about drug abuse and devote your energy to other extracurricular activities.
(e) If symptoms of depression and frustration become apparent, seek immediate professional and medical help from psychologists and psychiatrists.
16. Why is it that it is difficult to get rid of this habit once a person starts taking alcohol or drugs? Discuss it with your teacher.
Ans: Drug and alcohol consumption has an inherent addictive nature related to euphoria and a short-lived feeling of well-being. Repeated intake of medicine increases the tolerance level of the body’s receptors, resulting in more consumption of medicine.
17. In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?
Ans: Many factors are liable for motivating youngsters towards alcohol or drugs. The initial causes of motivation are curiosity, the need for adventure and excitement, experimentation. Some youngsters start consuming drugs and alcohol to beat negative emotions (such as stress, pressure, depression, frustration) and to excel in various fields. Several mediums like television, the internet, newspaper, movies, etc. are also responsible for promoting the idea of using alcohol for fun to the younger generation. Among these factors, reasons such as unstable and unsupportive family structures and peer pressure can also lead an individual to depend on drugs and alcohol. Preventive measures that work against addiction to alcohol and drugs too are given below:
(a) Parents should motivate and try to increase the willpower of their children.
(b) Parents should educate their children regarding the ill effects of alcohol. They should provide them with proper knowledge and counselling regarding the consequences of addiction to alcohol.
(c) It’s the responsibility of the parent to discourage a toddler from experimenting with alcohol. Youngsters should be kept far away from the company of friends who consume drugs.
(d) Children should be encouraged to devote their energy to other extra-curricular and recreational activities.
(e) Proper professional and medical help should be provided to the child if sudden symptoms and depression and frustration are observed.
Topics Covered in Chapter 8
Human and health and diseases, chapter 8 contains the following topics discussed throughout the chapter.
Introduction to health
Common diseases in humans
Innate immunity
Acquired immunity
Active and passive immunity
Allergies
Human immune system
AIDS
Cancer
Drugs and alcohol abuse: effects and prevention
Key Points at a Glance
Health can be defined as the condition or state in which an individual is completely well functioning in terms of physical, mental, social, and psychological well-being.
A disease is a condition when the functioning of one or more organs or systems of the body is adversely affected. Often the disease is accompanied by various symptoms.
Diseases can be broadly categorised on the basis of their transferability as Infectious and non-infectious diseases.
The disease which can pass from one individual to another through physical or non-physical contact is known as infectious diseases.
When we are exposed to disease-causing chemicals, our immune system plays a critical role in avoiding disease.
Innate and acquired immunity are two types of immunity in the immune system.
Innate immunity is a sort of non-specific defence that is present at birth. Different forms of pathogen entry barriers are used to accomplish this.
Physical, physiological, cytokine, and cellular barriers are different types of barriers found in innate immunity.
Acquired immunity is pathogen-specific acquired immunity. Memory is a defining feature of it. In case of acquired immunity when the body encounters a pathogen for the first time, it creates a low-intensity initial reaction.
A secondary or anamnestic response is elicited by subsequent encounters with the same pathogen.
Cancer is defined as the uncontrolled division of cells that results in the growth of malignant tumours.
NCERT Solutions for Class 12 Biology Chapter 8 - Human Health and Disease
The NCERT solutions of Class 12 Biology Chapter 8 PDF will give you the basic idea about the chapter. It will help the students to understand human health, diseases, and the other important terms related to it. The format of the answers will assist you in learning the chapter very well. Students can download the 12th Biology human Health and Disease PDF and refer them for practicing the questions given in the chapter.
Human Health and Disease with NCERT Solutions for Class 12 - Download PDF Now!
The NCERT Solutions for Human Health and Disease Class 12 PDF will help you to understand the chapter precisely. The chapter describes the definition of human health and certain diseases affecting it.
The NCERT Class 12 Biology Chapter 8 PDFs are prepared by experts and will assist the students to grasp the theories of Human Health and Diseases. The chapter consists of theories on diseases causing pathogens and agents. It will give a clear idea of how the pathogens use an infected human body as a host for resuming a part of its lifecycle. Students will get to learn what pathogens are and how it damages the critical parts of human physiology. The concept of immunity, AIDS, cancer, and drugs and alcohol issues in society are also covered in the NCERT Solutions of Class 12 Biology - Human Health and Disease.
In Human Health and Disease NCERT Solutions, students will get all the answers to all the questions given in the exercise of the chapter which will help them to learn the chapter systematically.
Understand the Weightage of Human Health and Disease NCERT Solutions
The Human Health and Disease Class 12 NCERT Solutions PDF will build a strong understanding of the theories covered in the chapter and also help you learn the question patterns and how to answer various types of questions. The total mark for Class 12 Biology is 70 marks for theory and 30 marks are allotted for the practical exam.
The marking scheme for unit 8 holds a weightage of 14 marks. The chapter will carry 2 to 5 marks excluding the practical exam. The Human Health and Disease Chapter 8 Biology Class 12 NCERT Solutions will help the students prepare the chapter for their exams.
Benefits of Human Health and Disease Class 12 NCERT Solutions
The NCERT Solutions of Class 12 Human Health and Disease will help the students to learn and understand the chapter thoroughly. Here are some of the benefits of studying the class 12th Biology - Human Health and Disease NCERT Solutions.
The questions and answers of the chapters are accurate and precise.
The solutions of the chapters are prepared by experienced science teachers to guide the students in understanding the chapter quickly.
These NCERT Solutions provide a brief knowledge of the subject matter and saves a lot of time during the preparation of the exam.
All the answers and the methods provided in the PDF are according to the CBSE guidelines.
The PDF files of Chapter 8 Biology Class 12 NCERT Solutions are easily accessible and free to download.
All essential questions are covered in the Class 12 Biology Chapter 8 NCERT Solutions. Hence, students will not have any difficulty gathering the study material.
Therefore, the NCERT Solutions for 12th Biology Human Health and Disease will help the students in understanding the concepts covered in the chapter and securing good marks in the exam.
Access Other Chapters of NCERT Solutions for Class 12 Biology
NCERT Solutions for Class 12 Biology Chapter 1 Reproduction in Organism
NCERT Solutions for Class 12 Biology Chapter 2 Sexual Reproduction in Flowering Plant
NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction
NCERT Solutions for Class 12 Biology Chapter 4 Reproductive Health
NCERT Solutions for Class 12 Biology Chapter 5 Principle of Intelligence and Variation
NCERT Solutions for Class 12 Biology Chapter 6 Molecular Basis of Inheritance
NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production
NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare
NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principle and Process
NCERT Solutions for Class 12 Biology Chapter 12 Biotechnology and Application
NCERT Solutions for Class 12 Biology Chapter 13 Organism and Population
NCERT Solutions for Class 12 Biology Chapter 15 Biodiversity and Conservation
NCERT Solutions for Class 12 Biology Chapter 16 Environmental Issues
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FAQs on NCERT Solutions for Class 12 Biology Chapter 8 - Human Health And Disease
1. What are the effects of overdose usage of LSD, amphetamines, and barbiturates in humans?
LSD, barbiturates, or amphetamines are used to treat mental illness. However, the excessive use of these medicines leads to a severe impact on the body. A person may have an appetite or weight fluctuations issues, social adjustment problems, depression, aggressive behaviour, or fatigue. The person may also go through anxiety, sweating, and nausea, shakiness, or loss of mind control. Due to extreme use of these dosages a person may sink to coma and even die due to cerebral hemorrhage respiratory failure or heart failure.
2. State the importance of vaccination.
Vaccines are the medications that prepare the body to battle against a disease without getting endangered to the disease. It is a substance that incites a person’s immune system to build immunity for a specific disease, defending the person from that disease. Vaccines are generally offered through needle injections, but can also be administered by spraying into the nose or mouth. The vaccine is based on the principle of ‘memory’ of the immune system. In vaccination, a form of antigenic proteins is injected into the body. These antigens produce a primary immune response by producing antibodies with memory B-cells and T-cells.
3. What is the difference between infectious and non-infectious diseases?
Infectious diseases are caused by pathogenic microorganisms like bacteria, viruses, fungi, and protozoa, whereas non-infectious diseases are caused by factors like genetic abnormalities, lifestyle, environment, and nutrition.
4. What is the difference between a virus and a bacterium?
Bacteria are unicellular prokaryotic organisms, while viruses are non-living particles that require a host cell to replicate. Bacteria are susceptible to antibiotics, while viruses are not.
5. What is HIV/AIDS?
The Human Immunodeficiency Virus (HIV) is a virus that targets the immune system, the body's natural defense against infections and diseases. The virus predominantly targets CD4+ T cells, a kind of white blood cell that is essential to the immune system. The virus gradually destroys these cells as it replicates, resulting in a compromised immune system.
AIDS (Acquired Immunodeficiency Syndrome) is a disease that occurs when the immune system is severely compromised by HIV, leaving the body vulnerable to a variety of infections and disorders. People living with AIDS frequently develop life-threatening illnesses such as pneumonia, tuberculosis, and certain types of cancer. If not treated appropriately, AIDS can be lethal.
HIV is spread mostly through contact with infected bodily fluids such as blood, sperm, vaginal secretions, and breast milk. The virus can be transmitted by unprotected sexual contact, needle sharing, mother-to-child transmission during pregnancy, childbirth, or breastfeeding, and, in rare cases, transfusion of contaminated blood. Although there is no cure for HIV/AIDS, antiretroviral therapy (ART) can help manage the virus and prevent the disease from progressing to AIDS.
6. What is the difference between acute and chronic diseases?
Acute diseases are those that develop suddenly and last for a short period, usually days or weeks. They are often caused by infections and injuries, and the symptoms can be severe. Examples of acute diseases include influenza, appendicitis, and pneumonia. Acute diseases can often be treated effectively with medications and other medical interventions, and the patient typically recovers within a few weeks.
Chronic diseases, on the other hand, develop slowly and persist for a long time, usually for months or years. They are often caused by genetic or lifestyle factors such as poor diet, lack of exercise, or smoking. Chronic diseases can cause irreversible damage to the body's organs and tissues, and the symptoms can be mild or severe. Examples of chronic diseases include diabetes, arthritis, and heart disease. While there may be no cure for chronic diseases, they can be managed through lifestyle changes, medications, and other medical interventions.