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

As per the revised curriculum of CBSE Syllabus 2023-24, this chapter, previously known as Chapter 8, has now been renumbered as Chapter 7. Stay updated with the latest changes in the curriculum.

Human Health and Disease Class 12 NCERT Solutions are all about human health and human-related disease. These NCERT Solutions are prepared by our Top Biology Experts in order to take care of all Important Topics that might be asked in the upcoming examination 2023. So, Students can also refer to these solutions for their final Examination preparation.

This Class 12 Biology Chapter 7 Human Health and Disease NCERT solution was carefully developed using easy-to-understand language while adhering to the guidelines for solving NCERT Solutions for Class 12. Working through these solutions can be highly beneficial for students in their board exams, as well as in preparing for future competitive Exams.

Human Health and Disease Class 12 Questions and Answers

NCERT Solution for Chapter 07 Human Health and Disease explain how various pathogens complete their life cycles, how they infect us, and how their transmission occurs. It also helps us to understand the immune system of our body along with its various components. Revise the basic concepts of Human Health and Disease for quick revision and class notes.

Q1: What are the various public health measures, which you would suggest as a safeguard against infectious diseases?

Answer:

Various public measures should be taken as a safeguard against infectious diseases;

1. Sewages and excreta must be treated and disposed of properly.
2. Cleaning and sanitization of public water sources should be made periodically.
3. Personal hygiene like regular baths and hand washes should be maintained properly.
4. Washing and cleaning of food items should be done properly before consumption.
5. Clean water should be used for consumption.
6. Clothes should be washed regularly.
7. Infected persons should be isolated and then treat properly to prevent the spread of diseases.
8. Surroundings should be cleaned regularly to prevent the breeding of disease-carrying vectors. 

Q2: In which way has the study of biology helped us to control infectious diseases?

Answer:

The study of biology and the developments associated with it has helped us to understand how various mechanisms in our body work, how various diseases affect our body’s system, and how our immune system works. The study of biology helped us to understand how the life cycle of parasites and their vectors work. With the help of this information, scientists were able to design vaccines like rabies vaccine, smallpox vaccine, BCG vaccine, etc. This information also helped the scientist to design more suitable and effective drugs, antitoxins, and antibiotics that play an important role in the treatment of various communicable diseases. 

Q3: How does the transmission of each of the following diseases take place? 

• Amoebiasis
• Malaria 
• Ascariasis 
• Pneumonia

Answer:

The causative agent of Amoebiasis is Entamoeba histolytica which is transmitted by the vector housefly to the food and water bodies thus contaminating them when taken causing the infection. The causative agent of Malaria is Plasmodium sp. and is transmitted by the vector female Anopheles mosquito. The causative agent of Ascariasis is Ascaris lumbricoides which is transmitted by contaminated food and water with the fecal matter of the infected person. The causative agent of Pneumonia is Streptococcus pneumonia which is transmitted by sputum droplets from an infected person. 

Q4: What measures would you take to prevent water-borne diseases?

Answer:

Waterborne diseases like typhoid, amoebiasis, cholera, etc. can be prevented by drinking boiled water, disinfecting and cleaning public water sources like reservoirs, ensuring proper disposal of wastes, sewage, excreta, keeping the surroundings clean, eliminating breeding grounds for vectors and parasites, etc. 

Q5: Discuss with your teacher what ‘a suitable gene’ means, in the context of DNA vaccines.

Answer:

To prepare a DNA vaccine a target DNA is required that when inserted inside the cells of the host’s body results in the production of certain specific proteins that helps in providing immunity against the disease and helps to cure the condition.

Q6: Name the primary and secondary lymphoid organs.

Answer:

Lymphoid organs are those organs of the lymphatic system of the body where the origin, maturation, and proliferation of lymphocytes take place. There are two types of lymphoid organs found in the body; primary lymphoid organs which include bone marrow and thymus, and secondary lymphoid organs which include tonsils, lymph nodes, spleen, Peyer’s patch of small intestine, and appendix. 

Q7: The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form: 

• MALT 
• CMI 
• AIDS 
• NACO 
• HIV

Answer:

Full forms of the given abbreviations are;

1. MALT– Mucosa-Associated Lymphoid Tissue
2. CMI– Cell-Mediated Immunity
3. AIDS– Acquired Immuno Deficiency Syndrome
4. NACO– National AIDS Control Organization
5. HIV– Human Immuno-Deficiency Virus

Q8: Differentiate the following and give examples of each:

• Innate and acquired immunity
• Active and passive immunity

Answer:

(a) Innate and acquired immunity

Innate Immunity	Acquired Immunity
The type of immunity that is inherited from parents since birth.	It is acquired from the surrounding after birth.
It is a non-specific type of defense mechanism.	It is a specific type of defense mechanism.
It provides a barrier against the entry of infectious agents.	It provides primary and secondary cellular defense after the entry of an infectious agent.
It does not provide any specific memory against the pathogen.	It provides specific memory against the pathogen.
Example includes skin, stomach acid, etc.	Examples include T-cells, B-cells, etc.

(b) Active and passive immunity

Active Immunity	Passive Immunity
The immunity develops when the immune system comes in contact with the pathogen.	The immunity develops when readymade antibodies are injected directly into the body.
It is a slow but long-lasting form of immunity.	It is fast acting but short-lasting form of immunity.
It doesn’t have any side effects.	It may show a reaction.
Creates a memory.	Does not create a memory.
Example includes the polio vaccine, etc.	Example includes tetanus antitoxin, etc.

Q9: Draw a well-labeled diagram of an antibody molecule.

Answer:

Well, labeled diagram of an antibody molecule;

Q10: What are the various routes by which transmission of human immunodeficiency virus takes place?

Answer:

Routes of transmission of human immunodeficiency virus;

1. Sexual contact with multiple partners is unprotected.
2. Sharing of needles or syringes.
3. Transmission through the placental barrier from an infected mother to the fetus.
4. Transfusion of infected blood from one person to another.

Q11: What is the mechanism by which the AIDS virus causes a deficiency of the immune system of the infected person?

Answer:

The virus enters the human circulatory system either through sexual contact or by blood-to-blood transfer. Once inside the circulatory system, it infects the macrophages where the genetic material of the virus gets incorporated with the cell’s genetic material thus directing the synthesis of more viral particles. Then the virus particles attacks T-lymphocyte cells and infect them to produce more viral progenies. This results in the rapid increase of viral load in the body and the destruction of immune cells to fight against them makes the host immune-compromised. 

Q12: How is a cancerous cell different from a normal cell?

Answer:

Cancerous cells lack the property of contact inhibition i.e. they do not stop dividing even in contact with other cells, they do not undergo differentiation, and they can invade neighboring tissues causing a disturbance in their functioning. Whereas normal cells show contact inhibition, undergo differentiation, and remain confined to their particular location.

Q13: Explain what is meant by metastasis.

Answer:

It is a pathological condition in which a cancerous cell divides uncontrollably to form a mass of cells called the tumor that sloughs off and with the help of the circulatory system reaches different parts of the body where it invades the tissues and induces contact inhibition to form more cancerous cells. 

Q14: List the harmful effects caused by alcohol/drug abuse.

Answer:

The harmful effects of alcohol/drug abuse are;

1. The general functioning of the nervous system gets impaired due to which a person loses the ability to judge, behave, etc.
2. Drugs impair the functioning of the CNS which in turn impairs the normal functioning of various organs of the body. 
3. Causes gastric carcinoma, liver cirrhosis, peptic ulcer, etc. conditions.
4. The long-term effect includes reckless behavior, depression, weight loss, etc.
5. Sharing needles for taking drugs may spread various blood-borne transmissible diseases like AIDS, hepatitis, etc.
6. Loss of interest in social activities.
7. Makes a person aggressive, induces sudden mood swings, anti-social behavior, etc. 
8. Lack of concentration and focus to do any work.
9. May result in domestic violence, insecurity, etc. 
10. May result in heart failure, coma, and even death. 

Q15: Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?

Answer:

Yes, in my opinion, a person may get influenced by their peers. This is called peer pressure and to protect oneself from such negative pressure following steps can be taken;

1. Control over curiosity to try alcohol/drugs.
2. Must develop a strong willpower to stay away from drugs/alcohol.
3. Must seek help from parents, elders, or teachers.
4. Must keep one busy in positive and constructive extracurricular activities. 
5. Seek knowledge and counseling regarding alcohol/drug abuse.
6. Seek medical and professional help in case of requirement.
7. Avoid such company of friends who puts such pressure. 

Q16: 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.

Answer:

Alcohol and drugs impact the nervous system of the body that causes euphoria, temporary feelings of well-being, and addiction. More intakes cause psychological dependence that results in increased consumption and becomes very difficult to get rid of. And when forced to discontinue it causes withdrawal syndrome that may even become severe and life-threatening. 

Q17: In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided? 

Answer:

Motivating factors for youngsters to take alcohol or drugs are;

1. Curiosity to try
2. Need for excitement and adventure
3. As an attempt to overcome frustration, stress, and other negative emotions
4. As a stimulant to focus to excel 
5. As a result of an induced idea from various forms of media
6. Peer pressure
7. Unsupportive and unstable family conditions

To avoid such motivating factors one has to;

1. Support and understanding from parents
2. Proper education and knowledge of the ill effects
3. Discouraging to experiment with drugs and alcohol
4. Promotion of positive and constructive extra-curricular activities
5. Seeking proper medical and professional help
6. Proper communication with children
7. Should stay away from bad company

Key Features of NCERT Solutions Class 12 Biology Chapter 7 Human Health and Disease

• They enhance the conceptual knowledge of the students.
• Clear and Comprehensible Content.
• Aid in Competitive Exam Preparation.
• The answers are provided by Top subject experts.
• Readily available and easily accessible.

FAQs on Human Reproduction Class 12 NCERT Solution

Q1: What is the name of chapter 7 of NCERT class 12 Biology?

Answer:

Class 12 Biology Chapter 7 name is Human Health and Disease which explains human diseases their cause and their Mode of Transmission.

Q2: Where can I find NCERT solutions for Class 12 Biology Chapter 7?

Answer:

NCERT solutions for Class 12 Biology Chapter 7 can be found on various online platforms such as the official NCERT website, GeeksForGeeks, and more.

Q3: Why are NCERT Solutions for Class 12 Biology Chapter 7 beneficial for the students??

Answer:

The benefits of using the NCERT Solutions for Class 12 Biology Chapter 7 are:

1. Completely solved answers for all the questions present in the NCERT textbook are available in PDF format.
2. Simple and easy-to-understand language is used to make learning fun for the students.
3. Top Subject matter experts prepare the solutions after conducting vast research on each concept.
4. The solutions not only help students with their board exam preparation but also for various competitive exams like JEE, NEET, etc.