CBSE Class 12 Biology Human Health And Disease Study Guide

Download CBSE Class 12 Biology Human Health And Disease Study Guide in PDF format. All Revision notes for Class 12 Biology have been designed as per the latest syllabus and updated chapters given in your textbook for Biology in Standard 12. Our teachers have designed these concept notes for the benefit of Grade 12 students. You should use these chapter wise notes for revision on daily basis. These study notes can also be used for learning each chapter and its important and difficult topics or revision just before your exams to help you get better scores in upcoming examinations, You can also use Printable notes for Class 12 Biology for faster revision of difficult topics and get higher rank. After reading these notes also refer to MCQ questions for Class 12 Biology given our website

Human Health And Disease Class 12 Biology Revision Notes

Class 12 Biology students should refer to the following concepts and notes for Human Health And Disease in standard 12. These exam notes for Grade 12 Biology will be very useful for upcoming class tests and examinations and help you to score good marks

Human Health And Disease Notes Class 12 Biology




CIRRHOSIS :- A fatal disease of liver causes due to chronic use of alcohol. 

CONTACT INHIBITION :- A property of normal cells due to which contact with othercells inhibits their uncontrolled growth. Cancerous cells have lost the quality of contact inhibition hence divide uncontrollably.

DIEASE :- A state when functioning of one or more organs or systems of the body is adversely affected, characterized by various symptoms, we say that we have a disease. 

HEALTH :- A state of complete physical, mental and social well being. 

IMMUNITY :- The overall ability of organisms to fight the disease causing pathogens, conferred by the immune system is called immunity. 

VACCINE :- Weakened pathogen or antigenic proteins of the pathogen introduced / injected into a healthy person to protect him from disease is called vaccine e.g. pulse polio.


Assignment Questions 


1.It is advised to always complete the course of an anti biotic prescribed by the physician. Give the scientific reason? 

2.Why is the antibody –mediated immunity called humoral immunity? 

3.Why do children of metro cities of India suffer from allergies and asthma? 

4.What is the role of following in body defence against infections? 

(i) B-cells (ii) Histamine (iii) interferons 

5.Some viruses can make DNA copy from RNA strand .Explain the mechanisms behind this processes 


1A pathogen enters the small intestine through food and water contamination and migrates through blood, the sustained high fever weakness, stomach pain are symptoms. Which test confirms this disease. 

2Once a person starts taking alcohol (or)drugs . how he may protect himself 

3.Only female Anopheles mosquito acts as a vector? Why?

4. Name a plant other than coca plant that has hallucinogenic property?

5.A group of viruses infected only nose and the respiratory passages but not the lungs. Mention the disease and its causative organism.

6.Enumerate any two properties that distinguish the cancer cells from normal cells.

7.A person suddenly develops fever diarrhoea and weight loss. After test his blood was found low in lymphocytes.

(i) What could be the disease he is suffering from?

(ii) Name the confirmatory test to diagnose the disease.

(iii)Which particular part of the immune system is likely to get affected and in what manner?

8.Which chemicals are produced during allergic reactions? Also name the cells which produce these chemicals?

1.complete the table

CBSE Class 12 Biology - Human Health And Disease Study Guide

2.A person need to take immune-suppressive agents all through his/her life after an organ transplant. Why?

3.Name the organism where antigenic polypeptide is produced by recombinant DNA technology 4.A person‘s nails and lips turn grey to bluish. Find out the disease he is suffering from. Name the pathogen.

5.Name the missing organisms/disease in the table below:-

CBSE Class 12 Biology - Human Health And Disease Study Guide

6.Lymph nodes are small solid structures located at different points along the lymphatic vessels. How are they involved in our immune system?

7. A person claimed that he has seen sounds, heard colours and smelt light.

(i) What could be the possible reasons?

(ii) Name two chemicals responsible for this condition.

Mention any one source for these chemicals.

Questions for Self Evaluation
Q 1 Name the type and give the effects of the following drugs on humans-

A ) LSD B) Morphine C) Barbiturates.

Q2 What are the two chemical substances released into the blood by the mast cells ?

Specify the effect of each .

Q3 Why are some children diseases not appear for a second time ?

Q4 How does the skin serve as the first line of defence ?

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