Chapter 7: Human Health and Disease Assertion-Reason Questions | biology Class 12 CBSE

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 1

Logic Check

Assertion (A): Typhoid fever is confirmed by the Widal test. Reason (R): The Widal test detects specific antibodies produced against Salmonella typhi antigens in the patient's blood.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 2

Logic Check

Assertion (A): Malignant malaria caused by Plasmodium falciparum can be fatal. Reason (R): Plasmodium falciparum causes more severe destruction of RBCs and produces haemozoin, leading to life-threatening complications.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 3

Logic Check

Assertion (A): Innate immunity is a non-specific type of defence. Reason (R): Innate immunity provides defence that is specific to a particular pathogen and develops after exposure to infection.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 4

Logic Check

Assertion (A): The secondary immune response is more intense than the primary immune response. Reason (R): The immune system retains memory of the first encounter with a pathogen through memory B and T cells.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 5

Logic Check

Assertion (A): Colostrum provides passive immunity to the newborn. Reason (R): Colostrum is rich in IgA antibodies that protect the infant from infections.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 6

Logic Check

Assertion (A): Interferons are antibodies produced by B-lymphocytes in response to viral infections. Reason (R): Interferons are proteins secreted by virus-infected cells that protect non-infected cells from further viral infection.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 7

Logic Check

Assertion (A): Cell-mediated immunity is responsible for graft rejection. Reason (R): T-lymphocytes can recognise 'non-self' antigens on transplanted organs and initiate an immune response against them.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 8

Logic Check

Assertion (A): Benign tumours are more dangerous than malignant tumours in cancer. Reason (R): Malignant tumours exhibit metastasis, spreading to distant organs through blood, which makes them life-threatening.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 9

Logic Check

Assertion (A): HIV is classified as a retrovirus. Reason (R): HIV contains an RNA genome and uses the enzyme reverse transcriptase to convert its RNA into DNA inside the host cell.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 10

Logic Check

Assertion (A): AIDS cannot be transmitted through casual contact such as hugging or sharing utensils. Reason (R): HIV spreads only through body fluids such as blood, sexual secretions and breast milk.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 11

Logic Check

Assertion (A): Heroin is obtained from the inflorescences of Cannabis sativa. Reason (R): Heroin (smack) is chemically diacetylmorphine, derived by acetylation of morphine extracted from Papaver somniferum.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): Tobacco smoking reduces haemoglobin-bound oxygen in the blood. Reason (R): Smoking increases carbon monoxide (CO) content in blood, which reduces the oxygen-carrying capacity of haemoglobin.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 13

Logic Check

Assertion (A): Active immunity is fast-acting and provides immediate protection. Reason (R): Active immunity is developed by the host after exposure to antigens and takes time to mount a full effective response.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): The thymus gland is largest at birth and decreases in size with age. Reason (R): The thymus provides a microenvironment for the development and maturation of T-lymphocytes.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 15

Logic Check

Assertion (A): Allergy symptoms are caused by the release of histamine and serotonin from mast cells. Reason (R): Allergens trigger the production of IgE antibodies, which bind to mast cells and cause them to release histamine and serotonin.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 16

Logic Check

Assertion (A): Wuchereria causes elephantiasis by blocking the lymphatic vessels of the lower limbs. Reason (R): The filarial worms are transmitted through contaminated food and water.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 17

Logic Check

Assertion (A): Cancer cells show the property of contact inhibition. Reason (R): Loss of contact inhibition in cancer cells leads to uncontrolled proliferation and tumour formation.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 18

Logic Check

Assertion (A): The spleen acts as a filter of blood by trapping blood-borne microorganisms. Reason (R): The spleen contains lymphocytes and phagocytes and also serves as a reservoir for erythrocytes.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 19

Logic Check

Assertion (A): Pneumonia causes the alveoli to fill with fluid, leading to breathing difficulty. Reason (R): Pneumonia is caused by Streptococcus pneumoniae and Haemophilus influenzae infecting the alveoli of the lungs.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 20

Logic Check

Assertion (A): Vaccines generate memory B and T cells that provide long-term protection. Reason (R): On subsequent exposure to the same pathogen, memory cells enable a rapid and intensified immune response.

Reasoning Options

ByteNotes

Chapter sections

Chapter 7: Human Health and Disease | Assertion-Reason

Assertion (A): Typhoid fever is confirmed by the Widal test. Reason (R): The Widal test detects specific antibodies produced against Salmonella typhi antigens in the patient's blood.

Assertion (A): Malignant malaria caused by Plasmodium falciparum can be fatal. Reason (R): Plasmodium falciparum causes more severe destruction of RBCs and produces haemozoin, leading to life-threatening complications.

Assertion (A): Innate immunity is a non-specific type of defence. Reason (R): Innate immunity provides defence that is specific to a particular pathogen and develops after exposure to infection.

Assertion (A): The secondary immune response is more intense than the primary immune response. Reason (R): The immune system retains memory of the first encounter with a pathogen through memory B and T cells.

Assertion (A): Colostrum provides passive immunity to the newborn. Reason (R): Colostrum is rich in IgA antibodies that protect the infant from infections.

Assertion (A): Interferons are antibodies produced by B-lymphocytes in response to viral infections. Reason (R): Interferons are proteins secreted by virus-infected cells that protect non-infected cells from further viral infection.

Assertion (A): Cell-mediated immunity is responsible for graft rejection. Reason (R): T-lymphocytes can recognise 'non-self' antigens on transplanted organs and initiate an immune response against them.

Assertion (A): Benign tumours are more dangerous than malignant tumours in cancer. Reason (R): Malignant tumours exhibit metastasis, spreading to distant organs through blood, which makes them life-threatening.

Assertion (A): HIV is classified as a retrovirus. Reason (R): HIV contains an RNA genome and uses the enzyme reverse transcriptase to convert its RNA into DNA inside the host cell.

Assertion (A): AIDS cannot be transmitted through casual contact such as hugging or sharing utensils. Reason (R): HIV spreads only through body fluids such as blood, sexual secretions and breast milk.

Assertion (A): Heroin is obtained from the inflorescences of Cannabis sativa. Reason (R): Heroin (smack) is chemically diacetylmorphine, derived by acetylation of morphine extracted from Papaver somniferum.

Assertion (A): Tobacco smoking reduces haemoglobin-bound oxygen in the blood. Reason (R): Smoking increases carbon monoxide (CO) content in blood, which reduces the oxygen-carrying capacity of haemoglobin.

Assertion (A): Active immunity is fast-acting and provides immediate protection. Reason (R): Active immunity is developed by the host after exposure to antigens and takes time to mount a full effective response.

Assertion (A): The thymus gland is largest at birth and decreases in size with age. Reason (R): The thymus provides a microenvironment for the development and maturation of T-lymphocytes.

Assertion (A): Allergy symptoms are caused by the release of histamine and serotonin from mast cells. Reason (R): Allergens trigger the production of IgE antibodies, which bind to mast cells and cause them to release histamine and serotonin.

Assertion (A): Wuchereria causes elephantiasis by blocking the lymphatic vessels of the lower limbs. Reason (R): The filarial worms are transmitted through contaminated food and water.

Assertion (A): Cancer cells show the property of contact inhibition. Reason (R): Loss of contact inhibition in cancer cells leads to uncontrolled proliferation and tumour formation.

Assertion (A): The spleen acts as a filter of blood by trapping blood-borne microorganisms. Reason (R): The spleen contains lymphocytes and phagocytes and also serves as a reservoir for erythrocytes.

Assertion (A): Pneumonia causes the alveoli to fill with fluid, leading to breathing difficulty. Reason (R): Pneumonia is caused by Streptococcus pneumoniae and Haemophilus influenzae infecting the alveoli of the lungs.

Assertion (A): Vaccines generate memory B and T cells that provide long-term protection. Reason (R): On subsequent exposure to the same pathogen, memory cells enable a rapid and intensified immune response.

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