NIOS Class 12 Biology Chapter 29 Some Common Human Diseases

NIOS Class 12 Biology Chapter 29 Some Common Human Diseases Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Biology Chapter 29 Some Common Human Diseases Notes and select need one. NIOS Class 12 Biology Chapter 29 Some Common Human Diseases Question Answers Download PDF. NIOS Study Material of Class 12 Biology Notes Paper 314.

NIOS Class 12 Biology Chapter 29 Some Common Human Diseases

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Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Biology Chapter 29 Some Common Human Diseases Solutions, NIOS Senior Secondary Course Biology Solutions for All Chapter, You can practice these here.

Some Common Human Diseases

Chapter: 29




1. Define the term disease.

Ans: Any condition that “interfers with the normal functioning of body” is called a disease.

2. Give appropriate terms for:

(a) The kind of disease which is present from birth.

Ans: Congenital disease.

(b) Disease caused by malfunctioning of vital organs.

Ans: Degene-rative disease.

3. Name any two communicable and any two non-communicable diseases in humans.

Ans: (a) Communicable Diseases-

(i) Chicken pox.

(ii) Measles.

(b) Non-communicable Diseases-

(i) Diabetes mellitus.

(ii) Hypertension.

4. What does infestation mean?

Ans: The presence of large number of organisms which are parasites on the surface of body is known as the infestation.


1. How does chicken pox spread?

Ans: By contact/scabs.

2. Mention the most obvious symptom of measles. 

Ans: It is the appearance of rashes on the body. 

3. Which organ system of the body is affected by the polio virus?

Ans: Nervous system is affected.

4. Name the causative organism of hydrophobia.

Ans: Rabies virus.

5. Which mosquito spread dengue?

Ans: Aedes aegypti.


1. Name the causative bacterium of: 

(a) TB.

Ans: TB = Mycobacterium tuberculosis.

(b) Typhoid.

Ans: Typhoid = Salmonella typhi.

(c) Cholera.

Ans: Cholera = Vibrio cholerae.

2. State the most obvious symptom of diphtheria.

Ans: Oozing of the semisolid material in throat that forms a membrane which blocks air passage.

3. What is the mode of transmission of leprosy?

Ans: By prolonged contact with patient.


1. Which mosquito carries stages of life history of the malarial parasite?

Ans: Female Anopheles mosquito.

2. Which protozoan causes amoebic dysentery?

Ans: Entamoeba histolytica.

3. Name the disease caused by Wuchereria bancrofti.

Ans: Elephantiasis/Filariasis.


1. Why is diabetes called a hereditary disease?

Ans: This is passed down from parents to the offsprings.

2. What happens to the blood pressure in persons with hypertension?

Ans: Blood pressure remains persistently high.

3. State one point of difference between malignant and benign tumour.

Ans: Benign tumour does not spread to other parts of the body. The malignant tumour cells spread to different parts of human body.


1. How is HIV transmitted? Mention any three ways of infection.

Ans: (i) Sexual contact by infected person.

(ii) By sharing infected needles.

(iii) Blood transfusion.

2. Mention any two methods to prevent AIDS.

Ans: (i) Avoid sexual contact with infected person.

(ii) Use of condom during intercourse.

3. Write full form of HIV.

Ans: HIV = Human Immunodeficiency Virus.

4. Give any two symptoms of AIDS.

Ans: (i) Memory is lost.

(ii) Nerves damaged.

5. Mention three general points the knowledge of which may control STD.

Ans: (a) The screening for STD.

(b) Create awareness among the people/Education of STD.

(c) Partner-notification.


1. Name the pathogen that causes syphilis.

Ans: Treponema pallidum.

2. Mention any two symptoms of the disease gonorrhoea.

Ans: (a) Burning sensation during passing of urine.

(b) Swelling of mucous membrane of the urinogenital tract.

3. Give the main method of checking syphilis.

Ans: (a) Ban on the prostitution and homo-sexuality.

(b) Some medicines may check diseases.


1. What is a disease? How does it differ from disorder?

Ans: Disease: Any condition that “interferes with normal functioning of body is known as a disease.”

The disorder is an irregularity in the functioning of an organ or part of body. The disorder may be in physical or psychological state of a person. The disorder is also a disease.

2. Name the two categories of acquired diseases.

Ans: Communicable and non-communicable

diseases are two categories of acquired diseases.

The acquired diseases are generally classified into four groups as:

(a) Degenerative Disease: It is caused by malfunction of certain vital organs of body (e.g., heart failure).

(b) Infectious Disease: It can be trans-mitted from person to person (e.g., measles).

(c) Cancer: It is defined as “an abnormal, uncontrolled and unwanted growth of cells” (e.g., breast cancer in females).

(d) Deficiency Disease: It is caused by nutritional deficiency e.g., minerals or vitamin deficiency in diet; say anaemia (Fe); beri-beri (vitamin B).

3. Explain the term:

(i) Parasitism.

Ans: Parasitism: It is “relationship in which an organism called the parasite gets nourishment and shelter from host.”

(ii) Reservoir.

Ans: Reservoir: It is “an organism which harbours pathogens in large number but does not suffer itself.’

4. Give two symptoms of coronary diseases and of typhoid.

Ans: Two Symptoms of Coronary Diseases:

(i) Severe pain in chest.

(ii) Profuse sweating.

Two symptoms of typhoid:

(i) Continuous fever.

(ii) Headache and slow pulse.

5. What precautions should be taken to prevent malaria?

Ans: Precautions to check Malaria:

(i) Wire gauze on the doors and windows in houses be fitted.

(ii) Mosquito nets and repellants may be used.

(ii) Kerosene oil or DDT in ditches, ponds should be sprinkled.

(iv) Antimalarial drugs must be used.

(v) Water should not be collected in ditches.

6. Name the pathogen that causes diphtheria and the causes cholera.

Ans: Corynebacterium diphtheriae causes diphtheria. Vibrio cholerae causes cholera disease.

7. Mention the four types of acquired diseases.

Ans: Four types of Acquired Diseases:

(i) Infectious diseases: They may be transmitted from person to person e.g., Measles.

(ii) Degenerative diseases : They are caused by malfunction of some vital organ e.g., heart, etc.

(iii) Deficiency diseases: They are caused due to nutritional deficiency e.g., beri-beri.

(iv) Cancer: Abnormal and uncontrolled growth of cells causes cancer. e.g., lung cancer.

8. Differentiate between:

(i) Communicable and non-communicable diseases.

Ans: Difference between Communi-cable and Noncommunicable Diseases:

Communicable DiseaseNon-communicable Disease
1. They are easily trans- mitted from one per-son to the other. They spread by air, water, soil and vectors and pathogens etc.They do not transmit from one person to another.
2. e.g., typhoid, plague, pneumonia, AIDS, mal-aria, kala-azar etc.e.g., cancer, diabetes hypertension, coronary heart diseases, osteo- porosis and allergy etc.

(ii) Pathogen and vector.

Ans: Difference between Pathogen and Vector:

It is a living organism that produces a disease.It harbours the pathogen of a disease.

(iii) Syphilis and gonorrhoea.

Ans: Difference between Syphilis and Gonorrhoea:

1. STD caused by Trepo-nema pallidium (bacterium).STD caused by Neisseria gonorrhoea (bacterium).
2. It spreads by sexual contact with infected person (Incubation period 3 weeks).It spreads by sexual con-tact with infected person. (Incubation period 2-5 days).

(iv) HIV and AIDS.

Ans: Difference between HIV and AIDS:

1. Its full form is Human Immuno-deficiency Virus.Its full name is Acquired Immuno-Deficiency Syn- drome.
2. It is a pathogen virus of AIDS disease.It is a fatal disease.

(v) Benign and malignant tumours.

Ans: Difference between Benign and Malignant Tumour:

Benign TumourMalignant Tumour
1. Uncontrolled growth is restricted andenclosed in local tissues remain confined to original tissues.Uncontrolled growth is not restricted and do not remain confined to origi-nal tissues.
2. Not fatal.It is fatal.

9. How does polio virus enter human body? How does it paralyse limbs?

Ans: Polio Virus enters human body by water or food. It multiplies in intestinal cells and reaches our brain by blood. It damages brain and nerves causing paralysis.

10. A nursing mother is given an immunisation for BCG and DPT to the baby. What are the diseases againts which she would be protected?

(i) BCG.

Ans: TB of lungs.

(ii) DPT.

Ans: Diphtheria, Pertusis and Tetanus. 

11. Give the cause, symptoms and treatment of haemorrhagic dengue fever.

Ans: Cause of Haemorrhagic Dengue fever: It is acute infectious viral disease. It spreads by bite of an infected Aedes aegypti (mosquito). 


(i) Weakness, cold skin.

(ii) dry mouth.

(iii) black stool.

(iv) frequent vomiting.

(v) pain in abdomen.

(vi) bleeding from nose/mouth or in internal organs.

Treatment: Take rest. Drink much fluids and blood transfusion for controlling bleeding.

12. Give full form of STD.

Ans: STD = Sexually Transmitted Disease.

13. Mention any two symptoms of syphilis.

Ans: Two symptoms of syphilis:

(i) Inflammation of the mucous membrane of urinogenital tract.

(ii) Female sterility and pain in joints.

14. State the means which may prevent and cure gonorrhoea.

Ans: Prevention and Cure of Gonorr-hoea:

(i) Prostitution and homosexuality must be banned.

(ii) Education of STD.

(iii) Antibiotic drugs and medicines.

15. What does the term AIDS stand for?

Ans: AIDS = Acquired Immuno Deficiency Syndrome.

16. Write four possible symptoms of AIDS.

Ans: Four Possible Symptoms of AIDS:

(i) Skin cancer.

(ii) Damage to the nerves.

(iii) Reduced number of leukocytes, and platelets.

(iv) Lymph nodes swollen, fever and loss of weight.

17. Mention three general points which may control sexually transmitted diseases.

Ans: (i) The Partner notification: Identify the person.

(ii) The Education of STD: Educated the people about disease.

(iii) The Screening for STD: Sereological screening of blood groups etc.

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