NIOS Biology Chapter 29 Some Common Human Diseases

Class 12 NIOS Biology Intext Solutions Chapter 29

INTEXT QUESTIONS 29.1

1. Define the term disease.

Ans: Any condition that interferes with the normal functioning of the body. In other words, disease may be defined as a disorder in the physical, physiological, psychological, or social state of a person caused due to nutritional deficiency, physiological disorder, genetic disorder, pathogen, or any other reason.

2. Give appropriate terms for

(i) the kind of disease that is present from birth.

(ii) disease caused by the malfunctioning of vital organs.

Ans: (i) congenital (ii) degenerative

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

Ans: Communicable diseases: Chicken pox and measles.

Non-communicable diseases: Diabetes and cancer

4. What does infestation mean?

Ans: Presence of a large number of parasitic organisms on the surface of the body of the host or on the clothing.

INTEXT QUESTIONS 29.2

1. How does chicken pox spread?

Ans: By contact or through scabs

2. Mention the most obvious symptom of measles.

Ans: Appearance of rashes on the body.

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

Ans: Nervous system

4. Name the causative organism of hydrophobia.

Ans: Rabies virus

5. Which mosquito spreads dengue?

Ans: Aedes aegypti

INTEXT QUESTIONS 29.3

1. Name the causative bacterium of (i) TB (ii) Typhoid (iii) Cholera.

Ans:

(i) Mycobacterium tuberculosis
(ii) Salmonella typhi
(iii) Vibrio cholerae

2. State the most obvious symptom of diphtheria.

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

3. What is the mode of transmission of leprosy?

Ans: Prolonged contact with the patient.

INTEXT QUESTIONS 29.4

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

Ans: Female Anopheles

2. Which protozoan causes amoebic dysentery?

Ans: Entamoeba histolytica

3. Name the disease caused by Wuchereria bancrofti.

Ans: Elephantiasis or Filariasis

INTEXT QUESTIONS 29.5

1. Why is diabetes called a hereditary disease?

Ans: It is passed down from parents to offspring.

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

Ans: The blood pressure remains persistently high.

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

Ans: Benign tumors do not spread to other parts of the body, whereas malignant tumors cells spread to other parts of the body.

INTEXT QUESTIONS 29.6

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

Ans: Any three points mentioned under “mode of transmission”

2. Mention any two methods to prevent AIDS.

Ans:

(i) There should not be any sexual contact with the person who has HIV infection or an STI. Since STI causes some damage to the genital area and mucous layer, and thus facilitate the entry of HIV into the body.
(ii) Use a disposable syringe and needle.
(iii) The blood to be transfused to the needy person should be free from HIV germ.
(iv) Prostitution and homosexuality should be avoided.
(v) A Condom should always be used during intercourse.

3. Write the full form of HIV.

Ans: Human immunodeficiency virus.

4. Give any two symptoms of AIDS.

Ans:

(i) A type of lung disease develops (tuberculosis).
(ii) A skin cancer may be observed.
(iii) Nerves are affected.
(iv) The Brain is badly damaged with the loss of memory, the ability to speak, and to think.

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

Ans:

(i) Partner notification.

(ii) Education on STDs.

(iii) Screening for STDs.