NCERT Class 12 Biology: Chapter – 8 Human Health and Diseases Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 17:

Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The component causing this could be:

a. Nicotine

b. Tannic acid

c. Curaimin

d. Catechin

Answer: (a)

Question 18:

Anti-venom against snake poison contains:

a. Antigens

b. Antigen-antibody complexes

c. Antibodies

d. Enzymes

Answer: (c)

Question 19:

Which of the following is not a lymphoid tissue?

a. Spleen

b. Tonsils

c. Appendix

d. Thymus

Answer: (c)

Question 20:

Which of the following glands is large sized at birth but reducies in size with aging?

a. Pineal

b. Pituitary

c. Thymus

d. Thyroid

Answer: (c)

Question 21:

Haemozoin is:

a. a precursor of haemoglobin

b. a toxin from Streptococcus

c. a toxin from Plasmodium species

d. a toxin from Haemophilus species

Answer: (c)

Question 22:

One of the following is not the causal organism for ringworm

a. Microsporum

b. Trichophyton

c. Epidermophyton

d. Macrosporum

Answer: (d)

Question 23:

A person with sickle cell anemia is

a. More prone to malaria

b. More prone to typhoid

c. Less prone to malaria

d. Less prone to typhoid

Answer: (c)

Very Short Answer Type Questions

Question 1:

Certain pathogens are tissue/organ specific. Justify the statement with suitable examples.

Answer:

Pathogens are disease causing agents. Certain pathogens are tissue/organ specific as they only attack a certain tissue as seen in the case of:

A. Typhoid: Salmonella Typha only infects the small intestine.

B. Intestinal Endoparasities only infects large intestine, causing Amoebic dysentery.

Question 2:

The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.

a. Name the disease the patient is suffering from.

b. What is the causative organism?

c. Which cells of body are affected by the pathogen?

Answer:

a. The patient is suffering from Acquired Immuno Deficiency syndrome (AIDS) . In this disease body՚s immune system is compromised by the HIV.

b. The causative organism is the Human Immuno Deficiency Virus (HIV) . This virus interferes with the body՚s ability to fight a disease hence making body more susceptible to various diseases.

C. T4 lymphocytes or helper cells are affected in this disease.