NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease
Neha Tanna27 Dec, 2024
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NCERT Solutions for Class 12 Biology Chapter 7: Chapter 7, Human Health and Disease , in Class 12 Biology, focuses on understanding health, common diseases, their causes, and preventive measures. It explains the immune system, its components (innate and adaptive immunity), and mechanisms like the antigen-antibody interaction.
The chapter covers infectious diseases like malaria, AIDS, and cancer, detailing their symptoms, causes, and treatment. Lifestyle disorders such as drug and alcohol abuse are also discussed, emphasizing their impact on health. Additionally, the chapter highlights vaccination, principles of immunization, and public health strategies to combat diseases, fostering awareness about maintaining a healthy lifestyle and combating various health challenges.NCERT Solutions for Class 12 Biology Chapter 7 Overview
Chapter 7, Human Health and Disease, in Class 12 Biology is crucial for understanding the factors influencing health and managing diseases. It explores the immune system, its role in combating pathogens, and mechanisms like vaccination and immunization. The chapter addresses the importance of disease prevention and management, covering ailments like malaria, AIDS, and cancer. It also emphasizes the consequences of lifestyle choices such as drug and alcohol abuse. By providing insights into public health strategies and immunity principles, this chapter equips students with the knowledge to make informed health decisions, contributing to individual well-being and a healthier society.NCERT Solutions for Class 12 Biology Chapter 7 PDF
Chapter 7, Human Health and Disease , in Class 12 Biology explains the immune system, common diseases, their causes, and preventive measures. It highlights concepts like vaccination, immunity, and disease management. To help students understand better, we have provided detailed NCERT Solutions for this chapter in PDF format, which you can download below for easy reference and exam preparation.NCERT Solutions for Class 12 Biology Chapter 7 PDF
NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease
Below is the NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease -1. What are the various public health measures, which you would suggest as safeguard against infectious diseases?
Solution:
Public health measures are the measures taken to prevent and check the spread of different infectious diseases. It is taken to lessen contact with infectious agents. Some of these preventive measures are as follows:- Isolation – It prevents the spreading of airborne diseases (chicken pox, pneumonia, tuberculosis, etc.). We isolate an infected person to reduce the chances of the disease spreading.
- Vaccination – It protects the body against communicable diseases by administering some agents that impersonate the microbe in the body. This helps in rendering passive immunization to the body. Vaccines are available for some diseases, such as mumps, polio, measles, etc.
- Vector-borne diseases like dengue and malaria can be prevented by keeping the environment clean and stopping mosquito breeding. This includes preventing water from stagnating near homes, regularly cleaning water coolers, and using mosquito nets and insecticides. Adding fish like Gambusia to ponds can also help control mosquito larvae.
- Maintaining hygiene is key to avoiding infectious diseases. Personal hygiene involves keeping the body clean, eating healthy food, and drinking clean water. Public hygiene includes properly disposing of waste, treating water reservoirs, and ensuring sanitation to keep the surroundings clean and safe.
2. In which way has the study of biology helped us to control infectious diseases?
Solution:
Biology is a vast field of Science dealing with life forms and their processes. It has helped in controlling infectious diseases in the following ways:- Complete eradication of fatal diseases such as smallpox was possible with the use of immunization schemes and vaccines
- Other infectious diseases, such as diptheria, polio, pneumonia, etc., have been successfully controlled with the use of vaccines
- Treatment of several infectious diseases have successfully been carried out with the use of antibiotics and other drugs
3. How does the transmission of each of the following diseases take place?
(a) Amoebiasis (b) Malaria (c) Ascariasis (d) Pneumonia
Solution:
The transmission of diseases is as given in the table:| Name of the disease | Transmission |
| Amoebiasis | Ingestion of quadrinucleated cysts of Entamoeba histolytica can cause the cysts to be passed from the patient’s faeces via water and food. |
| Malaria | Plasmodium, or the malarial parasite, is communicated to a healthy person from a patient when bitten by a female Anopheles mosquito |
| Ascariasis | It can be passed by ingesting contaminated water and food with the embryonated eggs of Ascaris |
| Pneumonia | Transmitted by droplets and sputum given out when patient coughs. It is a bacterial disease |
4. What measure would you take to prevent water-borne diseases?
Solution:
Measures taken to prevent water-borne diseases are as follows:- Provision of clean water for drinking
- Industries should be prohibited from discharging wastes into water bodies
- Frequent cleaning and disinfecting of water tanks and reservoirs
5. Discuss with your teacher what does ‘a suitable gene’ mean, in the context of DNA vaccines.
Solution:
The phrase "suitable gene" describes a specific DNA segment that can be changed in the host to produce a specific protein that targets and eliminates a particular disease-causing organism.6. Name the primary and secondary lymphoid organs.
Solution:
Primary lymphoid organs are – Thymus and bone marrow Secondary lymphoid organs are – Mucosal-associated lymphoid tissues (MALT), Lymph nodes, Spleen, Peyer’s patches (small intestine)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
Solution:
The expansion is as follows: (a) MALT – Mucosal-Associated lymphoid tissues (b) CMI – Cell-mediated Immunity (c) AIDS – Acquired Immuno-Deficiency Syndrome d) NACO – National Aids Control Organization (e) HIV – Human Immuno-deficiency Virus8. Differentiate the following and give examples of each:
(a) Innate and acquired immunity (b) Active and passive immunity
Solution:
The differences are as follows:(a) Innate and acquired immunity
| Innate immunity | Acquired immunity |
| Non-specific in nature | Specific in nature |
| Present from birth | It is acquired in response to a particular pathogen |
| Has different barriers | Has a memory of antibody |
| For instance, mucus traps bacteria and other particles | For instance, post-vaccination antibodies respond |
(b) Active and passive immunity
| Active immunity | Passive immunity |
| In response to pathogens, the body releases antigens | To initiate immunity, an antigen is injected |
| Slower response | Faster response |
| For instance, post-vaccination antibodies respond | For instance, Colostrum is rich in antibodies |
9. Draw a well-labelled diagram of an antibody molecule.
Solution:
The diagram is as follows:
10. What are the various routes by which transmission of human immunodeficiency virus takes place?
Solution:
The various routes by which transmission of the human immunodeficiency virus (HIV) takes place are as follows:- Sexual relation with the person infected
- Organ transplantation from an infected person
- Transfusion of contaminated blood products and blood
- Transmitted from mother to the child through the placenta
11. What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?
Solution:
When HIV enters the body, it targets macrophages, where its RNA is converted into DNA using the enzyme reverse transcriptase. This viral DNA merges with the host cell's DNA, causing the infected cells to produce new virus particles. Macrophages act as factories for HIV production. HIV also infects helper T-lymphocytes, where it replicates and releases new viruses into the blood. These viruses attack more helper T-lymphocytes, repeating the cycle and progressively reducing their number. Over time, this leads to a significant drop in helper T-lymphocytes, weakening the immune system. This condition is known as acquired immunodeficiency.12. How is a cancerous cell different from a normal cell?
Solution:
The differences are as follows:| Cancerous cell | Normal cell |
| As these cells do not possess the property of contact inhibition, they keep dividing, forming a cluster of cells | As these cells possess the property of contact inhibition, they stop dividing once they come in touch with other cells |
| Do not experience differentiation | Experience differentiation after attaining growth |
| Cells are not confined; they move to the adjacent tissues and interrupt their functioning | The cells are confined to a specific location |
13. Explain what is meant by metastasis.
Solution:
Metastasis is a harmful process seen in malignant tumors where cancer cells spread to other parts of the body. These cells break away from the original tumor, enter the bloodstream, and travel to distant areas. Once there, they start dividing uncontrollably, forming new tumors in different parts of the body.14. List the harmful effects caused by alcohol/drug abuse.
Solution:
Here are the harmful effects of alcohol and drug abuse in simple terms:- Physical Health Issues : Causes liver damage, heart problems, and weakens the immune system.
- Mental Health Problems : Leads to anxiety, depression, and memory loss.
- Addiction : Makes it hard to stop using, causing dependence on alcohol or drugs.
- Behavioral Changes : Causes aggression, poor decision-making, and social withdrawal.
- Impact on Family : Creates conflicts, stress, and financial problems.
- Social Issues : Leads to poor performance in studies or work and damages relationships.
- Accidents : Increases the risk of road accidents and injuries.
- Risk of Diseases : Raises chances of infections like HIV and hepatitis due to unsafe practices.
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?
Solution:
Yes, friends can have an influence on friends to start taking drugs and consuming alcohol. The following actions can be taken as precautionary measures to protect oneself from alcohol/drug abuse, they are:- One must have a strong control over his/her will. One should refrain from experimenting with alcohol just for the sake of trying/curiosity/fun, etc.
- Stay away from people who are into drugs.
- Seek elderly advise, peer or medical assistance.
- Enlighten yourself with enough knowledge about the consequences of drug abuse.
- Go in for a counselling session.
- Take up some hobby/extracurricular activity.
- If depression or frustration levels persist or heighten, seek immediate medical or professional help.
16. Why is it that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.
Solution:
Alcohol consumption and usage of drugs have a significant, addictive impact related with euphoria, rendering a short feeling of well-being. Regular intake of drugs can increase the tolerance level of the receptors of the body, which furthermore leads to increased drug consumption.17. In your view, what motivates youngsters to take to alcohol or drugs and how can this be avoided?
Solution:
Several factors lead young people to use drugs or alcohol. Common reasons include curiosity, excitement, a sense of adventure, or wanting to try something new. Some turn to these substances to cope with negative emotions like stress, depression, or frustration, hoping it will help them perform better. Media, like TV, movies, or the internet, often promote alcohol use, influencing the youth. Other reasons include lack of family support, unstable relationships, and peer pressure, which can push individuals toward drug or alcohol use. Some of the preventive measures against the use of drugs and alcohol are as follows:- Motivation from parents and elders to develop strong willpower against it
- Awareness about the ill effects of alcohol should be inculcated in children by parents. Proper counselling and knowledge must be given regarding the repercussions of alcohol addiction.
- Parents should take responsibility for monitoring the social circle of their children and must advise them against the wrong company
- Encourage students to dedicate their energy to other activities
- Proper medical and professional assistance should be provided if symptoms of depression and frustration are observed.
Benefits of Using NCERT Solutions for Class 12 Biology Chapter 7
Using NCERT Solutions for Class 12 Biology Chapter 7, Human Health and Disease , offers several benefits:Comprehensive Understanding : Provides detailed answers that help clarify complex concepts like immunity, vaccination, and disease mechanisms.
Exam Preparation : Offers step-by-step explanations aligned with the NCERT syllabus, aiding in scoring well.
Concept Reinforcement : Strengthens understanding of diseases, their prevention, and health management.
Time-Saving : Helps students quickly find accurate answers, saving time during revision.
Confidence Building : Clear explanations boost confidence in tackling textbook questions.
Accessible Format : Available in PDF for easy access anytime, anywhere.
NCERT Solutions for Class 12 Biology Chapter 7 FAQs
What is the concept of human health and disease?
What is the relationship between disease and health?
What are antibodies in human health and disease?
How many types of diseases are in the human body?
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