Xam Idea Class 12 Biology Chapter 8 Solutions: Human Health & Diseases

Xam Idea Class 12 Biology Solutions for Chapter 8 ‘Human Health & Diseases’ will give you a brief description of the topics mentioned in the chapter. Our Xam Idea solutions shed light on some of the significant topics of the chapter such as diseases and their causes, forms of diseases, and some specific diseases. They also introduce you to wellbeing and different facets of wellness, such as the nature of human health and its significance. This chapter also deals with hazardous diseases called AIDS.

Xam Idea Biology Class 12 Human Health & Diseases solutions persist a total of 194 questions that are classified into four groups. These are very short answers, short answer types (I and II) and long answers type questions. The Xam Idea exercise questions are focused on aspects like immunity and its form, disease, diagnosis, causes, and symptoms. Our solutions for Xam Idea exercises resolves all these problems explicitly and accurately.

Our Xam Idea Solutions for Class 12 Biology chapters will help you perform exceptionally well in the board exams. You will benefit from these solutions remotely at any time of your convenience. Our solutions are really simple to grasp. These approaches are just what you need for fast, productive, and efficient knowledge and revision for entrance exams also like NEET.

Important topics of Xam Idea Class 12 Biology Solutions Chapter 8. Human Health & Disease

Human health described as the stable state of physical, social, as well as mental well-being, but not the absence of disease, sickness, or frailty, is as crucial as water, food, or energy.


Importance of Human Safety:


A healthy lifestyle is at the heart of human happiness and well-being. It also provides a significant difference to economic growth, provided that healthier people live longer, become more competitive.

  • A disease is a specific uncommon growth that has a negative influence on the development or function of some or all of parts of the body that is not attributable to any immediate external damage or injury.
  • Diseases are sometimes recognized to be health issues affiliated with specific symptoms and signs.
  • The illness can be triggered by environmental causes, such as viruses or internal dysfunctions. For instance, internal immune system dysfunction may contribute to several diseases, including various forms of immunodeficiency, hypersensitivity, allergies, or autoimmune disorders.


Four types of diseases:


There are four major types of diseases: bacterial infections, deficiency diseases, hereditary diseases (both from genetic to non-genetic disorders) as well as physiological diseases.


Common diseases in human beings are as follows:


  • A contagious disease is a subcategory of communicable diseases that are conveyed to other persons, by either physical contact with the individual suffering from the disease or through casual contact with their glands or objects infected with the disease or by air travel, among several other routes.
  • Non-infectious diseases are not spread from one human to the next and are not triggered by pathogens. Non-infectious disorders of hereditary origin are not preventable.
  • Infectious diseases are serious illnesses, which means that they may transmit from one individual to the next. Infectious diseases caused by microorganisms named pathogens.

Disease Organisms responsible Symptoms Effects
Typhoid Salmonella typhi high fever, weakness, stomach pain, Headache, high fever, etc.
Pneumonia Streptococcus pneumonia & Hemophilic influenza Fever, cough & headache. Alveoli filled fluid creates problems within the respiration system.
Common cold Rhinoviruses Nasal congestion & discharge, cough & headache. Nasal infection through the respiratory passage.
Malaria Plasmodium (P. vivax, P. malaria, and P. falciparum) Body shivers along with high fever up to 4 days Parasite replicates in liver cells, then attacks RBCs.
  • The Life Cycle of Plasmodium: 

Two species are active in the malaria parasite life cycle. A malaria-infected female Anopheles mosquito incorporates sporozoites inside the human host at the time of a blood meal. Sporozoites not only invade liver cells but also mature into schizonts that break up and release merozoites.

  • Plasmodium tries to reach the human body as tiny sporozoites from the saliva of poisoned female anopheles and replicate inside of the liver cells. The RBCs are then infected as a result of exposure to the infectious chemical, hemozoin, which is responsible for heightened temperature and recurrence of shivers for nearly 4 days.
  • Immunity is the capacity of eukaryotic cells to oppose the entry of harmful microorganisms. Immunity includes both specific and non-specific components. Non-specific components serve as barriers or removers of a range of pathogens, regardless of their antigenic structure.
  • There are 2 types of Immunity — passive and active:   active immunity occurs when our immune system is essential for safeguarding us from pathogens. Passive immunity tends to occur when we are protected from pathogens by someone’s immunity.
Line of Defense Timeline Cells Antigen Dependency Examples
1st Instant response (0–96 hours) Macrophages, neutrophils, dendritic cells, mast cells, eosinophils Natural killer cells. Always Independent Skin mucous membranes, phagocytes, granulocytes, hair.
2nd Response for a longer time (more than 96 hours) T & B lymphocytes Always Dependent Pus, pain, T, and B lymphocyte response.

Structure of an Antibody:

  • Antibodies are immune-related proteins found within the body named as immunoglobulins.  Each antibody consists of 4 polypeptides – 2 hard chains as well as 2 light chains fused to create a “Y” molecule shape.


  • Five Classes of Antibodies:


There are 5 classes of immunoglobulin of antibodies found in plasma: IgG, IgM, IgA, IgE, and IgD. These are characterized by the type of heavy chain that they hold. IgG molecules have heavy chains recognized as Y chains; IgMs possess μ-chains; IgAs possess α-chains; IgEs possess ε-chains, and IgDs possess δ-chains.

Structure :

  • The constant region involves determining the mechanism that is used to demolish the antigen.
  • The variable region has been further segmented into a hypervariable (HV) and framework (FR) areas. Hyper variant regions do have a large ratio of specific amino acids in a specific position compared to some of the most typical amino acids within this position. 
  • There are 3 hypervariable regions inside the light and heavy chains – HV 1, 2, and 3. Four FR regions with a more secure sequence of amino acids differentiate the HV regions.
  • Allergies – The unusual reactions of the immune system to a certain antigen in the atmosphere are termed allergies.
  • Cancer is a category of diseases that include irregular cell growth with the ability to infiltrate or spread to other areas of the body. These compared with benign tumours that do not spread.
  • Tumour types –
  • Tumours are of benign origin.
  • Malignant tumours.
  • Human Immunodeficiency Viruses (HIV) are 2 types of Lentivirus (retrovirus subgroup) that infect humans. Over time, it triggers acquired immunodeficiency syndrome (AIDS), a disease wherein gradual weakening of the immune system enables life-threatening unscrupulous diseases and cancers to grow.

Discussion of exercises of Xam Idea Class 12 Biology Solutions Chapter 8: Human Health & Diseases

This chapter contains 194 questions in total which are divided into four categories and further into PYQ (past years questions) and OIQ (objective inventory questionnaires). They are all answered precisely as well as in-depth.

Very Short Answer Questions

  • This section includes a total of 65 problems out of which 23 problems placed under the PYQ segment and the rest 42 problems placed under the OIQ segment. 
  • This section covers definitions like immunity, health, biopsy, and different types of diseases.

Short Answer Questions Type – I

  • In this section, there are 65 questions in total that are classified in 37 PYQ and 28 OIQ problems.  
  • You need to present a neat diagrammatic representation replication of retroviruses.

Short Answer Questions Type – II

  • This section essentially contains 42 questions settled under 29 PYQ and rest 13 problems in the OIQ segment.  
  • This covers lymphocyte types and allergic reactions.

Long Answer Type Questions

  • Here there will be 22 questions in total that are segmented into 10 PYQ questions and 12 OIQ problems. 
  • Topics cover the life cycle of plasmodium and types of cancer cells.

Why Use Xam Idea Class 12 Biology Solutions Chapter 8: Human Health & Diseases by Instasolv?

  • Our team of experts presented the Xam Idea Class 12 Biology Solutions based on the updated CBSE syllabus for Class 12
  • The main objective of preparing these solutions is to provide you with complete and detailed knowledge of all topics throughout the chapter so that you can understand them thoroughly, more efficiently, and quickly.
  • Instasolv Xam Idea Biology Solutions for Class 12 encompass all the key aspects of the chapter by adding a wide range of relevant questions that are crucial from the exam point of view.