Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Diseases

ffImage
widget title icon
Latest Updates

widget icon
Start Your Preparation Now :
CBSE Date Sheet 2025 Class 12 Released

Class 12 Biology Chapter 7 Human Health and Diseases NCERT Solutions- FREE PDF Download

Embark on your journey with Vedantu through Class 12 Biology Chapter 7, Human Health and Diseases NCERT Solutions. This chapter includes topics such as diseases, immunity, AIDS, cancer, etc. This gives access to human health and diseases class 12 PDF. By accessing Biology Chapter 7, Human Health and Diseases Class 12 NCERT, students gain comprehensive insights into the core concepts outlined in the curriculum. 

toc-symbol
Table of Content
1. Class 12 Biology Chapter 7 Human Health and Diseases NCERT Solutions- FREE PDF Download
2. Glance on Biology Chapter 7 Human Health and Diseases Class 12 NCERT Solutions
3. Class 12 Biology Chapter 7 - Human Health and Diseases NCERT Solutions
4. Topics Covered in Class 12  Chapter 7: Human Health and Diseases
5. Benefits of Learning With Human Health and Diseases Class 12 NCERT Solutions
6. Important Study Materials For Chapter 7- Human Health and Diseases 
7. NCERT Solutions for Class 12 Biology | Other Chapter-wise Links
8. Other Related Links for Class 12 Biology
FAQs


With a focus on clarity and depth, these resources serve as indispensable tools for students navigating through human health and diseases NCERT PDF. Download the Human Health and Diseases Class 12 PDF, which is updated according to the revised class 12 Biology syllabus. Get started with Vedantu to embark on a journey of academic excellence. 


Glance on Biology Chapter 7 Human Health and Diseases Class 12 NCERT Solutions

  • Detailed explanations for human health and diseases NCERT Solutions and a free PDF packed with clear concepts are provided.

  • The 12th biology 7th chapter exercise will give you a basic idea about the chapter. It will help the students understand human health, diseases, and other important related terms. 

  • 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 to resume a part of their lifecycle. 

  • Students will get to learn what pathogens are and how they damage critical parts of human physiology. The concepts of immunity, AIDS, cancer, and drug and alcohol issues in society are also covered in the NCERT Solutions of Class 7 Biology Human Health and Disease. 

  • In Human Health and Diseases Class 12 NCERT solutions, students will get all the answers to all the questions given in the chapter exercise, which will help them learn the chapter systematically.

Competitive Exams after 12th Science
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow

Class 12 Biology Chapter 7 - Human Health and Diseases NCERT Solutions

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:

        Disease

  Causative Organism

                  Mode of Transmission

(a) Amoebiasis 

Entamoeba histolytica

It is a vector-borne disease and it spreads by the means of contaminated food and water. The housefly is the vector involved in the transmission of this disease.

(b) Malaria  

Plasmodium spp.

It is a vector-borne disease that spreads by the biting of the female Anopheles mosquito.

(c) Ascariasis 

Ascaris lumbricoides

It spreads via contaminated food and water through faecal-oral transmission.

(d) Pneumonia 

Streptococcus pneumoniae

It spreads through the sputum of an infected person via droplet infection.


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:

Innate  Immunity 

Acquired Immunity

It is a non-pathogen-specific type of defence mechanism.

It is a pathogen-specific type of defence mechanism.

It is inherited from parents and protects the individual from birth.

It does not remain present in the individual from birth but is acquired after birth.

This type of immunity provides barriers against the entry of foreign infectious agents.

It operates by providing primary and secondary responses, which are mediated by B-lymphocytes and T-lymphocytes.

It does not have a specific memory.

It is characterized by immunological memory.


(b) Active and passive immunity 

Ans:

Active Immunity 

Passive Immunity 

It is a type of acquired immunity in which the body produces its antibodies against disease-causing antigens.

It is a type of acquired immunity in which readymade antibodies are transferred from one individual to another.

It has a long-lasting effect.

It does not have a long-lasting effect.

It is slow and takes time in producing antibodies and giving the response.

It is fast and provides immediate relief.

Microbes are injected inside the body through the process of vaccination. This is an example of active immunity.

The transfer of antibodies that are present in the mother’s milk, to the infant is an example of passive immunity.


9. Draw a well-labelled diagram of an antibody molecule. 

Ans: A well-labelled diagram of an antibody molecule is drawn below.


Antibody Molecule


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:

  1. Making unprotected sexual contact with an infected person.  

  2. Transfusion of an infected person’s blood to a healthy person.

  3. Sharing of infected needles and syringes.  

  4. 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.

Normal Cell

Cancerous Cell

The normal cells show the property of contact inhibition. Therefore, when these cells come into contact with other cells, they stop dividing.

The cancerous cells lack the property of contact inhibition. Therefore they continue to divide, thereby forming a mass of cells or tumours.

After attaining a specific growth level, the normal cells undergo the process of differentiation.

They do not undergo differentiation.

At a particular location, the normal cells remain confined.

These cells do not remain confined at a particular location. They move into neighbouring tissues and disturbs their function.


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. 

  1. 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. 

  2. 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 Class 12  Chapter 7: Human Health and Diseases

List of Topics Covered in Class 12 Chapter 7: Human Health and Diseases

Topics

Subtopics

Common diseases in humans

-

Immunity 

Innate Immunity, Acquired Immunity, Active and Passive Immunity, Vaccination and Immunisation, Allergies, Autoimmunity, Immune System in the Body,

AIDS

-

Cancer

-

Drugs and alcohol abuse

Adolescence and Drug/Alcohol Abuse, Addiction and Dependence, Effects of Drugs/Alcohol Abuse



Benefits of Learning With Human Health and Diseases Class 12 NCERT Solutions

The Human Health and Diseases class 12 NCERT will help the students to learn and understand the chapter thoroughly. Here are some of the key features of studying the 12th biology 7th chapter exercise.


  • Detailed explanations and step-by-step solutions for all topics in the chapter.

  • Includes topics like common diseases in humans, immunity, AIDS, cancer, drugs, and alcohol abuse.

  • NCERT Solutions for Human Health and Diseases Class 12 is curated by experienced educators to ensure accuracy and clarity.

  • Covers important concepts such as the immune system, types of immunity, and the role of pathogens in diseases.

  • Clear and concise explanations using precise biological terminology.

  • Detailed analysis of the causes, symptoms, and prevention of various diseases.

  • Aligned with the latest CBSE syllabus and exam pattern.

  • In-depth analysis of key concepts and their applications in real-life scenarios.

  • Detailed explanation of topics like the lifecycle of the malarial parasite, cancer and its types, and the effects of drugs and alcohol on the human body.


Important Study Materials For Chapter 7- Human Health and Diseases 



Conclusion

The human health and diseases class 12 NCERT solutions provide an invaluable resource for students studying the topic in-depth. The 12th biology 7th chapter exercise covers all the questions related to the chapter. The solutions provide accurate answers and offer additional explanations, examples, and relevant diagrams to facilitate better comprehension of the subject matter and effectively prepare students for board exams.


NCERT Solutions for Class 12 Biology | Other Chapter-wise Links

The other chapter-wise links for NCERT Solutions for Class 12 Biology are given below.




Other Related Links for Class 12 Biology

FAQs on NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Diseases

1. What are the effects of overdose usage of  LSD, amphetamines, and barbiturates in humans from human health and diseases class 12 exercise?

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 discussed in human health and diseases class 12 NCERT.

Vaccines are medications that prepare the body to battle a disease without getting endangered by 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 HIV/AIDS from human health and diseases NCERT?

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.

5. 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.

6. What do you mean by human health and diseases NCERT PDF?

Human Health and Diseases class 12 PDF comprises all the questions and answers related to the 12th biology 7th chapter exercise, which helps students solve and clear their doubts about this chapter.

7. Why is the Human Health and Diseases Class 12 PDF important?

The Human Health and Diseases NCERT PDF is designed to give clear and effective answers for students preparing for their board exams.

8. According to class 12 Biology Chapter 7, how do we maintain our health?

Here are some points:

  • Eat a balanced diet.

  • Limit processed foods.

  • Maintain a healthy weight.

  • Get enough sleep.

  • Manage stress.

  • Schedule regular checkups.

Students can learn more about health and related concerns for human health and diseases in class 12 exercise.

9. Where can we find human health and diseases NCERT solutions?

Vedantu provides all the solutions related to Chapter 7 and access to human health and diseases NCERT PDF for all the students navigating through the questions and doubts related to Class 12 Biology Chapter 7.